Onion Insect Biology and Management

Onion Insect Biology and Management
Peter J. Jentsch
Cornell University’s
Hudson Valley Laboratory
Highland, NY 12528
Seed Treatments for Managing Onion Maggot in Three NY Sites. - 2007
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
0c
11.9 b
3
Trigard 75WP
Incotec
1.8 cd
0c
1.8 e-g
4
Lorsban + Trigard
Incotec
0.7 cd
0c
0.2 fg
5
Entrust
Incotec
2.7 cd
0c
2.7 e-g
6
Mundial 500
Incotec
2.8 cd
0c
3.6 e-g
7
Poncho 600
Incotec
2.5 cd
0c
0.8 fg
Planted on 24 April in Sodus, 4 May in Pine Island and 7 May in Elb a .
Onion Bulb Mite
Biology: Overwinters in the soil and
found in cover crop seed coat feeding
on fungi. Also very abundant OW on
volunteer field onion and cull piles.
LT50 Adult ♀= 17oF, LT50 Egg = 10oF
Under ideal conditions OBM increase in
number to feed on developing onion in
early spring to reduce stand count.
OBM on barley
All three life stages (adult, egg & nymph)
found throughout the year.
OBM on volunteer onion
Impact of Seed Treatments on Onion Bulb Mite
Efficacy of onion seed-treatments against OMB establishment and
survival in greenhouse bioassays. Cornell’s Hudson Valley Lab,
Highland NY, 1999.
Average number of bulb mite
.
Treatment
Rate
20 DAP
roots
bulb
30 DAP
bulb
40 DAP
bulb
Carzol
50g/kg
0.5b
0.2a
-
-
Vydate
50g/kg
0.2ab
<0.1a
0.5a
5.8b
Fipronil
+Carzol
30g/kg
50g/kg
<0.1ab
<0.1a
0.0a
0.0a
Fipronil
+Vydate
30g/kg
50g/kg
0.0a
0.0a
0.0a
0.0a
Fipronil
30g/kg
0.0a
0.0a
0.4a
0.2a
Untreated
-
3.4c
3.1b
-
-
Seedcorn Maggot
Biology: Invasive pest from European origin.
Adult flies emerge during late April and early
May. Eggs are deposited on or near the soil
surface, plant stems at the soil surface.
Eggs hatch in a few days and the maggots work
their way into the soil in search of food.
They complete their development in a week to 10
days.
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 to
manage the OM and SEC in NY.
Mature seedcorn maggot
Getting the Upper Hand on Onion
Thrips and IYSV
Brian A. Nault
Associate Professor
Department of Entomology
Cornell University, NYSAES,
Geneva, NY
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 and
their 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
Major Onion Producing Regions in NY
Oswego Co.
Orleans Co. Wayne Co.
Genesee Co.
Geneva
Yates Co.
Ithaca
Orange Co.
Onion Planting
Planting onion seeds
Transplanting onion plants
87% of acreage
13% of acreage
*Onions are rarely rotated into other fields
Onion Production in New York
Transplanting
Harvest
Direct seeding
15-Mar
14-Apr
14-May
13-Jun
13-Jul
12-Aug
11-Sep
11-Oct
Thrips Infestations in New York Onion
Fields
Thrips in Direct seeded
Thrips in Transplants
Transplanting
Direct seeding
15-Mar
14-Apr
14-May
Harvest
13-Jun
13-Jul
12-Aug
11-Sep
11-Oct
Onion Thrips Life Cycle
Adult
- All female populations
- Mating is not necessary
for reproduction!
PARTHENOGENESIS
- In NY, all female AND
male + female
populations
exist.
