Premium
The influence of temperature on the susceptibility of vine weevil, Otiorhynchus sulcatus (Fabricius) (Coleoptera: Curculionidae), larvae to Metarhizium anisopliae (Deuteromycotina: Hyphomycetes)
Author(s) -
MOORHOUSE E R,
GILLESPIE A T,
CHARNLEY A K
Publication year - 1994
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1994.tb04127.x
Subject(s) - biology , metarhizium anisopliae , hyphomycetes , curculionidae , weevil , fungi imperfecti , virulence , conidium , metarhizium , larva , pest analysis , botany , horticulture , veterinary medicine , microbiology and biotechnology , medicine , biochemistry , gene
Summary Mortality of Otiorhynchus sulcatus (Fabricius) larvae at 10 o C, 15 o C, 20 o C and 25 o C following treatment with 10 7 conidia ml“ 1 suspensions of six Metarhizium anisopliae (Metschnikoff) Sorokin isolates was temperature dependent. In all cases, the LT 50 s were inversely related to temperature, but the nature of this response varied between isolates. Strain 101‐82 was the most virulent isolate at 25 o C with an LT 50 of 3.7 days, but it was the least virulent isolate at 15 o C and it failed to kill any O. sulcatus larvae at 10 o C. In contrast, strain 159‐83 had the lowest virulence at both 20 o C and 25 o C, whereas it was the most virulent isolate at 10 o C with an LT 50 of 20.0 days. The mortality rates followed a similar pattern and were positively related to temperature in all cases with the exception of strain 159‐83 at 25 o C. Mycosis development was examined on larvae treated with strain 275‐86 and significant differences were obtained between all four temperatures. Sporulation commenced after approximately 2.75 days at 25 o C, but took nearly 11 days at 10 o C. The infection rates also varied between temperatures; sporulation occurred on 98% of the treated larvae at 25 o C, but only on 93%, 87% and 49% of the larvae at 20 o C, 15 o C and 10 o C, respectively. The results of these bioassays demonstrate that temperature has a significant effect on the virulence of M. anisopliae. The differences between fungal strains also emphasises the importance of selecting isolates for specific situations on the basis of their temperature profiles.