onion insect biology and management - leek moth...

Onion Insect Biology and ManagementOnion Insect Biology and Management

Peter J. JentschPeter J. JentschCornell UniversityCornell University’’ss Hudson Valley LaboratoryHudson Valley LaboratoryHighland, NY 12528Highland, NY 12528

Mean % onion plants killed by onion maggot

Treatment Seed

Treater Sodus Elba Pine Island

1 Non-treated Incotec 14.5 a 7.2 a 17.2 a

2 Lorsban 4E (drench) Incotec 0.0 d 0 c 11.9 b

3 Trigard 75WP Incotec 1.8 cd 0 c 1.8 e-g

4 Lorsban + Trigard Incotec 0.7 cd 0 c 0.2 fg

5 Entrust Incotec 2.7 cd 0 c 2.7 e-g

6 Mundial 500 Incotec 2.8 cd 0 c 3.6 e-g

7 Poncho 600 Incotec 2.5 cd 0 c 0.8 fg

Planted on 24 April in Sodus, 4 May in Pine Island and 7 May in Elb a .

Seed Treatments for Managing Onion Maggot in Three NY Sites. - 2007

Onion Bulb Mite

Biology: Overwinters in the soil andfound in cover crop seed coat feedingon fungi. Also very abundant OW onvolunteer field onion and cull piles.

LT50 Adult ♀= 17oF, LT50 Egg = 10oF

Under ideal conditions OBM increase innumber to feed on developing onion inearly spring to reduce stand count.

All three life stages (adult, egg & nymph)found throughout the year.

OBM on barley

OBM on volunteer onion

Impact of Seed Treatments on Onion Bulb Mite

Efficacy of onion seed-treatments against OMB establishment andsurvival in greenhouse bioassays. Cornell’s Hudson Valley Lab,Highland NY, 1999.

Average number of bulb mite .

20 DAP 30 DAP 40 DAPTreatment Rate roots bulb bulb bulb

Carzol 50g/kg 0.5b 0.2a - -Vydate 50g/kg 0.2ab <0.1a 0.5a 5.8bFipronil 30g/kg+Carzol 50g/kg <0.1ab <0.1a 0.0a 0.0aFipronil 30g/kg+Vydate 50g/kg 0.0a 0.0a 0.0a 0.0aFipronil 30g/kg 0.0a 0.0a 0.4a 0.2aUntreated - 3.4c 3.1b - -

Seedcorn Maggot

Mature seedcorn maggot

Biology: Invasive pest from European origin.

Adult flies emerge during late April and earlyMay. Eggs are deposited on or near the soilsurface, plant stems at the soil surface.

Eggs hatch in a few days and the maggots worktheir way into the soil in search of food.

They complete their development in a week to 10days.

Egg to adult is between 3 to 4 weeks.There are 3 to 5 generations each year in NY.

Trigard is ineffective against the SCM.Lorsban / Trigard combination is required tomanage the OM and SEC in NY.

Brian A. NaultAssociate ProfessorDepartment of EntomologyCornell University, NYSAES,Geneva, NY

Getting the Upper Hand on OnionThrips and IYSV

Outline of Presentation

I. Overview of Onion Production in NY,Thrips and Iris Yellow Spot Virus (IYSV)

II. Potential Sources of IYSV in NY

III. Thrips Densities, Prevalence of IYSV andtheir Relationship in Onion Fields

IV. Thrips Management

Onion Production in New York• Dry bulb onion, Allium cepa L.

• Fresh-market crop valued at $45 to 55 million/yr

• 13,500 acres

• Onion crop in NY ranks 6th in the US

Orleans Co.

Orange Co.

Oswego Co.

Wayne Co.

Yates Co.

Geneva

Ithaca

Major Onion Producing Regions in NY

Genesee Co.

Onion Planting Planting onion seeds Transplanting onion plants

87% of acreage 13% of acreage

*Onions are rarely rotated into other fields

15-Mar 14-Apr 14-May 13-Jun 13-Jul 12-Aug 11-Sep 11-Oct

Direct seeding

Transplanting

Harvest

Onion Production in New York


Direct seeding

Transplanting

Harvest

Thrips Infestations in New York OnionFields

Thrips in Transplants

Thrips in Direct seeded

Onion Thrips Life CycleAdult

- In NY, all female AND male + femalepopulations exist.

