THE ROLE OF HOST PLANTS AND PARASITOIDS ON OF HELIOTHIS SPP. IN ARIZONA by Robin Jean...
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The role of host plants and parasitoids on the abundanceof spring populations of Heliothis spp. in Arizona
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THE ROLE OF HOST PLANTS AND PARASITOIDS ON
THE ABUNDANCE OF SPRING POPULATIONS
OF HELIOTHIS SPP. IN ARIZONA
by
Robin Jean Rathman
A Thesis Submitted to the Faculty of the
DEPARTMENT OF ENTOMOLOGY
In Partial Fulfillment of the Requirements For the Degree of
MASTER OF SCIENCE
In the G raduate College
THE UNIVERSITY OF ARIZONA
1 9 8 1
STATEMENT BY AUTHOR
This thesis has been subm itted in partial fulfillment of req u ire ments for an advanced degree at The U niversity of Arizona and is deposited in the U niversity L ibrary to be made available to borrow ers under rules of the L ibrary .
Brief quotations from th is thesis are allowable without special perm ission, provided th a t accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of th is m anuscript in whole or in p a rt may be granted by the head of the major departm ent or the Dean of the Graduate College when in his judgment the proposed use of the material is in the in te rests of scholarship. In all o ther in stances, however, permission must be obtained from the au thor.
SIGNED: j s&tLr
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below:
T. F. WATSON Professor of Entomology
ACKNOWLEDGMENTS
I would like to exp ress my sincerest appreciation to my major
p ro fessor. D r. Theo F. Watson, for his patience, guidance, in te re s t,
and encouragem ent th roughout the course of th is research . I would
also like to thank D rs. Roger T . Huber and H arry M. Graham for review
ing th is m anuscript and serv ing on my graduate committee. I am ap p re
ciative of the assistance of D r. Floyd G. Werner in identify ing parasito ids
collected in th is s tu d y .
I am especially gratefu l to Scott Tollefson for his advice and
enthusiasm and to Joel Floyd for his photographs.
I would like to thank my paren ts for th e ir support and under
stand ing .
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TABLE OF CONTENTS
LIST OF T A B L E S ..................................................................................... vi.
LIST OF ILLUSTRATIONS.................................................................................. vii
A BSTR A CT...............................................................................................................viii
INTRODUCTION ....................................................................................................... 1
LITERATURE REVIEW............................................................................................... 3
Seasonal H istory and Food Habits of Heliothis sppEmergence from D ia p a u s e .........................................H ost-plant S e lec tio n ......................................................Natural E n em ies................................................................................... 11
MATERIALS AND M ETHOD S............................................................... 15
R ESU LTS...................................................................................................................... 20
Rainfall D a t a .................................................................................................. 20Field Samples, 1979 .......................................................................................... 21Field Samples, 1980 ...................................................................................... 22Miscellaneous P lants Sam pled...................................................................... 23Plant D escriptions ......................................................... 24
Sphaeralcea coulteri (A ts .) G ra y .....................................................Erodlum cicutarium (L.) L 'H er........................................................... 24Erlgeron d ivergens T o rr. & G r a y ................................................. 25Cicer arietinum L. .............................................................................. 25Caesalpinnia gilliesii Wall...................................................................... 27Proboscidea parv iflora (W o o to n ) ..................................................... 27Hoffmanseggia densiflora B en th .......................................................... 27
Mortality on D ifferent Host P l a n t s ............................................................. 29Common Parasitoid S p e c ie s .............................................................................. 33H ost-plant S p e c if ic i ty ...................................................................................... 35Pheromone Monitor T r a p s ............................................................................. 37Unit Area S am ples.......................................................................................... 38
D IS C U S S IO N ........................................................................................................... 39
SUMMARY....................................................................................................................... 47
APPENDIX A: PLANT SPECIES SAMPLED FOR HELIOTHISSPP. IN 1979 48
Page
'
CO LO
CO
V
APPENDIX B
TABLE OF CONTENTS—Continued
Page
: PLANT SPECIES SAMPLED FOR HELIOTHISSPP. IN 1980 ...................................................................... 50
REFERENCES 52
LIST OF TABLES
1. Rainfall recorded a t the Casa Grande Ruins NationalMonument, Casa G rande, Arizona, October th roughMay, 1978-79 and 1979-80 ................................................................ 20
2. Species composition of Heliothis on th ree sp ring hostp lants in Pinal County in 1979 ..................................................... 22
3. Species composition of Heliothis on th ree sp ring andearly summer host p lan ts in Pinal County in 1980 ................. 23
4. Summary of Heliothis v irescens host p lants recordedduring sp ring 1979 and 1980 su rveys in centralA r i z o n a ................................................................................. 31
5. Relative parasitism of th ree Heliothis spp . on d ifferen thost plants in cen tral Arizona in 1979 ......................................... 32
6. Relative parasitism of th ree Heliothis spp . on d ifferenthost p lants in cen tral Arizona in 1980 ......................................... 32
7. Relative abundance of Heliothis sp p . larvae on d ifferen tsp ring host p lants in Pinal C ounty, A riz o n a ............................. 34
8. Species of parasito ids found on Heliothis spp . incentral Arizona during the sp rings of 1979 and 1980 . . . . 36
9. Host utilization by Heliothis s p p . on a given host p lantin .the sp rings of 1979 and 1980 in cen tral A r iz o n a ................. 37
Table Page
vi/
LIST OF ILLUSTRATIONS
1. Inner surface of la te -in s ta r larvae of tobaccobudworm (left) showing prom inent retinaculum and of bollworm (right) showing concave inner surface without the r e t in a c u lu m ................................................. 17
2. Lateral view of abdominal segment eight of la te -in s ta r tobacco budworm larva showing d istinctmicrospines on the t u b e r c l e ......................................................... 18
3. Lateral view of abdominal segment eight of la te -in s ta r cotton bollworm larva showing tuberclewithout m icro sp ines........................................................................... 18
4. Tobacco budworm larvae on red stem filaree,Erodium c ic u ta r iu m .......................................................................... 26
Figure Page
5. Tobacco budworm larva feeding on unopened flowerof yellow b ird -o f-p a rad ise , Caesalplnnia gilliesii . . . . . 28
6. Seasonal sequence of some p lan ts found to behosts of the tobacco budworm in A r iz o n a ................................. 30
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ABSTRACT
Surveys were conducted in 1979 and 1980 to determine the species
of wild and cultivated p lants utilized as hosts by the tobacco budworm,
Heliothis v irescens (F ab ric iu s), and the cotton bollworm, Heliothis zea
(Boddie) in the early -season in central Arizona before cotton begins
squaring . Tobacco budworm and cotton bollworm larvae were collected
from nine plant species. D uring April and May in 1979 large Heliothis spp .
populations were found on redstem filaree, Erodlum cicutarium (L .) , a
common d esert weed. Yellow b ird -o f-parad ise , Caesalpinnia gilliesii W all.,
and garbanzo bean, Cicer arietinum L . , were prim ary sp ring hosts in
1980. An obscure species, Heliothis phloxiphaga (Grote and Robinson),
was collected on daisy fleabane, Erigeron divergens T o rr. & G ray, in
large numbers in 1979 and on Erodium cicutarium in 1979 and 1980.
Seven species of hym enopterous parasito ids were identified from
the 1979 and 1980 collections: Campoletis sonorensis (C am .), Pristom erus
sp inator (F .) , Hyposoter exiguae (Vierreck) (Family Ichneum onidae);
Microplitis croceipes (C ressoh), Rogas perp lexus Gaham ., Cardiochiles
seminiger (Cresson) (Family Braconidae); and Spilochalcis sp . (Family
Chalcidae). Additionally, four species of dipterous parasito ids in the
family Tachinidae emerged from collected larvae: Lespesia archippivora
(R iley), Eucelatoria s p . , Chaetogaedia s p . , and A rchytas marmoratus
(T n s .).
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INTRODUCTION
Among the most damaging pests of ag ricu ltu re in the United
States are the cotton bollworm, Heliothis zea (Boddie), and the tobacco
budworm, Heliothis v irescens (F ab ric iu s). They a ttack a wide range of
valuable crops, including co tton , corn , tomatoes, soybeans, grain so r
ghum, and tobacco.
Heliothis sp p . have shown g rea t adaptability in developing
resistance to insecticides, and the chemical in d u stry has been hard
p ressed to meet the demands for effective chemicals to combat the Helio
th is problem in certa in a reas. Perhaps th is problem is best illu stra ted
by the demise of the cotton in d u stry in the Tampico-Mante area in the
S tate of Tamaulipas, Mexico, due , in p a r t , to methyl parathion res is
tance in the tobacco budworm (Lukefahr 1970).
The tobacco budworm did not become a major p est on cotton in
Arizona until 1971 (Watson 1974). Recorded resistance to methyl p a ra
thion in Arizona (Crowder, Tollefson, and Watson 1979) and the potential
for developing resistance to the newly developed syn thetic py re th ro ids
make it imperative th a t da ta be available on all factors th a t could influence
the population dynamics of the species. It is essential th a t the in te rac
tions between a p est population and associated environm ental factors be
determ ined, because the success of most management program s is based
on the facts known about the p e s t 's ecology (Davis 1974).
The life system of an insect population is th a t p a r t of the eco
system th a t determ ines its existence, abundance, and evolution (Clark
1
et al. 1967). This concept was developed as a guide to understand ing
population dynamics. T raditionally , ecologists have considered the host
plant (s) as a major element in the life system of insects with emphasis
usually placed on host abundance.
