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Gingerwilt complex is a major threat to Ginger cultivation and food security in north East India

P Raja: College of Horticulture and Forestry

<div>Cultivation of Ginger in the virgin soil is the age old practice in Arunachal Pradesh, India at the altitude of 100 MSL to 600 MSL. Yield loss upto 90% was noticed due to rhizome rot in the field where ginger is cultivated continuously. The study was conducted on disease incidence in relation with altitude, rainfall and continuous cultivation. <em>Fusarium oxysporum </em>f. sp<em>. zingiberi</em> was found up to 250 and 600 MSL respectively. Disease incidence was highly correlated with rainfall (486 mm to 1625 mm) during planting season (May –June). Disease incidence of 5 to 10, 15 to 30 and 60 to 80 per cent was noticed in 1<sup>st</sup>, 2<sup>nd</sup> and 3<sup>rd</sup> year respectively in the same field and inoculum potential was raised from 3x10<sup>2</sup> to 5x10<sup>5</sup>cfu/g. Biocontrol agent (BCA) <em>Trichoderma</em> isolates were collected and evaluated for their antagonistic potential in addition to mycelial growth, conidial production and mycelial weight <em>in vitro</em> and <em>in vivo</em>. Further suitable carrier material, shelf life, competitive saprophytic ability reveals that rice bran (15x10<sup>9</sup>CFU) and paddy straw (11x10<sup>9</sup>CFU) supported maximum population. The <em>Trichoderma</em> population was stable at 20˚C storage temperature (12 x10<sup>9 </sup>CFU) followed by 25˚C (10x10<sup>9 </sup>CFU). Saprophytic ability of native <em>Trichoderma</em> <em>viride </em>was very high in virgin soil (14.66 x10<sup>9</sup> CFU) than sterilized one. Soil application of BCA mixed with Farm Yard Manure (FYM) (20g/kg of FYM) 7 days before sowing has increased the yield upto 56.7% (31.6t/ha) followed by seed rhizome treatment with BCA @ 2g/l water for 30 minutes plus soil application of BCA @ 5% (29.93 t/ha). Different methods of storage of the seed ginger rhizome study revealed that <em>Trichoderma viride </em>(0.5%) treated rhizomes stored in the pits (3x1x3 m) layered with FYM, Trichoderma and sand was the best method.</div>