(IPPM) in Vegetables - Vegetableipmasia.org

Resource Manual on IPPM in Vegetable
World Education Philippines, Inc.
Disease is more serious problem in onion production rather than insect pest. Different
types of diseases infect the onion from seedling up to the storage which greatly reduces
profit.
Damping off at seedling stage and purple blotch at plantation are the most serious
problem of onion. Other problems occur during its growing period are Stemphylium,
downy mildew, botrytis leaf blight, cercospora leaf spot, basal plate rot and pink root
disease.
i. Weeding
Weeds are serious problem in onion production. Yield decreases with increasing
population of weeds. A weed-free condition must be observed during the first 30-45 days
after transplanting or 45-60 days after seeding. Hand-pull the weeds as they appear or
use selective herbicide
j. Harvesting
Softening of neck, color change of the leaves from green to yellow, falling over of tops
and death of roots are manifestation of maturity, signs that the onions are ready to
harvest. Onion is a shallow-rooted plant and usually only the roots are in contact with the
soil. It is best to use hand tools like trowel or dibble to uproot the plant in order to
minimize damage. Selective harvesting is suggested to avoid rapid deterioration of
immature bulbs in a lot that may enhance the deterioration or more matured bulbs.
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