Exudate from sporulating cultures of Hirsutella thompsonii inhibit oviposition by the two-spotted spider mite Tetranychus urticae.
The acaricidal mycopathogen Hirsutella thompsonii has been found to secrete metabolites that are active against female Tetranychus urticae. Specifically, the rose-colored exudate produced on sporulating cultures of Mexican HtM120I strain sterilized female spider mites in a dose-dependent fashion. Topical application of the exudate resulted in a 100% reduction in mite fecundity over the initial six days of experimentation. Depending upon the exudate dosage, mites partially recovered within 3 and 6 d post-treatment and produced a limited number of eggs. The spider mite active HtM120I exudate contained less detectable HtA toxin than the HtM120I broth filtrate, and it was innocuous when injected into the greater wax moth Galleria mellonella L. larvae. Broth filtrates of HtM120I cultures, although toxic to assayed G. mellonella larvae, did not inhibit mite oviposition to the degree or duration of the exudate preparations. These findings suggest that the factor responsible for suppressing oviposition in female spider mites is linked to the sporulation process and is distinct from the well-characterized HtA produced by vegetative cells.
Rosas-Acevedo
José Luis
JL
Centro de Desarrollo Regional, Unidad de Estudios de Posgrado e Investigación de Acapulco, Universidad Autónoma de Guerrero, Apdo. Postal 612, 39301 Acapulco, Gro., Mexico.
Boucias
Drion G
DG
Lezama
Roberto
R
Sims
Kelly
K
Pescador
Alfonso
A
D000818:Animals; D003603:Cytotoxins / Q000378:metabolism; D005122:Exudates and Transudates / Q000378:metabolism; D005260:Female; D005656:Fungal Proteins / Q000378:metabolism; D006999:Hypocreales / Q000378:metabolism*; D008924:Mite Infestations / Q000517:prevention & control*; D010058:Oviposition; D010572:Pest Control, Biological; D013172:Spores, Fungal / Q000378:metabolism; D040102:Tetranychidae / Q000254:growth & development / Q000382:microbiology*
D003603:Cytotoxins; D005656:Fungal Proteins; C121692:Hirsutellin A protein, Hirsutella thompsonii