01942naa a2200205 a 450000100080000000500110000800800410001902400570006010000230011724501280014026000090026852012560027765000260153365300120155965300230157165300270159470000170162170000180163877300800165612124422022-04-06 2000 bl uuuu u00u1 u #d7 ahttps://doi.org/10.1590/S1517-838220000004000022DOI1 aCOSTA, J. L. da S. aBiological control of Phytophthora root rot of avocado with microorganisms grown in organic mulches.h[electronic resource] c2000 aOrganic mulches colonized with microbial biocontrol agents, termed bioenhanced mulches, were tested for their ability to reduce Phytophthora root rot of avocado (Persea americana Mill.). Benomyl-resistant mutants of Gliocladium virens (KA 230-1) and Trichoderma harzianum (KA 159.2) isolated from suppressive soils and selected as efficient antagonists of P. cinnamomi were evaluated for their ability to colonize different mulches under controlled laboratory conditions. Sudangrass and a coarse yardwaste were found to be better substrates than a fine yardwaste, woodwaste or rice hulls for biocontrol agents propagules production. The most suitable conditions for colonization were an optimum temperature of 24°C, a moisture content of 20% for sudangrass and 30% for the coarse yardwaste, and a continuous light exposure during a 15-day incubation period. In the greenhouse, fresh sudangrass and a coarse yardwaste colonized with G. virens and used as a surface mulch proved to be the best combination for reducing the population of P. cinnamomi in 4-liter pots containing artificially-infested soil. Healthy avocado roots made up 31-37% of the roots in the G. virens-mulch combinations compared to 0% healthy in infested controls after two months. aTrichoderma Harzianum aAvocado aGliocladium virens aPhytophthora cinnamoni1 aMENGE, J. A.1 aCASALE, W. L. tBrazilian Journal of Microbiologygv. 31, n. 4, p. 239-246, Oct./Dec. 2000.