After 5 to 6 days, the eggs develop what appears to be black spots, which are actually the head capsules of young borer larvae. [16], Production of the specific pheromone blend in females is controlled by a single autosomal factor. Flights of adults can be predicted when 300 degree-days have been accumulated. A mixture of isomers is much more efficient in attracting the moth than a single component. [2] Since its initial discovery in the Americas, the insect has spread into Canada and westward across the United States to the Rocky Mountains. This decreases agricultural yield. The whorl of the plant will show the first signs of damage, specifically for corn. Determine the average number of egg masses per plant for the field and/or the average number of larvae per plant. Larvae may bore into the ears where they feed on the kernels and cob, resulting in yield losses, as well as avenues for attack from secondary insects and pathogens (e.g., ear rots). Full grown larvae are approximately 0.8” to 1.2” (20 to 30 mm) in length. Look for egg masses, signs of feeding, and larvae. Larva hatch from the eggs. The first generation of corn borers which develops during the late spring feeds on the leaves and stalks of corn plants. Scout earliest planted corn fields first.
The European corn borer, an introduced species, has been an important pest of corn in the Midwest since the 1920's. This can be done in late fall or early spring. For first generation larvae, focus on the middle third of the plant. The number of egg masses averages 1/4 per plant. The boring damage may weaken the plant enough to cause subsequent stalk breakage later in the season, typically occurring below the ear. Female moths are a light yellow-brown color, with wavy lines across the wings. Higher humidity also induces the calling behavior, while desiccation, or drying out, decreases the calling behavior. Furthermore, mating with multiple males ensures that the female receives enough sperm to completely fertilize her eggs. Meanwhile, the adults have an average wingspan of 1 inch. If a third generation is produced, it will feed on the ear, the leaf sheath, and the ear shank. E-mail: IPM@missouri.edu, (stage attracted to and captured in traps), Printable European Corn Borer Field Guide, European Corn Borer: A Multiple-Crop Pest in Missouri (G7113), Missouri Pest Management Guide: Corn, Grain Sorghum, Soybean, Winter Wheat (M171), equal opportunity/access/affirmative action/pro-disabled and veteran employer, Wingspan of 0.75 to 1 inch; female moth is larger than male moth, Several dark zigzag markings across the wings, Male moths: thinner body, darker tan-to-brown wings, Young larvae are initially dirty white; color may change to light tan or pinkish gray as larvae mature, Skin is smooth and free of hairs with numerous round dark spots scattered over top and sides, Four prolegs (3rd, 4th, 5th, 6th and 10th abdominal segments). Two or three generations are possible in Missouri each year. They may look dry and will also experience tunneling. European corn borers also eat the ear—which reduces crop yield—and the ear shank which often results in the ear falling to the ground, making it unharvestable.[21][19]. Count and record the number of plants showing foliar feeding damage. Larvae have five instars or sub-stages of development. The insect is referred to as a borer in its larval stage and as a moth in its adult stage. The tip of its abdomen protrudes beyond its closed wings. They develop quicker when the weather is warm. Anticipated yield is 150 bu/A and the crop is valued at $2.75 per bushel. DMCA and other copyright information. Since then it has spread rapidly throughout North America westward to the Rockies. Males are generally smaller in size and darker in color. Thresholds for pesticide application have been established in Missouri only for corn. Carefully examine each plant for egg masses and note if live larvae are present. The black head capsules of developing alrvae become more visible within the eggs as they mature and are an indication that the larvae are about to hatch. Insecticides are no longer effective after the larva has entered the stem. This is also where mating happens. The larval stage is followed by a period of diapause or hibernation in a pupa. A good estimate of control might be 75%. Tall, lush, early planted corn is the preferred oviposition site for the first generation moths; whereas second generation moths target actively pollinating corn, which is usually planted late. Contact your state Cooperative Extension Service for resistance management plans. This involves having to handpick the European corn borer. If they have the chance to mate, the eggs will look almost like the scales of fish in sets of around 20 eggs per laying. Finally, response to the pheromone is controlled by two factors, a sex-linked gene on the Z chromosome and another on an autosome. The egg masses are all laid within five leaves of the central ear leaf. Homyden.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

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