Two-Spotted Spider Mite Control on Tart Cherry, 2016* Open Access

This trial was conducted at the MSU Northwest Michigan Horticulture Research Center in Traverse City, MI. Treatment plots consisted of single tree plots with four replicates per treatment, arranged in RCB design in a 22-yr-old tart cherry block (row spacing 20 × 18 ft.). Maintenance materials were applied across the block and included Chlorothalonil, Captan, Actara, Admire Pro, Ethrel, Delegate, Syllit, Luna Sensation, Gem, Assail, Imidacloprid, Indar, and Asana. Princep, Roundup-Ultra, and Gramoxone were banded below trees for weed control. Test materials were applied at the TSSM threshold (3–5 mites per leaf) on 29 July. All applications were made with an FMC 1229 airblast sprayer calibrated to deliver at 120 GPA at 1.5 mph.

Pre-counts were conducted; with post-treatment counts made on 7-d intervals (see Table 1). Evaluations were conducted by picking a 25-random-leaf-sample per plot. Mites were removed from leaves with a mite-brushing machine and counted under a Stereo microscope. All mite data are reported as the mean number of mites per leaf. While actual counts are presented, ANOVA was run on log transformed data. Transformed treatment means were analyzed using ANOVA and means separation by Tukey’s HSD at P = 0.05.

All treatments significantly reduced the incidence of motile TSSM within 14 d of the threshold application (Table 1). A rate response was observed for Magister with significantly lower motile TSSM in the 18 Aug evaluation.

Author notes