(E40)
POTATO: Solanum tuberosum L., ‘Katahdin’.
CONTROL OF APHIDS ON IRISH POTATO, 2006
Gary H. Sewell
Aroostook Farm
59 Houlton Rd.
Presque Isle, ME 04769
Phone: (207) 768-5963
Fax: (207) 764-6740
[email protected]
Andrei Alyokhin
5722 Deering Hall, Rm 315E
University of Maine
Orono, ME 04469
Phone: (207) 581-2977
Fax: (207) 581-2969
[email protected]
Buckthorn aphid (BA): Aphis nasturtii Kaltenbach
Potato aphid (PA): Macrosiphum euphorbiae (Thomas)
Green peach aphid (GPA): Myzus persicae (Sulzer)
The RCB design experiment was replicated 5 times and conducted at Presque Isle, ME on land that was in clover in 2005. It
was planted 30 May leaving a 10 ft fallow space between blocks and a 6 ft space between the four-row plots. Two-oz seed
was hand planted at 12 inch spacing and all rows were 50 ft long. Fertilizer and hilling practices were normal for the area.
Early and late blight were controlled by seven foliar applications of mancozeb. Foliar insecticide applications were made
with a Century boom sprayer, three nozzles per row at 60 psi pressure and 50 gpa. Numbers of aphids (by species) were
counted on a top, middle, and bottom leaf on 20 plants in the middle two rows of each plot. When dates of count and
application were the same, aphid counts were made prior to applications of the insecticide. ANOVA were calculated
following transformation of the data using log10(x + 1). Transformed means of the total number of wingless aphids were
compared using Fisher's LSD Test. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul,
and Aug was respectively 4.7, 5.5 and 2.7 inches and the average temperature was 66, 70 and 63°F.
Composition of the 2006 aphid populations by species was as follows: early Jul - PA 100%; late Jul – GPA 0.9% and PA
99.1%; early Aug – BA 0.7%, GPA 1.6% and PA 97.7%; late Aug - PA 100%. One application of all materials
significantly reduced populations compared to the untreated control (UTC), but numbers of aphids in the Monitor treatment
were significantly lower than the others. The addition of adjuvants to BY108330 aided efficacy. No obvious specificity of a
material for an aphid species was noted and no phytotoxicity was observed.
Transformed no.
all species aphids/20 plants
Treatment/
formulation
Rate/acre
Application
dates
Assail 30SG
UTC
Monitor 4L
BY108330 150 g/liter OD
BY108330 150 g/liter OD +
MSO 100EC
BY108330 150 g/liter OD +
Silwet L-77 100EC
BY108330 150 g/liter OD +
Induce 100EC
4.0 oz wt
--32 fl oz
8 fl oz
8 fl oz +
64 fl oz
8 fl oz +
32 fl oz
8 fl oz +
64 fl oz
3 Aug
--3 Aug
3 Aug
3 Aug
3 Aug
3 Aug
3 Aug
3 Aug
3 Aug
27 Jul
02 Aug
09 Aug
16 Aug
18.2a
22.5a
19.5a
11.6a
23.8a
38.3a
39.3a
45.2a
43.6a
47.6a
13.4abc
31.8a
0.8d
20.2ab
9.1bc
1.4a
1.4a
0.8a
1.0a
0.2a
22.2a
52.0a
8.6bc
1.0a
25.3a
43.9a
4.2c
0.4a
Means in a column followed by the same letter are not significantly different (LSD, P = 0.05).