Lincoln (1972) noted th a t seasonal abundance of the cotton boll-
worm and tobacco budworm is strongly influenced by the sequential
availability of favorable hosts. A continuous series of host p la n ts , both
cultivated and noncultivated , is requ ired to support these species during
th e ir active period (Snow and Brazzel 1965). The objective of th is re
search was to study Heliothis spp . populations and associated parasito ids
on sp ring host p lants in cen tral Arizona.
LITERATURE REVIEW
The tobacco budworm is apparen tly most abundant in the tro p ic s ,
and i ts range extends through the West Indies and South America as far
south as A rgentina (Neunzig 1969). The species is frequen tly encoun
tered in the sou thern United S tates and at times is found as fa r north
as O ntario, Canada (Forbes 1954).
Heliothis spp . a re ra th e r general fee d e rs , having a wide varie ty
of cultivated and wild host p lants (Snow and Brazzel 1965). Tietz (1972)
listed 31 host p lants for the tobacco budworm and 106 hosts for the cotton
bollworm. Corn appears to be the p re fe rred host p lant of H. zea;
tobacco and cotton are major hosts of H. v irescens (Lincoln 1972).
Lacroix (1936) listed H. v irescens as an occasional pest of tobacco in
Connecticut. The f ir s t reference to th is species attacking cotton was
made by Wilson (1923) in the Virgin Islands. No mention of the tobacco
budworm damaging cotton in the continental United S ta tes, however,
occurred until Folsom reported i t in Louisiana in 1936.
Seasonal H istory and Food Habits of Heliothis spp .
The seasonal h isto ry and food habits of II. v irescens were studied
as early as 1926 by Chamberlin and Tenhet (1926a) in the sou theastern
United S tates. Tobacco, Nicotiana s p . , and beggarw eed, Meioboma s p . ,
were im portant food p lan ts. B arber (1937) listed Florida beggarw eed, M.
p u rp u re a , as an im portant fall host in eastern Georgia. Hambleton (1944)
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listed the following species as host p lants in the Canete Valley, Peru :
Cajanus cajan . Geranium s p . , Petunia s p . , Verbena s p . , C ucurbita s p . ,
and Rosa sp .
Snow and Brazzel (1965) listed 81cultivated and 11 wild species of
plants as hosts in M ississippi. Among the im portant wild p lants were
toadflax , Linaria canadensis, and d ee rg rass , Rhexia sp . Neunzig (1963)
also listed these two p lants as im portant a lternate hosts in easte rn North
Carolina. Snow, Hamm, and Brazzel (1966) found Geranium carolinianum
to be an early host of Heliothis spp . in the sou theastern United S ta tes.
In the Lower Rio Grande Valley, Texas (Graham and Robertson 1970) and
in Brownsville, Texas (Graham, H ernandez, and Llanes 1972) wild tobacco,
Nicotiana rep an d a , was reported as an im portant early-season host.
Payne and Polles (1973) found larvae of Heliothis spp . feeding on
the foliage, terminal b u d s, and nu tle ts of pecans in Georgia. In coastal
southern California, H. v irescens is an occasional pest of lettuce (Oatman
and P lainer 1972), and a t S t. Croix, U .S . Virgin Islands, major hosts
attacked are pigeon pea, Cajan cajan , and the malvaceous p lan t, B astardia
vlscosa (Snow et al. 1974). Harding (1976) conducted a su rvey during
1969-1973 in the Lower Rio Grande Valley of Texas; cotton, soybeans,
and tomatoes were the only cultivated hosts used by the tobacco budworm.
Sunflowers (Helianthus sp.) were the most common wild hosts; husk tomato
(Solanum s p . ) , passion flower (Passiflora s p . ) , and vervain (Verbena s p .)
were also su itab le.
O ther hosts of H. v irescens cited in the lite ra tu re include sesame,
Sesamum indicum (R ivers, Meisch, and Hamman 1965), cultivated snap
dragon, Antirrhinum majus (Tilden 1968) and cultivated sunflow ers,
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Helianthus s p . (T eetes, Randolph, and Kinman 1970). L aster, M artin,
and Pair (1976) collected tobacco budworm larvae from burcucum ber,
Slcyos angu la ta , from 1973-75 near Stoneville, M ississippi. B atra (1979)
listed the quickw eeds, Galinsago ciliata and G. parv iflo ra , as having
H. v irescens associated with them. In a more recen t s tu d y , Stadel-
bacher (1979) described the influence of Geranium dissectum on the
population dynamics of H. zea and H. v irescens in the Mississippi Delta.
In sou thern Arizona, H. zea has been collected on a wild mallow
species, Sphaeralcea emoryi (Stoner 1972). Sluss and Graham (1979)
collected Heliothis spp . from roses in Peoria, Arizona, and from yellow
b ird -o f-parad ise , Caesalpinnia gilliesii, near Tucson, Arizona.
The preceding repo rts show th a t the species composition of
host-p lan t complexes of Heliothis spp . varies widely between geographic
regions and agroecosystem s. Brazzel e t al. (1953) have suggested th a t
these host relationship differences can be explained by regional d iffer
ences in the availability of wild and cultivated host p lants or can possibly
be a ttrib u ted to the presence of biological races. Roach (1975) sta ted
th a t Heliothis populations, especially those in early sp ring and fall,
depend on only a few major p lants species. A pparently , both species of
Heliothis build up to damaging num bers on cultivated hosts and use wild
hosts to maintain the species when cultivated hosts are unavailable
(Harding 1976).
Emergence from Diapause
The tobacco budworm is active throughout the w inter in the Lower
Rio Grand Valley, Texas (Fife and Graham 1966; Graham and Robertson
1970) bu t not in sou thern Louisiana (Brazzel e t al. 1953) or in central
Arizona (Potter and Watson n .d . a ) , where diapausing pupae constitu te
the dormant stage. Populations of Heliothis sp p . begin increasing in the
late sp ring and early summer following emergence from diapause. Fife and
Graham (1966) monitored the emergence of H. v irescens and H. zea from
cotton and pepper fields near Brownsville, T exas. Adult tobacco bud-
worms were found from early February until late May; peak emergence
was in March. In a similar s tudy in Tucson, Arizona, by Fye and
C arranza (1973), g rea test emergence was from late April to mid-May.
Potter and Watson (n .d .b ) collected pupae from cotton fields near La
Palma, Arizona, in the m id-winter periods of 1978 and 1979. Adult
emergence from outdoor flats of soil took place from mid-March to early
May, with most moths appearing during the f irs t four weeks of April.
P o tte r, H uber, and Watson (n .d .) determined heat un it accumulations
for these overw intering tobacco budworms. They suggested th a t physio
logical processes associated with diapause were nearly complete by early
January . A fter th a t date a total accumulation of 173 centigrade heat
units (CHU) was required for emergence to occur. Early spring hosts
may play an im portant role in ca rry -o v er of Heliothis spp . to co tton ,
which requ ires an accumulation of 667 CHU afte r January 1 until f irs t
square (H uber, n .d . ) .
Knipling (1971) acknowledged th a t no precise data are available
on the actual num bers of moths th a t emerge in the sp ring in a given a rea .
Based on limited egg and larval records on host p la n ts , especially on
tobacco, and on lig h t-trap -c a tch data , Knipling has regarded 1,000 moths
6
per square mile as a reasonable estimate of the overw intering population
in typical ag ricu ltu ral a re a s .
Isely (1935); Brazzel e t al. (1953), Snow and Brazzel (1965), and
Lincoln e t al. (1967) found th a t in A rkansas, Louisiana, and no rtheastern
M ississippi, respectively , leguminous crops a re the major hosts of the
f ir s t generation of bollworms in the sp rin g . Corn is the im portant host
plant for the second generation in June and Ju ly . Snow and Brazzel
(1965) reported the occurrence of two generations on corn in M ississippi.
In early A ugust when corn is not longer a suitable host, th e th ird and
fou rth generations use cotton as the prim ary host. In the area around
College Station, T exas, oviposition on leguminous p lants and on corn
determ ines the bollworm infestation on cotton (Lopez 1976). In the Avra
Valley, Arizona, the lush growth of alfalfa during early sp ring and into
late May provides a food source fo r bollworms, which then move into corn
and cotton (Fye 1975).
In co n tra s t, the tobacco budworm appears to rely most heavily on
wild hosts early in the growing season (Neunzig 1963). F irst-genera tion
eggs and larvae a re found on a varie ty of fru iting p lan ts , as previously
d iscussed . Eggs are f ir s t found in April in cen tral Texa, cen tral Missis
sippi and southern A rkansas; th e re a fte r , larvae a re continuously p resen t
through O ctober (Lincoln 1972).
Tobacco is the favored host fo r the second and la te r generations
of H. v irescen s. In the absence of tobacco, cotton is the principal sum
mer host (Lincoln 1972). For a discussion of the relative seasonal abun
dance of Heliothis on cotton in the Southw est, see Quaintance and B rues
7
(1905), Brazzel and Newton (1963), Sundman and Hanna (1963), and
Henry and Adkisson (1965).
H ost-plant Selection
The term "host-p lan t specificity" re fe rs to the range of p lant
species on which a given insect is known to occur in na tu re . "H ost-plant
selection" is the behavioral sequence by which an in sect d istinguishes
between host and nonhost p lan ts. A th ird term , "host-p lan t p reference ,"
is used to describe an in sec t's predilection to select some plants in p re f
erence to o thers within its host-p lan t range (Maxwell and Jennings 1980).
