Integrated management of powdery mildew of gerbera under polyhouse condition in Arunachal Pradesh

Powdery mildew caused by the fungus Erysiphe cichoracearum DC. is a common disease of gerbera grown in Indian conditions. Fungicidal and varietal trial was conducted at Instructional farm, Department of Floriculture, College of Horticulture and Forestry, Central Agricultural University, Pasighat, during April 2011 to March 2012. In fungicidal disease management, least disease severity (5.23%) was observed in spray of wettable sulphur @2.5g/l of water followed by Carbendazim @ 2g/l of water foliar spray (7.23 %). Whereas, the unprotected treatment showed highest disease severity (65.30 %). The highest number of flowers m-2/year (195.00) and number of suckers / plant / year (6.60) were also recorded in wettable sulphur @ 2.5g/l of water foliar spray. Powdery mildew symptoms were first observed on the leaves of the varieties viz. Pia, Rionegro and Tecala on 30th day after planting. In Manizales, Teresa and Galileo powdery mildew incidence was started only after 38 days of planting. On the other varieties Figaro, Marinila and Palmira powdery mildew incidence was started only after 68 days of planting. Palmira variety showed resistance to powdery mildew with per cent disease index of 9.27% at the end of 160 days after planting followed by Figaro and Marinila with PDI of 9.73% and 10.23%, respectively. Variety Teresa showed moderately resistant reaction (24.57 %) against powdery mildew infection. Varieties Pia and Tecala were highly susceptible to powdery mildew through out the experiment which showed per cent disease index of 65.30% and 54.27%, respectively. Other varieties like as Galileo (34.73%), Manizales(46.93%) and Rionegro (49.67%) showed susceptible reaction to powdery mildew infection.