- Live for 13 to 47 d

- All female populations- Mating is not necessary for reproduction! PARTHENOGENESIS


Egg- 60 to 200 eggs/female- Deposited singly in leaves- Hatch in 4-10 days


Egg

Larva (2 instars)

Hatch in 4-10 days

Lasts 7-14 days


Egg

Larva (2 instars)

Prepupa +Pupa

Hatch in 4-10 days

Lasts 7-14 days

Do NOT feedIn soil for 5-7 days

Onion Thrips Life Cycle*

Adult

Egg

Larva (2 instars)

Prepupa +Pupa

Hatch in 4-10 days

Lasts 7-14 days

In soil for 5-7 days

*17-30 days total

Onion Thrips Survival, Fecundity and GenerationTimes (Days) at Various Temperatures

Days

Factor 680 F 77

0 F 86

0 F

Survival 47 25 13

Eggs laid/ female 210 165 63

Generation time 48 30 17

Murai (2000)

Onion Thrips Population Growth Number of Females

Date 680 F

July 1 1

July 8

July 15

July 22

July 29

August 5

August 12

August 19 210

August 26

September 2

Number generations 1


Date 680 F 77

0 F

July 1 1 1

July 8

July 15

July 22

July 29 165

August 5

August 12

August 19 210

August 26

September 2 27,225

Number generations 1 2


Date 680 F 77

0 F 86

0 F

July 1 1 1 1

July 8

July 15 63

July 22

July 29 165 3,969

August 5

August 12 250,047

August 19 210

August 26 15,752,961

September 2 27,225

Number generations 1 2 4

• Family: BunyaviridaeGenus: Tospovirus

• Only transmitted byonion thrips (i.e., notseed-transmitted)

• Symptoms may beobvious on scape, butnot leaves- Lesions can coalesce, weaken

scape, resulting to seed loss

- Reduces photosynthesis,affecting bulb yield

Iris yellow spot virus (IYSV)

Iris yellow spot virus (IYSV)

• First detection in NYoccurred in an onion cullpile in Elba in June 2006(Hoepting et al. 2006)

• Confirmed via DAS-ELISAand RT-PCR

• First detection in a bulbcrop in Elba in late July2006

Elba, NY

IYSV Detection Survey Results

IYSV positiveCounty surveyed

2006Orleans, Genesee,Yates, Livingston,Wayne, Ontario:37 out of 41 fields(90%)

2007Oswego : 7 out of 9fields (78%); 45% ofsamples

Orange: 8 out of 10fields (80%); 52% ofsamples


Direct seeding

Transplanting

Harvest

When does IYSV occur and wheredoes it come from?



IYSV?


I. Overview of Onion Production in NY,Thrips and Iris Yellow Spot Virus



IV. Onion Thrips Management

Potential Sources of IYSV in NY

Transplants from Arizona

Volunteer onions

Weeds

Bulbs imported from western US

Testing Plant Samples for IYSV

• DAS-ELISA• Some samples testing (+) confirmed w/ RT-PCR• For onions, multiple leaves and bulbs tested

separately• 1 g/10 ml extraction buffer• 20 minutes• Threshold = 3x (-) control• AgDia supplies

center

Transplants Tested for IYSV in 2007

Cultivar No. of Plants Sampled

Yellow Bulb

Corona 300

Highlander 600

Kasmer Homegrown 600

Milestone 600

Millennium 300

Ricochet 600

Empire Sweet 600

Red Bulb

Mercury 600

Red Wing 600

Red Zeppelin 300

Rhumba 300

Note: DAS-ELISA was used to test plants for IYSV

Transplants Infected with IYSV in 2007

Cultivar No. of Plants Sampled No. of IYSV Infected

Yellow Bulb

Corona 300 0

Highlander 600 0

Kasmer Homegrown 600 0

Milestone 600 0

Millennium 300 0

Ricochet 600 0

Empire Sweet 600 0

Red Bulb

Mercury 600 0

Red Wing 600 0

Red Zeppelin 300 0

Rhumba 300 0

Note: DAS-ELISA was used to test plants for IYSV

Volunteer Onions Sampled in 2007

Orleans Co.4 sites

Orange Co.