H ost-plant selection is im portant when considering the population
dynamics of lepidopterous species. Because immature stages of Heliothis
have somewhat res tric ted mobility, eggs must be oviposited by female
moths on or near suitable hosts to ensure surv ival. Beck (1974) sta ted
tha t a t the behavioral level, the g rea tes t proportion of host-p lan t speci
ficity is a function of the ovipositing females. T hus, an understand ing
of the oviposition process of Heliothis spp . is of prime concern in studying
the population dynamics and host selection of these species.
Specific stimuli th a t errianate from host p lan ts and release ovi-
positional responses are numerous and are im portant factors in determ in
ing host specificity (de Wilde and de Loof 1973). Odors emanating from
rapidly growing cotton p lan ts have been reported to be a ttrac tive to H.
zea moths and to stimulate oviposition. F letcher (1929) a ttrib u ted the
attraction of bollworm moths to cotton p lan ts to increased nectar secretion .
Thomas and Dunnam (1931) showed th a t bollworm infestations do not al
ways develop when th ere is an abundance of nectar; in stead , adult
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H. zea moths show a s trong preference for succulent, lush p lan t grow th.
Gaines (1932) and F letcher (1941) also found th a t odors from rank-grow ing
cotton p lants appear to be im portant fac to rs influencing infestation .
Available food before o r during oviposition may enhance a ttra c
tiveness of certain p lants to the boll worm moth (Nutty combe 1930). How
ever, Quaintance and B rues (1905) and Palmiter (1966) sta ted th a t moths
do not always oviposit on the same p lants on which they feed . Palmiter
hypothesized th a t the adu lt female H. zea may oviposit on a host species
selectively w ithout being influenced by the food source. Jerm y, Hanson,
and D ethier (1968) suggested th a t food p lant p reference of leipdopterous
larvae appears to be individually modifiable and related to previous ex
perience. They observed such behavioral p lasticity in oligophagous
species such as the tobacco horn worm, Manduca sexta (L innaeus), as well
as in polyphagous species such as H. zea.
Chemical stimuli a re probably the a ttrac tive fac to rs among dif
fe ren t p lan ts , b u t tactile perception of the p roper surface fo r oviposition
determ ines where the eggs are laid (Callahan 1957). Ditman and Cory
(1933) showed th a t the upper villous surface of corn leaves received 21.6%
of the to tal eggs of H. zea, w hereas the lower glabrous surface received
only 8.1%. L ukefahr, Noble, and Houghtaling (1966) showed no signifi
cant difference between the number of eggs deposited on glanded and
glandless cotton s tra in s . The principal constituen t of these glands is
gossypol, which apparen tly did not influence oviposition. T heir study
did, however, show significantly fewer eggs laid on two stra in s of gla
brous cotton. Gillham (1963) and S tadelbacher and Scales (1973) screened
a large num ber of cotton varie ties fo r oviposition preference and found
10
h irsu te cotton heavily favored by Heliothis spp . L ukefahr, Houghtaling,
and Graham (1974) found th a t a fte r five seasons of testing glabrous cot
ton s tra in s in T exas, reduction in oviposition ranged from 36% in 1966 to
80% in 1969. Glabrous leaves provided an unsatisfactory surface fo r ovi
position resu lting in few er eggs, fewer larvae, and fewer damaged
squares. Nicotiana p lants with 250 or more H. v irescens eggs had leaves
with many p ro trud ing tricornes and were v e ry villous, whereas p lan ts with
50 or fewer eggs had smooth leaf su rfaces (Greene and T hurston 1974).
Hillhouse and Piire (1976) determined the p refe rred oviposition sites of
H. zea and II. v irescens on soybeans; both species p re fe rred the more
pubescent lower leaf surface fo r egg deposition.
Host a ttrac tiveness is a complex phenomenon, and o ther factors
th a t have been reported to influence oviposition include th e fitn e ss of the
host (Adkisson 1958), number and acreages of host crops (Dicke 1939),
competition from o ther hosts (Lopez 1976), and phonological s ta te s of the
hosts (Isely 1935).
Johnson, S tinner, and Rabb (1975) studied the ovipositional
response of the boll worm to various phonological s ta tes of corn , tobacco,
and soybeans. Flowering stages of all the crops were the p re fe rred phon
ological s ta te of oviposition. Comparisons made of the flowering stages of
the crops showed th a t the ovipositional response was g rea tes t on corn
and decreased successively fo r tobacco, soybeans, and cotton. When
G arza-B lanc and Mathieu (1972) planted co rn , sorghum , co tton , and
tomato in close proximity and sequenced for concurren t flowering, they
found an obvious bias of the bollworm for corn. Extensive studies have
also been conducted on the ovipositional p reference of a closely related
11
species, Heliothis arm igera Hubner, Parsons (1940) determined th a t ovi-
posltion was confined to the period of inflorescence in 23 species of sh o rt
flowering crops and th a t the ovipositional relationship applied to the crop
as a whole, ra th e r than to single p lan ts .
Natural Enemies
Ecologists are giving much atten tion to understand ing causes for
observed fluctuations in insect population num bers. Yearly fluctuations
of Heliothis sp p . on major hosts are determined by a complex of factors in
addition to availability and a ttrac tiveness of food p lan ts; these include
climatic in teractions such as rainfall and cooling o r warming tre n d s , as
well as p red a to rs , p a rasites , and pathogens (Davis 1974).
Many beneficial species have a rep ressive effect on Heliothis
populations. Over 600 p reda to rs have been recorded in A rkansas cotton
fields (Whitcomb and Bell 1964); over 350 p reda to rs and parasites have
been estimated to occur in California cotton fields (van den Bosch and
Hagen 1966). Over 40 parasites of Heliothis have been reported (Muese-
beck and Krombein 1951; Stone e t al. 1965).
The composition of the p red a to r complex varies with location,
crop, and time of year. Genera such as Geocoris, N abis, O rius,
C hrysopa, Hippodamia, and Coleomegilla contain species th a t a re of major
importance in regulating Heliothis populations (Ridgway e t al. 1967).
Spiders (Araneida) (Whitcomb 1967a, 1967b) and an ts (Formicidae) and
certain wasps (Vespidae) (Whitcomb 1967a, 1967b; Lincoln e t 'a l . 1967)
may be im portant in reducing Heliothis populations. For a more complete
12
listing of p redato rs of Heliothis spp . see F letcher and Thomas (1943),
Whitcomb and Bell (1964), and L ingren, Ridgway, and Jones (1968).
The num ber of parasitoid species th a t a ttack Heliothis is much
more limited because parasito ids have a more specific host range than
p reda to rs. Parasites of Heliothis spp . a re usually most active in early
summer or late fall (Lewis and Brazzel 1968; Graham et al. 1972;
Harding 1976). In the la s t 50 years su rveys have been conducted in
various areas of the United S tates to identify parasito ids associated with
Heliothis species.
Chamberlin and Tenhet (1926b) observed the effectiveness of the
parasitoid Cardiochiles n igriceps Vier in controlling H. v irescens on
tobacco in Florida and Georgia. Wene (1943), who worked with tobacco
budworm in Virginia, reported Sagaritis p rovancheri (Dalle Torre)
(=Campoletis a rgen tifrons) (Cresson) as an im portant parasitoid of H.
v irescen s . Grayson (1944) made a su rvey to determine the effectiveness
of these two p arasito id s, C . n igriceps and S. p rovancheri. He observed
a 28%-94% reduction of Heliothis larvae on tobacco when these parasito ids
were p resen t. Snow et al. (1966) and Neunzig (1963) found a varie ty of
parasitoids attacking Heliothis on wild hosts . In collections from Carolina
cranesbill. Geranium carolinianum , an early-season host. Snow e t a l.
(1966) reared out five species of hym enopterous parasito ids from H.
v irescen s, C. n ig ricep s, M icroplitis corceipes (C resson ), Apanetele
m arginiventris (C resso n ), H yposoter s p . , and Netelia sp . Only one
species, M. croceipes, was found parasitiz ing H. zea . Neunzig (1963)
reared the parasito ids Campoletis perd is tinc tu s (Vierick) and Netelia sp .
from H. zea larvae associated with toadflax (Linaria canadensis v a r.
13
texana and C. n igriceps from tobacco budworm larvae feeding on deer-
g rass , Rhesda s p . In Mississippi (Lewis and Brazzel 1968) and in North
Carolina (Neunzig 1969), the two braconids, M. croceipes and C. n ig ricep s,
were the predom inant larval parasito ids. In addition to these two species,
Roach (1975) found th a t Campoletis sonorensis (Cam.) and Campoletis
flavicincta (A sh.) parasitized Heliothis in most areas of the Pee Dee region
of South Carolina. The tachinid species, A rchytas marmoratus (T n s .)
and Lespesia aletia (R iley), were also listed as occasional parasito ids of
Heliothis la rv ae .
Graham et al. (1972) studied the incidence of parasitism in the
Lower Rio Grande Valley, T exas. On larvae collected from March to
September on th ree species of wild p la n ts , Nicotlana rep an d a . Verbena
neomexlcana, and Ruellia runyonii, Graham e t al. found Completis spp . to
be the most common parasito ids. In to ta l, 6 d ip teran and 13 hym enopteran
species were recorded . B utler (1958a, 1958b) made extensive field collec
tions of lepidopterous larvae from cotton, alfalfa, co rn , sorghum , and
desert weeds in Arizona. He found Eucelatoria arm igera (Coquillett) and
M. croceipes to be the most numerous parasito ids of Heliothis. O ther
species included C. tex a n u s , Lespesia archippivora (Riley) , and Chaeto-
gaedia sp . Werner (1978) listed the following species as associated with
H. v irescens in Arizona; C. n ig ricep s, Ap an teles m arginventris (C resso n ),
M. croceipes, and Campoletis flavicincta sonorensis.
Some parasito ids such as Trichogramma s p . and C . texanus attack
Heliothis eggs (Muesebeck and Krombein 1951). O ther genera such as
A panteles, Campoletis, and to some ex ten t Microplitis a ttack mostly early
in s ta r larvae, whereas C ardjochiles, Eucelatorla, and Lespesia tend to
p re fe r la rg e r, la te r 'in s ta r larvae (Ridgway and L ingren 1972).
