Optimal Spray Timing of Oberon and Courier for Managing
Bemisia Whiteflies in Spring Cantaloupes
John C. Palumbo
Abstract
Studies were conducted on spring cantaloupes from 2004-2006 to evaluate two
adult and nymph based thresholds used for timing the application of Oberon
(spiromesifen) and Courier (buprofezin) in spring melons for controlling
whiteflies. The results of these studies demonstrate that these selective
insecticides offer melon growers effective foliar management alternatives for
controlling whiteflies. Both Oberon and Courier provided economic control of
whitefly nymphs and significantly prevented sooty mold contamination when
applied after populations exceeded either an adult threshold of 2 adults per leaf
or an immature threshold or 0.5 large nymph per 2 cm2 leaf disc. Applied at
these thresholds, both compounds provided consistent residual suppression of
whitefly immature population growth for 21-28 days under spring growing
conditions.
Introduction
Bemisia whiteflies are a major pest of spring cantaloupes causing yield and quality losses by contaminating
marketable fruit with honeydew and sooty mold. However, during the past decade whiteflies have been relegated to
a managed pest in Arizona melons. This was achieved through the development of area-wide management programs
in cotton, melons and vegetables which utilized cultural practices, sampling and monitoring plans, and the
optimally-timed use of new, selective insecticide chemistries. Growers in all commodities have been quick to adopt
and modify these management strategies as new insecticide compounds are made available. Admire® (imidacloprid),
was one of the first new compounds registered for whitefly in melons. It’s sustained efficacy over the past 14 years
has exceeded the expectations of many who speculated that whiteflies would quickly evolve resistance. No field
failures have been reported to date, in part, because imidacloprid has been used sparingly in cotton. However, the
registration of several new neonicotinoid compounds on cotton, melons and vegetables has expanded the number of
compounds available for whitefly control on these crops. Their potential use on all crops and has place increased
selection pressure on this chemistry, particularly in multi-cropping communities where these compounds could be
applied to a number of successive whitefly generations on neighboring crops throughout the year. Given the
tremendous value of the neonicotinoid chemistry, it is important that new insecticide alternatives be developed and
implemented into our melon pest management programs to help sustain the long-term management of whiteflies in
all crops.
______________________________________________________________________________
This is part of the University of Arizona College of Agriculture 2006 Vegetable Report, index at:
http://cals.arizona.edu/pubs/crops/az1419/
Melon growers presently have two selective, foliar insecticides available to them that are effective in reducing
whitefly populations on Arizona melons and can be used to augment whitefly control, either in the absence of, or
following Admire applications. However, thresholds for timing spray applications of these compounds or other
insecticides to prevent honeydew contamination in spring melons are not available. Courier® (buprofezin) is an
IGR that inhibits chitin syntheses and Oberon® (spiromesifen) is an IGR-like compound that inhibits lipid
biosynthesis. Both compounds prevent the molting of nymphal stages; however neither compound kills adults.
Because of this specific activity against immatures, efficacy studies have demonstrated that sprays applied early in
population development effectively prevented yield and quality losses to spring cantaloupes. These studies further
suggested optimal spray timing coincided with low adult and immature densities. The purpose of the present
research was to evaluate and compare different spray timings based on pre-determined thresholds at which these
compounds could be applied to manage Bemisia whiteflies and avoid sooty mold contamination on spring melons.
