Potential for biological control ofCercosporidium personatumleafspot of peanuts byDicyma pulvinata

摘要

The biology ofDicyma pulvinata(Berk. amp; Curt.) v. Arx, a mycoparasite ofCercosporidium personatum(Berk. amp; Curt.) Deighton, was investigated under both laboratory and field conditions. At 26 deg;C, conidia ofD.pulvinataclose to both hyphae and conidia ofC.personatumgerminated within 11ndash;17ensp;h. Visible signs of colonization of lesions ofC.personatumbyD.pulvinataappeared within 58ndash;65ensp;h (21ndash;31.5ensp;h leaf wetness).Dicyma pulvinatawas an effective protectant when plants were exposed to continuous leaf wetness at 26 deg;C for 5 days. In field microplot studies, lesions ofC.personatumwere visibly colonized by both mutant and wild-type isolates ofD.pulvinatawithin 4 days after applying their conidial suspensions. Environmental conditions during this 4-day period were 40ensp;h leaf wetness, 60ensp;h of 23ndash;28 deg;C (optimal temperatures for growth of the wild-type isolate), and 17.31ensp;cm rainfall.