Host p lants fo r a num ber of crop pests in Arizona and th e ir
associated predato rs and parasito ids have been discussed by Fye (1972,
1975). A large segm ent of the insect population in sou thern Arizona
overw inters on London rocket. Sisymbrium irio . As the London rocket
m atures, the in sects move to d e se rt plants th a t grow when w inter rains
are adequate (Fye 1975). The foremost host in some d esert areas is
d ese rt mallow, Sphaeralcea spp . (Stoner 1972); however, o ther d e se rt
plants are reservo irs of both beneficial and pest species. Knowledge
about the d istribu tion of Heliothis spp . on such hosts is im portant to
an understand ing of the ir long-term population dynamics in central
Arizona.
MATERIALS AND METHODS
Surveys for a lternate host p lants of Heliothls sp p . were made
from F ebruary until June in 1979 and 1980. Most of the acreage checked
was in Pinal County, Arizona, within a 25-mile radius of the City of
Coolidge. Major crops grown in th is area include su g arb ee ts , alfalfa,
and lettuce in the w inter and alfalfa, cotton, and corn in the summer.
In 1979 one area in Maricopa C ounty, the Kelly rose farm near Sun C ity,
was checked periodically in late w inter and early sp ring for Heliothis.
These resu lts were omitted because of inconsistent sampling times.
Heliothis larval populations developing on uniform stands of
sp ring hosts were sampled with a 39.1-cm insect sw eep-net. With plant
species not growing in dense s ta n d s , examinations of en tire p lants were
made to locate eggs and larvae. A fter Heliothis sp p . were found associ
ated with a pa rticu lar p lant species in a given area , samples were taken
at the site at weekly and bi-weekly in tervals until the p lants reached
senescence or until no more eggs and larvae were found. Usually only
fru iting forms of potential host-p lan t species were checked for Heliothis.
The number of sweep samples and number of p lants examined to establish
approximate population densities varied between collection dates and lo
cations because of such factors as manpower, host availability, and
infestation level.
Eggs and larvae found were taken back to the labora to ry , sepa
rated from those of o ther species, and placed individually in 31-g, clear,
plastic cups approxim ately tw o-th irds full of a modified lima bean-agar
15
diet (Patana 1969). Samples were held in the laboratory a t 25°C under
naturally occurring day lengths for identification and parasite emergence.
H. zea and H. v irescens larvae were separated under magnifica
tion by the characteristics listed by Boyer, Burleigh, and Wall (1977) and
Brazzel e t al. (1953). Using only the presence or absence of a mandibu
lar retinaculum as a method of identification, as shown in Figure 1,
Heliothis larvae were difficult or impossible to identify until they reached
the th ird in s ta r . The most reliable characteristic for identification was
the presence of microspines on the e ighth abdominal (dorsal) tubercle of
the budworm and their, absence in the bollworm, as shown in Figures 2
and 3, respectively . Both charac teristics were used when necessary .
Heliothis phloxiphaga (Grote and Robinson) larvae were d istinguished from
H. zea by descrip tions given by Hardwick (1965) and by emergence of
adult m oths. Eggs of jH. v irescens and H. zea were distinguished by the
condition of the micropyle (Phillips 1978). Collections of damaged eggs
and of larvae th a t died as f irs t o r early second in s ta r o r th a t were too
damaged to identify were omitted from the re su lts .
Records were kept of p lant species, collection d a te s , Heliothis
s p p . , and larval in s ta r as well as parasito ids, disease, pupation, and
diapause of collected larvae. Parasitoids em erging from all collected
larvae were pinned and la te r identified by Dr. Floyd W erner, Departm ent
of Entomology, The U niversity of Arizona. Plant specimens were iden ti
fied by individuals from the U niversity of Arizona Herbarium.
Between May 13 and May 27, 1980, unit area samples were taken
of Heliothis larval populations developing on redstem filaree, Erodium
16
cicutarium . This p rocedure consisted of m easuring and marking an
17
Figure 1. In n er surface of la te -in s ta r larvae of tobacco budworm (left) showing prominent retinaculum and of bollworm (right) showing concave inner surface without the retinaculum
18
Figure 2. Lateral view of abdominal segment eight of la te -in s ta r tobacco budworm larva showing d istinc t microspines on the tubercle
Figure 3. Lateral view of abdominal segment eight of late-instar cotton bollworm larva showing tubercle without microspines
0.5-m2 circu lar area in a uniform stand of the p la n ts , carefully clipping
the p lants a t ground level, placing them in a plastic bag , and bring ing
the sample back to the laboratory to check for eggs and larvae.
A lis t of all p lants smapled in 1979 and 1980, num ber of sweeps
taken or num ber of p lants examined, and dates when samples were taken
is given in Appendices A and B. the percen t parasitism for each Helio-
th is species collected on each host as well as percen t pupation was com
piled. Precipitation data fo r the fall, w inter, and sp ring of 1978-79 and
1979-80 were obtained from the National P ark Service a t Casa Grande
Ruins National Monument. Heat un it da ta for th is time period were sup
plied by D r. Roger T . H uber, Departm ent of Entomology, The U niversity
of Arizona.
In the sp ring of 1980 tobacco budworm pheromone trap s were
placed in Pinal County by M. S. Tollefson, Extension P est Management
Specialist, The U niversity of Arizona, to monitor early season moth ac
tiv ity . T rap design was the cone-75-50 type as described by H artstack ,
Witz, and Buck (1979). Pheromone wicks, which were obtained from
Zoecon Corporation, Palo Alto, California, contained v ire lu re in a 16:1
ratio of (Z -ll-hexadecenal to (Z) -9 -te tradecenal (Tumlinson e t al. 1975).
T hree trap s were in operation along irrigation ditches in Magma, Eloy,
and Coolidge, Arizona, and were checked weekly from April 7 until
June 15..
19
RESULTS
Rainfall Data
In the d esert Southw est, cultivated p lants depend en tire ly on
irrigation for the water requ ired in th e ir production. Noncultivated
p lan ts, how ever, occur sporadically , depending on the amount and p a t
te rn of rainfall. For th is s tu d y , rainfall data for the fall, w inter, and
sp ring periods preceding the two Heliothis sampling periods were obtained
from the National Park Service, Casa Grande National Monument, to d e te r
mine the association of fall and w inter rainfall with plant species occurring
the following sp rin g . These data are p resen ted in Table 1.
Table 1. Rainfall recorded at the Casa Grande Ruins National Monument, Casa G rande, Arizona, October th rough May, 1978-79and 1979-80
Rainfall (inches pe r m onth), Oct. th rough May
Month 1978-79 1979-80
October 1.62 0.21November 2.08 0.02December 3.68 0.09January 2.87 1.71February 0.38
^ 2.693.54
March 1.12April 0.05 0.17May 0.57 0.17
Total for 8 months 13.94 7.03
20
21
Field Samples, 1979
In the sp ring of 1979, Heliothis larvae were found as early as
April 16 on C oulter's globe mallow, Sphaeralcea coulter! (W ats.) G ray, in
two locations near F lorence, Arizona. Of a total of 36 larvae collected on
th is host between April 16 and May 1, 1981, 86.1% were bollworms and
13.9% were tobacco budworms. On April 24, sp ring populations reached
a level of 17 H. zea and 3 H. v irescens larvae in 400 sweeps on the above
host.
On May 7, 1979, Heliothis sp p . were found infesting redstem
filaree, Erodium cicutarium (L.) L 'H e r., along roadside areas near Magma,
Arizona. Larvae were collected on dense stands of th is plant species until _
June 12, 1979, at five locations in Pinal County: Magma, Florence, Pica-
cho. La Palma, and along the Pinal Pioneer Parkway. A total of 220 larvae
was collected with species composition as follows: 61.8% H. v irescens,
28.9% H. phloxiphaga, 3.1% H. zea, and 6.2% undeterm ined Heliothis sp p .
Spring populations on th is host p lant reached a peak on June 1, 1979;
400 sweeps yielded the following num bers of la rv a e : 26 H. v ire sce n s ,
8 H. phloxiphaga, and 3 H. zea.
Another p lan t species infested with Heliothis larvae du ring th is
same time period was daisy fleabane, Erigeron d iv erg en s. Sw eep-net
samples taken a t weekly in tervals near Coolidge and La Palma between
May 12 and June 21, 1979 yielded 524 larvae of which 99.4% were iden ti
fied as H. phloxiphaga and 0.6% as H. v irescen s . On May 15, 1979, 100
sweeps collected 132 H. phloxiphaga larvae and 1 H. v irescens larva;
numbers decreased sharp ly a fte r th is date . T hese data are p resen ted in
Table 2.
