Insect

Treatment

Onion eelworms: Tiny worms which attack the roots and the base of onion plants

Pull up and burn infested plants. Disinfect the soil with boiling water, or with Vapam or Nemagon. Good crop rotation.

Onion fly: Its maggots eat the bulbs, and the bulbs rot

Control the maggots by treating the plants with Aldrin or DDT.

Disease

Treatment

Onion smut: Seedlings do not grow well; black or grey lines appear on the leaves

Disinfect the seeds. Disinfect the soil with Formol or Thiram

Downy mildew: Yellow spots appear on the leaves. The whole plant becomes yellow and dies

When the mildew appears, treat onion plants with copper based products, or with Thiram, Zineb, or Ziram.

Rots: These are due to funguses which attack onion seeds, destroy the roots and bulbs of seedlings, cause the leaves to wither and kill the onion plant

Control rots by disinfecting the soil with boiling water, or with Formol.

Later, treat onion plants with copper-based products, or with Thiram Zineb or Ziram