Corn leaf aphid
Blue green aphids crowd the whorl and the tassel, which turn sticky and then black with sooty mold.
Also called
Aplat (Ilocano), dugos dugos (Cebuano)
Crops it attacks
Where the damage shows
When to act
From late whorl to tasseling, check 20 plants at each of five spots each week. Act only when more than half the plants carry colonies of 100 or more aphids on the whorl or tassel before pollen shed, mostly in a dry spell. After pollen shed a spray rarely pays.
What to spray
- PymetrozineIRAC 9BShopeeLazada
- ThiamethoxamIRAC 4AShopeeLazada
- Lambda cyhalothrinIRAC 3AShopeeLazada
- Lambda cyhalothrin plus thiamethoxamIRAC 3A plus 4AShopeeLazada
- MalathionIRAC 1BShopeeLazada
- DiazinonIRAC 1BShopeeLazada
- FipronilIRAC 2BShopeeLazada
Active ingredients only, never brands. The IRAC group tells how it works: switch to a different group next time, so the pest does not learn to survive it. Spray only when the damage is worth the cost, and only with products registered with the Fertilizer and Pesticide Authority for your crop. Follow the label. The Shopee and Lazada links only show who sells something with that active ingredient, not a recommendation of any seller or product.
On labels for it, but not advised
- Buprofezin: A growth regulator for hoppers and whiteflies. Aphids barely respond to it.
How to prevent it
- Plant on time and water in dry spells: drought stressed corn suffers most from aphids.
- Keep itch grass, Johnson grass and other grassy weeds off the borders. They host the aphid between crops.
- Feed balanced nitrogen, since heavy urea makes soft growth that aphids crowd on.
- Pull out plants with mosaic streaks early, because this aphid also spreads mosaic viruses.
Natural enemies and biological help
- Lady beetles, hover fly larvae, lacewings and tiny parasitic wasps often wipe out colonies on their own. Spare them.
- Heavy rain also knocks colonies down, so watch a few days before you spray.
- Beauveria or Lecanicillium fungus infects aphids in humid weather.
Not sure it is this one?
Many pests look alike. Send a photo to Anee, the smart farm technician in anee.io. She reads it with your crop, its age and the weather, and tells you what it most likely is and what to do first. In Tagalog or English.