MANAGEMENT OF THRIPS, VECTOR OF TOSPOVIRUSES AFFECTING PEPPER IN SOUTH FLORIDA

Rafia A. Khan and D. R. Seal

PEPPER PRODUCTION IN MIAMI-DADE

COUNTY

PEPPER AGRO-ECOSYSTEM

Agro-ecosystem

Uniform crop

Plant population

Weed communities

Animal communities

Microbial communities

Physical environment

TOMATO CHLOROTIC SPOT VIRUS(TCSV)

TCSV infected plants

TCSV infected fruits

• Virus family

Bunyaviridae

• Genome

Tripartite (S RNA, M RNA, and L RNA)

• Symptoms

Necrosis and leaf distortion

• Hosts

Tomato, pepper, lettuce, long beans and

impatiens

• Yield loss

5 – 10%

• Vector

Thrips

VECTORS OF TCSV

Western flower thrips(Frankliniella occidentalis)

Common blossom thrips (Frankliniella schultzei)

• Transmission of tospovirus- persistent propagative

• Early larval instars - acquire viruses from an infected plant parts

• Adults- transmit the virus into a newly non-infected plants

THRIPS AND TCSV ABUNDANCE IN

AGROECOSYSTEM

Vegetable Western

flower thrips

Common

blossom

thrips

Melon

thrips

TCSV

Pepper + + + +

Tomato + + + +

Squash + + + -

Bean + + + -

Eggplant + + + -

Okra + + + -

Cucumber + + + -

TCSV disease started from the edge of the crop field

ALTERNATIVE HOSTS OF TCSV

VECTORS

Reservoir of

Pathogen

Both

Reservoir of

pathogen vectors

OBJECTIVES

• Observe the abundance of TCSV vector thrips in some weed hosts

• Observe the abundance of TCSV vector thrips in some ornamental hosts

• Determine the effect of some ornamental plants in the incidence of TCSV in peppers

• Determine the reservoir of TCSV through molecular analysis

OBJECTIVE 1

• Sampling fields

Tropical Research and Education Center (TREC) and growers field, Homestead, FL, USA

• Sampling

Randomly collected from each side

• Sample size

2 oz. of leaf and flower

• Study period

May, 2017-September, 2017

• Statistical analysis

Proc GLM (SAS institute Inc.)

Observe the

abundance of TCSV

vector thrips in some

weed hosts

SAMPLING PROCEDURE

Samples are placed in a

collection cup (2 pint)

Samples were shaken

in 70% alcohol to dislodge

thrips

Remove leaves/flowers and keep

alcohol

Count and identify thrips under microscope at 40X

ALTERNATIVE HOSTS- WEEDS

Family Scientific name of weeds

Asteraceae Tridax procumbens, Parthenium hysterophorus, Bidens alba,

Emilia fosbergii, Ambrosia artemisiifolia , Conyza

canadense, Calyptocarpus vialis, Sonchus asper, Ageratum

houstonianum

Amaranthaceae Amaranthus polygonoides, A. spinosus, Chenopodium

album

Acanthaceae Ruellia ciliatiflora, Asystasia gangetica

Euphorbiaceae Chamaesyce hyssopifolia , Euphorbia hirta, Acalypha

alopecuroidea, Acalypha setosa, Euphorbia heterophylla,

Phyllanthus amarus

Fabaceae Desmodium incanum, Stylosanthes hamata, Rhynchosia

minima

Malvaceae Sida ulmifolia, Sida spinosa

Rubiaceae Spermacoce verticillata , Ricardia grandiflora, Morinda royoc

18 families, 40 species of weeds

Family Scientific name of weeds

Verbenaceae Lantana camara, Phyla nodiflora

Zygophyllaceae Kallstroemia maxima

Cucurbitaceae Momordica charantia

Solanaceae Solanum americanum

Onagraceae Oenothera laciniata

Liguminosae Macroptilium lathyroides

Convolvulaceae Ipomoea hederifolia, Ipomoea alba

Oleaceae Jasminum fluminense

Nyctaginaceae Boerhavia erecta

Oxalidaceae Oxalis latifolia

Portulaceae Portulaca oleracea

THRIPS ABUNDANCE IN WEEDS

Western flower thrips, F=0.89; df=12,35; P>.5638

Common blossom thrips, F=2.52, df=12,35; P>0.0166

Melon thrips, F=6.98; df=12,35; P<.0001

0

50

100

150

200

250

300

No.

