We investigated the changes in diversity of the soil arthropod community following the introduction of a composted organic mulch in an avocado orchard in Temecula, Riverside County, California. The mulch was introduced in March 2000 in an attempt to reduce the pupation rates of Scirtothrips perseae beneath avocado trees. This thrips is a serious pest of avocado in California. Monitoring of S. perseae emergence from mulch indicated that peak emergence rates were reduced by 50% in comparison to controls. One potential suppressive mechanism could be microarthropods that colonized the mulch are antagonistic towards thrips propupae and pupae.
Berlese funnel extractions, of mulch and naturally-occurring leaf duff, were conducted monthly to census the microarthropod fauna at the trial site. The total number of specimens collected from berlese funnell extractions at the site through the spring and summer increased twofold. Arthropods recovered from mulch and leaf duff included thrips (predatory and phytophagous), mites, collembola, sowbugs, beetles, bugs, ants, and wasps. The phenology and relative abundance of microarthropods in composted mulch are compared to untreated leaf duff and soil, and these results are presented here. Companion studies are investigating the potential suppressiveness of entomopathogenic fungi and nematodes against S. perseae.
Species 1: Laurales Lauraceae Persea americana (avocado)
Species 2: Thysanoptera Thripidae Scirtothrips perseae (avocado thrips)
Species 3: Thysanoptera Aeolothripidae Franklinothrips orizabensis
Keywords: thrips, soil predators
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA