TY - JOUR
T1 - Pathogenicity of blastospores and conidia of Paecilomyces fumosoroseus against larvae of the Mexican bean beetle, Epilachna varivestis mulsant
AU - Behle, R. W.
AU - Garcia-Gutierrez, C.
AU - Tamez-Guerra, P.
AU - McGuire, M. R.
AU - Jackson, M. A.
PY - 2006/12
Y1 - 2006/12
N2 - The effects of blastospores and conidia of Paecilomyces fumosoroseus were compared for insecticidal activity against 3-day old larvae of Mexican bean beetle (MBB), Epilachna varivestis Mulsant. Blastospores of P. fumosoroseus were produced using strain ARSEF 3581 grown in a liquid basal medium, whereas conidia were produced on potato dextrose agar. Initial insecticidal activity was demonstrated with a single-dosage dipped-leaf assay using a concentration of 1 × 108 conidia or blastospores/mL. Blastospores, conidia, and no fungus control treatments averaged 90%, 86%, and 19% larval mortality, respectively, after 3-day continuous exposure. Subsequently, a dosage response assay was completed to compare two assay conditions, dipped-leaf and topical application techniques. Five spore concentrations, 1.2×109, 2.4×108, 4.8×107, 9.6×106, and 1.9×106 spores/mL, were prepared and used for both assay techniques. For the dipped-leaf technique, 25 larvae were exposed to treated leaf disks, five larvae to each of five treated leaf disks per spore concentration. For the topical assay, 5 μL was applied directly to each of 25 larvae for each spore concentration. After 3-day incubation, blastospores of P. fumosoroseus showed higher activity than conidia, and the topical application technique was more effective (lower LC50 values and lower X 2 values) than the dipped leaf assay technique. This research demonstrates the insecticidal activity of P. fumosoroseus on MBB and provides a comparison of two basic bioassay techniques that may be useful in future research on this topic.
AB - The effects of blastospores and conidia of Paecilomyces fumosoroseus were compared for insecticidal activity against 3-day old larvae of Mexican bean beetle (MBB), Epilachna varivestis Mulsant. Blastospores of P. fumosoroseus were produced using strain ARSEF 3581 grown in a liquid basal medium, whereas conidia were produced on potato dextrose agar. Initial insecticidal activity was demonstrated with a single-dosage dipped-leaf assay using a concentration of 1 × 108 conidia or blastospores/mL. Blastospores, conidia, and no fungus control treatments averaged 90%, 86%, and 19% larval mortality, respectively, after 3-day continuous exposure. Subsequently, a dosage response assay was completed to compare two assay conditions, dipped-leaf and topical application techniques. Five spore concentrations, 1.2×109, 2.4×108, 4.8×107, 9.6×106, and 1.9×106 spores/mL, were prepared and used for both assay techniques. For the dipped-leaf technique, 25 larvae were exposed to treated leaf disks, five larvae to each of five treated leaf disks per spore concentration. For the topical assay, 5 μL was applied directly to each of 25 larvae for each spore concentration. After 3-day incubation, blastospores of P. fumosoroseus showed higher activity than conidia, and the topical application technique was more effective (lower LC50 values and lower X 2 values) than the dipped leaf assay technique. This research demonstrates the insecticidal activity of P. fumosoroseus on MBB and provides a comparison of two basic bioassay techniques that may be useful in future research on this topic.
UR - http://www.scopus.com/inward/record.url?scp=33845932930&partnerID=8YFLogxK
M3 - Artículo
SN - 0147-1724
VL - 31
SP - 289
EP - 295
JO - Southwestern Entomologist
JF - Southwestern Entomologist
IS - 4
ER -