The eggs of European corn borer appear in masses, with each having an average of length of 1/8 to 3/16 inches. Each cluster can have as much as 30 eggs. They start as white but as they mature and when they are about to hatch, they become cream. Before the egg hatches, the back head of its larva will be visible outside of the shell. The body of the larvae can be gray to cream with visible dark spots. The length can range from ¾ to 1 inch. Meanwhile, the adults have an average wingspan of 1 inch. Females are usually larger and lighter in color.
European Corn Borer’s Habitat
The development of the pest starts in spring or when the temperature reaches 50 degrees Fahrenheit. Pupation usually happens in May or June. They develop quicker when the weather is warm. During the daytime, moths will be feeding in grasses and weeds. This is also where mating happens. They will chew on the corn kernels and the leaves of their host plant. Although the pest is a native from Europe, it is now damaging plants all over the world, such as North America, Canada, and Northern Africa, among others.
Identifying European Corn Borer’s Damage
European corn borer is a serious pest to more than 200 plants. Generally speaking, they will feed on herbaceous plants with a large stem, which will provide them with a suitable entry point. The western strain of the pest feeds primarily on corn. The northern strain, on the other hand, tends to have a wider range of host. Aside from corn, other host plants include snap beans, lima beans, potato, pepper, buckwheat, and soybean. Occasionally, they also feed on flowers like dahlia and zinnia.
The following are some of the most common symptoms that are indicative of the presence and damage from European corn borers:
- The whorl of the plant will show the first signs of damage, specifically for corn. There will be shot hole patterns, which will be reflective of the entry of the larvae. There will also be tunnels on the midrib of the leaves.
- From the leaves, the larvae will move to the stalk, which is where they will create holes as well. Another sign is the appearance of frass, an excrement that is like sawdust.
- The stalk will become weaker overtime as the holes become larger. This inhibits the ability to transport water and the essential nutrients. This will make the plant weak and dry. It will compensate its structural integrity as well.
- The corn ear, cob, kernels, and tassels will also show visible signs of damage. They may look dry and will also experience tunneling.
Results of Infestation
With the feeding characteristics of the European corn borer, the host plant suffers from physiological stress. It becomes weak and limits its ability to absorb the nutrients that it requires for survival. With this, it suffers from breakage and in the end, the crop yield will be significantly lesser. The crop will also show cosmetic damage, making it unmarketable. Hence, commercial growers can suffer from profit loss.
How to Get Rid of European Corn Borer
Natural and Organic Solutions
For natural and safe elimination of European corn borer, the following are some of the things that you should do:
- Manual control should be on the top of the list. This involves having to handpick the European corn borer. Learn about its physical characteristics so that it will be easy to spot their presence. It will be good to do this early or before the egg hatches. Be sure to throw them in a bucket of soapy water, which will be effective in killing the larvae and adults. However, since this is an exhausting task, this will work best only in small areas.
- You can also consider the use of traps to attract the pest. Among others, pheromone traps will be effective. They emit a unique odor that attracts male European corn borers. This will aid in the prevention of mating, and hence, will regulate their population. A daylight blue lamp is another simple way of attracting them.
- It will also be good to use biological control. In this case, you can take advantage of the natural enemies of European corn borers. They will kill the pest before they can spread the infestation. Some of the best predators are tachinid flies, braconid wasp, lacewing larvae, ladybugs, and minute pirate bug, among others. While you can buy them, you can also alter the external environment in such a way that it will be more attractive to these predators.
- The use of vegetable oil is a natural and promising solution that you might want to try. Using a medicine dropper, squirt a small amount of oil on the tip of the corn’s ear. Do this only once the silk starts turning brown. Doing this earlier is not recommended as it will inhibit pollination.
- Insecticides may have a bad reputation, but this holds true only for those that contain chemicals. With this, there are organic insecticides that can prove to be promising. Among others, look for those that contain Bacillus thuringiensis. The latter is made using biological ingredients, and hence, they will not be harmful to humans or other pests. Nonetheless, use this solution only as a last option.
For the longest time, the use of chemicals seems to be the go-to option for many people, especially for commercial corn growers. To yield the highest level of effectiveness, the right timing is one of the most important things. It is best to do so when the tassels emerge. This is also the time wherein the larvae become more active, and hence, there is a higher likelihood of killing them upon having contact with the insecticide.
Among others, Furadan is one of the most popular brands of pesticides for the control and elimination of European corn borer. Since its introduction in 1967, it has gained a reputation as one of the most effective chemical treatment for corn and a variety of crops.
How to Prevent European Corn Borer
Regular cleaning and proper maintenance are some of the best preventive measures against the European corn borer. Make sure that the environment is clean, and hence, it will not be attractive to pests. After the growing season, it is also advisable to destroy the stalks and throw them away. It serves as a site for overwintering, so it is a good idea to discard them so that the pest will not be able to find a suitable breeding ground. As much as possible, you should also concentrate planting varieties that can resist European corn borer.