Methods and Materials
2004 Experiment:
Cantaloupe plots planted with ‘Esteem’ were established at the Yuma Agricultural Center on Mar 19, 2004 and
managed similarly to local growing practices. Plots consisted of two 80-inch beds, 70 ft long with a 15 buffer
between each plot. The study was designed as a split plot design 4 replicates / treatment. The main plots consisted of
plots treated with Admire and untreated plots, and the subplots consisted of the Courier 40SC (13.5 oz) and Oberon
2SC (8.5 oz) treatments applied at two predetermined thresholds. Treatment combinations are show in the table
below:
Admire (16 oz/acre) was
Soil
Foliar
Rates /
Spray
applied 3" below the seed line
Treatments Treatments
Thresholds
acre
Dates
prior to seed placement in 30
GPA on 19 Mar. The foliar
spray treatments were applied
Oberon
2 adults / leaf
8.5 oz
24 May
with a CO2 backpack sprayer
Admire
Oberon
0.5 nymph/2 cm2 disc
8.5 oz
5 June
that delivered 20 GPA at 60
(at planting)
psi, using 4 - TX18 ConeJet
16 oz
Courier
2 adults / leaf
13 oz
24 May
nozzles per bed. All foliar
Courier
0.5 nymph/2 cm2 disc
13 oz
5 June
treatments were applied when
thresholds were exceeded. All
Untreated
---spray treatments included
DyneAmic at 0.06% v/v.
Oberon
2 adults / leaf
8.5 oz
24 May
0.5 nymph/2 cm2 disc
Populations of whitefly adults
and immatures were evaluated
Courier
2 adults / leaf
13 oz
24 May
at 7 day intervals.
Adult
2
populations
were
estimated
by
Courier
0.5 nymph/2 cm disc
13 oz
8 May, 5 June
taking leaf turn samples from
the 5th terminal leaf on the
Untreated
---primary melon vine of 10
randomly selected plants per replicate. Immature densities were estimated by sampling 5 plants / plot, where 4
leaves were collected from each plant on the 5th, 10th, 15th, and 20th leaves from the terminal on the primary vine.
Leaves were taken into the laboratory where densities of eggs, nymphs, and eclosed pupae were counted on 2-cm2
leaf discs of each leaf using a dissecting microscope. Data for adults were estimated as numbers of adults per leaf.
Immature densities were averaged across all leaf positions on each sample date and reported as immature numbers
per 2-cm2 per leaf. Yields and quality were measured by harvesting the total number of full slip melons in a 15 row
ft area within each replicate every other day over a 2 week period (8 harvest dates). Quality was assessed by
estimating the percentage of harvested melons that were visibly contaminated with sooty mold on at least 25 cm2 of
No Admire
applied
Oberon
8.5 oz
8 May, 5 June
the fruit surface area. Because of heterogeneity of mean variances, insect data were transformed [log(y+0.5)] prior to a
two-way analysis of variance. The mean values were then subjected to a protected LSD (p<0.05) F test to distinguish
treatment mean differences. The untransformed mean values for each life stage are presented in the figures and
tables.
2005 Experiment:
Cantaloupe plots planted with ‘Gold Express’ were established at the Yuma Agricultural Center on Mar 16, 2005
and managed similarly to local growing practices. Similar to the 2004 study, plots consisted of two 80-inch beds, 70
ft long with a 15 buffer between each plot. The study was designed as a split plot design with 4 replicates per
treatment. The main plots consisted of Admire and untreated plots, and the subplots consisted of the Courier 40SC
(13.5 oz) and Oberon 2SC (8.5 oz) treatments applied using both thresholds. Treatment combinations were similar to
the 2004 study; however, two treatments of Assail 30SG (4 oz/ac) were included and applied at both thresholds. Due
to resistance management concerns, Assail was only applied to plots not treated with Admire. See Tables 3 and 4
for application dates for each treatment. Populations of whitefly adults and immatures were evaluated at weekly
intervals beginning on 26 Apr using sampling procedures similar to the 2004 study. Yields and quality were
measured by harvesting the total number of melons in 15 row ft per treatment every other day over a 2 week period.
Melon quality was assessed similar to the 2004 study.
