Impact of Nosema (Microsporidia) infection and fumagillin treatment on Lygus lineolaris (Hemiptera: Miridae).

A consistent supply of healthy tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is necessary for the development of novel management strategies targeting this pest. After being in culture for several years, a substantial portion of a tarnished plant bug colony was found to be infected with a Nosema (Microsporidia) species. Studies were subsequently undertaken to evaluate the impact of Nosema infection on tarnished plant bug productivity and to test the efficacy of fumagillin to treat this infection. Using buffalo black stain, infections could not be reliably detected in adult tarnished plant bugs until adults were 6-8 days post eclosion. Nosema infections reduced adult longevity and fecundity. Maximum fecundity was restored using a concentration of 16.8 ppm fumagillin while maximum longevity for females was at a concentration of 33.6 ppm fumagillin incorporated into the tarnished plant bug diet. Minimum infection scores were obtained at 67.2 ppm, the highest concentration tested. A field survey of tarnished plant bugs in Mississippi found Nosema infections in 3% of wild tarnished plant bugs.