Epidemiology and management of downy mildew of vegetable pea incited by Peronospora viciae f. sp. pisi Sydow Boerema & Verhoeven
Loading...
Date
2022-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G. B. Pant University of Agriculture & Technology, Pantnagar, Uttarakhand. PIN 263145
Abstract
Downy mildew caused by Peronospora viciae f. sp. pisi (Sydow) Boerema & Verhoeven is a serious foliar disease of vegetable pea. It may cause yield losses up to 55 per cent in susceptible varieties. Seed treatment and foliar fungicides provide an effective means of disease management but when this management strategy combined with sustainable approaches, the disease can be managed successfully. In the present study, efforts were made to investigate the yield loss due to downy mildew, use of chemical and biological seed treatments to reduce seed borne inoculum, cost-effective chemical control through new molecules, effect of sowing, varieties and influence of weather parameters on disease development. Screening of vegetable pea germplasms against downy mildew was also undertaken. Maximum avoidable yield losses due to protection by foliar spray of Cymoxanil
8% + mancozeb 64% were found in Arkel (34.29%), followed by AP-3 (29.44%) on first date of sowing (17th November), while in PSM-3 maximum (23.52%) avoidable yield losses was found at 3rd date of sowing (1st December). Among the fungicides and biological seed treatments under glasshouse conditions, seed treatment with combination of Metalaxyl 35% WS + Bacillus subtilis var. amyloliquefaciens and Metalaxyl 35% WS + Streptomyces lydicus found to be the best with less disease incidence and severity. Seed treatment with Metalaxyl 35% WS and 2 foliar sprays at 15 days interval starting 30 days after sowing by Fluopicolide 4.44% + fosetyl-Al 66.67% WG @ 2000 g ha-1
provided the minimum disease severity (15.78 PDI) and highest yield (52.53 q ha-1) followed by Iprovalicarb 5.5% + propineb 61.25% WP @ 1600 g ha-1 and Famoxadone 16.6% + cymoxanil 22.1% SC @ 500 g ha-1 but, Famoxadone 16.6% + cymoxanil 22.1% SC provided highest net benefit cost ratio (2.22) followed by Cymoxanil 8% + mancozeb 64% WP (2.05). Lesser disease and higher yield were obtained from variety PSM-3 sown on 24th November. The maximum increase in downy mildew was recorded 40 days after sowing, and temperature range of 5.5-22.05°C and 55-96.05% relative humidity along with 7.5 mm rainfall favored the disease development. Disease severity was found to be positively correlated with minimum temperature and rainfall. Out of 89 vegetable pea germplasms screened under natural epiphytotic conditions, PSM-11, PCPGR-6091 and Selection-23 were found to be resistant, while Multi frozen, Pila Lubix, Little Marvel Lincoln, EFL-9, PSM-3, Pant Upahar were found to be moderately resistant to downy mildew.