Aphid and Mite Suppression on Strawberries, 198

'Tufts' strawberries were transplanted Nov 3 '81 into drip-irrigated, double-row raised beds. Beds were mulched with clear plastic approximately 1 week following transplanting. Vydate was injected through the drip line by reversing a standard line filter, adding the chemical, and allowing the water and Vydate mixture to be forced through the system. The water was turned on ca. 1 hr prior to application and allowed to run for 1.5-2hr following application. Water pressure averaged 13 psi. Treatments were made weekly beginning Jan 19 until Feb 16 (5 applications) at 1.12 kg/ha. Remaining 11 weekly applications were at 0.56 kg/ha. Each plot was 22.9 m (2 rows/bed) and was replicated 4 times in an incomplete block design. Edge effects were reduced by leaving at least 4 buffer rows on each side of the test and 4.25 m on each end. On Jan 26, Feb 9, and on alternate weeks thereafter (7 sample dates), mites and aphids in treatment plots were evaluated by whole plant counts from one randomly chosen sub-bed per replicate (16 plants). Infestations were classified by the following index: 0 = 0, 1-5 = 1, 6-20 = 2, 21-50 = 3, 51+ = 4. Additionally, 10 leaves were selected at random from each replicate and examined with a dissecting microscope. The number of mite-infested leaves per replicate and an index of pest population size (size previous index) were recorded on each sampling date.