THE SEASONAL ABUNDANCE OF ARTHROPODS ON PEACH TREES IN SOUTH CAROLINA

A project was begun in 1977 to survey the arthropod complexes in the peach tree canopy, to devise a sampling apparatus to sample entire trees and allow for replication, and to compare faunal densities in sprayed and unsprayed blocks in an experimental peach orchard in Anderson County, South Carolina. A closed-canopy sampling apparatus, comprised of an aluminum conduit frame and polyethylene tree and ground covers, was constructed to encompass a mature peach tree. Clamps sealed the system and a pyrethrin-piperonyl butoxide aerosol was used to knock down the arthropods. The apparatus and technique were efficient in sampling fauna from all surface microhabitats in the canopy.; The plum curculio, Conotrachelus nenuphar (Herbst), exhibited two distinct generations per year in South Carolina. Overwintered adults emerged in March, and fed and oviposited in developing fruit. The second generation numbers peaked in late August to middle September, depending on temperature and rainfall, with numbers averaging 117.0 per tree in 1978 and 151.5 per tree in 1979. In 1980, peak fruit injury by the overwintered adults occurred in mid-April.; Numbers of spider mites and predators were determined for two years during this project. A heavy infestation of the twospotted spider mite, Tetranychus urticae Koch, occurred in 1978, a hot, dry year. Predator population curves of Stethorus punctum LeConte, Orius insidiosus (Say), and Chrysopa rufilabris Burmeister, closely correlated with the T. urticae population curve and were the predominant predators. Several other predators showed responses to populations of T. urticae and the European red mite, Panonychus ulmi (Koch), during the two-year study.; Spiders (Araneida), collectively, comprised a significant ecological force in the peach tree canopy. Philodromid, thomisid, anyphaenid, clubionid, salticid, and araneid spiders were most abundant. Hunting spiders were more prevalent than webspinners in mature trees. Insecticide applications, although ending in June, lowered the spider populations throughout the growing season. Considering the fruit damage in the unsprayed block, spiders were ineffective in reducing major pest numbers.