Twospotted Spider Mite Control on Strawberries, 1983

‘Tufts’ strawberries were transplanted 2 Nov., 1982, into drip irrigated, double-row raised beds. Beds were mulched with clear plastic approximately 1 week following transplanting. Treatments were arranged in a randomized complete block design with four replicates of each treatment. Each replicate consisted of two sub-beds (17 plants per sub-bed). I-secticides were applied on 9 Mar. and 25 May, using two hollow cone nozzles per row with D3, orifices, #33 cores and 50-mesh sceens. Operating pressure was 6.33 kg/cm2 and delivery rate was 1,402 liter/ha. All applications except those including MK-396 contained 0.04% spreader per sticker (Biofilm). Spider mite populations were assessed by collecting the oldest functional trifoliate leaf per plant for five plants per replicate and counting the numbers of (1) eggs, (2) larvae + nymphs + adult males, and (3) adult females for 8 weeks following the first application and for 3 weeks following the second application. The egg stage was not counted following the second (late season) treatment or for the week immediately after the first application.