Wayne Co.1 site

Yates Co.2 site

Geneva

Ithaca

Genesee Co.2 sites

Oswego Co.1 site

9 sites; 30 plants/ site

Volunteer Onions Infected with IYSV in2007 (n= 30 plants/site; 355 plants total)

0

5

10

15

20

25

30

GEN-1 GEN-2 ORL-1 ORL-2 ORL-3 ORL-4 OSW WAY YAT

Field Location

No.

of I

YSV

(+) S

ampl

es

Testing Weeds for IYSV

• 2006 and 2007

• 12 locations

• 29 plant species

• 120 plants tested

Dandelion

Weeds Infected with IYSV in 2006-2007

No. of IYSV Infected Plants

Weed Species Biology DAS-ELISA RT-PCR

Common burdock, Atrium minus biennial 10 yes

Dandelion, Taraxacum officinale perennial 4 yes

Wild raspberry, Rubus spp. perennial 2 N/A

Sowthistle, Sonchus arvensis perennial 1 N/A

Bramble spp. perennial 1 N/A

Common purslane, Portulaca oleracea annual 1 N/A

Common ragweed, Amrosia artemisifolia annual 4 yes

Redroot pigweed, Amaranthus retroflexus annual 1 N/A

Unidentified Brassica spp. weed annual 1 N/A

20 other weed species - 0 -

Total 25/120= 21%

II. Potential Sources of IYSV in NY -Summary

Transplants – 0% infected

Volunteer onions – < 2% infected

Weeds – 21% infected

Bulbs imported from western US – N/A

Direct-seeded (DS) and Transplanted (TR)Onion Fields Sampled in 2007

Direct Seeded Transplanted

Direct-seeded (DS) and Transplanted (TR)Onion Fields Sampled in 2007

• Transplants may be infested with thripsbefore planting

• Thrips may preferentially colonizetransplants

Direct Seeded Transplanted

Santana

Sedona Sherman

Highlander

Elba Muck (E-1 through E-8)

DS

TR

VarietiesSantana

Sedona

Sherman

Highlander

Sampling Design

60 Sampling PointsSamples taken every 2 weeks

starting June 11

5 plants for IYSV analysis

Thrips: adults & larvae

Early Season Onion Thrips Pressure(mean of first 2 sample dates; before spraying)

0

50

100

150

200

250

Larvae Adults

Direct Seeded

Transplant

Mea

n N

umbe

r Thr

ips

per F

ield

N = 6p = 0.02

N = 6p = 0.01

Cumulative counts: 11 + 25 June 2007

4 Sept

0Red Bull – TRL-12

0Red Bull – DSL-11

0Milestone – TRL-10

0Milestone – DSL-9

1Highlander - TRE-8

0Highlander – DSE-7

0Sherman – TRE-6

0Sherman – DSE-5

0Sedona – TRE-4

0Sedona – DSE-3

0Santana – TRE-2

0Santana – DSE-1

17 Sept20 Aug6 Aug23 JulyVarietyField

IYSV Over Time (out of 60 sites)*No positives on 11 and 25 June, 9 July

4 Sept





Harvested1Highlander - TRE-8

Harvested0Highlander – DSE-7

10Sherman – TRE-6

20Sherman – DSE-5

30Sedona – TRE-4

00Sedona – DSE-3

00Santana – TRE-2

00Santana – DSE-1



4 Sept





HarvestedHarvested1Highlander - TRE-8

HarvestedHarvested0Highlander – DSE-7

310Sherman – TRE-6

1120Sherman – DSE-5

330Sedona – TRE-4

100Sedona – DSE-3

400Santana – TRE-2

100Santana – DSE-1



1

0

Harvested

0

Harvested

Harvested

Harvested

23

harvested

5

6

2

4 Sept





HarvestedHarvested1Highlander - TRE-8

HarvestedHarvested0Highlander – DSE-7

310Sherman – TRE-6


330Sedona – TRE-4

100Sedona – DSE-3

400Santana – TRE-2

100Santana – DSE-1



1

0

Harvested

0

Harvested

Harvested

Harvested

23

harvested

5

6

2

4 Sept

harvested100Red Bull – TRL-12

harvested000Red Bull – DSL-11

harvested200Milestone – TRL-10

harvested000Milestone – DSL-9

harvestedHarvestedHarvested1Highlander - TRE-8

harvestedHarvestedHarvested0Highlander – DSE-7

harvested310Sherman – TRE-6


harvested330Sedona – TRE-4

harvested100Sedona – DSE-3

harvested400Santana – TRE-2

harvested100Santana – DSE-1



Thrips Pressure and IYSV Prevalence

R2 = 0.429N = 12, df = 10

P = 0.021

R2 = 0.411N = 12, df = 10

P = 0.025

0

2

4

6

8

10

12

0 2000 4000 6000 8000 10000 12000

Cumulative No. Larvae

No.

