What are Corn Earworms?
Known as the greatest threat for sweet corn production, earworms are an insect that can be hard to control and kill in the garden area. Corn earworms have various different color combinations including green or brown. The problem with not effectively removing earworms is they can overwinter in the soil which will allow them to come back and cause even more issues in the garden. Like several other insects killing them in the nymph or early stages will stop them from becoming impossible to kill in the adult stages. Most of the earworm damage is done at the ear tips leaving the corn deformed and susceptible to mold and diseases. To ensure you are preventing earworms in corn the best method is to have a preventative program in place for the vegetable garden.
Preventing Earworms in Corn
On this week’s episode, Travis identifies ways of preventing earworms from becoming a major problem in the vegetable garden. Travis has planted his sweet corn for the fall growing season. He decided to plant a couple of rows of the hybrid ambrosia variety. The Ambrosia Sweet Corn is a white and yellow bicolor that has a sugary-enhanced flavor profile. After harvesting, it can be stored for up to 10 days and a little longer when creamed and frozen. When deciding how to plant corn in the garden area it should be planted in square plots instead of long rows for germination and pollination purposes. The recommended way to plant sweet corn in the garden is with our walk behind garden seeder. The durable garden seeder has seed plates that are also adjustable for other seeds when planting. On corn, the silks and tassels are simply the male and female part of the corn that ensures pollination. The tassels job is to produce pollen which encourages growth and riping of the corn ear. While the silks job is to take up the pollen that the tassel makes and create corn kernels. Once the corn has reached the silks and tassel stage with pollination that is when we start to see earworms beginning to damage the tops of our corn ears. The larval form of a moth likes to lay eggs on the corn plants. These moths are attracted to the smell of the corn silks and that is typically where they will lay their eggs. The best organic control for earworms is our Spinosad Garden Insect Spray. Similar to Monterey B.t., Spinosad is derived from a naturally occurring bacteria. For B.t. to work, the insects should ingest the insecticide. However, spinosad works on contact and ingestion by the insects. The mixing ratio is two ounces of spinosad and one gallon of water. The recommended application rate for spinosad on corn is one gallon per 150 to 200-row feet of corn. Another benefit of using Spinosad is insects and pest cannot build a resistance to it, unlike other organic controls. To get really good coverage it’s important to spray this Spinosad on the tops of the silks and tassels of the corn where the earworms are known to be hiding out. Travis likes to begin spraying spinosad once the silks start to become visible on the corn. He will start a program and spray this insecticide at least 4 to 5 days until the corn is ready to harvest in the garden. It also works great on controlling other worms like caterpillars, thrips, fire ants, and other insects. Overall, when preventing earworms it is important to apply organically controlled insecticides in the garden before it causes major damage in your sweet corn.