Seedlings collapsing at soil line in cucurbit and cole nursery in wet weather, prevention.
7 जवाब
Damping off makes nursery seedlings rot and collapse at the soil line, and it is worst in wet, crowded, poorly drained nursery beds or trays. Prevent it by raising seedlings in sterilised media or pro trays with cocopeat, providing good drainage and air flow, avoiding overwatering and over sowing, and giving raised beds a slope so water drains. Treat seed with a recommended fungicide or bioagent like Trichoderma before sowing, and drench the media with a recommended product only if needed. Do not water in the evening, since wet cool conditions overnight favour the fungus. Confirm seed treatment and any drench with your KVK, and discard badly affected trays rather than trying to save them.
In Thrissur my cucurbit nursery collapsed at the soil line in the rains until I moved to pro trays with cocopeat and raised, sloped beds for drainage. Treating seed with Trichoderma before sowing helped too.
A caution: never water the nursery in the evening during the monsoon. The cool wet overnight conditions brought on damping off, morning watering and not over sowing kept the trays healthy.
A tip: I give the nursery beds a slope and good air flow and never over sow. Crowded wet trays were where my damping off always began in the rains.
Once a tray went down badly I stopped trying to save it and discarded it. Holding on to a rotting tray just let it spread to the neighbours, throwing out the bad ones kept the rest of the nursery clean.
Sterilised cocopeat in pro trays instead of field soil made the biggest difference for me. The old soil filled beds carried the fungus, the clean media trays stayed healthy through the monsoon.
I treat the seed with Trichoderma before sowing and drench only if something shows up, after checking the product with the KVK. Starting with treated seed in good draining media gave me far fewer collapses than drenching after the fact.