Foliar Sprays of Synthetic Pyrethroids and Numbered Chemicals for Control of Colorado Potato Beetle, Test 10, 1978

Abstract

Abstract 'Russet Burbank potatoes were planted on Mar 30 in Rirzville silt loam soil (Mesic Calciorthidic Haploxerolls) at Yakima, WA. A high infestation of the second generation of Colorado potato beetle (CPB) adult and larvae were defoliating the plants by Aug 7, the time of insecticide application. The insecticides were applied as foliar sprays in 40 gal/acre with a 2-row portable boom CO2 hand sprayer. The plots were 2-rows wide (5.6 ft) and 25-ft long and each treatment was replicated 4 times in a randomized complete block design. The number of live adults and larvae per rr/ of potato foliage per plot was counted on Aug 8 and 11 (1 and 4 days after treatment). Also, on Aug 8 the potato foliage between the 2 rows of each plot was separated and the number of dead and live adults and larvae per m* of soil surface plot was counted. Since both dead and live adults and larvae were on the soil and only live adults and larvae were on the plants, the percent mortalities were determined as follows: 1) percent mortality for adults or larvae on the soil based on number dead out of total number dead and live on soil; 2) percent mortality of adults or larvae based on number dead on soil out of total number on plants and soil; 3) percent mortality of CPB population based on number dead adults and larvae on soil out of total numbers of dead adults and larvae on plants and soil. The number of insects and the calculated percent mortality for each plot were subjected to analysis of variance using DMRT.