2006 Experiment:
Cantaloupe plots planted with ‘Valley Gold’ were established at the Yuma Agricultural Center on Apr 6, 2006 and
managed similarly to local growing practices. Similar to 2004 and 2005, plots consisted of two 80-inch beds, 70 ft
long with a 15 buffer between each plot. The study was designed as a split plot design with 4 replicates per
treatment. The experimental design and treatment combinations were similar to the previous two years with the
exception that Venom (4 oz/ac) was applied to instead of Assail. Again do resistance management concerns, Venom
was only applied to plots not treated with Admire. See Tables 5 and 6 for application dates for each treatment.
Populations of whitefly adults and immatures were evaluated at weekly intervals beginning on 4 May using
sampling procedures similar to the 2004 and 2005 study, as were yields and quality estimates.
Results
2004 Experiment:
Whitefly pressure became heavy when adult populations migrated into the plots in mid-May. This caused the adult
threshold treatments to trigger in late May in both the Admire-treated and untreated main plots (Figure 1 and 2).
These plots were not retreated. The nymph threshold treatments triggered and received foliar sprays first in the plots
where no Admire was applied on May 8, and were retreated on 5 Jun (Figure 2). In plots where Admire was
applied at-planting, the nymph threshold wasn’t triggered until about 4 weeks later on June 5 (Figure 1).
In the Admire-treated main plots, numbers of immature whiteflies in the spray treatments were significantly lower
than the check for most sample dates (Figure 1). Eggs and small nymphs were lower in the Oberon treated plots,
regardless of threshold, than in the Courier plots at harvest. Large nymphs were greater in the Courier (adult
threshold) and Admire-only plots, than in all other sprayed plot (Figure 1). Numbers of eclosed pupae did not differ
among the spray treatments. Similar results were seen for the plots where no Admire was applied (Figure 2), where
densities of large nymphs were significantly lower in all spray treatments compared with the untreated check.
Furthermore, large nymph densities did not differ among the threshold treatments for either Oberon or Courier.
Averaged across all sample dates, seasonal densities of eggs, nymphs and eclosed pupae in the Admire-treated
plots (Table 1) did not differ among the insecticide*threshold combinations with the exception of egg numbers in
the Courier treatments applied with the Adult threshold. In the plots where no Admire was applied (Table 2), only
the Oberon treatments and the Courier adult threshold treatment significantly reduced immature densities compared
to the untreated check. Adults per leaf were not significantly affected by any of the insecticide*threshold
combinations (Table 1and 2).
Yield estimates showed that total cumulative melon fruit yields were not significantly different among any of the
insecticide*threshold combinations, irregardless of whether they were treated with Admire or not (Table 1 and 2).
However, differences were observed in fruit quality. All spray treatment combinations contained significantly less sooty
mold contamination than the Admire-only and untreated check plots, where 43 and 87 % of the total melons harvested
respectively were contaminated (Table 1 and 2). The Admire-treated main plots that were over-sprayed with Courier
using the nymph threshold had significantly more sooty mold than Courier treatment using the Adult threshold (Figure
1 and Table 1). In plots where no Admire was applied, the Courier treatments, regardless of threshold used, did not
differ significantly from each other (Fig 2 , Table 2). This was similar for Oberon threshold treatments as well.
2005 Experiment:
Whitefly pressure was light in this study, as indicated by the late spray dates for each threshold. In fact, both the adult
and nymph thresholds triggered at the same time in the Admire-treated plots (7-d prior to harvest). In the plots where
no Admire was applied action thresholds triggered earlier; the nymph threshold about 2 weeks (14 May) earlier than the
adult threshold (1 Jun). Adult populations continued to increase following the spray applications and increased to more
than 20 per leaf in the untreated plots at harvest (Figure 3 and 4). All spray treatments had significantly fewer adults that
the untreated control at the beginning of harvest (June 14), but averaged over the season, adult number did not differ
among the insecticide*threshold treatments and the untreated check (Table 3 and 4).