- Live for 13 to 47 d
Onion Thrips Life Cycle
Adult
Egg
- 60 to 200 eggs/female
- Deposited singly in leaves
- Hatch in 4-10 days
Onion Thrips Life Cycle
Adult
Egg
Hatch in 4-10 days
Larva (2 instars)
Lasts 7-14 days
Onion Thrips Life Cycle
Adult
Prepupa +
Pupa
Do NOT feed
In soil for 5-7 days
Egg
Hatch in 4-10 days
Larva (2 instars)
Lasts 7-14 days
Onion Thrips Life
Adult
*
Cycle
*17-30 days total
Prepupa +
Pupa
Egg
In soil for 5-7 days
Hatch in 4-10 days
Larva (2 instars)
Lasts 7-14 days
Onion Thrips Survival, Fecundity and Generation
Times (Days) at Various Temperatures
680 F
47
Days
770 F
25
860 F
13
Eggs laid/ female
210
165
63
Generation time
48
30
17
Factor
Survival
Murai (2000)
Onion Thrips Population Growth
Date
July 1
July 8
July 15
July 22
July 29
August 5
August 12
August 19
August 26
September 2
Number generations
Number of Females
680 F
1
210
1
Onion Thrips Population Growth
Date
July 1
July 8
July 15
July 22
July 29
August 5
August 12
August 19
August 26
September 2
Number generations
Number of Females
680 F
770 F
1
1
165
210
27,225
1
2
Onion Thrips Population Growth
Date
July 1
July 8
July 15
July 22
July 29
August 5
August 12
August 19
August 26
September 2
Number generations
Number of Females
680 F
770 F
860 F
1
1
1
63
165
3,969
250,047
210
15,752,961
27,225
1
2
4
Iris yellow spot virus (IYSV)
• Family: Bunyaviridae
Genus: Tospovirus
• Only transmitted by
onion thrips (i.e., not
seed-transmitted)
• Symptoms may be
obvious on scape, but
not leaves
-
Lesions can coalesce, weaken
scape, resulting to seed loss
-
Reduces photosynthesis,
affecting bulb yield
Iris yellow spot virus (IYSV)
• First detection in NY
occurred in an onion cull
pile in Elba in June 2006
(Hoepting et al. 2006)
• Confirmed via DAS-ELISA
and RT-PCR
• First detection in a bulb
crop in Elba in late July
2006
Elba, NY
IYSV Detection Survey Results
2006
Orleans, Genesee,
Yates, Livingston,
Wayne, Ontario:
37 out of 41 fields
(90%)
2007
Oswego : 7 out of 9
fields (78%); 45% of
samples
IYSV positive
County surveyed
Orange: 8 out of 10
fields (80%); 52% of
samples
When does IYSV occur and where
does it come from?
IYSV?
Thrips in Direct seeded
Thrips in Transplants
Transplanting
Direct seeding
15-Mar
14-Apr
14-May
Harvest
13-Jun
13-Jul
12-Aug
11-Sep
11-Oct
Outline of Presentation
I.
Overview of Onion Production in NY,
Thrips and Iris Yellow Spot Virus
II.
Potential Sources of IYSV in NY
III.
Thrips Densities, Prevalence of IYSV and
their Relationship in Onion Fields
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
Highlander
Kasmer Homegrown
Milestone
Millennium
Ricochet
Empire Sweet
300
600
600
600
300
600
600
Red Bulb
Mercury
Red Wing
Red Zeppelin
Rhumba
600
600
300
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
Highlander
Kasmer Homegrown
Milestone
Millennium
Ricochet
Empire Sweet
300
600
600
600
300
600
600
0
0
0
0
0
0
0
Red Bulb
Mercury
Red Wing
Red Zeppelin
Rhumba
600
600
300
300
0
0
0
0
Note: DAS-ELISA was used to test plants for IYSV
Volunteer Onions Sampled in 2007
9 sites; 30 plants/ site
Orleans Co.
4 sites
Wayne Co.
1 site
Oswego Co.
1 site
Geneva
Ithaca
Genesee Co. Yates Co.
2 sites
2 site
Orange Co.
No. of IYSV (+) Samples
Volunteer Onions Infected with IYSV in
2007 (n= 30 plants/site; 355 plants total)
30
25
20
15
10
5
0
GEN-1 GEN-2
ORL-1
ORL-2 ORL-3 ORL-4
OSW
Field Location
WAY
YAT
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
-
0
-
20 other weed species
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
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 and
their Relationship in Onion Fields
IV.
