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Studies on the biology and control of cavity spot of carrots
Author(s) -
WHITE J. G.
Publication year - 1988
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1988.tb03302.x
Subject(s) - biology , metalaxyl , pythium , mancozeb , fungicide , horticulture , pythium ultimum , botany , biological pest control
SUMMARY Using a selective medium of corn meal agar with pimaricin and rifamycin, isolations from asymptomatic periderm of carrots grown on experimental plots or in commercial crops most frequently yielded the fast‐growing species Pythium intermedium, P. sylvaticum or P. ultimum. In contrast isolations from cavity spot lesions mostly produced the slow‐growing species P. violae and P. sulcatum. Following treatment of crops with metalaxyl + mancozeb, few isolations from asymptomatic periderm produced Pythium spp. and generally there was a reduction in the number of cavities. Treatment had little or no effect on size distribution of cavities. Cavity spot incidence was significantly less at higher pH values, fields of pH 8·0 and above producing carrots with little or no disease.