COMPARATIVE-EVALUATION OF A TRACTOR MOUNTED SAMPLER FOR SAMPLING ARTHROPODS IN COTTON

Population estimates of selected arthropods including lepidopterous la rvae, spiders, and adult and immature hemipterous and chewing predator s in early season cotton, by sweep net, drop cloth, and a tractor-moun ted sampler were compared. Population estimates by the tractor-mounted sampler were usually highly correlated to those provided by one or bo th of the other methods except for arthropods observed only at very lo w population levels. The tractor-mounted sampler most frequently detec ted presence of most arthropods at low population levels, and generall y provided lower estimates of relative sample variation than sweep net or drop cloth methods. The need for modifications to the tractor-moun ted sampler to improve the efficiency of collection of hemipterous nym phs is suggested. Our results indicate the tractor-mounted sampler pro vides an adequate means of sampling arthropods in early season cotton and may be particularly useful in monitoring arthropods occurring at l ow population levels.