Under these lighter, spring whitefly conditions, control of whitefly nymphs was comparable for both the adult and
nymph thresholds following treatments, regardless of insecticide used (Figure 3-4). This was the case for both Admiretreated melons as well as melon plots where no Admire was applied at planting. In some cases, the adult thresholds for
all compounds in the melon plots not treated with Admire provided significantly better control of eclosed pupae at the
end of harvest than in plots where only Admire was applied. This suggests that the whitefly populations in the sprayed
plots consistently prevented nymphs from colonizing plants. In contrast, nymph numbers were not different from the
untreated check at the end of harvest in the Admire-only treatment (Figure 3). This is expected as previous research has
shown that Admire has an effective residual of about 45-60 days under spring melon growing conditions, and in this
study the Admire probably offered little control to the late arriving migrant adults. When averaged across all sample
dates, the adult action threshold of 2 adults/ leaf provided very consistent control of whitefly populations when used to
time spray applications of Oberon, Courier and Assail (Table 3 and 4).
Similar to the previous year, yield estimates showed that total cumulative melon fruit yields were not significantly
different among the treatments (Table 3 and 4). This is not surprising considering the light infestation levels occurring
prior to fruit set. Sooty mold contamination was light in the untreated melons relative to the previous spring study
(Figure 3 and 4). However, all the insecticide*threshold treatments provided statistically similar reductions in sooty
mold contamination (including the Admire-only treatment) compared with the untreated check.
2006 Experiment:
Melons were planted later in an attempt to encourage larger whitefly numbers than experienced in 2005. Whitefly adult
numbers were very light for the first 6 weeks following seedling emergence, but in mid-May a significant flight of
adults moved into the experimental area from an adjacent melon field that was being harvested. This triggered the adult
thresholds for all treatments in both the Admire and non-Admire treated plots (Figure 5 and 6). Similarly, nymph
thresholds triggered for all treatments ~ 2 weeks later. Just prior to harvest adult numbers increased to very high
numbers, a result of migration from an adjacent commercial melon field.
All threshold treatments had significantly maintained immature densities at very low levels compared with the untreated
check (Figure 5 and 6) prior to harvest. However, as a result of the aforementioned late adult immigration into the
experimental area, immature densities developed quickly prior to and during the harvest period. This was especially
evident for the immature densities in the adult threshold treatments where no Admire had been applied (Figure 5).
Under similar conditions, a commercial melon grower would have been advised to treat with a synergized pyrethroid in
order to knock down the adult populations. However, in this experiment the unchecked adult population resulted in
excessive immature population build-up. This was most damaging to the adult threshold treatment because it had been
30 days since the treatments were applied. It is highly unlikely that any effective residue remained on the treated plants.
Consequently, seasonal average densities of large nymphs were significantly higher in the adult threshold treatments
than in the nymph thresholds, which were treated about 1 week before the adults moved in (Table 5 and 6).
Despite the late build up of immatures, yield estimates showed that total cumulative melon fruit yields were not
significantly different among the treatments (Table 5 and 6). Again, this is not surprising considering the light
infestation levels occurring prior to harvest. However, sooty mold contamination, particularly in the adult threshold
treatments and Admire-only treatment, were higher than observed in previous studies (Figure 5 and 6). In plots where
Admire was applied at harvest, Oberon treatments resulted in the same level of quality, irregardless of threshold. This is
likely due to the effects of both the Admire and the residual activity of the Oberon suppressing development on crown
leaves. However, the other adult threshold treatments did not provide the same level of protection as the nymph
thresholds (Table 5 and 6).
The Venom (dinotefuron) treatments were inconsistent in preventing sooty mold
contamination under these conditions.
