Divisi
Rice gall midge
Orseolia oryzivora · Insect
The African rice gall midge (Orseolia oryzivora) is a tiny, reddish, mosquito-like fly — no bigger than a grain of rice — whose maggot bores into the growing heart of a young rice tiller. Instead of a leafy shoot that would carry grain, the plant is tricked into growing a hollow, pale tube — the tell-tale 'silver shoot' or 'onion leaf' — and that tiller is lost for good. It thrives in warm (24–30 °C), humid, cloudy, rainy weather during tillering, and a heavy attack at that stage can gut a rice harvest.
Why it matters
Every tiller the midge attacks turns into a hollow, onion-like tube that never grows a head of grain (a panicle) — so the very shoots you are counting on for your harvest become dead ends. In a bad year, on a variety the midge likes and in warm, wet weather, it can take up to 60% of your rice. It is so hard to beat because the maggot sits sealed inside the gall where no spray can reach it, and by the time you spot the silver shoots those tillers are already lost for good. That is why this fight is won early — with the right variety and early, all-together planting — not with a sprayer once the damage shows.
When to act
more than about 5 percent of tillers showing silver-shoot galls during tillering
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full rice gall midge field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to rice gall midge — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify rice gall midge?
The tell-tale sign — the 'silver shoot': where you expect a normal folded leaf, an attacked shoot instead pushes up a hollow, pale, tube-shaped growth that looks just like an onion or spring-onion leaf — round, smooth and silvery-green. It stands taller than the healthy leaves around it, and that shoot will never carry a head of grain.
When should I take action against rice gall midge?
more than about 5 percent of tillers showing silver-shoot galls during tillering
How do I control rice gall midge?
Prevent it — start with the right seed. Your single strongest tool is to plant a gall-midge-resistant or tolerant rice variety suited to your area. ('Resistant' = the plant shrugs the midge off; 'tolerant' = it still yields even when attacked.) Ask your extension officer or a trusted seed supplier which local varieties stand up to gall midge.
Which crops does rice gall midge affect?
Among the crops covered here: Rice.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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