Evaluation of selected acaricides against twospotted spider mite (Acari: Tetranychidae) on greenhouse XXXX using multispectral data.

@entity14653 @entity7213 @entity51861 @entity2708
UNASSIGNED: Twospotted spider mite (TSSM), @entity7213 Koch, is an early season pest of @entity2708 in the mid-southern USA and causes reduction in yield, fiber quality and impaired seed germination. Objectives of this study were to investigate the efficacy of @entity51861 and @entity14653 with two divergent LC50 values against TSSM in a computer-operated spray table which simulated aerial application parameters. Combined with a pressure of 276  kPa and a speed of 8  km/h, a 650033 nozzle delivered a spray rate of 18.7 L/ha. The active ingredient rates were 1/8, 1/4, 1/2 and the lowest label recommended rates for early season @entity2708 . The intent was to study efficacy relative to deposition characteristics at active ingredient rates equal to and lower than those recommended by the label. Spectral reflectance values from a multispectral optical sensor were used to calculate the Normalized Difference Vegetation Index which numerically described the surface reflectance characteristics of @entity2708 canopies concomitant to damage caused by @entity7213 in the greenhouse. Water sensitive paper samplers described spray droplet spectra parameters (Dv0.1, Dv0.5 and Dv0.9,   m) and percent spray coverage. The volume median diameter (Dv0.5,   m) for @entity51861 and @entity14653 were respectively, 218 and 258 at one-half rate of the lowest label rate. These spray droplets were well above the driftable portions of the spray volume (<141    m) for both @entity51861 and @entity14653 . Efficacy evaluations indicated that @entity14653 was more effective than @entity51861 in controlling @entity7213 on early season @entity2708 at one-half rate of the lowest label rate. Results reported herein demonstrate that the multispectral optical sensor in lieu of manually counting @entity7213 appears to be a promising tool for efficacy evaluations against acaricides for early season plants grown in greenhouses.