Pos

itive

Site

s

Cumulative No. Adults

0

2

4

6

8

10

12

0 500 1000 1500 2000 2500

Larvae Adults

1

harvested

harvested

harvested

harvested

23

harvested

5

6

2

4 Sept

harvested1Red Bull – TRL-12

harvestedRed Bull – DSL-11

harvested2Milestone – TRL-10

harvestedMilestone – DSL-9

harvestedharvestedharvested1Highlander - TRE-8

harvestedharvestedharvestedHighlander – DSE-7

harvested31Sherman – TRE-6


harvested33Sedona – TRE-4

harvested1Sedona – DSE-3

harvested4Santana – TRE-2

harvested1Santana – DSE-1



Spatial Distribution of Onion Thrips

TransplantedOnions

No. timessite tested

positive

Spatial Distribution of IYSV

Relationship Between Thrips and IYSV

Thrips IYSV


Direct seeding

Transplanting

Harvest

IYSV in New York Onion Fields Relativeto Thrips Activity and Harvest



IYSV

III. Prevalence of IYSV, Thrips Densitiesand Relationship in Onions - Summary

• Transplanted fields had significantly more larval andadult thrips early in season

• IYSV prevalence was greater in transplanted fields

• Cumulative larval and adult counts are significantpredictors of IYSV incidence

• Transplanted onions may have less risk of yield lossbecause fields are harvested early

ManagingVegetable

Insect Pests

PlantResistance

BehavioralControl

Cultural Control Biological Control

General Approaches Taken to Manage Insectsthat Attack Vegetable Crops – IPM Tactics

Chemical Control


A. Evaluation of onion varieties for thrips/IYSV resistance

B. Evaluation of insecticides for thripscontrol

C. Sequences of products for season-longthrips control

Onion Variety Screening Trial - 2007

• 22 varieties screened for resistance to onion thrips/ IYSV• varieties arranged in a RCBD replicated 4 times• ten plants per variety• recorded thrips on 10 plants/ plot and took damage rating

Potter, NY

Lines with different letter are significantly different (P <0.05, Tukey’s test)

Days after transplanting

Cum

ulat

ive

num

ber o

f lar

vae/

plan

t

f

ab a

a-c a-c cd c-ed-fefef

Screening Experiment

Screening ExperimentVariety Damage

Red Beauty 4.4 ± 0.5 a

BGS-236 4.1 ± 0.9 a

Red Wing 4.1 ± 0.5 a

BGS-234 4.0 ± 0.4 ab

Infinity 4.0 ± 0.7 ab

Red Bull 4.0 ± 1.1 ab

Santana 4.0 ± 0.4 ab

Milestone 3.9 ± 0.9 ab

Nebula 3.9 ± 0.8 ab

Fortress 3.8 ± 0.3 ab

Millenium 3.6 ± 0.3 a-c

Bunker 3.5 ± 0.0 a-d

SYN-H7 3.5 ± 0.4 a-d

606-1 3.4 ± 0.5 a-d

BGS-230 2.8 ± 0.3 b-e

Calibra 2.4 ± 0.6 c-e

Delgado 2.4 ± 0.5 c-e

Tioga 2.4 ± 0.5 c-e

Cometa 2.3 ± 0.6 de

Colorado 6 2.0 ± 0.4 e

Peso 1.9 ± 0.3 e

OLYS05N5 1.6 ± 0.5 e

*Damage rating taken89 days aftertransplanting

Leaf damage rating

1: No damage

3: 25% leaf area injured




Means followed by different letters are significantly different (P <0.05, Tukey’s test)

Prevalence of IYSV - 2007

Overall % Infected:11.2%

Four VarietiesShowing Thrips

Resistance:6.6%

Eighteen others:12.2%

Variety Infected (%) Red Beauty 5.9

BGS-236 16.7

Red Wing 13.8

BGS-234 11.1

Infinity 3.0

Red Bull 15.4

Santana 12.9

Milestone 3.2

Nebula 11.6

Fortress 8.0

Millenium 15.4

Bunker 12.0

SYN-H7 15.4

606-1 31.0

BGS-230 8.0

Calibra 9.7

Delgado 18.6

Tioga 4.3

Cometa 2.7

Colorado 6 10.7

Peso 8.3

OLYS05N5 8.8

A. Summary – Plant Resistance

• Colorado 6, OLYSO5N5, Cometa and Tioga,had lowest densities of onion thrips and lowlevels of damage, suggesting that thesevarieties may be less susceptible orresistant.

