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Traits associated with virulence to the aphid Macrosiphoniella sanborni in eighteen isolates of Verticillium lecanii
Author(s) -
JACKSON C. W.,
HEALE J. B.,
HALL R. A.
Publication year - 1985
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.1744-7348.1985.tb03092.x
Subject(s) - virulence , biology , aphid , microbiology and biotechnology , verticillium dahliae , entomopathogenic fungus , fungus , extracellular , spore , conidium , germination , chitinase , botany , biological pest control , enzyme , beauveria bassiana , gene , biochemistry
SUMMARY Eighteen isolates of the entomopathogenic fungus Verticillium lecanii from various world‐wide locations, from insect hosts and soil were bioassayed against the aphid Macrosiphoniella sanborni in the laboratory. Virulence ranged from an isolate which achieved 100% mortality and LT 50 value (adults) of 3 days ± 0· 2 at 24 ° C, compared with the least virulent isolates causing less than 10% mortality over 14 days (when treated with an inoculum of 1 × 10 6 conidiospores/ml). All isolates produced extracellular protease and lipase, irrespective of their virulence. A number of traits were frequently associated with the expression of virulence including fast germination, high sporulation rate, an absence of extracellular amylase activity and high extracellular chitinase activities. Large spore size was not strongly associated with virulence. There were exceptions in each variate studied, suggesting that overall expression of virulence is a result of the total complex of these and other traits still to be determined.