Onion Thrips Management
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 thrips
before planting
• Thrips may preferentially colonize
transplants
Direct Seeded
Transplanted
Elba Muck (E-1 through E-8)
Varieties
Santana
Sedona
Santana
Sherman
Highlander
Sedona
Sherman
Highlander
DS
TR
Sampling Design
60 Sampling Points
Samples taken every 2 weeks
starting June 11
5 plants for IYSV analysis
Thrips: adults & larvae
Early Season Onion Thrips Pressure
Mean Number Thrips per Field
(mean of first 2 sample dates; before spraying)
250
Direct Seeded
200
150
100
N=6
p = 0.01
50
Transplant
N=6
p = 0.02
0
Larvae
Adults
Cumulative counts: 11 + 25 June 2007
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
E-1
Santana – DS
0
E-2
Santana – TR
0
E-3
Sedona – DS
0
E-4
Sedona – TR
0
E-5
Sherman – DS
0
E-6
Sherman – TR
0
E-7
Highlander – DS
0
E-8
Highlander - TR
1
L-9
Milestone – DS
0
L-10
Milestone – TR
0
6 Aug
20 Aug
4 Sept
17 Sept
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
6 Aug
E-1
Santana – DS
0
0
E-2
Santana – TR
0
0
E-3
Sedona – DS
0
0
E-4
Sedona – TR
0
3
E-5
Sherman – DS
0
2
E-6
Sherman – TR
0
1
E-7
Highlander – DS
0
Harvested
E-8
Highlander - TR
1
Harvested
L-9
Milestone – DS
0
0
L-10
Milestone – TR
0
0
20 Aug
4 Sept
17 Sept
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
6 Aug
20 Aug
E-1
Santana – DS
0
0
1
E-2
Santana – TR
0
0
4
E-3
Sedona – DS
0
0
1
E-4
Sedona – TR
0
3
3
E-5
Sherman – DS
0
2
11
E-6
Sherman – TR
0
1
3
E-7
Highlander – DS
0
Harvested
Harvested
E-8
Highlander - TR
1
Harvested
Harvested
L-9
Milestone – DS
0
0
0
L-10
Milestone – TR
0
0
2
4 Sept
17 Sept
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
6 Aug
20 Aug
4 Sept
E-1
Santana – DS
0
0
1
2
E-2
Santana – TR
0
0
4
6
E-3
Sedona – DS
0
0
1
5
E-4
Sedona – TR
0
3
3
harvested
E-5
Sherman – DS
0
2
11
23
E-6
Sherman – TR
0
1
3
Harvested
E-7
Highlander – DS
0
Harvested
Harvested
Harvested
E-8
Highlander - TR
1
Harvested
Harvested
Harvested
L-9
Milestone – DS
0
0
0
0
L-10
Milestone – TR
0
0
2
Harvested
17 Sept
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
6 Aug
20 Aug
4 Sept
17 Sept
E-1
Santana – DS
0
0
1
2
harvested
E-2
Santana – TR
0
0
4
6
harvested
E-3
Sedona – DS
0
0
1
5
harvested
E-4
Sedona – TR
0
3
3
harvested
harvested
E-5
Sherman – DS
0
2
11
23
32
E-6
Sherman – TR
0
1
3
Harvested
harvested
E-7
Highlander – DS
0
Harvested
Harvested
Harvested
harvested
E-8
Highlander - TR
1
Harvested
Harvested
Harvested
harvested
L-9
Milestone – DS
0
0
0
0
harvested
L-10
Milestone – TR
0
0
2
Harvested
harvested
Thrips Pressure and IYSV Prevalence
No. Positive Sites
Larvae
Adults
12
12
10
10
8
8
6
6
4
4
2
2
0
0
0
2000
4000
6000
8000
10000
Cumulative No. Larvae
R2 = 0.429
N = 12, df = 10
P = 0.021
12000
0
500
1000
1500
2000
Cumulative No. Adults
R2 = 0.411
N = 12, df = 10
P = 0.025
2500
IYSV Over Time (out of 60 sites)
*No positives on 11 and 25 June, 9 July
Field
Variety
23 July
6 Aug
20 Aug
4 Sept
17 Sept
E-1
Santana – DS
1
2
harvested
E-2
Santana – TR
4
6
harvested
E-3
Sedona – DS
1
5
harvested
E-4
Sedona – TR
3
3
harvested
harvested
E-5
Sherman – DS
2
11
23
32
E-6
Sherman – TR
1
3
harvested
harvested
E-7
Highlander – DS
