Stability of microsclerotial inoculum of Colletotrichum truncatum encapsulated in wheat flour–kaolin granules

被引:20
作者
W.J. Connick
M.A. Jackson
K.S. Williams
C.D. Boyette
机构
[1] ARS,Southern Regional Research Center
[2] USDA,National Center for Agricultural Utilization Research
[3] Agricultural Research Service,undefined
[4] USDA,undefined
关键词
Colletotrichum truncatum; formulation; granules; microsclerotia; storage; water activity;
D O I
10.1023/A:1018517409756
中图分类号
学科分类号
摘要
Maintaining adequate viability of microorganisms in products for biocontrol is critically important for commercial reasons. Microsclerotia (MS) of the mycoherbicide agent, Colletotrichum truncatum, are its hardy, over-wintering fungal structures. Microsclerotial inoculum at 2, 7, and 23 MS/granule were matrix-encapsulated in wheat flour–kaolin granules (‘Pesta’), in which the flour provided gluten for the matrix and a food base for the fungus. Pesta granules were dried to a water activity of 0.18–0.29. After storage for 52 weeks at 25°C, granules containing 7 and 23 MS were 100% viable and granules with 2 MS were 95% viable. Granules with 7 MS were 50% viable after 36 weeks at 35°C. Pesta granules (440 granules/g) with conidial inoculum at 3.3×105 c.f.u./g were less storage-stable than granules at the 2 MS/granule level. At all MS inoculum levels, granules stored for up to 2years produced 108 c.f.u./g in vitro when incubated on water agar. High water activity was detrimental to long-term viability. In the greenhouse, 7 MS/granule samples controlled 94% of hemp sesbania when incorporated into the soil pre-planting. The strategy of encapsulation of the naturally stable C. truncatum MS and drying to a favourable water activity led to excellent shelf-life for a live biocontrol agent.
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页码:549 / 554
页数:5
相关论文
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