22
Table 2. Species composition of Heliothis on th ree sp ring host p lants in Pinal County in 1979
No. of Larvae
Percent of Each Heliothis Species
Plant Species v irescens zea phloxiphaga undeterm ined
Sphaeralceacoulter! 36 13.9 86.1 0.0 0.0
Erodiumcicutarium 220 61.8 3,1 28.9 6.2
Erigerondivergens 524 0.6 0.0 99.4 0.0
Field Samples, 1980
In the sp ring of 1980, Heliothis larvae were p resen t on garbanzo
bean, Cicer arietinum L . , a t two locations near Eloy. Eight H. zea larvae
were collected on th is cultivated host between April 15 and May 1; how
ever, between May 10 and May 29, 225 larvae were collected with the fol
lowing species composition: 92.5% H. v ire sce n s , 3.1% H. zea , and 4.4%
unidentified Heliothis species. On May 22, 20 p lants were examined and 86
tobacco budworm larvae collected. Populations declined a fte r th a t date as
the p lants dried up .
In 1980, growth of Erodium cicutarium was limited, and only 51
larvae were collected between May 10 and June 5 from a single location
near Coolidge, Arizona. The following species percen tages were obtained:
15.7% 13. zea, 51.0% H. phloxiphaga, 25.5% II. v ire sce n s , and 7.8% unde
term ined Heliothis species. Populations on th is host peaked on May 27;
100 sw eep-net samples were taken and eight H. phloxiphaga, e ight H.
v irescen s , and two H. zea larvae were iden tified .
23
Yellow b ird -o f-p a rad lse , Caesalpinnia gilliesli W all., proved to be
a suitable host for tobacco budworms in the late sp ring and early summer.
From May 27 until June 26, 171 larvae were collected on th is p lan t species
near Coolidge, and all were identified as H. v irescen s . On June 12, ap
proximately 30 p lants were examined for Heliothis spp . and 85 tobacco
budworm larvae were collected (Table 3).
Table 3. Species composition of Heliothis on th re e sp ring and early summer host p lan ts in Pinal County in 1980
No. of Larvae
Percent of Each Heliothis Species
Plant Species v irescens zea phloxiphaga undeterm ined
Cicerarietinum 233 92.5 3.1 0.0 4.4
Erodiumcicutarium 51 25.5 15.7 51.0 7.8
Caesalpinniagilliesii 171 100.0 0.0 0.0 0.0
Miscellaneous Plants Sampled
Low numbers of Heliothis were found on le ttuce , Lactuca sa tiva L . ,
alfalfa, Medicago sa tiva L . , field bindweed. Convolvulus s p . , p ig n u t,
Hoffmanseggia densiflora B e n th ., and devils-claw, Proboscidea parv iflo ra
(Wooton) Woot. & S tandi. The following p lants were sampled rou tinely ,
i . e . , more than th ree dates at th ree o r more locations, with which no
Heliothis larvae were found associated: London rocket. Sisymbrium irio L . ,
little mallow, Malva parv iflora L . , lupine, Lupinus s p . , annual yellow
24
sweetclover, Melllotus indicus (L. ) , d esert senna. Cassia covesii G ray,
slimleaf b u r-sag e . Ambrosia confertiflora DC, small flower gau ra , Gaura
parviflora D oug l., tree tobacco, Nlcotiana glauca Graham, and pecan.
Carya illinoensis Koch.
P lant D escriptions
Sphaeralcea coulteri (W ats.) Gray
T here are 16 species of globe mallow native to Arizona, many of
which are difficult to d istingu ish . D esert mallow, S . cou lte ri, is an
annual found on sandy soils along roadsides, fields, and mesas from
January to May in Pinal, Maricopa, Pima, and Yuma Counties a t elevations
of 2,500 feet or lower (P arker 1972). The peak flowering period for
desert mallow is March 20 (McGinnies 1980).
Erodium cicutarium (L.) L 'H er.
T here are two species of Erodium in Arizona. E. cicutarium and
E. texanum . Red stem filaree , E. cicutarium , is an annual, w inter annual,
or biennial and is found in g rea t abundance on plains and mesas th rough
out the s ta te from F ebruary until Ju ly a t elevations up to 7,000 feet
(Parker 1972). The peak flowering period is March 30 fro areas near
Tucson and a week to 10 days earlie r fo r warmer regions west of Tuson
(McGinnies 1980).
Dense stands of th is p lan t species were sampled along roadsides
and field bo rders in cen tra l Arizona in 1979 and 1980. Flowers occur in
an umbrellalike c lu s te r a t the end of long stalks arising from the leaf axils;
the fru it is elongate and beaklike (Kearney and Peoples 1950). Feeding
by Heliothis spp . was confined to the t ig h t, cymose flower heads and
succulent fru its as shown in Figure 4; la rg e r larvae consumed en tire
fru iting s tru c tu re s and were never observed feeding on leaves.
Erigeron d ivergens T o rr. & Gray
Daisy fleabane, E. d iv erg en s, is a common herbaceous species
found throughout Arizona on d ry , rocky slopes and mesas and in open
pine woods from February to O ctober a t elevations of 1,000 to 9,000 feet
(Parker 1972). Many Erigeron species have a ttrac tiv e daisylike heads
with blue, lavender, or white rays (Kearney and Peoples 1950). In 1979,
this plant species was p resen t in abundance in d istu rbed d esert areas
and along roadsides near Coolidge. H. phloxiphaga larvae increased to
large numbers on th is host and were observed feeding on both flower
heads and stem s.
Cicer arietinum L.
Chickpea, or garbanzo bean, C. arietinum , is a cultivated p lan t
grown for its edible seeds. It is an annual, 1 to 2 feet ta ll, e rec t and
b ranched , with g landu lar-pubescen t leav es. Flower are solitary and
white with pods 0.75 to 1 inch long, usually with one or two seeds
(Bailey 1925). This crop is grown extensively in Mexico, bu t 1980 was
the f irs t year it was planted in Pinal C ounty, Arizona.
Samples were taken from two fields near Eloy. Oviposition
occurred on leaves, stem s, and pods. Small larvae fed on leaves and on
the ou ter surface of the pod; la rg e r larvae bored into the pod and con
sumed the developing seeds.
25
26
27
Caesalpinnia gilliesii Wall.
Yellow b lrd -o f-p a rad ise , C. gilliesii, is an introduced p lant from
South America. I t is a sh rub up to 7 feet in height with yellow flowers
which begin blooming in late sp ring and continue until m id-June
(McGinnies 1980). The terminal racemes a re la rg e and showy and the
inflorescence densely glandular (Bailey 1925). This plant is grown in
Arizona as an ornamental in residential a reas. I t occasionally escapes
from cultivation and may be naturalized in Mohave, Gila, Maricopa,
Cochise, and Pima Counties (Kearney and Peoples 1950).
On C. gilliesii, H. v irescens eggs were located on unopened floral
buds; larvae fed on these as well as on opened flowers as shown in
Figure 5. Very few larvae were observed to feed on the g reen pods of
these p lan ts .
Proboscidea parviflora (Wooton)
Devils-claw, P. p a rv iflo ra , flowers from m id-June th rough
September and is common in Arizona along the Gila R iver (Kearney and
Peoples 1950). Plants are coarse , v isc id -pubescen t annual h e rb s , with
large , somewhat fleshy f ru it, ending in a long , incurved beak.
For th is su rv ey , p lants were sampled in cotton fields in the
Blackwater Farms area near Sacaton, Arizona. A few large larvae were
collected from the leaves of th is p lan t in June 1980 and were identified
as H. v iresceris.
Hoffmanseggia densiflora B enth.
These perennial, herbaceous p lants are found along roadsides
from Navajo to Mohave C ounty, south to Graham, Cochise, Pima, and
28
Figure 5. Tobacco budworm larva feeding on unopened flower of yellow b ird -o f-p a rad ise# Caesalpinnia gilliesii
29
Yuma Counties, a t elevations of 5,000 fee t o r lower. The inflorescence is
conspicuously glandular, and the flowers occur from April to Septem ber
(Parker 1972). S tands of II. denslflora were examined for Heliothis in
May 1980, and a few IL v irescens eggs were collected.
F igure 6 shows the seasonal sequence of these host plants iden
tified in the su rv ey . Information about flowering seasons was found in
McGinnies (1980) and is based on 13 y ears of observations. Estimated
flowering peaks a re fo r d ese rt areas near Tucson and may be a week to
10 days earlier in warmer regions west of Tucson. Table 4 p resen ts an
a rb itra ry ra ting of II. v irescens host p lants recorded in the T-year s u r
vey and is based on number and size-of larvae collected.
Mortality on D ifferent Host P lants
A ccurate percentages of parasitism could not be determined be
cause of high larval mortality resu lting from sw eep-net in ju ry and the
failure of Heliothis larvae to develop sufficiently for parasites to emerge
because of v ira l, fungal, and bacterial infections. However, the species
involved and th e ir relative im portance was determ ined.
