Virulence of the Entomogenous Fungi Metarhizium anisopliae (Metschnikoff) Sorokin, M. flavoviride Gams and Rozsypal and Beauveria bassiana (Ballsamo) Vuillemin to Adoryphorus couloni (Burmeister) (Coleoptera: Scarabaeidae)

Abstract

Tw.0 isolates of hleturhi:i~rt~? ani.wpliae and one isolate each of hil. ,f/uvoviride and Bruirrrerirr bussiunu, originally isolated from the redheaded pasture cockchafer, Adorfphonts couloni, were bioassayed for their virulence against both L3 larvae and adults. Only M. anisopliue DAT F-001 was highly virulent to both larvae and adults. At a concentration of 2 x lo6 spores/g sandpeat, the LT.,, for larvae at 20°C was 24.5 d. ,$I, ,f/ai$oviride was not pathogenic to larvae but was pathogenic to adults at all three concentrations tested (2 x lo', 2 x 10'. 2 x 10' sporeslg sandpeat mix). B. bussiuna was not pathogenic to either larvae or adults, but this isolate, hf. flavoviride and M . trnisopliue DAT F-001 reduced the number o f eggs produced by 50.75% at the 10' and lo" concentrations. Germination studies on the iwlate, showed that M. anisop/iue DAT F-001 and hl. ,f/m*oviride could germinate at temperature\ relevant to field conditions (5-15°C).

The Susceptibility of Boophilus annulatus (Ixodidae) Ticks to Entomopathogenic Fungi

“…Therefore, the timing of when females drop oV their host onto fungi-contaminate d soil, and the point at which egg laying is reduced, may be of critical importance in terms of reducing the tick population . The time interval between tick inoculatio n and death and the dose which caused the high mortality were similar to those of many susceptible insects, that are known as natural hosts for M. anisopliae (Liu et al, 1989, Butt et al, 1992, Rath et al, 1995.…”

The effect ofMetarhizium anisopliae (DAT F-001) concentration and exposure time on the survival of the subterranean pasture pest,Adoryphorus couloni (Col.: Scarabaeidae)

“…While DAT F-054 is a pathogenic isolate of low virulence for L3 larvae of A. couloni (Rath et al, 1995b), all larvae were still alive at Frass production of L3 larvae of A. couioni …”

“…L3 larvae (45) were placed in individual Petri dishes of sand-peat (1:1 v/v; 20% water w/w) at 20~ for 10 days prior to experimentation. After this time larvae were rolled in 14-day sporulating cultures of DAT F-001 (15 larvae) or DAT F-054 (M. anisopliae weakly pathogenic to L3 A. couloni - Rath et al, 1995b) (15 larvae) grown on Sabouraud dextrose agar (SDA; Oxoid CM41) + 2% yeast extract. The remaining 15 larvae were used as untreated controls.…”

“…The two-year life-cycle and the damage caused by the pest is described by McQuil'lan & Iresoo (1987) and summarised by Rath et al (1995b). A biological control program using an isolate of Metarhizium anisopliae (Metschn.)…”

“…In laboratory studies, Rath et al (1995b) found that the LTso for L3 larvae of A. couloni at 20~ was 24.5 days at a M. anisopliae DAT F-001 concentration of 2 x 106 spores/g sand-peat mix (s/g s.p.). They also showed that DAT F-001 was pathogenic to adults at concentrations of 10 5 and 106 s/g s.p.…”