STUDIES ON ALTERNARIA BLIGHT OF SUNFLOWER INDUCED BY ALTERNARIA HELIANTHI (HANSF.) TUB. & NISH. IN NIGERIA » Download Project Topics

Abstract:

Some aspects of the control of Altenaria blight of sunflower incited by Alternaria helianthi (Hans.) Tub. & Nis. were studied in Samaru during the 1991 and 1992 wet seasons. Laboratory studies confirmed that the pathogen is seed-borne and that ail the five sunflower varieties evaluated were susceptible to the disease. In both glasshouse and field trials, it was demonstrated that seed treatment with metalaxyl + carboxin, carbendazim + maneb, mancozeb and carbendazim + iprodione each at. 1,2 and 5g a.i/kg seed significantly increased seedling emergence and also reduced incidence of seedling blight, numbers of leaves shed and leaf spot severity compared with the untreated check. Metalaxyl + carboxin at 1 and 2g a.i/kg seed gave the overall best results. The three fungicides (benomyl, Carbendazim + maneb and mancozeb) evaluated for the control of Alternaria leaf spots significantly reduced the leaf spot severity compared with the unsprayed check. Carbendazim + maneb at 2.4kg a.i/ha gave the best leaf spot control probably because of its systemic and protectant qualities. Whereas the differences among the five sunflower varieties (Record, Funtua, Chernaanka, Isanka and Smena) screened for resistance to Alternaria blight in respect of needling emergence, numbers of leaves shed prematurely and blight severity were not significant during the 1991 wet season, those of 1992 were significant. Smena bad the highest blight- severity while Funtua and Chernaanka had the lowest. An integration of chemical and other disease control strategies has been recommended for control of Alternaria blight,

STUDIES ON ALTERNARIA BLIGHT OF SUNFLOWER INDUCED BY ALTERNARIA HELIANTHI (HANSF.) TUB. & NISH. IN NIGERIA