of in

sects

/2 o

z. of w

eed

Common weeds around commercial pepper field

Western flower thrips Common blossom thripsMelon thrips Larvae

ab

bcbc

cab a

a ac bc cc cb c

cc c ccc c c cbc

cc d c cc c

c c c ccc c c

a a

b

b

c

OBJECTIVE 2 • Sampling area

Nurseries in Homestead, FL

• Sample size

10 flowers

• Study period

March, 2018-June, 2018

• Statistical analysis

Proc GLM (SAS institute Inc.)

Observe the

abundance of TCSV

vector thrips in some

ornamental hosts

ALTERNATIVE HOSTS ORNAMENTAL

PLANTS

Family Scientific Name Common name

Linderniaceae Torenia spp. Wishbone flowers

Malvaceae Hibiscus spp. China rose

Onagraceae Fuchsia spp. Fuchsia

Asteraceae Ericameria arborescens Golden Fleece

Asteraceae Cosmos spp. Cosmos

Asteraceae Tagetes spp. Marigold

Asteraceae Helianthus annuus Sunflower

Asteraceae Gazania linearis Treasure flower

Asteraceae Gerbera spp. Garbers Daisy

Portulacaceae Portulaca oleracea Purslane

Rubiaceae Pentas lanceolata Egyptian starcluster

Verbenaceae Lantana camara Lantana

19 plant families, 24 plant species

Family Scientific Name Common name

Balsaminaceae Impatiens walleriana Busy lizzy

Begoniaceae Begonia semperflorens Begonia

Crassulaceae Kalanchoe blossfeldiana Kalanchoe

Liliaceae Lilium matrix Lilium

Solanaceae Petunia spp. Petunia

Apocynaceae Catharanthus roseus Rose periwinkle

Cannaceae Canna spp. Cannatropical

Amaranthaceae Celosia argentea Plumed cockscomb

Plumbaginaceae Plumbago auriculata Blue plumbago

Lamiaceae Agastache spp. Arozona Sandstone

Agastache

Asphodelaceae Hemerocallis lilioasphodelus Daylily

THRIPS ABUNDANCE IN ORNAMENTAL

PLANTS

Western flower thrips, F=1.88; df=11,24; P>.0946

Common blossom thrips, F=0.67, df=11,24; P>.7552

Melon thrips, F=6.44; df=11,24; P<.0001

Larvae, F=5.20; df=11,24; P>.0004

OBJECTIVE 3

Determine the

effect of some

ornamental plants

in the incidence of

TCSV in peppers

Experi

mental

design

Plot

size

Pepper

variety

Treatments Samp

le

size

Rando

mized

comple

te

block

design

7’lo

ng

x6’

wid

e

with

5’

long

buff

er

Jalapeno 1.Pepper+ Purslane

2.Pepper+Lantana

3.Pepper+Hibiscus

4.Pepper+Mandevilla

5.Pepper+Gazania

6.Pepper+Hemerocallis

7.Pepper+ Arizona

Sandstone Agastache

8. Pepper (Untreated

control/check)

5

flower

s for

all

treat

ments

EVALUATION OF ORNAMENTAL

TREATMENTS

Sampling

• Pepper (5 flowers, randomly

selected from 5 plants)

• Ornamental plants (5 flowers,

randomly selected from 5

plants)