The percentage of parasitism for Heliothis species on d ifferen t
host plants is shown in Tables 5 and 6. The most significant information
these tables provide is a comparison between levels of parasitism on the
d ifferen t host p lants utilized by H. v ire scen s . In 1979 and 1980, p a ra
sitism of tobacco budworms on E. cicutarium was 55.0% and 63.6%, respec
tively . This con trasts with 0.7% parasitism on C. gilliesii and 16.7% on
C. arietinum in 1980.
I Cicer arietfnum ̂ ^ Proboscideo parviflora
I Caesolpinnia gilliesii ^
Erodium cicutarium |---------------------:-------1
Sphaeralcea coulferiI------------------------- 1
Gossipium hirsutumI-
I 10 20 30 10 20 30 10 20 30 K) 20 30 K) 20 30 10 20 30
MARCH APRIL MAY JUNE JULY AUGUST
Figure 6. Seasonal sequence of some plants found to be hosts of the tobacco budworm in Arizona
31
Table 4. Summary of Hellothis v irescens host p lants recorded during sp ring 1979 and 1980 su rveys in cen tra l Arizona
Host Eggs
Forms Found
L arvae3
Small Large Host Rating*3
Cultivated
Cicer arietinum X X X Good
Caesalpinnia gilliesii X X X Good
Rosa sp . X X X Good
Gossypium hirsutum X X X Good
Wild
Sphaeralcea coulter! X X X Fair
Convolvulus arvensis X Poor
Erodium cicutarium X X X Fair
Hoffmanseggia densiflora X X Poor
Proboscidea parviflora X Fair
Erigeron divergens X Poor
a. Small = up to th ird in s ta r; la rge = fo u rth , fifth in s ta rs .✓
b. Good = many large largfae, eggs; fair = eggs, small larvae; poor = a few small larvae, eggs.
32
Table 5. Relative parasitism of th ree Heliothis spp . on d ifferen t host p lants in central Arizona in 1979
Percent Parasitism 3
Plant Species H. zea H. v irescens H. phloxiphaga
Erodium cicutarium 5/12-6/12 0.0 (6) 55.0 (100) 34.9 (43)Sphaeralcea coulter! 4/24-5/1 5.0 (20) 0.0 (3) 0.0 (0)Lactuca sativa 4/12-4/19 0.0 (4) 0.0 (0) 0.0 (0)Medicago sativa 5/3 0.0 (1) 0.0 (0) 0.0 (0)Erigeron d ivergens 5/12-6/21 0.0 (0) 66.7 (3) 23.4 (32)
a. Number of larvae observed (in paren theses) does not include larvae th a t died from in jury or d isease.
Table 6. Relative parasitism of th ree Heliothis s p p . on d ifferen t host p lants in cen tral Arizona in 1980
Percent Parasitism a
Plant Species 11. zea H. v irescens 1}. phloxiphaga
Cicer arietinum 4/15-5/27 26.7 (15) 16.8 (1677) 0.0 (0)Erodium cicutarium 5/10-6/5 25.0 (8) 63.6 (11) 31.2 (16)Proboscidea
parviflora 6/18-6/26 0.0 (0) 16.7 (18) 0.0 (0)Caesalpinnia
gilliesii 5/27-6/26 0.0 (0) 0.7 (133) 0.0 (0)
a. Number of larvae observed (in paren theses) does not include larvae th a t died from in ju ry or disease.
33
In considering overall m ortality a ttrib u ted to bacteria , v iru s ,
fungi, in ju ry , and parasites , the number of larvae reaching the pupal
stage on each host is also compared in Table 7. Between May 12 and
June 12, 1979, 135 tobacco budworm larvae were collected on E. cicu-
tarium , with 33.3% reaching the pupal stage. In 1980, on th is same host, ,
only 13 H. v irescens larvae were collected between May 10 and June 5,
with 30.8% becoming pupae. On the hosts , Cicer arietinum and Caesal-
pinnia gilliesii, 209 and 171 larvae, respectively , were collected between
April 15 and May 27 on the form er and between May 17 and June 26 on
the la tte r species; pupation was 76.1% and 77.2%, respectively .
Daisy fleabane, Erigeron d iv erg en s, was an im portant spring
host fo r 11. phloxiphaga in 1979. This noctuid species has never been
recorded as a pest of cotton; however, i t was reported to a ttack tomatoes
in central California (Lange and M ichelbacher, 1937). Parasitism reached
moderate levels for larvae of th is species feeding on E. d iv erg en s; of
521 larvae collected, 23.4% were parasitized (Table 5) and 47.5% pupated
successfully as shown in Table 7. In 1979 and 1980, 65 and 26 11.
phloxiphaga larvae, respectively , were also collected on red stem filaree,
Erodium cicutarium , with 34.9% and 31.2% parasitism recorded, as shown
in Tables 5 and 6.
Common Parasitoid Species
Parasito ids common to H. v irescens and H . phloxiphaga collected
on Erodium cicutarium include the following species: Campoletis sonoren-
s is , Pristom erus sp inator (F .) , Hyposoter exiguae (V ierreck ), Lespesia
a rch ipp ivera , and Microplitis croceipes. Spilochalci sp . (sida group) and
34
Table 7. Relative abundance of Hellothis spp . larvae on d ifferen t sp ring host p lants in Pinal C ounty, Arizona
H. v irescens Larvae Collected
PupatingCollection % of Total ---------------------------
Host Plant Period Number Collected Number Percent
H. v irescens
1979
Sphaeralcea coulteri 4/16-4/21 5 3.4 NAConvolvulus arvensis 5/1 1 0.7 NAErodium cicutarium 5/12-6/12 135 93.8 45 33.3Erigeron divergens 5/12-5/22 3 2.1 1 33.3
1980
Erodium cicutarium 5/10-6/5 13 3.2 4 30.8Cicer arietinum 5/10-5/29 209 50.8 159 76.1Caesalpinnia gilliesii 5/17-6/26 171 41.6 132 77.2Proboscidea parv iflora 6/18-6/26
H.
18
zea
4.4 15 83.3
1979Sphaeralcea coulteri 4/16-5/1 31 59.6 20 76.9Convolvulus arvensis 5/1 5 9.6 NAErodium cicutarium 5/12-6/1 7 13.5 6 85.7Convolvulus tinc tu riu s 5/12 4 7.7 4 100.0Lactuca sativa 4/12-5/1 4 7.7 4 100.0Medicago sativa 5/3 1 1.9 1 100.0
1980Erodium cicutarium 5/10-5/27 8 34.8 6 75.0Cicer arietinum 4/15-5/13 15
H. phloxiphaga
65.2 10 66.7
1979'Erodium cicutarium 5/12-6/12 65 11.1 27 41.5Erigeron d ivergens 5/12-6/21 521 88.9 249 47.8
1980Erodium cicutarium 5/10-6/5 26 100.0 11 42.3
35
Rogas perp lexus Gaha, were found to emege only from tobacco budworm
larvae, whereas Cardiochiles seminger (Gresson) was res tric ted to H.
phloxlphaga on both red stem filaree and daisy fleabane.
Only th ree tobacco budworm larvae were collected from daisy
fleabane in 6 weeks of sampling, and from these , two parasitoid species,
P . sp inator and L. arch ipp ivora , em erged. H_. phloxlphaga larvae from
th is p lant yieleded the following parasito id species: L. a rch ipp ivo ra ,
Eucelatoria sp . (arm igera g ro u p ) , A rchytas m arm oratus, Chaetogaedia
s p . , M. croceipes, Cardiochiles sem iniger, Campoletis sonorensis, P .
sp in a to r, and Hyposoter ex iguae. These data a re p resen ted in Table 8.
In early sp ring of 1979, 31 H. zea larvae were collected from
Sphaeralcea coulter! and only 1 parasito id , Rogas p e rp lex u s, emerged;
from the plant host Erodium cicutarium , 7 bollworms were collected with
no parasitoid emergence. In 1980, 8 II. zea larvae were collected from
red stem filaree with two parasitized by Campoletis sonorensis. Cicer
arietinum was a host of H. zea from April 15 until May 22, 1980, with
22.7% parasitism by C. sonorensis! and Hyposoter ex iguae. These data
a re p resen ted in Tables 7 and 8.
H ost-plant Specificity
Table 9 shows the host p lants used by each Heliothis species in
1979 and 1980. II. v lrescens was found on e igh t d ifferen t p lant species
and H. zea , collected on seven hosts , was most abundan t in early sp ring
bu t decreased noticeably from samples taken a fte r late A pril. The species
H. Phloxlphaga was found on Erodium cicutarium and Erigeron d ivergens
in 1979. In 1980, E. d ivergens was absen t from the d esert landscape.
Table 8. Species of parasito ids found on Heliothis s p p . in central Arizona during the sp rings of 1979 and 1980
Parasitoid Heliothis spp . Host Plant
D iptera
Tachinidae
Lespesie archippivora v irescens. redstem filaree.phloxiphaga daisy fleabane,
devils-clawEucelatoria sp . phloxiphaga daisy fleabaneChaetogaedia sp . phloxiphaga daisy fleabane
Hymenoptera
Braconidae
Microplitis croceipes v ire scen s , redstem filaree .phloxiphaga daisy fleabane
Rogas perp lexus v ire sce n s , redstem filaree.zea C oulter's globe
mallowCardiochiles seminiger
Ichneumonidae
phloxiphaga redstem filaree, daisy fleabane
Campoletis sonorensis v irescens. redstem filaree.
Pristom erus sp inator
Hyposoter exiguae
zea,phloxiphaga
v ires cen s, phloxiphagav ire sce n s ,phloxiphaga,zea
daisy fleabane, b ird -o f-parad ise , devils-claw s, chickpearedstem filaree, daisy fleabaneredstem filaree, daisy fleabane, devils-claw s, chickpea
Chalcididae
virescens redstem filareeSpilochalcis sp.
Table 9. Host utilization by Heliothis s p p . on a given host p lant in the sp rings of 1979 and 1980 in central Arizona
37
Plant Species
Heliothis Species
H. v irescens H. zea H. phloxiphaga
Lactuca sativa XSphaeralcea coulteri X XConvolvulus arvensis XMedicago sativa XErodium cicutarium X X XCarthamus tinc tu riu s XCicer arietinum X XCaesalpinnia gilliesii XHoffmanseggia densiflora XProboscidea parv iflora XErigeron divergens XRosa sp . X X
in 1979. In 1980, E. divergens was absen t from the d esert landscape bu t
moderate numbers of H. phloxiphaga were found on Erodium cicutariiim .
