Department of Plant Pathology, Punjab Agricultural University, Ludhiana-141004
National Symposium on “Plant Pathology in the Changing Global Scenario” held at National Bureau of Plant Genetic Resources, New Delhi on February 27–28, 2009
The efficacy of some recently developed fungicides having different modes of action and their combination products i.e. Infinito 68.75% SC (fluopicolide 6.25%+ propamocarb chloride 62.5%), Amistar 25% SC (azoxystrobin), Acrobat 50% WP (dimethomorph), Mandipropamid 250 SC, Kocide 46.1% DF (copper hydroxide), Curzate M-8 72 WP (cymoxanil 8% + mancozeb 64%), Ridomil Gold 68 WP (mefanoxam 4%+ mancozeb 64%) along with Ridomil MZ 72 WP (metalaxyl 8% + mancozeb 64%), and Indofil M-45 (mancozeb 75%) was determined against late blight of potato caused by Phytophthora infestans under artificial inoculation conditions in field during 2007–08 crop season. Potato cultivar Kufri Chandramukhi (KCM) which is highly susceptible to late blight was used for conducting the experiment and standard agronomic practices were followed to raise the crop planted in the 2nd fortnight of October, 2007. Three replications were used per treatment and each replication had a plot size of 3.5 m x 3.5 m. First application of the test fungicides was given during second week of November followed by inoculations with sporangial suspension of Phytophthora infestans (4 x 104 sporangia/ml) in the evening after about 24 hrs of the first spray. Three more sprays were given at 10 days interval. The data on disease severity were recorded after 10 days of the last spray following a 0–5 rating scale. The results showed that Mandipropamid 250 SC, Ridomil Gold 68WP, Curzate M-8 72 WP, Infinito 68.75% SC and Amistar 25% SC were found to be highly effective for the management of late blight of potato showing disease severity of 0.5, 1.0, 1.0, 1.5 and 0.5%, respectively. Their efficacy was found to be at par with standard fungicide Ridomil MZ. Acrobat 50% WP and Kocide 3000, 46.1% DF were found next in order of efficacy with the disease severity of 3.0 and 8.0%, respectively as compared to 80.0% in untreated control. These new fungicides hold promise for the effective management of late blight of potato.
