RELATIVE DENSITIES OF PREDACIOUS AND PHYTOPHAGOUS MITES ON THREE VARIETIES OF APPLE TREES

Abstract

AbstractIn two well-kept but nonsprayed orchards, the European red mite, Panonychus ulmi (Koch), was more numerous and caused more leaf damage to Delicious than to Spartan or McIntosh apple trees. The predacious phytoseiid mites, Metaseiulus occidentalis (Nesbitt) and Neoseiulus caudiglans (Schuster), were more numerous on both Spartan and McIntosh than on Delicious. The differences in the external structure of the leaves may be the reason for the greater abundance of phytoseiids on Spartan and McIntosh.