harvested
harvested
harvested
harvested
E-8
Highlander - TR
harvested
harvested
harvested
harvested
L-9
Milestone – DS
L-10
Milestone – TR
1
harvested
2
harvested
harvested
Spatial Distribution of Onion Thrips
Transplanted
Onions
Spatial Distribution of IYSV
No. times
site tested
positive
Relationship Between Thrips and IYSV
Thrips
IYSV
IYSV in New York Onion Fields Relative
to Thrips Activity and Harvest
IYSV
Thrips in Direct seeded
Thrips in Transplants
Transplanting
Harvest
Direct seeding
15-Mar
14-Apr
14-May
13-Jun
13-Jul
12-Aug
11-Sep
11-Oct
III. Prevalence of IYSV, Thrips Densities
and Relationship in Onions - Summary
• Transplanted fields had significantly more larval and
adult thrips early in season
• IYSV prevalence was greater in transplanted fields
• Cumulative larval and adult counts are significant
predictors of IYSV incidence
• Transplanted onions may have less risk of yield loss
because fields are harvested early
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 and
their Relationship in Onion Fields
IV.
Onion Thrips Management
General Approaches Taken to Manage Insects
that Attack Vegetable Crops – IPM Tactics
Chemical Control
Plant
Resistance
Managing
Vegetable
Insect Pests
Cultural Control
Behavioral
Control
Biological Control
IV. Onion Thrips Management
A. Evaluation of onion varieties for thrips/
IYSV resistance
B. Evaluation of insecticides for thrips
control
C. Sequences of products for season-long
thrips control
Onion Variety Screening Trial - 2007
Potter, NY
• 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
Cumulative number of larvae/plant
Screening Experiment
a
ab
a-c
a-c
cd
c-e
d-f
ef
ef
f
Days after transplanting
Lines with different letter are significantly different (P <0.05, Tukey’s test)
Screening Experiment
Variety
Red Beauty
BGS-236
Red Wing
BGS-234
Infinity
Red Bull
Santana
Milestone
Nebula
Fortress
Millenium
Bunker
SYN-H7
606-1
BGS-230
Calibra
Delgado
Tioga
Cometa
Colorado 6
Peso
OLYS05N5
Damage
4.4 ± 0.5 a
4.1 ± 0.9 a
4.1 ± 0.5 a
4.0 ± 0.4 ab
4.0 ± 0.7 ab
4.0 ± 1.1 ab
4.0 ± 0.4 ab
3.9 ± 0.9 ab
3.9 ± 0.8 ab
3.8 ± 0.3 ab
3.6 ± 0.3 a-c
3.5 ± 0.0 a-d
3.5 ± 0.4 a-d
3.4 ± 0.5 a-d
2.8 ± 0.3 b-e
2.4 ± 0.6 c-e
2.4 ± 0.5 c-e
2.4 ± 0.5 c-e
2.3 ± 0.6 de
2.0 ± 0.4 e
1.9 ± 0.3 e
1.6 ± 0.5 e
*Damage rating taken
89 days after
transplanting
Leaf damage rating
1: No damage
3: 25% leaf area injured
5: 50% leaf area injured
7: 75% leaf area injured
9: 100% leaf area injured
Means followed by different letters are
significantly different (P <0.05, Tukey’s test)
Prevalence of IYSV - 2007
Variety
Red Beauty
BGS-236
Red Wing
BGS-234
Infinity
Red Bull
Santana
Milestone
Nebula
Fortress
Millenium
Bunker
SYN-H7
606-1
BGS-230
Calibra
Delgado
Tioga
Cometa
Colorado 6
Peso
OLYS05N5
Infected (%)
5.9
16.7
13.8
11.1
3.0
15.4
12.9
3.2
11.6
8.0
15.4
12.0
15.4
31.0
8.0
9.7
18.6
4.3
2.7
10.7
8.3
8.8
Overall % Infected:
11.2%
Four Varieties
Showing Thrips
Resistance:
6.6%
Eighteen others:
12.2%
A. Summary – Plant Resistance
• Colorado 6, OLYSO5N5, Cometa and Tioga,
had lowest densities of onion thrips and low
levels of damage, suggesting that these
varieties may be less susceptible or
resistant.