Discussion
The results of these experiments demonstrate that Oberon and Courier are effective foliar alternatives for controlling
whiteflies in spring melon crops when applied appropriately. Previous efficacy studies have suggested that the residual
activity of these compounds against nymph populations is about 21-28 days under spring conditions. The present
studies provide further evidence of this. The intention of these experiments was determine whether spray timing could
be based on adult abundance for two compounds that have little effects on adult mortality. Our premise for this was
two-fold. First, research has shown that whiteflies could be effectively controlled and spring cantaloupes could be
protected from sooty mold contamination if nymph densities were maintained under 0.5 nymphs / cm2 (Riley and
Palumbo, 1995. J. Econ. Entomol, 88:1726-1732). These same studies also suggested that adult abundance (2 adults per
leaf) was consistently correlated with large nymphs (0.5 per cm). Thus, we hypothesized that either of these two
densities would serve as appropriate triggers for the application of these two selective insecticides under spring growing
conditions. From a practical perspective, we also felt that a simple adult-based threshold would be ideal for timing
sprays of these insecticides because a reliable sampling procedure already existed for adult sampling (leaf turn method)
which is quicker and easier for a PCA to use than immature counts. Furthermore, making spray decisions based on
nymph densities can be difficult due to their small size and lack of clarity on which leaf to sample from on a flowering
or fruiting cantaloupe plant.
For the most part, the results of these three experiments support our contention that an adult-based action threshold of 2adults per leaf can consistently perform as well a threshold that relies on sampling for immatures. Although the adult
threshold did not perform comparably in 2006, both Oberon and Courier provided 28 days of significant immature
population suppression. This further illustrates the need to continue adult sampling following applications of Admire
and IGR-like compounds, as well as the necessity to treat for heavy adult immigration near harvest. Consequently, these
studies suggest that IGRs and similar compounds are probably best suited for use 21-28 prior to harvest when
population levels have been maintained below threshold levels, which is often the case when cantaloupes have been
treated with Admire or grown under cool spring growing conditions. Although these compounds have shown similar
efficacy in fall cantaloupe production, the use of adult thresholds may not be appropriate early in the season when high
numbers of whitefly adults are migrating into fields. Rather, treatment with a synergized pyrethoid or other adulticides
would be more useful. Once migrations of adults had diminished, then a nymph-based threshold may be more
appropriate to time applications of Oberon and Courier. Studies to evaluate this management approach are presently
underway.
Acknowledgements
These studies would not have been possible without the funding and support provided by the California Melon Research
Board, Bayer CropSciences, Nichino America, Valent and Cerexagri. I gratefully acknowledge the excellent assistance
from the personnel at the Yuma Agricultural Center including my research associates Clay Mullis, Andreas Amaya,
Luis Ledesma, Leonardo Chavez, Javier Ruis, Gerardo Villegas, and the YAC farm manager, Jesus Pereria.
2004 - Admire (at planting)
120
120
100
Adults / Leaf
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Admire only
Untreated
80
Nymph
100
80
60
60
40
40
Adult
20
0
20
29
Apr
5
May
13
May
20
May
27
May
3
Jun
0
10
Jun
2004 - Admire (at planting)
16
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
14
12
2
Large Nymphs / cm / Leaf
16
10
14
12
10
Nymph
8
8
6
6
Adult
4
4
2
0
2
29
Apr
5
May
13
May
20
May
27
May
3
Jun
10
Jun
16
Jun
0
2004 - Admire (at planting)
% Total Cumulative Fruit
Contaminated with Sooty mold
100
100
80
60
40
80
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
60
40
20
20
0
0
16
Jun
18
Jun
20
Jun
22
Jun
24
Jun
26
Jun
Figure 1. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons treated with Admire at planting, 2004
2004 - No Admire Applied
120
120
100
Adults / Leaf
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Untreated
80
Nymph
80
60
60
40
40
Adult
Nymph
20
0
100
20
29
Apr
5
May
13
May
20
May
27
May
3
Jun
0
10
Jun
2004 - No Admire Applied
16
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Untreated
14
12
2
Large nymphs / cm / Leaf
16
14
12
Nymph
10
10
8
8
6
6
Adult
Nymph
4
4
2
2
0
0
29
Apr
5
May
13
May
20
May
27
May
3
Jun
10
Jun
16
Jun
% Total Cumulative Fruit
Contaminated with Sooty mold
2004 - No Admire Applied
100
100
80
80
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Untreated
60
40
60
40
20
20
0
0
16
Jun
18
Jun
20
Jun
22
Jun
24
Jun
26
Jun
Figure 2. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons where no Admire was applied, 2004.
