SAMPLING THE DENSITY AND DISTRIBUTION OF AMBLYSEIUS FALLACIS (ACARINA: PHYTOSEIIDAE) IN THE GROUND COVER OF MICHIGAN APPLE ORCHARDS

Publisher Website
Google Scholar
Abstract
An extraction method, timed counts taken from broadleafed forbs, and counts taken on apple sucker leaves were evaluated as sampling methods to estimate populations of the predatory phytoseiid mite Amblyseius fallacis Garman in the ground cover of commercial apple orchards. All three gave comparable density estimates at moderate and high population levels. The extraction sample technique was most effective in measuring low population densities, however the timed vegetational procedure was deemed the most practical method for monitoring these mites for pest management purposes. With respect to predator distribution in the ground cover, mites were aggregated somewhat in the heterogeneous understory, but were almost randomly distributed on apple sucker leaves. Predators were equally likely to find prey irrespective of location beneath the tree canopy. They showed little preference for different plant species with the exception of a higher incidence than expected on apple (Malus) and possibly on grape (Vitus sp.) and Virginia creeper (Parthenocissus quinquefolia).