Onion Maggot Biology and ManagementOnion Maggot Biology and Management

Brian A. NaultDepartment of EntomologyCornell UniversityNYSAESGeneva, NY 14456

Brian A. NaultDepartment of EntomologyCornell UniversityNYSAESGeneva, NY 14456

Updated March 2007

Onion Maggot Life Cycle*Onion Maggot Life Cycle*

AdultAdult

EggEgg

LarvaLarva

PupariumPuparium

- Lives 2 to 4 weeks- Lives 2 to 4 weeks

-Lays hundreds of eggs-Hatch in 2 to 5 days-Lays hundreds of eggs-Hatch in 2 to 5 days

- Feeds for 2 to 3 weeks- Feeds for 2 to 3 weeks

- In soil for 2 to 4 weeks- In soil for 2 to 4 weeks

*37- 60+ days total*37- 60+ days total

12

0

4

8

4/26 5/18 5/31 6/13 6/30 7/12 7/25 8/8 8/22

Elba, NY -2005Elba, NY -2005Date

Num

ber o

f flie

s/tr

apSeasonal Activity of Onion Maggot

Flies In New York

* 3 generations/year

Onion Crop in JuneOnion Crop in June

Undamaged Damaged

Onion Crop in SeptemberOnion Crop in September

Onion Maggot is a Serious Problem in New York and Other Regions

Onion Maggot is a Serious Problem in New York and Other Regions

Infestations can be difficult to control

Continuous onion production in same fields exacerbates development of high onion maggot populations

Only two insecticides recommended (Trigard and Lorsban)

Widespread resistance to Lorsban and possibly beginning resistance to Trigard

General Pest Management Tactics

Chemical

Cultural

Plant Resistance

Biological

Chemical ControlChemical ControlFor Control of Maggots:

In-furrow treatments - chlorinated hydrocarbons, organophosphates and carbamates (up until 1970s and 1980s)In-furrow treatment - chlorpyrifos (Lorsban) (1970s –present)Seed treatment – cyromazine (Trigard) (1996 – present)

For Control of Flies:Foliar applications – pyrethroids or other inexpensive broad-spectrum materials

Insecticides Currently Recommended At-Planting for Onion Maggot Control

Product Active Ingredient Class Lorsban 4E chlorpyrifos Organophosphate Trigard 75WP cyromazine Triazine

Benefits of Seed Treatments as an Alternative to In-Furrow Treatments

Easy to use

Require less active ingredient (e.g., Trigard reduced amount of a.i. by 85% compared with Lorsban)

Precise amount of crop protectant applied to eachseed

Safer for workers

Taylor et al. (2001)

Onion Coatings Used for Seed Treatments

E. M. Chirco

UntreatedUntreated

EncrustedEncrustedFilm coatedFilm coated

PelletedPelleted

Promising New Insecticide Seed Treatments for Onion Maggot Control

Trade Name Active Ingredient Rate Mundial 500* fipronil 2.5 g a.i./ 100 g of seed Entrust spinosad 0.2 mg a.i./seed Poncho 600 clothianidin 0.18 mg a.i./seed

*Note: Mundial 500 formerly was called Regent*Note: Mundial 500 formerly was called Regent

Objectives

Compare efficacy of new seed treatments with efficacy of Lorsban and Trigard for controlling onion maggot

Identify optimum rates of Entrust and Poncho 600 for onion maggot control

Untreated controlUntreated control

0 10 20 30 40

Regent (2.5 g)

Poncho (5 g)

Poncho (2.5 g)

Poncho (1.25 g)

Entrust (5 g)

Entrust (2.5 g)

Entrust (1.25 g)

Trigard

Lorsban

Untreated

Mean Cumulative Seedling Loss (%)

Onion Seedling Loss Due to Onion Maggotin Orange County, New York in 2005 (n= 4)

a

bccd

dd

d

ab

dd

bc

(*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosad and 0.18 mg a.i./seed of clothianidin)

0 10 20 30 40

Regent (2.5 g)

Poncho (5 g)

Poncho (2.5 g)

Poncho (1.25 g)

Entrust (5 g)

Entrust (2.5 g)

Entrust (1.25 g)

Trigard+Lorsban

Trigard

Lorsban (drench)

Untreated

Mean Cumulative Seedling Loss (%)

Onion Seedling Loss due to Onion Maggot in Wayne Co., New York in 2005 (n=6)

a

bcdbc

ebc

cde

bde

bccde

de

(*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosad and 0.18 mg a.i./seed of clothianidin)

0 10 20 30 40 50

Regent (2.5 g)

Poncho (5 g)

Poncho (2.5 g)

Poncho (1.25 g)

Entrust (5 g)

Entrust (2.5 g)

Entrust (1.25 g)

Trigard+Lorsban

Trigard

Lorsban (drench)

Untreated

Mean Cumulative Seedling Loss (%)

Onion Seedling Loss due to Onion Maggot in Yates Co., New York in 2005 (n=6)

a

bcdbcd

cdeb

bcd

bcde

bcdee

e

(*Note: 2.5 g a.i./100 g of seed is equivalent to 0.2 mg a.i./seed of spinosadand 0.18 mg a.i./seed of clothianidin)

Summary

High rates of Entrust and Poncho were consistently effective against onion maggot and control was similar to levels provided by Regent and Trigard + Lorsban.

Trigard alone and Lorsban alone were generally less effective than the high rates of Entrust, Poncho, Regent and Trigard + Lorsban.

