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Post‐infection activities of fungicides against Cercospora arachidicola of peanut ( Arachis hypogaea )
Author(s) -
Johnson Robert C.,
Cantonwine Emily G.
Publication year - 2014
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3671
Subject(s) - fungicide , biology , arachis hypogaea , leaf spot , cercospora , inoculation , arachis , incubation period , incubation , agronomy , horticulture , biochemistry
BACKGROUND Despite strong indirect evidence of post‐infection activity by a selection of systemic fungicides against Cercospora arachidicola , the causal organism of early leaf spot of peanut, direct post‐infection activities in this pathosystem have yet to be reported in detail. This study was conducted to describe the activities of pyraclostrobin, penthiopyrad and prothioconazole on early leaf spot when each fungicide was applied after pathogen penetration began and throughout the incubation period . RESULTS Most C. arachidicola penetration events occurred between 3 and 5 days after inoculation (dai), and the mean incubation period was 11.8 dai. Post‐infection activities of the systemic fungicides were similar for all dependent variables measured. Systemic fungicides reduced lesion density compared with the non‐treated control when applied at 3, 5 and 7 dai, and disease severity was >60% less for leaves treated with a systemic fungicide at all application dates (3, 5, 7, 9, 11 and 13 dai) . CONCLUSIONS Pyraclostrobin, penthiopyrad and prothioconazole showed similar systemic mobility within peanut leaves and activities against C. arachidicola , and appear to completely arrest the development of the pathogen at least 2 days post penetration, and limit pathogen colonization even when applications occur after symptom onset. © 2013 Society of Chemical Industry