Moth larvae are striped green. They move in small armies and have the characteristic of eating everything in their path. They are common pests of grass and can also eat corn, beets, beans, clover, flax, millet and other grains.
Steps
Method 1 of 2: Control in the Grass
Step 1. Look for the first signs of damage from the larvae
Since they feed at night, you can't see them right away. The sooner you are able to intervene and treat the problem, the easier it will be to be able to control the infestation and limit the damage.
- An increase in the number of birds in the garden can be an indication of their presence. Birds eat caterpillars, but usually don't eat enough of them to keep the infestation in check.
- Dark spots on the lawn are often the first sign of a moth larvae problem.
Step 2. Mow the short grass and then water well to move the caterpillars off the leaves
Step 3. Generously spray liquid insecticide following the manufacturer's directions
Granular insecticides are generally less effective than liquid ones.
Step 4. Leave the insecticide to act on the lawn for at least 3 days, without cutting or watering it further and avoid walking on it if you can
Method 2 of 2: Check in the Field
Step 1. Monitor fields in spring if you notice any signs of maggot damage
Look for holes in the leaves or if they are worn on the edges from being eaten by caterpillars.
Step 2. Look under the plants if you see the larvae or if you notice any signs of their droppings
You can also find them under some vegetable scraps left in the field. If the field is cultivated with barley or wheat, the worms can be found inside the ears.
Step 3. Mow completely if these pests have infested the hayfield
When the hay dries, the larvae lose interest in this food source and leave.
Step 4. Apply insecticides in the field using ground or aerial equipment
The following insecticides have been shown to be effective in controlling the larvae:
- Esfenvalerate must only be applied to corn crops and must not be used within 21 days of harvesting.
- Permethrin should also be used only on corn and should not be applied within 30 days of harvesting.
- Carbaryl (Sevin) can be applied to both corn and wheat. Do not use it for more than 2 applications and do not spread it within 21 days of collection.
- Ethyl alcohol is useful for corn, sorghum and all small grains, but can only be applied by air. Do not spread it within 12 days of harvesting corn or sorghum, and within 15 days of harvesting small grains (millet, oats, hemp…). Once the insecticide has spread, put up a sign that the field has been treated and not to enter it for 3 days.
- Chlorpyrifos can be applied to corn and sorghum. Do not allow cattle to graze in the field for at least 15 days after application. Do not feed dairy or beef cattle with insecticide-treated cereals until at least 35 days have elapsed.
- Lannate and malathione can be used on all crops. Do not spray these insecticides within 7 days of harvest and stay out of the field for 2 days after treatment.
- Methyl is used for aerial application only on maize and small grains. Do not apply it within 12 days of the corn harvest or 15 days of the small grain harvest. Put a warning sign in the camp and don't enter it for 2 days.
- Lambda-cyhalothrin can be applied to corn, sorghum and wheat fields. Do not apply it within 20 days of harvesting corn or 30 days of harvesting sorghum and wheat.
