Epidemiology and management of downy mildew of vegetable pea incited by peronospora viciae f sp pisi sydow boerema and verhoeven

Abstract

Downy mildew caused by Peronospora viciae f. sp. pisi (Sydow) Boerema and newlineVerhoeven is a serious foliar disease of vegetable pea. It may cause yield losses up to 55 newlineper cent in susceptible varieties. Seed treatment and foliar fungicides provide an effective newlinemeans of disease management but when this management strategy combined with newlinesustainable approaches, the disease can be managed successfully. In the present study, newlineefforts were made to investigate the yield loss due to downy mildew, use of chemical and newlinebiological seed treatments to reduce seed borne inoculum, cost-effective chemical newlinecontrol through new molecules, effect of sowing, varieties and influence of weather newlineparameters on disease development. Screening of vegetable pea germplasms against newlinedowny mildew was also undertaken. newlineMaximum avoidable yield losses due to protection by foliar spray of Cymoxanil newline8% + mancozeb 64% were found in Arkel (34.29%), followed by AP-3 (29.44%) on first newlinedate of sowing (17th November), while in PSM-3 maximum (23.52%) avoidable yield newlinelosses was found at 3rd date of sowing (1st December). Among the fungicides and newlinebiological seed treatments under glasshouse conditions, seed treatment with combination newlineof Metalaxyl 35% WS + Bacillus subtilis var. amyloliquefaciens and Metalaxyl 35% WS newline+ Streptomyces lydicus found to be the best with less disease incidence and severity. newlineSeed treatment with Metalaxyl 35% WS and 2 foliar sprays at 15 days interval starting newline30 days after sowing by Fluopicolide 4.44% + fosetyl-Al 66.67% WG at 2000 g ha-1 newlineprovided the minimum disease severity (15.78 PDI) and highest yield (52.53 q ha-1) newlinefollowed by Iprovalicarb 5.5% + propineb 61.25% WP at 1600 g ha-1 and Famoxadone newline16.6% + cymoxanil 22.1% SC at 500 g ha-1 but, Famoxadone 16.6% + cymoxanil 22.1% newlineSC provided highest net benefit cost ratio (2.22) followed by Cymoxanil 8% + mancozeb newline64% WP (2.05). Lesser disease and higher yield were obtained from variety PSM-3 sown newlineon 24th November. The maximum increase in downy mildew was recorded 40 days after newlinesowing, and temper