• IYSV prevalence levels were low, but thefour onion varieties resistant to thripstended to have lower % IYSV

• Mechanism of resistance not known

Evaluation of Insecticides forThrips Control

B. Evaluation of Insecticides for ThripsControl

Product Active Ingredient Rate (amnt/acre)

MSR oxydemeton -methyl 32 fl oz

Lannate LV methomyl 48 fl oz

Carzol SP formetanate hydrocloride 0.5, 0.75, 1.0 lb

Radiant SC spinetoram 8 fl oz

Agri-Mek 0.15EC abamectin 10, 12, 14 fl oz

Movento 240SC spirote tramat 5, 8 fl oz

Assail 30SG acetamiprid 5.4 oz

* Products highlighted in yellow were labeled on onion in NY in 2007* Carzol - Section 18* MSR – Section 24c

Insecticide Evaluation Trial - 2007

Potter, NY

Variety ‘Infinity’

Planted 1 May 2007

First spray July 6

6 applications total

100 GPA; 40 psi

flat fan nozzle

Visual estimates ofthrips damage (1=high; 10=none)

Rating= 2Rating= 10

Final Thrips Count (Aug. 16, 2007)

0

20

40

60

80

100

120

140

160

180

200

Untr

eate

dM

SR

Lannat

e

Car

zol (

0.5)

Car

zol (

0.75

)

Car

zol (

1.0)

Rad

iant

Agri-

Mek

(10)

Agri-

Mek

(12)

Agri-

Mek

(14)

Move

nto (5

)

Move

nto (8

)

Ass

ail

Mea

n N

umbe

r of L

arva

e/Pl

ant

a

ab

bccd

de ecde cde cde

de de

a

N=5

Treatments (rates)

F= 7.6; df= 12,36; P<0.0001

0

100

200

300

400

500

Untr

eate

d

MSR

Lannat

e

Car

zol (

1.0)

Rad

iant

Agri

-Mek

(14)

Move

nto (8

)

Jumbo Standard

Marketable YieldPotter, NY Pulled 9/5; Weighed 10/1

Mar

keta

ble

Yiel

d (c

wt/a

cre)

TreatmentJumbo P = 0.0116; Total Marketable P= 0.0481

a

bcabc

c

abcab

abc

a

abaabcabc

B. Summary – Insecticide Evaluation

Onion crop was best protected from onion thripsusing:

- Radiant SC (8 fl oz/acre)- Carzol SP (1.0 > 0.5 lb/acre)- Agri-Mek 0.15EC (10-14 fl oz/acre)- Movento 240SC (5-8 fl oz/acre) *may only controllarvae

Lannate and MSR provided fair to poor levels ofprotection, respectively

Registration updates:Radiant received a Section 3 label in 9/07Carzol considered for Section 18s in many States

What sequences of productsshould be used to control thrips?

C. Sequences of Products Evaluated forOnion Thrips Control - 2007

MSR, Carzol and then Radiant

Radiant, Carzol and then Lannate

Carzol, Radiant and then Lannate

*Each product was applied during 2 consecutive weeks

Season Avg. Thrips Count - 2007

0

20

40

60

80

100

Untreated

MSR/C

arzol/Radiant

Radiant/Carzol/Lannate

Carzol/Radiant/Lannate

Mea

n N

umbe

r of L

arva

e/Le

af/

Sam

plin

g D

ate

a

b bb

N=5

F= 15.5; df= 3,9; P=0.0007

0

100

200

300

400

500

Untreated

MSR/Carzol/Radiant

Radiant/Carzol/Lannate

Carzol/Radiant/Lannate

Standard

Jumbo

Marketable YieldPotter, NY Pulled 9/5; Weighed 10/1

Mar

keta

ble

Yiel

d (c

wt/a

cre)

Jumbo P = 0.4743; Total Marketable P= 0.0464

a

b

ab ab

aaaa

C. Summary – Insecticide Sequences

• All treatments were effective

a) Starting with a weaker product and finishingwith strong ones

b) Starting with stronger products and finishingwith a weaker one

AcknowledgementsCollaborators: Tony Shelton, Marc Fuchs,Cynthia Hsu and ChristyHoepting

Graduate Students: Erik Smith and John Diaz

Technical Assistance: M.L. Hessney, K. Straight, R.Taylor, B. English-Loeb, T.Evans, C. McGreggor, J.Bergman and H. Schoonover

Funding:

NY Onion Researchand DevelopmentProgram

NY Farm ViabilityProgram

IR-4 Program

Bayer Crop Science,Cerexagri, Dow, DuPont,Gowan and Syngenta

The End

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