• IYSV prevalence levels were low, but the
four onion varieties resistant to thrips
tended to have lower % IYSV
• Mechanism of resistance not known
Evaluation of Insecticides for
Thrips Control
B. Evaluation of Insecticides for Thrips
Control
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 of
thrips damage (1=
high; 10=none)
Rating= 2
Rating= 10
SR
La
nn
at
C
e
ar
zo
l(
0.
Ca
5)
rz
ol
(0
.7
5)
C
ar
zo
l(
1.
0)
R
ad
A
ia
gr
nt
i-M
ek
A
(1
gr
0)
i-M
ek
A
(1
gr
2)
i-M
ek
(1
M
4)
ov
en
to
(5
M
ov
)
en
to
(8
)
As
sa
il
M
U
nt
re
at
ed
Mean Number of Larvae/Plant
Final Thrips Count (Aug. 16, 2007)
200
180
F= 7.6; df= 12,36; P<0.0001
160
80
40
bc
20
cd
de
N=5
a
140
120
a
100
ab
60
cde cde
e
Treatments (rates)
cde
de
de
0
Marketable Yield
500
Jum bo
400
bc
Pulled 9/5; Weighed 10/1
Standard
ab
abc
abc
abc
a
c
300
200
a
100
ek
i-M
gr
A
Treatment
(8
)
M
ov
en
to
4)
(1
nt
C
Jumbo P = 0.0116;
Total Marketable P= 0.0481
ab
ia
ad
R
zo
l(
nn
1.
at
e
0)
b
La
at
U
nt
re
c
M
SR
0
a
a
ar
abc
ed
Marketable Yield (cwt/acre)
Potter, NY
B. Summary – Insecticide Evaluation

Onion crop was best protected from onion thrips
using:
- 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 control
larvae

Lannate and MSR provided fair to poor levels of
protection, respectively

Registration updates:
Radiant received a Section 3 label in 9/07
Carzol considered for Section 18s in many States
What sequences of products
should be used to control thrips?
C. Sequences of Products Evaluated for
Onion 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
Mean Number of Larvae/Leaf/
Sampling Date
Season Avg. Thrips Count - 2007
100
N=5
a
80
60
40
20
b
b
0
d
ate
e
r
t
Un
e
e
ant
i
nat
nat
d
n
n
a
a
a
R
L
l/
/L
zol/
rzo
ant
r
i
a
a
d
C
t/C
Ra
R/
ian
MS
zol/
d
r
a
a
R
C
F= 15.5; df= 3,9; P=0.0007
b
Marketable Yield
Marketable Yield (cwt/acre)
Potter, NY
500
Pulled 9/5; Weighed 10/1
Standard
Jum bo
400
ab
a
ab
b
300
200
100
a
a
a
a
0
Un
t
te
rea
d
R
MS
/C
ol
z
r
a
Jumbo P = 0.4743;
Total Marketable P= 0.0464
/R
a
adi
nt
R
an
adi
t/C
o
arz
l/
na
n
a
L
C
te
o
arz
l/R
an
i
d
a
t/
na
n
a
L
te
C. Summary – Insecticide Sequences
• All treatments were effective
a) Starting with a weaker product and finishing
with strong ones
b) Starting with stronger products and finishing
with a weaker one
Acknowledgements
Collaborators:
 Tony Shelton, Marc Fuchs,
Cynthia Hsu and Christy
Hoepting
Funding:
Graduate Students:
 Erik Smith and John Diaz
 NY Farm Viability
Program
Technical Assistance:
 M.L. Hessney, K. Straight, R.
Taylor, B. English-Loeb, T.
Evans, C. McGreggor, J.
Bergman and H. Schoonover
 NY Onion Research
and Development
Program
 IR-4 Program
 Bayer Crop Science,
Cerexagri, Dow, DuPont,
Gowan and Syngenta
The End