ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
POTENTIAL OF FUNGAL PATHOGENS FOR THE CONTROL OF PEAR PSYLLA |
| Author: | Gary J. Puterka |
| Abstract:
Pear psylla, Cacopsylla pyricola L., is the most destructive insect pest of pear in the United States. Chemical control is the primary means of managing this pest but the pear psylla is rapidly developing resistance to many commonly used insecticides. Fungal pathogens of pear psylla and their potential for controlling this pest has not been investigated. Thus, our goal was to investigate the virulence of fungal pathogens to pear psylla. A detached-leaf laboratory bioassay was developed to evaluate the susceptibility of pear psylla nymphs to indigenous and exotic strains of fungi collected from aphids and other psylla species. Two species of Metarhizium and several strains of Beauveria bassiana, Paecilomyces farinosis, and Verticillium lecanii were evaluated. Nymphal mortalities occurred 1 day after applying fungal spores. Beauveria, Verticillium, and Paecilomyces caused 100% mortalities within 5 days after applying spore concentrations of 107 spores/ml. regardless of the strain used within fungal species. Both Metarhizium spp. only caused 40% mortalities at the same spore concentration and time. These results indicate that control of pear psylla with certain strains of fungal pathogens is possible. Field evaluations will be conducted this spring, 1993, to determine which fungal strains are most effective. | |
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