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Effects of leaf susceptibility and fungicide seed treatment on leaf spot of Pima cotton caused by Altenaria macrospora
Author(s) -
SHTIENBERG D.
Publication year - 1991
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.1991.tb02399.x
Subject(s) - fungicide , biology , sowing , seed treatment , seedling , tebuconazole , leaf spot , alternaria , alternaria solani , chlorothalonil , horticulture , agronomy , germination
Effects of leaf susceptibility and seed treatment with the systemic fungicides tebuconazole (Raxil) or difenoconazole (Dragon) on Altenaria macrospora in Pima cotton were examined under glasshouse conditions and in the field. In the absence of fungicide, the susceptibility of cotyledons to Alternaria‐ induced shedding increased with seedling age. Effects of seed treatment with fungicide were evident even on the third true leaves, and persisted up to 39 days after planting. Disease suppression was determined both by the fungicide and also by the susceptibility of the host tissue: seed treatment suppressed Alternaria‐induced shedding of cotyledons for 18 days, but not 29 days after planting In a field trial, disease progress was delayed by 20‐24 days in plots planted with treated seeds. The effect persisted for up to 86 days after planting. Alternaria‐induced defoliation at later stages of the season was not affected by the seed treatment. No significant differences in disease control were detected between the two fungicides.