Insecticide Sprays to Control Onion Maggot Flies

Insecticide Sprays to Control Onion Maggot Flies

Limitations and DetrimentsDirect contact with insecticide required to kill flies

Timing of spray is critical (dawn and dusk only)

Sprays predicted to contact 10-20% in May/June and 0.2 to 4% in September

Cost of insecticide, fuel and time

May kill beneficial organisms that attack onion maggot and onion thrips and may accelerate insecticide resistance in onion thrips populations

“Attract and Kill” Using Insecticide-Baited Devices

Prokopy et al. (2004). Fruit Notes.

Starker WrightStarker Wright

Objectives – 2006

To determine efficacy of spinosad-baited spheres for onion maggot fly control during entire season

To determine the rate of spinosad that is most effective against onion maggot flies

Treatments

012. 4 months0.5%11. 4 months1.0%10. 4 months09. 3 months0.5%8. 3 months1.0%7. 3 months06. 2 months0.5%5. 2 months1.0%4. 2 months03. 1 month0.5%2. 1 month1.0%1. 1 monthRate of SpinosadDuration in Field

* Split-plot experimental design ; each treatment replicated 6 times

Cage Setup

Sphere

Food

Water

-20 flies released(50:50 sex ratio)-Mortality recorded over 3 days

Conditions of Spinosad-Baited Spheres after Various Periods in Onion Field

Conditions of Spinosad-Baited Spheres after Various Periods in Onion Field

1month(mid May

to mid June)

2 months(mid May to

mid July)

4 months(mid May to mid

Sept)

3 months(mid May to mid

August)

Onion Maggot Fly Mortality After Exposure to Spinosad-Baited Spheres

Elba, NY 2006

0

20

40

60

80

100

1 month 2 months 3 months 4 months SeasonAverage

Control0.50%1.00%

Mea

n %

Mor

talit

y

a a a a

b bb

b

bb

b b

Duration of Spheres in Field

bb

a

Onion Maggot Female Mortality After Exposure to Spinosad-Baited Spheres

Elba, NY 2006

0

20

40

60

80

100

1 month 2 months 3 months 4 months

a

aa

a

Duration of Spheres in Field

Mea

n %

Mor

talit

y

Onion Maggot Male Mortality After Exposure to Spinosad-Baited Spheres

Elba, NY 2006

0

20

40

60

80

100

1 month 2 months 3 months 4 months

a

cab

bc

Duration of Spheres in Field

Mea

n %

Mor

talit

y

Onion Maggot Fly (Both Sexes) Mortality After Exposure to Spinosad-Baited Spheres

Elba, NY 2006

0

20

40

60

80

100

1 month 2 months 3 months 4 months

a

bab

ab

Duration of Spheres in Field

Mea

n %

Mor

talit

y

Total Amount of Rainfall in Elba, NY in 2006

0

1

2

3

4

5

6

1st month 2nd month 3rd month 4th month

Duration of Spheres in Field

Rai

nfal

l (in

ches

)

Mean Number of Onion Maggot Flies Captured per Sticky Card

050

100150200250300350400

1stmonth

2ndmonth

3rdmonth

4thmonth

SeasonTotal

MaleFemale

Period of Capture

Num

ber o

f Flie

s/C

ard Elba, NY 2006

Estimated Mean Number of Onion Maggot Flies Killed by a Single Spinosad-Baited Sphere

0

50

100

150

200

1 month 2 months 3 months 4 months SeasonTotalEs

timat

ed N

umbe

r Flie

sK

illed

/Sph

ere

Duration of Spheres in Field

182 total

36

147

Elba, NY 2006

Summary

Flies attracted to spinosad-baited spheres (can include additional attractants like Delia lure)

Spinosad is a safe biologically based insecticide

Effective for entire onion-growing season (e.g., 16 weeks) and estimated to kill 55% of flies that visit

One sphere estimated to kill 182 flies during season (36 females and 147 males)

Spinosad-baited spheres can be hung along onion field edges

Preliminary cost estimated to be $5 to $6 per trap

Cultural ControlCultural ControlCrop rotation – plant as far away as possible from last

year’s onion crop (Martinson et al., 1988)

Sanitation – remove volunteer and cull onions (Finch and Eckenrode 1985)

Avoid mechanical injury – during season and duringlifting (Eckenrode and Nyrop, 1986; Finch et al., 1986)

Delay planting date – reduce time plants are exposedto flies (Doane and Chapman, 1952; Nault et al.

unpublished)

Plant ResistancePlant Resistance

Allium cepa (onion)

Allium fistulosum (Japanese bunching onion)

hybrids

*In all cases, some varieties have some tolerance to onion maggot under low pressure (Ellis and Eckenrode, 1979)

Biological ControlBiological ControlPredators – Bembidion quadrimaculatum – carabid beetle

(Grafius and Warner 1989)

Aleochara bilineata – staphylinid beetle (Tomlin et al. 1985)

Parasitoid – Aphaereta pallipes – braconid wasp (Tomlin et al. 1985)

Nematode – Heterorhabditis bacteriophora – (Yildrim and Hoy 2003)

Fungi – Entomophthora muscae- (Carruthers and Haynes 1986); Tu and Harris 1988)

Paecilomyces fumosoroseus – (Majchrowicz et al. 1990)

Other TacticsOther TacticsNon-woven fiber barriers- ethylene vinyl

acetate, which operates as a physical barrier for oviposition (Hoffmann et al.,2001)

Sterile male release – radiation induced sterility (McEwen et al. 1984)

Ovipositional deterrents – cinnamyl derivatives and monoterpenoids (Cowles et al. 1990)

ConclusionsInsecticide use will continue to be the principal management tactic for onion maggot in onion

Seed treatments

Cultural controls are effective, but further adoption must be encouraged

Crop rotation, sanitation, delay planting date, etc.

Host plant resistance is not a viable strategy at this time

Biological control may have greater impact in future if broad-spectrum insecticide use on onion wanes