ABSTRACT

Surveys throughout the San Joaquin Valley of California revealed the presence of the entomopathogenic fungus Beauveria bassiana in Lygus hesperus populations. The fungus occurred in all counties sampled and at virtually all times of the year Lygus was present. In some samples more than 50% of the population was infected. In addition to the Valley-wide surveys, several fields were monitored weekly for Lygus population size and B. bassiana prevalence. Weak correlations occurred between population size and percentage infection and between time of year and infection levels. Again, in some samples, percentage infection exceeded 50% of the Lygus population.