Occasionally, early season onions may have onion maggots. These white root maggots burrow into the stems and bulbs. Discard infested plants or bulbs in a sanitary way so that the insect cannot complete its life cycle and cause problems in a subsequent season. Insecticidal control is possible only at time of planting. Diazinon is the best chemical control.
Onion thrips are tiny insects with unique fringed wings.
Both adults and immature stages feed on leaves, sucking plant juices after injuring the surface. Plant tips may turn brown and wither. Careful examination should reveal streaking, chlorotic areas where insects are feeding. Hot, dry weather is most favorable for this insect. Control is difficult, particularly since damage is often noticed after insects have caused considerable damage.