Statistical analysis

• Proc GLM Repeated

Measure (SAS institute Inc.) Experimental plots

THRIPS ABUNDANCE IN ORNAMENTAL

FLOWERS

0

10

20

30

40

50

60

Me

an n

o.

of th

rips/ 5

flow

ers

Ornamental treatments

Western flower thripsCommon blossom thripsMelon thripsLarva

b bcc

c b

cc

d

a

aab

a

b

bcdabc

c b

aab

b

b

dc

cbcd bc

b

Western flower thrips, F=12.35; df=6,189; P<.0001

Common blossom thrips, F=4.50, df=6,189; P> .0003

Melon thrips, F=4.01; df=6,189; P> .00008

Larvae, F=10.08; df=6,189; P<.0001

TCSV VECTOR THRIPS ABUNDANCE IN

PEPPER FLOWERS AND TCSV INCIDENCE

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Mean n

o. of th

rips/5

flo

wers

and

TC

SV

infe

cte

d p

lants

Pepper plants with different ornamental treatments

Western flower thrips Common blossom thrips

Melon thrips Larva

TCVSa

a

a

a

a

a

a

a

b

bba

a

b a

aa

a

aa

b b

bb

baa

a

b b

bb

c cb b

b b bb

Western flower thrips, F=0.41; df=7, 184; P>.8922

Common blossom thrips, F=0.86, df=7,184; P> .5416

Melon thrips, F=0.43 df=7,184; P> .8808

Larvae, F=0.70; df=7, 184; P>.6713; TCSV, F=1.13; df=7, 24, P> .3788

OBJECTIVE 4

Weeds and

ornamental plants

as reservoir/host

of TCSV

TCSV infected pepper plant

(leaf and flower)

(positive control)

Healthy pepper plant

(leaf and flower)

(negative control)

Weed and ornamental

plants (Leaf and flower)

(preserved in -80ºC)

IDENTIFY RESERVOIR OF TCSV

Gel electropho

resis to determine the size

Perform PCR

Perform reverse

transcription to make cDNA

Extract good quality

RNA

1 2 3 4 5 6 7 8 9 10 11 12 13 14

TC

SV

pe

pp

er

lea

f

A.

sp

ino

su

s

O.

latifo

lia

P .

hyste

rop

horu

s

L. ca

ma

ra

E.

hirta

J.

flu

min

en

se

P.

ole

race

a

A.

art

ime

sifolia

Po

sitiv

e c

on

tro

l o

f T

CS

V

Ma

rker/

lad

er

A.

po

lyg

onoid

es

C. a

lbu

m

K.

ma

xim

a

WEEDS AS RESERVIOR OF TCSV

ORNAMENTAL PLANTS AS RESERVIOR OF

TCSV

1 2 3 4 5 6 7 8 9 10 11 12 1 3 14 15 16

Pu

rsla

ne

lea

f

Pu

rsla

ne

flo

we

r

La

nta

na

le

af

La

nta

na

flo

we

r

Hib

iscu

s flo

we

r

Hib

iscu

sle

af

Ma

nd

evill

a le

af

Ma

nd

evill

a flo

we

r

Ga

za

nia

le

af

Ga

za

nia

flo

we

r

He

me

roca

llis le

af

He

me

roca

llis flo

we

r

Ag

asta

che

lea

f

Ag

asta

che

flo

we

rf

TC

SV

po

sitiv

e c

on

tro

l

Ma

rker/la

de

r

CONCLUSION

• TCSV vector thrips are abundant in some of the

weeds and ornamental plants in pepper

agroecosystem

• These host plants are the immediate source of

TCSV infection in peppers

• Growers are recommended to maintain proper

management to grow pepper and ornamental crops

in close proximity

• Vector status of melon thrips (Thrips palmi) requires to be determined

• All committee members

• Growers of commercial pepper fields

• Entomology lab members

• Tropical Research and Education Center, UF

ACKNOWLEDGEMENT