Table 1. Seasonal average whitefly densities, and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons treated with Admire applied at planting, 2004
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Application
date
Adults /
leaf
Eggs
Adult
24 May
11.1 a
11.8 cd
3.2 a
0.4 b
3.6 c
0.01 c
31.3 a
0.0 d
Oberon
Nymph
5 June
12.0 a
9.1 d
3.4 a
0.4 b
3.8 c
0.04 bc
36.0 a
9.4 d
Courier
Adult
24 May
11.6 a
20.8 ab
7.5 a
0.7 b
8.2 abc
0.00 c
33.3 a
3.4 d
Courier
Nymph
5 June
11.1 a
15.4 bcd
6.3 a
0.5 b
6.7 bc
0.06 abc
34.5 a
24.5 c
Treatment
Timing
Oberon
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold
Admire
-
23 March
9.9 a
17.6 bc
8.1 a
2.3 a
10.5 ab
0.19 ab
34.8 a
42.8 b
Untreated
-
-
17.1 a
27.6 a
10.6 a
3.6 a
14.2 a
0.24 a
34.3 a
78.4 a
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05)
Table 2. Seasonal average whitefly densities and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons where no Admire was applied, 2004.
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold
3.7 c
0.04 bc
31.8 a
0.0 b
0.5 b
4.5 bc
0.08 abc
31.8 a
5.3 b
5.9 a
0.4 b
6.3 bc
0.01 c
30.8 a
7.6 b
7.6 a
0.6 b
8.2 abc
0.22 a
29.8 a
9.9 b
Untreated
17.1 a
27.6 a
10.6 a
3.6 a
14.2 a
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05)
0.24 a
34.3 a
78.4 a
Treatment
Timing
Oberon
Adult
Oberon
Nymph
Courier
Adult
Courier
Nymph
Application
date
Adults /
leaf
Eggs
24 May
13.2 a
12.0 c
3.3 a
0.4 b
8 May, 5 Jun
13.2 a
10.2 c
4.0 a
24 May
13.1 a
18.9 bc
8 May, 5 Jun
18.6 a
22.6 a
2005 - Admire (at planting)
30
25
Adults / Leaf
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Admire only
Untreated
20
30
25
20
Nymph
Adult
15
15
10
10
5
5
0
4
May
11
May
18
May
25
May
31
May
7
Jun
14
Jun
21
Jun
0
2005 - Admire (at planting)
14
12
10
16
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
2
Large Nymphs / cm / Leaf
16
14
12
10
8
8
Adult
Nymph
6
6
4
4
2
2
0
10
May
18
May
24
May
31
May
7
Jun
14
Jun
21
Jun
29
Jun
0
2005 - Admire (at planting)
% Total Cumulative Fruit
Contaminated with Sooty mold
100
100
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
80
60
80
60
40
40
20
20
0
0
16
Jun
20
Jun
22
Jun
24
Jun
26
Jun
29
Jun
Figure 3. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons treated with Admire applied at planting, 2005
2005 - No Admire Applied
30
25
Adults / Leaf
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Assail (Adults)
Assail (Nymphs)
Untreated
20
15
30
25
20
15
10
10
Adult
Nymph
5
5
0
0
4
May
11
May
18
May
25
May
31
May
7
Jun
14
Jun
21
Jun
2005 - No Admire Applied
Large nymphs / cm2 / Leaf
16
14
12
10
16
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Assail (Adults)
Assail (Nymphs)
Untreated
14
12
10
8
8
6
6
Adult
Nymph
4
4
2
2
0
0
10
May
18
May
24
May
31
May
7
Jun
14
Jun
21
Jun
29
Jun
2005 - No Admire Applied
% Total Cumulative Fruit
Contaminated with Sooty mold
100
100
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Assail (Adults)
Assail (Nymphs)
Untreated
80
60
80
60
40
40
20
20
0
0
16
Jun
20
Jun
22
Jun
24
Jun
26
Jun
29
Jun
Figure 4. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons where no Admire was applied, 2005.