Pheromone Monitor T raps
In Coolidge, 225 H. v irescens moths were cap tured between
April 26 and May 26, 1980. Peak trap catches in Eloy occurred from
May 12 until May 23; 137 moths were collected. In Magma, only 26 moths
were trapped between April 7 and June 15.- i :
38
Unit Area Samples
Between May 13 and May 27, 1980, un it area samples were taken
on five separa te occasions on Erodium cicutarium . No eggs o r larvae were
collected using th is technique.
DISCUSSION
It is im portant th a t data be available on all factors th a t could
influence Heliothis population dynam ics. This study, completed in the
early summer of 1980, provides insigh t into the role of a lternate host
p lants in early-season activ ity of Heliothis species in Arizona. Such
information is necessary for in telligent management of Heliothis s p p .
Weather is the dominant factor influencing all components of the
life system of Heliothis spp . The d irect effects of its variable elements
(tem perature, m oisture, e tc .) on Heliothis a lte r not only behavior but
also ra te s of development, fecund ity , and survival of these p e s ts . The
effects of w eather on host plants and natu ra l enemies also regulate th e ir
synchrony with and impact on Heliothis spp . (S tinner, Rabb, and
Bradley 1977).
D esert regions have an environm ent characterized by low m oisture,
which is irregu larly d istribu ted in space and time, and d esert p lants have
a phenology closely related to rainfall and tem p era tu re , and , in p a rticu la r,
to soil m oisture (Ackerman and Bamberg 1974). The amount of moisture
in the soil at the s ta r t of the sp ring growth period determ ines initial
flowering response (McGinnies 1980; Ackerman and Bamberg 1974). Cli
matic information obtained from the Casa Grande Ruins National Monument
indicates th a t rainfall accumulation from October to December, 1978, was
7.38 inches, as shown in Table 1; flowering was exceptional for many
d esert p lants the following sp rin g . In 1979, rainfall du ring these same
th ree months was only 0.32 inch; flowering d ese rt p lants were scarce in
39
40
the sp ring of 1980. In the lower Sonoran d e se rt, ra infall-tem perature
combinations th a t produce good ea rly -sp rin g flowering seasons may occur
only once every 10 years and once every 30 to 40 years to produce an
exceptional early -sp rin g flowering display (McGinnies 1980). Wild hosts
in d ese rt regions appear to be an unpredictable food source for Heliothis
spp .
Among the d esert p lants found in great abundance in the sp ring
of 1979 were C oulter's globe mallow and redstem filaree. Sphaeralcea
coulteri se rves as a host of Heliothis zea before alfalfa and corn are
available. H. v irescens larvae were collected on redstem filaree at a
la ter date than H. zea larvae and were p resen t until th e end of May on
th is host. Henry and Adkisson (1965) reported th a t tobacco bud worm
infestations developed la te r than did bollworm in festa tions. Emergence
of bollworms from diapause is 2 to 3 weeks earlier than th a t of tobacco
budworms in Brownsville, Texas (Fife and Graham 1966).
In 1980, growth of native d e se rt p lants was limited to moist areas
such as canal banks. Heliothis populations were not p resen t in signifi
cant num bers on any wild host. Large numbers of larvae were collected
from two fields of garbanzo beans and also from yellow b ird -o f-parad ise .
On the host, Cicer arietinum ,a large percentage of larvae collected be
tween April 15 and May 1 was bollworms; between May 10 and May 29
most larvae collected from th is host were H. v irescen s . All larvae col
lected on Caesalpinnia gilliesii were tobacco budworms.
The climatic situation in cen tral Arizona is similar to th a t found
in the Presidio a rea of Texas where because of d e se rt ecology, suitable
host p lants for the bollworm and tobacco budworm are confined prim arily
to the Rio Grande Valley. C otton , alfalfa, and a small acreage of o ther
cultivated crops are the prim ary host p lants (Cole, Adkisson, and Fye
1973).
The kinds (host plant species and phenological sta tes) and
quantity (biomass and acreage) of food vary from area to a rea , year to
year, and seasonally. An early -season key host such as yellow b ird -o f-
paradise may be of no significance in late season and visa v e rsa . Sea
sonal production of moths depends on a complex of hosts th rough which
Heliothis biomass flows from sp rin g to fall.
Spring emergence of Heliothis s p p . in cen tra l Arizona occurs
approxim ately 1.5 months before cotton begins squaring . Diapausing H.
v irescens begin sp ring emergence a t 139 CHU and complete it a t 417 CHU
(Potter e t al. n .d . ) . In agreem ent with these heat unit values, emergence
in 1979 began March 7 and was completed by May 2. In 1980, activ ity
began February 13 and ended by April 18. These dates are based on
heat-un it accumulations determined by P o tter e t al. ( n .d . ) .
In 1979, most Gossypium hirsutum in Pinal County was planted
between March 11 and May 1 and in 1980 between March 1 and mid-April
(Tollefson, 1980, personal communication). Based on hea t-un it accumu
lations for cotton, as determined by Huber ( n .d . ) , f ir s t square produc
tion in these years occurred in early Ju ly and late Ju n e , respectively .
The thermal requirem ent for cotton to square is 389 CHU from planting
date .
Seasonal activ ity of Heliothis sp p . extends over a longer period
than does the growing season of any single species of host p lant.
Sphaeralcea coulter!, Erodium cicutarium , Cicer arietinum , Caesalpinnia
41
42
gilliesii, and Proboscidea parv iflora provide a food source for Heliothis
larvae at a time when cotton is unavailable, and , in tu rn , these larvae
serve as hosts for the buildup of parasitoid species th a t a ttack la te r
generations of Heliothis species on summer crop p lan ts.
Populations of Heliothis spp . on these d ifferen t hosts v a ry in
surv ival ra tes due to nutritional and microenvironmental d ifferences
Mortality from natural enemies is also influenced by factors in trin sic to
host p lan ts . Erodium cicutarium provides an excellent m icrohabitat for
parasito ids of Heliothis spp . In 1979 and 1980, eight parasito id species
were identified (Table 9). The closed-canopy growth charac teristic of
redstem filaree appears to a ttra c t parasito ids and apparen tly acts as a
buffer against harsh environm ental conditions. The fru iting s tru c tu re s
of th is plant fed on by Heliothis larvae facilitate a ttack by parasito ids
(Figure 4). On the host Caesalpinnia gilliesii, only one parasito id ,
Campoletis sonorensis , emerged from 171 H. v irescens larvae collected.
Collections were made in late May and early June when warmer tem pera
tu res may cause parasitoid populations to decline. On Cicer arietinum
only two parasito ids, Campoletis sonorensis and Hyposoter exiguae,
emerged from 233 collected la rv a e . Garbanzo bean p lants are exposed
to su n , ra in , and high tem peratures under field conditions and are
therefo re not v e ry a ttrac tiv e to parasito ids. Larvae penetra ting the pod
of th is p lan t and feeding on developing seeds are physically pro tected
from attack by most parasito ids species.
The effects of each natural enemy species d iffer m arkedly accord
ing to the host plant species and its phenological sta te (S tinner e t al.
1977). Examples of th is are tach in id , ichneumonid, and braconid species
43
which commonly take a heavy toll of H. zea on tobacco (Irabagon 1973)
and cotton and soybeans (Hughes 1975) bu t have little effect on larvae
feeding within pro tective corn husks (Hughes and Rabb 1976).
The p lant species Erigeron d iv erg en s , even though only an inci
dental host of H. v ire scen s , was im portant in supporting large numbers
of Heliothis phloxiphaga larvae. From these larvae emerged many para-
si toids common to both H. v irescens and H. zea, which probably built up
to high num bers on Erigeron d ivergens and Erodium cicutarium and then
moved to cotton to a ttack la ter generations of II. zea and H_. v irescen s .
The percentages of parasitism shown in Tables 5 and 6 are an
indication of the ability of parasito ids to locate the ir hosts. Numbers
given are relative because 10% to 40% of the larvae generally succumbed
to bacterial, fungal, and v iral infections before they were large enough
for parasitoid emergence. These larvae were excluded from the calcu
lations for percen t parasitism given in Tables 5 and 6. Parasitism was
still high; it averaged 22.1% for all tobacco budworm larvae collected in
1979 and 1980.
The tru e measure of the importance of a host p lant in the buildup
of an insect population is not the num bers of larvae infesting the host,
bu t the numbers of adu lts produced p e r unit area of the host and the
abundance of the host p lant in the agroecosystem (Stadelbacher 1979).
However, in all rep o rts except th a t of Graham and Robertson (1970), the
identification of early -season hosts was based on the num bers of larvae
collected. Similar criticism can be made of th is s tu d y . The d istribu tion
of the F i larval population th roughout an agroecocystem and the density
of the larval populations on various hosts at any given time are determined
44
by the selection of specific hosts by the ovipositing female moths and the
d istribution and abundance of the host. As the season p ro g resses , the
species composition of the plant complex as well as the stage of develop
ment of each p lant species varies according to the normal phenology of
the individual species (Stadelbacher 1980).
In the Arizona d e se rt, d istribu tion of Heliothis species on wild
host p lants is not uniform and is difficult to estimate accurately because
the hosts are so widely scattered and are a ttrac tive to ovipositing moths
for such a sho rt period of time. Populations are also extremely variable
from year to year; therefo re , it is difficult to assess the role these
plants play in Heliothis population dynamics.
