Pear rust mite,Epitrimerus pyri (Acari: Eriophyidae) oviposition and nymphal development on Pyrus and non-Pyrus hosts

The ovipositional response of deutogynes of the pear rust mite, Epitrimerus pyri Nalepa, and the rate of development of E. pyri nymphs differed according to the host plant to which mites were exposed. Among the fourteen Pyrus hosts examined, leaves from the Clapp's Favorite cultivar of P. communis elicited the strongest egg-laying response and the fastest rate of nymphal development, whereas egg-laying was least and nymphal development slowest on leaves from P. calleryana. Among the three non-Pyrus hosts, E. pyri oviposited and completed nymphal development on apple and quince leaves, but would not deposit eggs on apricot. Antixenosis appears to be the primary mechanism of resistance, although antibiosis may be operating to a lesser extent. These results are discussed in relation to the resistance of Pyrus to other arthropod pests.