Screening of entomopathogenic fungi against the brown-winged green bug, Plautia stali Scott (Hemiptera: Pentatomidae).

Abstract

Entomopathogenic fungi with high pathogenicity against the brown-winged green bug adult, Plautia stali, were selected from among the 711 isolates of entomopathogenic fungi in our laboratory culture collections including Beauveria, Metarhizium and Paecilomyces genera. For the first screening, a plate assay method, in which stink bugs contacted conidia on their developing plates, was used, and 31 isolates of Beauveria bassiana and 20 isolates of Metarhizium anisopliae were selected. For the second selection, stink bugs were dipped into a conidial suspension, and LC 50 values were estimated from the data of the 7th day after treatments. The results showed that Metarhizium isolates were relatively more virulent than Beauveria isolates. The minimum LC 50 value was obtained from M. anisopliae isolate FRM515, being 6ϫ10 4 conidia/ml. When the suspension of 1ϫ10 7 conidia/ml was used, LT 50 value of the isolate was 4.9 days. The highest pathogenicity of isolate FRM515 in our collections suggests that the isolate would be a potential candidate as a microbial control agent for the stink bug.

Laboratory studies on the infection of stink bugs with Metarhizium anisopliae strain FRM515

“…We used M. anisopliae strain FRM515, previously identified as a strain with high pathogenicity to P. c. stali (Ihara et al, 2001). Sabouraud maltose medium (SMY) con-taining 4% maltose, 1% peptone, and 1% yeast extract was used for liquid cultivation of the strain, and SMY solidified with 1.5% agar was used for solid cultivation.…”

“…Conidial suspensions (1ϫ10 7 and 1ϫ 10 8 conidia/ml) of M. anisopliae strain FRM515 for use in bioassays were prepared as described previously (Ihara et al, 2001). Each adult stink bug was dipped into 5 ml of conidial suspension in a 20-ml plastic vessel for 10 s at room temperature.…”

“…M. anisopliae strain FRM515 showed the highest pathogenicity to P. c. stali among the 711 isolates tested (Ihara et al, 2001). Two additional species, G. subpunctatus and H. halys, are (like P. c. stali) fruit-piercing stink bugs (Hasegawa and Umeya, 1974) that damage apple (Funayama, 1996), citrus (Ide, 1997), pear (Sato, 1997), and persimmon (Yanase, 1997).…”

“…A previous investigation evaluated the fungus Beauveria bassiana as a microbial pesticide for the control of P. c. stali (Tsuda et al, 1996(Tsuda et al, , 1997. Further, the high pathogenicity of Metarhizium anisopliae strain FRM515 to P. c. stali (Ihara et al, 2001) suggests that this organism is a candidate microbial control agent for stink bugs. However, other characters (i.e., factors affecting pathogenicity) of the fungus are currently unknown and must be addressed to clarify its suitability for this application.…”

Virulence of entomopathogenic fungi against Plagiodera versicolora (Laicharting, 1781) (Coleoptera: Chrysomelidae)

“…From these entomopathogenic fungi, M. anisopliae and B. bassiana are the most studied species and isolates of both have been registered by The United States Environmental Protection Agency (USEPA) (Rath, 2000). Up to now, the entomopathogenic fungus, B. bassiana, has been extensively used for the control of many important pests of various crops around the world and it has been tested on different target insects (Campbell et al, 1985;Leathers and Gupta, 1993;Inglis et al, 1996;Ihara et al, 2001;Padmaja and Kaur, 2001;Çam et al, 2002;Susumu and Motoko, 2002;Todorova et al, 2002).…”