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Can a chitin‐synthesis‐inhibiting turfgrass fungicide enhance black cutworm susceptibility to a baculovirus?
Author(s) -
BixbyBrosi Andrea J,
Potter Daniel A
Publication year - 2012
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.2252
Subject(s) - cutworm , fungicide , biology , chitin , biopesticide , pest analysis , microbiology and biotechnology , pesticide , agronomy , botany , toxicology , noctuidae , chitosan , biochemistry
BACKGROUND: Developmental resistance, i.e. reduced virulence and speed of kill of late instars, is a limiting factor in the use of baculoviruses for caterpillar control. Agrotis ipsilon multicapsid nucleopolyhedrovirus ( Agip MNPV) is highly infective to young black cutworms, Agrotis ipsilon , but too slow‐acting against late instars for effective curative control on golf courses or sports fields. Chitin‐synthesis‐inhibiting fungicides containing the active ingredient polyoxin‐d are used to control fungal diseases in turfgrass, and similar compounds have been shown in the laboratory to synergize baculoviruses by disrupting peritrophic membrane function. This study tested whether applying the virus together with such a fungicide can synergize Agip MNPV activity against A. ipsilon in turfgrass. RESULTS: The addition of a chitin synthesis inhibitor failed to increase Agip MNPV infectivity to A. ipsilon in the field. Rather, delayed and slightly reduced mortality from viral infection was seen when larvae fed on fungicide/virus‐treated grasses as opposed to virus‐only treatments. Choice tests revealed the fungicide residues to be a mild feeding deterrent. CONCLUSION: Because polyoxin‐d does not deactivate Agip MNPV, the two substances are compatible. However, combination applications of polyoxin‐d and Agip MNPV on turfgrass might interfere with larval ingestion of a lethal virus dose, resulting in prolonged larval feeding in the field. Copyright © 2011 Society of Chemical Industry