Table 3 Seasonal average whitefly densities and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons treated with Admire applied at planting, 2005
Adults /
leaf
Eggs
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold
Treatment
Timing
Application
date
Oberon
2 Adults
June 7
3.8 a
3.0 a
1.9 b
0.4 b
2.3 c
0.07 b
27.3 a
0.0 b
Oberon
0.5 Nymphs
June 7
3.5 a
2.5 a
2.5 b
0.5 b
3.1 bc
0.05 b
25.3 a
1.4 b
Courier
2 Adults
June 7
4.7 a
2.9 a
2.0 b
0.6 b
2.6 bc
0.06 b
25.3 a
0.0 b
Courier
0.5 Nymphs
June 7
3.3 a
3.1 a
2.4 b
0.8 b
3.1 bc
0.04 b
30.3 a
0.0 b
Admire
-
March 16
3.3 a
4.2 a
2.9 b
1.8 a
4.7 b
0.18 a
25.3 a
3.6 b
Untreated
5.0 a
4.8 a
5.6 a
2.1 a
7.7 a
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05)
0.21 a
23.5 a
15.4 a
Table 4. Seasonal average whitefly densities and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons where no Admire was applied, 2005.
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Treatment
Timing
Application
date
Adults /
leaf
Eggs
Oberon
2 Adults
1 June
3.4 a
3.7 a
2.8 b
0.8 b
3.6 b
0.02 b
22.5 a
0.0 b
Oberon
0.5 Nymphs
14 May
3.5 a
2.7 a
1.8 b
0.7 b
2.5 b
0.09 b
20.0 a
0.0 b
Courier
2 Adults
1 June
4.5 a
2.4 a
2.1 b
0.8 b
2.9 b
0.04 b
23.3 a
0.0 b
Courier
0.5 Nymphs
14 May
4.3 a
3.1 a
1.9 b
0.8 b
2.7 b
0.11 b
25.5 a
0.0 b
Assail
2 Adults
1 June
3.7 a
3.2 a
2.6 b
1.0 b
3.6 b
0.08 b
22.8 a
1.0 b
Assail
0.5 Nymphs
14 May
3.8 a
3.6 a
2.4 b
1.0 b
3.4 b
0.08 b
22.0 a
1.4 b
5.0 a
4.8 a
5.6 b
2.1 a
7.7 a
0.21 a
23.5 a
15.4 a
Untreated
-
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05)
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold
2006 - Admire (at planting)
140
140
120
Adults / Leaf
100
80
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Admire only
Untreated
60
Nymph
40
Adult
20
20
0
4
May
Large Nymphs / cm2 / Leaf
50
100
80
60
40
120
11
May
17
May
1
Jun
24
May
0
8
Jun
16
Jun
22
Jun
2006 - Admire (at planting)
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
40
30
50
40
30
20
20
Nymph
Adult
10
10
0
0
11
May
17
May
23
May
1
Jun
8
Jun
16
Jun
23
Jun
30
Jun
% Total Cumulative Fruit
Contaminated with Sooty mold
2006 - Admire (at planting)
100
100
80
80
60
60
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Admire only
Untreated
40
20
40
20
0
0
22
Jun
24
Jun
26
Jun
28
Jun
30
Jun
2
Jul
4
Jul
Figure 5. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons treated with Admire at planting, 2006
2006 - No Admire Applied
140
140
120
Adults / Leaf
100
80
Harvest
Oberon (2 Adults)
Oberon (0.5 Nymphs)
Courier (2 Adults)
Courier (0.5 Nymphs)
Venom (2 Adults)
Venom (0.5 Nymphs)
Untreated
60
Nymph
40
40
Adult
20
20
0
0
4
May
11
May
17
May
24
May
1
Jun
8
Jun
16
Jun
22
Jun
2006 - No Admire Applied
50
Harvest
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Venom (Adults)
Venom (Nymphs)
Untreated
40
2
Large nymphs / cm / Leaf
100
80
60
50
120
30
40
30
20
20
Adult
Nymph
10
10
0
0
11
May
17
May
23
May
1
Jun
8
Jun
16
Jun
23
Jun
30
Jun
2006 - No Admire Applied
% Total Cumulative Fruit
Contaminated with Sooty mold
100
100
80
80
Oberon (Adults)
Oberon (Nymphs)
Courier (Adults)
Courier (Nymphs)
Assail (Adults)
Assail (Nymphs)
Untreated
60
40
60
40
20
20
0
0
22
Jun
24
Jun
26
Jun
28
Jun
30
Jun
2
Jul
4
Jul
Figure 6. Adult abundance, large nymph densities and sooty mold contamination for insecticide*threshold
treatment combinations applied to spring melons where no Admire was applied, 2006.
