For Hellen Nambuya, a small-scale farmer in Kyabakadde in Mukono district, onion farming had always seemed like a promising venture.
She planted half an acre with hopes of reaping a good harvest. However, things took a different turn when her onions started showing signs of stress.
“I noticed the stems were becoming weak and bending over. Some leaves looked silvery, and others dried up prematurely. I didn’t know what was going on,” Nambuya says.
“Now, I fear I might lose most of my crop.”
Salimu Chebet, an agronomist says Nambuya’s challenge is not uncommon.
“From her description, the most likely culprit is thrips, small, fast-moving insects that feed by sucking sap from the leaves. They weaken the plant and reduce bulb formation,” Chebet explains.
“If not controlled early, they can cause major losses.”
Chebet advises using recommended insecticides such as those containing spinosad or dimethoate, but also stresses the importance of integrated pest management.
“Farmers should rotate crops, avoid overuse of nitrogen, and regularly inspect their gardens. Neem-based sprays can also help reduce thrip populations naturally.”
Joseph Munerya, a commercial onion farmer in Sebei region, has dealt with thrips, downy mildew, and purple blotch over the years.
He emphasises timing and consistency.
“Spraying should start early, as soon as the onions are two weeks old. Waiting until the damage is visible is often too late,” he says.
Munerya also advises on proper spacing and good airflow in the garden to reduce fungal diseases like downy mildew and purple blotch.
“You must combine cultural practices, regular monitoring, and timely spraying. That’s the only way to win.”
