Evaluation of microorganisms for biocontrol of Botrytis cinerea in container-grown black spruce seedlings
1994
Zhang, P.G. | Sutton, J.C.
Microbial isolates from conifer foliage and strawberry were evaluated for biocontrol of Botrytis cinerea Pers.:Fr. in container-grown seedlings of black spruce (Picea mariana (Mill.) B.S.P.). In growth room assays, seedlings were environmentally predisposed to the pathogen and coinoculated with the isolates and B. cinerea. Sporulation incidence of the pathogen was later estimated on needle segments that were cut from the seedlings and incubated on paraquat-chloramphenicol agar medium. The isolates suppressed sporulation by 0-100%. Those of Alternaria Cladosporium, Epicoccum, yeasts, and bacteria were of low to moderate effectiveness, but those of Gliocladium, Myrothecium, Trichoderma, and Trichothecium were moderately to highly suppressive. In two greenhouse tests, spore suspensions of Gliocladium roseum Link:Bainier and of Myrothecium verrucaria (Alb. & Schw.) Ditm. ex Stendel. (applied three times) at 2- to 3-week intervals suppressed incidence of B. cinerea by 50-69% and 42-60%, respectively, and were at least as effective as recommended fungicide treatments. Two or three additional applications of the antagonists did not further suppress the pathogen. Isolates of Fusarium sp. and Penicillium sp. were generally ineffective in the greenhouse tests. The four fungi ranked similarly in biocontrol effectiveness in the growth room and greenhouse. It is concluded that the growth room assay provided a strong indication of biocontrol performance in the greenhouse and that G. roseum and M. verrucaria have potential for managing B. cinerea in black spruce in greenhouses.
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