Divisi
Shoot borer
· Insect
Photo: Chirag85 · CC BY-SA 4.0
Shoot borer is not one insect but the young stage of several small moths — and, on sweet potato, a fat legless weevil grub — that bore into the soft, growing tips of vegetables like sweet potato, eggplant and okra, and of mango trees. The larva tunnels down inside a tender new shoot and kills the growing point, leaving a wilted, drooping dead-heart; as the plant flowers it moves on into the flower buds and young fruit. It thrives in warm, humid weather wherever the plant keeps pushing out fresh, tender flushes of new growth.
Mally R, Korycinska A, Agassiz DJL, Hall J, Hodgetts J, Nuss M · CC BY 3.0 
Scot Nelson · CC0
Why it matters
Shoot borer caterpillars tunnel straight into the tender growing tips of your sweet potato, eggplant, okra or mango and kill the growing point, so the shoot wilts and dies — a dead-heart. Then they move on into the flower buds and young fruit, so a heavy attack can cost you up to half your harvest (50%). The hard part is that once a caterpillar is deep inside a shoot or fruit, no spray landing on the outside can reach it — so by the time the damage is easy to see, it is often already too late for that shoot. Your win comes from catching them early, while they are still small on the soft new shoots, and cutting out every wilted tip before they spread.
When to act
wilting or dead shoot tips on more than about 5 percent of plants, or fresh bore holes with frass on tender shoots
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 shoot borer field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to shoot borer — 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 shoot borer?
The first thing you see is wilting. A soft, young shoot tip at the top of the plant suddenly droops, wilts and dries out. Unlike a thirsty plant, it does NOT perk up again in the cool of the evening or after watering — that dead, hanging tip is called a dead-heart.
When should I take action against shoot borer?
wilting or dead shoot tips on more than about 5 percent of plants, or fresh bore holes with frass on tender shoots
How do I control shoot borer?
Cut out the dead-hearts — your single strongest move (cultural sanitation). As soon as you spot a wilted, bored shoot, clip it off (cut a hand's width down into healthy stem) and burn or bury it away from the field. The caterpillar is still inside, so you kill it before it can move on to the next shoot or into the fruit. Do this every few days from the very first sign — staying on top of it is the most effective thing you can do, and it costs you nothing but your time.
Which crops does shoot borer affect?
Among the crops covered here: Eggplant, Ginger, Mango, Okra, Sweet potato, Turmeric.
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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