Virulence of the entomopathogenic fungus Beauveria brongniartii to several life stages of the yellowish elongate chafer Heptophylla picea Motschulsky (Coleoptera: Scarabaeidae)

Abstract

A strain of Beauveria brongniartii PBbr-1 was isolated from infected larvae of Heptophylla picea. This isolated strain attained 100% mortality of H. picea adults at a concentration of 1.0ϫ10 7 conidia/ml, with a short median lethal time of 8.4 d for females and 7.0 d for males. The number of eggs laid by adults and percent of eggs hatching for females inoculated with PBbr-1 were lower than those by healthy females. However, when PBbr-1 was inoculated directly to the eggs, hatchability was almost the same as that in non-inoculated eggs. Since infected females appeared to lay eggs just before death, the eggs from females infected with PBbr-1 were thought to be unfertilized. Furthermore, PBbr-1 showed a high virulence to the first-stage larvae. PBbr-1 not only had a high virulence to the adults, but also suppressed subsequent generations. PBbr-1 is thus thought to be a very effective control agent for H. picea in combination with Beauveria amorpha HpBa-1.

Virulence of Beauveria brongniartii and B. bassiana against Schizonycha affinis white grubs and adults (Coleoptera: Scarabaeidae)

“…Adults of S. affinis were more susceptible to isolates of B. brongniartii than both the second and third instar larvae of this species, which is in accordance with previously reported studies on white grubs (Strasser and Pernfuss ; Yaginuma et al. ). It seems prudent to select a B. brongniartii isolate which has greater virulence towards the long‐lived larvae than the shorter‐lived adults.…”

Pathogenicity ofMetarhizium anisopliae(Hypocreales: Clavicipitaceae) to Tick Eggs and the Effect of Egg Cuticular Lipids on Conidia Development

“…Roberts and Humber (1981) showed that eggs are the most fungi-resistant insect stage; moreover, eggs of certain insects can survive even with fungus growing on their cuticle surface (Inglis et al 1995). Coleopteran eggs are known often to be highly resistant to fungal infection (Long et al 1998, Rajendran 2002, Yaginuma et al 2006), but eggs of other insects, especially those of the orders Lepidoptera and Hemiptera, are relatively susceptible to entomopathogenic fungi such as Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae), Metarhizium anisopliae variety anisopliae (Metschn.) Sorokin (Hypocreales: Clavicipitaceae), and Paecilomyces fumosoroseus (Wize) Brown and Smith (Eurotiales: Trichocomaceae) (Maniania 1991, Ekesi et al 2002, Samuels et al 2002.…”