Arthropod Management Tests 2011, Vol. 36
doi: 10.4182/amt.2011.E65
E65
POTATO: Solanum tuberosum L., ‘Superior’
EVALUATION OF SEED TREATMENT AND IN-FURROW INSECTICIDES FOR THE CONTROL OF INSECTS IN
POTATOES IN VIRGINIA, 2010
Thomas P. Kuhar
Department of Entomology
Virginia Tech
Eastern Shore Agricultural & Extension Center
33446 Research Drive
Painter, VA 23420
Phone: (757)414-0724 ext. 14
E-mail: [email protected]
Peter Schultz
Hélène Doughty
Adam Wimer
Anna Wallingford
Heather Andrews
Chris Phillips
Meredith Cassell
James Jenrette
Colorado potato beetle (CPB): Leptinotarsa decemlineata (Say)
Wireworm: Melanotus communis (Gyllenhal)
Potato leafhopper (PLH): Empoasca fabae (Harris)
The objective of this experiment was to assess the efficacy of novel seed treatments and in-furrow insecticide applications for the
control of insects in potatoes. The trial consisted of 13 treatments arranged in a RCB design with four replicates. Potatoes were
planted on 25 Mar 2010 at the Virginia Tech Eastern Shore AREC near Painter, VA. Plots were 2 row wide and 20 ft (6.1 m) long
with unplanted guard rows on each side. Rows were planted on a 3 ft row center (0.9 m) with 11 inches (0.3 m) between plants, in a 6
tier field design with 8 ft (2.4 m) alleys between tiers and a 16 ft (4.9 m) center alley. Insecticide seed treatments were applied on 24
Mar using a standard cement mixer to tumble 50 lbs of seed, while the chemicals were applied directly to the seed with a hand-pump
spray bottle containing 100 ml water. All seed pieces were then treated with 8% alder bark at 16 oz / cwt. All in-furrow treatments
were applied in 900 ml of water at 19.8 GPA on 25 Mar using a single nozzle boom equipped with an 8003 even flat spray tip and
powered by a CO2 backpack sprayer at 30 psi. Furrows were cut using a commercial potato planter without the coulters on. Seed
pieces were hand dropped into the furrows. Immediately after the treatments were applied over top of seed-pieces, the seed was
covered with the planter. All plots were maintained according to standard commercial practices. On 19 May (56 DAT), 24 May (61
DAT) and 1 Jun (69 DAT), the number of CPB larvae was recorded per 10 vines for each plot. On 1 Jun (69 DAT), the number of
PLH nymphs was recorded per 10 compound leaves. On 3 Jun (71 DAT), % defoliation was visually assessed in each plot. On 1 Jul,
potato tubers were harvested and weighed. A sub-sample of 50 tubers was taken to evaluate for wireworm damage. All data were
analyzed using ANOVA. Proportion data were arcsine square root transformed prior to analysis. Means were separated using Fisher’s
Protected LSD at the 0.05 level of significance.
CPB pressure was moderate with densities averaging 80 to 90 larvae (small and large) per 10 vines in late May in the untreated
control plots. There was a significant treatment effect on numbers of CPB larvae on all sample dates (Table 1) as well as percentage
defoliation (Table 2). All insecticide treatments had significantly fewer CPB small and large larvae and less defoliation compared to
the untreated control, and no differences in efficacy were seen among the treatments (Table 1). At 69 DAT, there was a significant
treatment effect on numbers of PLH nymphs. Admire Pro, Platinum 75SG and the A16901 treatments were the only treatments that
provided significant control of PLH compared to the untreated control (Table 2). There was a significant treatment effect on tuber
yield as well (Table 2). Treatments containing neonicotinoid insecticides yielded higher than any of the HGW86 alone treatments
probably because of the PLH control (Table 2). There was no significant treatment effect on wireworm tuber damage ratings due to
variability. However, numerically, the untreated control plots averaged at least twice as much wireworm damage as any of the
insecticide treatments. No signs of phytotoxicity were observed.
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Arthropod Management Tests 2011, Vol. 36
doi: 10.4182/amt.2011.E65
Table 1.
Mean no. CPB larvae/ 10 stems
Treatment/
formulation
Untreated Control
HGW86 600FS
HGW86 600FS
HGW86 600FS
HGW86 200FS
HGW86 200FS
HGW86 200FS
Admire Pro
Admire Pro
A16901
A16901
Platinum 75SG
Platinum 75 SG
Rate
Appl.
Method
4.5 fl oz / acre
6.75 g [ai] / 100 kg
9 g [ai] / 100 kg
10.27 fl oz / acre
13.7 fl oz / acre
9 g [ai] / 100 kg
8.7 fl oz / acre
9.36 g [ai] / 100 kg
6.25 oz/ acre
10 oz/ acre
1.68 oz / acre
2.66 oz / acre
IF
ST
ST
IF
IF
ST
IF
ST
IF
IF
IF
IF
19-May
(56 DAT)
Small
Large
55.0a
0.0c
8.3b
2.0bc
0.0c
0.0c
3.5bc
0.0c
0.0c
0.0c
0.0c
0.0c
0.0c
35.3a
0.0b
0.0b
0.8b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
24-May
(61 DAT)
Small
Large
22.5a
0.0b
6.5b
4.0b
0.8b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
58.3a
0.0b
0.8b
0.3b
1.5b
0.0b
0.8b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
1-Jun
(69 DAT)
Small
Large
7.0
1.5
1.8
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
8.8a
0.0b
0.3b
0.0b
0.0b
0.0b
0.5b
0.0b
0.0b
0.3b
0.0b
0.0b
0.0b
All data were analyzed using analysis of variance procedures. Means were separated using Fisher’s LSD
at the 0.05 level of significance. Means followed by the same letter within a column are not significantly
different (P>0.05).
Table 2.
Treatment/
formulation
Untreated Control
HGW86 600FS
HGW86 600FS
HGW86 600FS
HGW86 200FS
HGW86 200FS
HGW86 200FS
Admire Pro
Admire Pro
A16901
A16901
Platinum 75SG
Platinum 75 SG
Rate
4.5 fl oz / acre
6.75 g [ai] / 100 kg
9 g [ai] / 100 kg
10.27 fl oz / acre
13.7 fl oz / acre
9 g [ai] / 100 kg
8.7 fl oz / acre
9.36 g [ai] / 100 kg
6.25 oz/ acre
10 oz/ acre
1.68 oz / acre
2.66 oz / acre
Mean no. PLH /
10 compound
Appl.
leaves
% Defoliation Tuber Yield
Method
(69 DAT)
(71 DAT)
lb / plot
IF
ST
ST
IF
IF
ST
IF
ST
IF
IF
IF
IF
11.0a
8.8a
12.5a
10.5a
10.0a
9.3a
14.0a
0.0b
0.5b
0.8b
0.3b
0.0b
0.0b
29.0a
0.0b
2.5b
2.0b
0.0b
0.0b
10.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
35.7d
41.7bcd
47.8abc
41.3bcd
39.6cd
42.9bcd
45.2a-d
50.6ab
50.6ab
49.2abc
54.1a
50.4ab
49.0abc
% Wireworm
damage
12.0
4.0
4.5
4.5
3.0
1.5
5.5
2.5
2.0
5.0
2.5
7.5
3.5
All data were analyzed using analysis of variance procedures. Means were separated using Fisher’s LSD at the 0.05
level of significance. Means followed by the same letter within a column are not significantly different (P>0.05).
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