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Title: EFFECTS OF COMPOSTS AND SOIL AMENDMENTS ON SOIL MICROFLORA AND PHYTOPHTHORAROOT AND CROWN ROT OF BELL PEPPER

Author
item KIM, K - UNIV. OF FLORIDA
item Nemec Jr, Stanley
item MUSSON, G - UNIV. OF FLORIDA

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Root and crown rot of bell pepper is caused by the fungus Phytophthora capsici and is a destructive soilborne disease. The control used for this disease widely has been applications of methyl bromide with chloropicrin. Methyl bromide depletes the ozone layer and is scheduled to be phased out by January 1, 2001, in the U.S. This situation has stimulated agricultural research sectors to find alternatives for methyl bromide. Soil amendments and composts have the potential to reduce root and crown rot of bell pepper. Three research field tests were conducted at Boynton Beach, Florida, during 1995-1996 to evaluate the efficacy of various composts and soil amendments to control this disease. Chitosan, crab shell waste, humate, municipal solid waste, perennial peanuts, seed peanuts, sewage sludge-yard trimming, and wood chips were tested. Crab shell waste and chitosan reduced disease occurrence and disease severity of root and crown rot of bell pepper. Sewage sludge-yard trimming and wood chips increased soil microbial activity and populations, some of which were related to suppress the disease. This compost research shows that chitosan and crab shell waste are promising control measures for this root and crown rot disease of bell pepper.

Technical Abstract: Three field tests were established at Boynton Beach, Florida, during 1992 to 1995, to evaluate various composts and soil amendments incorporated into the top 20 cm of beds for control of Phytophthora root and crown rot of bell pepper caused by Phytophthora capsici. Test plots were treated with one of the following: chitosan, crab shell waste, humate, municipal solid waste, perennial peanuts, seed peanuts, sewage sludge-yard trimming (SY), and wood chips. Untreated plots served as controls. Soil populations of five microbial functional groups and total microbial activity were monitored by measuring fluorescein diacetate hydrolysis analysis. Two plantings (September 11 and November 16, 1995) of cv. Boynton Belle were evaluated in each test. Crab shell waste (1.335 t.ha-1) reduced disease incidence and chitosan (0.2%, w/v) reduced disease incidence and severity compared to controls in one test. Perennial peanuts reduced disease incidence and severity of Phytophthora root and crown rot in another test. Several treatments, especially SY and wood chips, increased total microbial activity and soil populations of certain microbial functional groups, some of which were negatively correlated with disease incidence and severity.