SEASONAL INCIDENCE OF METEORUS AUTOGRAPHAE1 ON SOYBEAN LOOPER2 LARVAE ON SOYBEAN IN SOUTH CAROLINA, AND THE INFLUENCE OF HOST DENSITY ON PARASITIZATION3

Abstract

The seasonal incidence of Meteorus autographae Muesebeck (Hymenoptera: Braconidae) on larvae of the soybean looper, Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae), in soybean fields in South Carolina was monitored at two locations during 1981, 1982, and 1983. In most instances, parasitism of soybean looper larvae by M. autographae was detected 7 to 14 days after soybean looper larvae were first found in the fields. During this three-year study, maximum parasitism of soybean looper larvae by M. autographae within a season ranged from 4.6 to 19.8%. In the laboratory, numbers of hosts parasitized per 24 hours by M. autographae increased with each successive increase in host density. At a host density of 40 larvae per 1.75-liter cylindrical container, an average of 26 hosts were parasitized by one M. autographae during 24 hours. Percent parasitism remained about the same (64 – 70%) at all host densities.