H. v irescens appears unlikely to increase greatly on wild hosts
because of the inconsistency of the rainfall essential to p lant growth and
also due to high larval m ortaility. P lants such as yellow b ird -o f-parad ise
are more perm anent food sources and may produce a large percentage of
the adult population th a t m igrates to cotton and produces the initial larval
infestations on cotton in Arizona. Cage studies a re needed to calculate
actual num bers of moths emerging from each host listed to determine its
tru e importance.
Pheromone trap -ca tch records provided by Tollegson (1980, p e r
sonal communication) indicated th a t large num bers of F2- and Fa-
generation moths emerged in the sp ring of 1980 near Eloy and Coolidge,
Arizona, from areas where ornamental plants were relatively abundan t.
In Peoria, Arizona, a severa l-acre n u rse ry field of roses produced large
num bers of Heliothis, which moved into adjacent cotton fields (Sluss and
45
Graham 1979). In C entral Arizona, ornamental p lants may be very impor
tan t in the early-season dynamics of Heliothis species.
Henry and Adkisson (1965), working in cen tra l T ex as, and
L aster and F u rr (1971), working in M ississippi, suggested th a t stub
cotton may be im portant in sustain ing populations of overw intering Helio
th is in these a reas. During the w inter of 1979-80, approxim ately 60,000
acres of stub cotton were cultivated in Arizona (Taylor and Hathorn 1981).
This cotton fru its 3 to 4 weeks earlie r than planted cotton and essentially
fills the host plant gap between early June and early Ju ly when planted
cotton begins to square . F u rth e r research is needed to determine the
size of Heliothis populations in these ratoon fields. Taylor and Hathorn
(1981) observed large populations of p reda to rs and parasites in stub
fields and low num bers of bollworm-budworm damaged term inals. These
beneficials may la te r move to planted cotton.
Knipling (1966) proposed th a t Heliothis spp . might be controlled
over a region by releases of ste rile in sects or th rough the in teraction of
sterile insects with p reda to r and parasitoid releases. S terile in sect re
leases should be most successful when populations a re low, when females
a ttrac t the la rg e s t number of males, and when the incidence and f re
quency of mating is low (Stadelbacher, L aste r, and Pfrimmer 1972). Moth
populations in early sp rin g , originating from su rv ivo rs of diapausing
pupae, a re p resen t in low num bers. For example, Blanchard (1942) esti
mated 99% w inter mortality of H. zea during 1941, and Phillips and B arber
(1929) reported an average of 95% w inter m ortality. S tadelbacher and
Martin (1980) reported th a t 87.3% of the larvae of tobacco budworms caged
46
in the fall of 1976 and 60.05% of those caged in the fall of 1977 died before
emergence.
To obtain the ratio of sterile to fertile male moths requ ired to
supp ress a population, one must determine moth density on each major
host p lant species a t a given time for a given acreage p rio r to release.
However, in Arizona the information needed to fully understand Heliothis
spp . dynamics is still incomplete. Population models th a t take into ac
count species biology and seasonal occurrence and abundance of host
p lants along with densities of Heliothis populations per un it a rea are
needed. These a re the critical param eters in developing any successful
sterile in sect release and biological control program s.
Population suppression with released parasito ids o r disease may
not be feasible on wild host p lants in Arizona because acreages are so
variable from year to y ear. B lanketing the en tire d ese rt with enough
parasito ids and disease to control Heliothis populations in the sp ring
would be an enormous task and is not cu rren tly justified due to the cost
of the microbial agen ts and lack of rearing facilities fo r the parasito ids.
However, if populations increase on ornam entals and cultivated p lan ts as
suspected , a control program th a t involves the use of favorable hosts
such as Cicer arietinum and Caesalplnnia gilliesil as trap crops might be
successful in destroy ing a large percen tage of the and F2 generations.
This method could lower the level of subsequent Heliothis populations on
cotton.
SUMMARY
Data from two years of collection show the abundance in the >. 1
sp ring of fru iting ornamental p lants such as Caesalpinnia gilliesii as well
as cultivated c rops, i . e . , Clcer arietinum , are probably of considerable
importance to the buildup of populations of Heliothis spp . in central
Arizona before cotton is available as a host. D esert p lants such as
Sphaeralcea coulter! and Erodium cicutarium are variable in th e ir abun
dance due to inconsistent rainfall; these hosts also seem to suppo rt a
large natural enemy complex th a t regu lates the buildup of large numbers
of Heliothis larvae. T hus, these p lants seem to play a minor role in
Heliothis population dynamics. However, fu r th e r studies should be
made to establish more definitely the role of each of these hosts in af
fecting Heliothis s p p . abundance.
47
APPENDIX A
PLANT SPECIES SAMPLED FOR HELIOTHIS SPP.IN 1979
Family
Compositae
Convolvulaceae
C ruciferae
Geraniaceae
SampleGenus and --------------------------------- — g-
Species Common Name Date Size3 Location0
Erigerondivergens
Helianthusannus
Lactucasativa
Convolvulussp .
Sisymbriumirio
Erodiumcicutarium
daisy fleabane
commonsunflower
lettuce
field bindweed
London rocket
redstem filaree
5/12 1005/15 1005/15 505/22 505/22 1005/22 505/29 505/29 1006/6 1006/6 506/12 1006/21 50
4/17 205/1 255/22 75
4/12 254/19 254/19 205/1 20
5/1 205/12 505/22 50
1/18 4003/15 400
4/16 204/21 205/1 205/12 6005/12 75
(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e
(p) b(P) b(s) e
(P) f(P) f(p) c(P) b
(a) b(p) e(p) e
(s) a(s) a
(s) b(s) b(s) b(s) b(s) b
48
49
FamilyGenus and
Species
Sample
Date Size3 Location ̂
Geraniaceae Erodium red stem filaree 5/15 70 (s) bcicutarium 5/15 215 (s) d(co n .) 5/22 100 (s) b
5/22 50 (s) d5/22 20 (s) e5/22 100 (s) g5/29 100 (s) b ’6/1 400 (s) g6/6 400 (s) g
' 6/6 200 (s) b6/6 25 (s) e6/12 100 (s) b6/12 100 (s) g6/21 50 (s) b6/21 50 (s) g
Leguminosae Lupinus sp . lupine sp . 4/17 50 (s) b4/17 50 (s) d
Medicago alfalfa 5/3 30 (s) fsativa
Malvaceae Malva little mallow 4/3 500 (s) bparviflora 4/17 200 (s) b
Sphaeralcea C oulter's 4/16 10 (s) bcoulteri • globe mallow 4/17 200 (s) b
4/19 10 (s) c4/21 10 (s) b4/24 400 (s) b5/1 500 (s) d5/1 400 (s) b
Rosaceae Rosa sp . cultivated roses 4/19 200 (p) c4/26 400 (p) c5/17 250 (p) c5/29 75 (p) c6/12 100 (p) c
a. (s) = sw eep-net samples; (p) = plant samples.b . Approximate locations: a = Casa G rande; b = Magma; c = Peoria;
d = Florence; e = La Palma; f = Yuma; g = Picacho.
APPENDIX B
PLANT SPECIES SAMPLED FOR HELIOTHIS SPP.IN 1980
Family
SampleGenus and ------------------ =------------------- g
Species Common Name Date S izea LocationD
C ruciferae Sisymbrium London rocket 2/28 100 ( s ) airio 2/28 100 (s) b
Geraniaceae Erodium Redstem filaree 2/28 100 ( s ) bcicutarium 2/28 50 (s) d
2/28 150 (s) c3/12 100 ( S ) c3/25 50 ( S ) d5/10 200 (s) e5/13 100 ( s ) e5/13 40 (p) e5/22 100 (S ) e5/27 100 ( s ) e5/29 100 ( s ) e6/5 100 ( s ) e
Leguminosae Caesalpinnia yellow b ird -o f- 5/27 5 (p) fgilliesii paradise 6/5 5 (p) f
6/12 50 (p) f6/12 5 (p) f6/20 30 (p) f6/26 5 (p) f
Cicer garbanzo bean 4/15 20 (p) garietinum 4/26 20 (p) a
5/1 20 (p) a5/10 20 (p) g5/10 20 (p) a5/13 75 (p) a5/22 20 (p) a5/27 20 (p) a5/29 20 (p) g
Hoffamanseggia hog potato 5/29 30 (p) edensiflora 6/5 30 (p) e
50
51
FamilyGenus and
Species Common Name
Sample
Date S ize3 Location ^
Leguminosae Medicago alfalfa 5/10 100 (s) f(co n .) sativa 5/10 100 (s) e
5/13 100 (s) e5/13 100 (s) e5/13 100 (s) f5/22 100 (s) e5/22 100 (s) g5/27 100 (s) e5/27 100 (s) e6/5 100 (s) e
Melilotus annual yellow 3/28 100 (s) bindicus sweetclover 3/25 100 (s) b
3/25 50 (s) d
Malvaceae Malva little mallow 2/28 50 (s) bparviflora
Sphaeralcea globe mallow 2/28 50 (s) bsp . 3/12 100 (s) c
Martyniaceae Proboscidea devils-claw 6/18 10 (p) hparviflora 7/1 5 (p) h
a. (s) = sw eep-net samples; (p) = p lan t samples.
b . Approximate locations: a = La Palma; b = Magma; c = Marana; d = Picacho; e = Florence; f = Coolidge; g = Eloy; h = Blackwater.
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B utler, G. D. 1958a. Braconid wasps reared from lepidopterous larvae in Arizona in 1957. Pan-Pacific Entomol. 34: 221-23.
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