Table 5. Seasonal average whitefly densities and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons treated with Admire applied at planting, 2006
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold
Treatment
Timing
Application
date
Adults /
leaf
Eggs
Oberon
2 Adults
25 May
30.7 a
24.7 a
12.2 a
3.3 bcd
15.5 b
0.3 c
25.5 a
15.9 d
Oberon
0.5 Nymphs
9 June
31.6 a
21.5 a
11.4 a
1.7 d
13.1 b
0.2 c
30.3 a
5.5 d
Courier
2 Adults
25 May
39.7 a
30.8 a
18.1 a
6.6 bc
24.5 ab
1.0 bc
28.5 a
23.3 c
Courier
0.5 Nymphs
9 June
30.6 a
22.4 a
14.0 a
2.0 cd
16.0 b
0.1 c
23.0 a
12.7 d
Admire
-
6 April
20.7 a
28.8 a
16.1 a
7.1 b
23.1 ab
1.5 b
30.0 a
57.1 b
Untreated
-
-
18.0 a
29.8 a
18.4 a
13.3 a
31.8 a
3.5 a
25.0 a
71.3 a
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05).
Table 6. Seasonal Average whitefly densities and yield and quality estimates for insecticide*threshold treatment combinations applied to spring
melons where no Admire was applied, 2006.
Treatment
Avg. whiteflies / cm2 / leaf
Small
Large
Total
nymphs
nymphs
nymphs
Timing
Application
date
Adults /
leaf
Eggs
Oberon
2 Adults
25 May
21.7 a
24.2 a
11.4 a
3.3 b
14.6 b
0.2 b
28.0 a
29.4 b
Oberon
0.5 Nymphs
9 June
21.0 a
12.9 a
7.3 a
1.7 c
9.0 b
0.2 b
28.0 a
19.9 c
Courier
2 Adults
25 May
23.7 a
24.3 a
12.1 a
4.2 b
16.3 b
0.4 b
25.0 a
32.2 b
Courier
0.5 Nymphs
9 June
30.9 a
25.9 a
14.4 a
3.7 b
18.2 b
0.2 b
30.0 a
20.9 c
Venom
2 Adults
25 May
33.3 a
22.4 a
13.7 a
4.0 b
17.8 b
0.5 b
31.3 a
27.9 bc
Venom
0.5 Nymphs
9 June
23.8 a
26.5 a
14.7 a
2.9 b
17.6 b
0.4 b
28.5 a
35.1 b
-
-
18.0 a
29.8 a
18.4 a
13.3 a
31.8
3.5 a
25.0 a
71.3 a
Untreated
Means followed by the same letter are not significantly different, ANOVA , protected LSD (P>0.05).
Eclosed
pupae
Yields (fruit / plot)
% sooty
Total
mold