APHID MANAGEMENT ON HEAD CABBAGE, 1997:

R. F. L. Mau and L. R. Gusukuma-Minuto

University of Hawaii

Dept. of Entomology

3050 Maile Way, Rm. 310

Honolulu, HI 96822

Phone: (808) 956-7063

CABBAGE: Brassica oleracea L. ‘Tastie’

Cabbage aphid (CA); Brevicoryne brassicae L.

Green peach aphid (GPA); Myzus persicae (Sulzer)

The study was conducted at the substation of the Kula Research Station, Maui Agricultural Park. A randomized complete block design with six treatments and four replications (blocks) was used. Each treatment plot consisted of a single row of cabbage planted at 18 in. between plant spacing. Each row consisted of 45 plants for a total length of approximately 70 ft. Treatment plots were separated by a 48 in. spacing. Blocks were separated by a 60 in. spacing. Total field size was 0.15 acres. Admire was applied on 25 Jun, one week after transplanting seedlings into the field. A hand injector was used to place the insecticide in the root zone. The field was irrigated immediately following the Admire application. Foliar treatments were applied on 22 July at a rate of 100 GPA and 60 psi using a CO₂ backpack sprayer. The spray wand was equipped with a single hollow cone TX-26 nozzle. Aphid counts were made at pre-treatment, 6, 13, and 20 DAT. In conducting the surveys, the same ten plants in each treatment plot were examined. Alatae and apterous counts were made for the pretreatment, 6 and 13 DAT surveys. Only the total number of aphids was recorded at the last survey. Aphid species determination was made by the Entomology Departments’ insect taxonomist.

Aphid alatae were observed on the plants during the first four weeks after transplanting. Initial infestations consisted of CA and GP. Treatments were made when aphid colonies exceeded 5 apterous aphids/plant. Acetamiprid and Provado foliar treatments effectively controlled the aphids with just one application. Effective control was maintained for about two weeks as shown by 6 and 13 DAT aphid counts. Aphid colonies increased rapidly in all acetaprimid treatments after the 13 DAT survey. At 20 DAT, aphid counts were very high in the UTC, moderate in the acetamiprid treatments and lowest in the Provado plots. The Admire treatment provided excellent aphid control for about 6 weeks.

Means in the same column followed by a different letter are significantly different (P<0.0001, SAS for Windows version 6.11). Data was transformed by square root (Y+0.5) prior to analysis. Untransformed means are presented.

Means in the same column followed by a different letter are significantly different (P<0.0001, SAS for Windows version 6.11). Data was transformed by square root (Y+0.5) prior to analysis. Untransformed means are presented.