Seed Health Management for Better Productivity - Govind Ballabh ...

(Seed Health Management for Better Productivity)disseminate from the primary infection centers by wind driven rain droplets, aerosols or farmingpractices. The disinfection of infested or infected seeds by heating or chemicals is, therefore animportant and effective measure to eliminate the primary inoculum and to prevent diseaseestablishment in fields.Hot water treatment of 45 0 C for 20 minutes effectively eliminated Erwinia spp. on bulb ofgarlic and increased the yield by 26.68 %. Application of Agreft 20WP (0.2%) applied as drenchingand spraying could suppress Erwinia spp. infection by 38% (Hanudin and Handayati, 1992). Hotwater and bactericide treatment of seeds has been found effective in reducing disease incidenceof watermelon fruit blotch (Nomura & Shirakawa, 2001). Hot water treatment of seeds at 50 0 C for15-20 minute has been found effective for the management of black rot of crucifers. Infection ofbacterial canker of tomato is also eradicated by treating with hot water at 55 0 C for 25 minutes.F Disease escapePlants can escape from bacterial infection by a change in their cultivation period. Severedamage of BLB in rice could be avoided by planting early maturing cultivars and setting thecultivation period early enough to harvest before the typhoon season starts.G RotationBecause the same pathogen may survive in the field and cause infection in addition toinfection through infested and infected seed, disease development may be controlled by practicingat least 3-4 years crop rotation. However, rotation may not be effective when the pathogen havewide host ranges or are well adapted for long term survival in the field.H. IrrigationIn potato common scab caused by Streptomyces scabies, irrigation for several weeks aftertuber initiation is effective in reducing scab. Practical control of the disease at the RothamstadExperiment station is accomplished by irrigation that maintains a soil moisture deficit of 0.6 for 3-4weeks in the tuber initiation period.I. Nutrition and Plant DensityAdequate plant density and fertilization are obviously important for growing healthy plants.High nitrogen levels and dense spacing may increase disease susceptibility of host plants andresident populations of the pathogen because proliferated dense foliage reduces air movementand drying of leaf and stem surfaces.J. GraftingMuskmelon and watermelon are usually grafted on pumpkin root stocks to prevent infectionof Fusarium oxysporum f. sp. melonis and F. oxysporum f. sp. niveum. Severe infection due to P.syringae pv. lachrymans and X. campestris pv. cucurbitae may occur on these plants throughpumpkin stocks that are raised from infected seeds. To control bacterial wilt, tomato and eggplantmay be grafted on root stocks of LS-89, Solanum torvum, S. intergrifolium or S. mammosum thatare highly resistant to R. solanacearum.- 152 -