Beat fall armyworm the organic way

Since it arrived, fall armyworm has become one of the most serious threats to maize in Zimbabwe — chewing leaves, tassels and cobs, and dragging down both yield and grain quality. One study in eastern Zimbabwe put average losses at around 12% (ScienceDirect). The good news: you can hold it back with cheap, organic methods — if you catch it early.

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Scout early, scout often

You can’t manage what you don’t see. Start scouting about a week after emergence and keep going at least twice a week (FAO):

• Walk the field in a zig-zag, stopping at about five spots and checking 10–20 plants at each.
• Look for “window-paning” (see-through scratches on young leaves), ragged holes, fresh moist frass (droppings) in the funnel, and the larvae themselves.

Act on thresholds, not panic. As a guide, consider control when about 20% of plants show fresh damage at the early whorl stage, rising to about 40% from the V7 stage to tasseling. Below that, your crop and its natural helpers can often cope.

Protect your helpers

Zimbabwe already has an army of natural enemies — parasitic wasps, ladybirds, earwigs, ants and birds — that quietly kill fall armyworm eggs and larvae. Evidence across Africa shows these provide significant free biological control (CABI). Blanket-spraying harsh chemicals kills them too, and often makes the next outbreak worse. Spare them wherever you can.

Low-cost organic tools

• Neem and Bt (Bacillus thuringiensis) biopesticides work well on young (early-instar) larvae — target them while caterpillars are small (FAO).
• A pinch of wood ash, sand or fine soil dropped into the funnel is a long-standing farmer practice thought to abrade or dry out the larvae. It’s low-cost and worth trying on small plots, though the scientific evidence is still limited (Frontiers).
• Hand-picking and squashing egg masses and larvae genuinely works on small fields — do it as you scout.

Push-pull and good husbandry

• Push-pull — planting a repellent companion (like desmodium) between rows and an attractant grass border — reduces infestation and feeds natural enemies (CABI).
• Weed often. Clean, vigorous fields consistently suffer less damage; in Zimbabwe, frequent weeding and minimum tillage were linked to lower fall armyworm pressure — and intercropping with pumpkins to more (ScienceDirect).

Strong plants shrug off damage

A vigorous, well-fed maize plant outgrows and tolerates pest damage far better than a stunted one on sour, exhausted soil. Building organic matter with PCAT BLOCK C before the season gives your crop the strong, early start that helps it stay ahead of fall armyworm — one more reason healthy soil is your first line of defence. Zimbabwe’s national strategy leans on exactly this kind of integrated, farmer-led approach rather than chemicals alone (CIMMYT).

Do this now

1. Scout twice a week from one week after emergence.
2. Spare your natural enemies — don’t blanket-spray.
3. Hit young larvae with neem or Bt; try ash in the funnel on small plots.
4. Weed hard and keep the crop vigorous.
5. Build healthy soil so plants grow away from damage.

PCAT BLOCK C — the locally-made, field-proven compost that rebuilds Zimbabwe’s tired, acidic soils.

Next: time your season right with the maize planting calendar.