Bolting: Premature seed stalk
Disorder
Symptoms
When onion crop is grown for bulbs some premature seed stalks are produced before completing the normal life cycle of the onion bulbs known as ‘bolting’. These bulbs become fibrous and light in weight. The leaves and bulbs become unfit for consumption.
Causes
Rabi onion starts to bolt at 20-25 ° C temperature. Early transplanting (August) and late (end of December-January) induce bolting in Kharif and Rabi onion, respectively. The restricted or poor vegetative growth, Low temperature (10-12 ° C) and transplanting of aged seedlings of above 10 weeks leads to bolting.Varietal difference-white cultivars are more sensitive to bolting.
Control
Adjust the time of transplanting in such a way that the crop may exposed to moderate temperature at bulbing. Maturity of Rabi crop coincides with high temperature compared to kharif crop.
Grow non-bolting cultivars like Early Grano, Texas Early Grano, etc.
Transplant healthy and 6 to 7 week old seedlings.
Supply recommended dose of nitrogen.
Cut the seed stalk at early stage.