Prevalence of naturally occurring Beauveria bassiana in Lygus lineolaris (Heteroptera : Miridae) populations from wild host plants of Mississippi

摘要

Surveys of natural Beauveria bassiana (Balsamo) infection levels in tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), populations from wild host plants in Mississippi were conducted. Populations of L. lineolaris were sampled from nine dominant wild host plants by sweep net and held for sporulation as evidence of infection with B. bassiana. Infection rates from L. lineolaris populations on wild host plants ranged from 0% to 8% and averaged 0.3%. Incidence of L. lineolaris infection was not correlated with Julian date but was inversely correlated with L. lineolaris population density. The highest incidence of natural infection was found in populations from goldenrod, Solidago altissima (L.) and natural infection among populations from all other wild host plants were similar. Despite the low incidence of natural infection, 23 new isolates of B. bassiana from L. lineolaris were discovered, which will be evaluated for characteristics relevant to developing a microbial biocontrol strategy for L. lineolaris. Natural infection levels will be useful when evaluating the efficacy of B. bassiana in field trials targeting these populations and evaluating potential for displacement of naturally-occurring B. bassiana isolates.