Corn culture is one of the widespread in Georgia, growing quality corn is associated with many challenges and requires a lot of knowledge and experience from the farmer. One of the main problems in corn culture is corn borer.

In this article, we want to talk about the life cycle of the above-mentioned pest, its harmfulness and measures to fight it.

Pest biology and life cycle

Parvana of corn

Corn borer is a polyphagous pest. We meet its 2 generations during the year. Adult caterpillars overwinter in the parts of the plant stem that remain in the field after harvest. In the spring, the caterpillars sometimes feed additionally or in most cases they hatch directly. The caterpillars make a thin bag of abalone and a hole in the wall of the stem for the butterfly to fly out of.

The first generation of butterflies hatches in May-June, and egg-laying begins 4-5 days after hatching. A female butterfly can lay up to 400-600 eggs. The butterfly lays eggs in groups on the underside of the leaf. The hatched caterpillar enters the leaf plate, then its stalk, and starts feeding here. Later, the caterpillars move into the stem of the plant and onto the stalk.

Parvana of corn

Parvana caterpillars are quite easy to spot. It is about 1-2 centimeters in size and has a greenish-brown color. They hatch around the end of July-August, and in September the second generation butterfly begins to lay eggs.

Parvana of corn

Newly hatched caterpillars gather first at the base of the leaf, and then enter the stem and taro, where they feed quite aggressively and thus cause great damage to the plant. By this time, the caterpillars are already preparing for wintering.

Temperature and soil moisture play a big role in the reproduction of Parvana. Favorable climatic conditions for Parvana occur when day and night temperatures are almost equal and there is less precipitation. This pest hides during the day, but becomes active at night and at dawn, which makes fighting with it much more difficult.

Harmfulness of parvana

The corn borer, at different stages of its life cycle, damages the corn leaf, stem, and taro.

Parvana of corn

First-generation caterpillars mainly damage green mass, while second-generation caterpillars can additionally damage taro. In case of damaged leaves, photosynthesis in the plant decreases.

Damage to the stem prevents the movement of water and nutrients in the plant, and the stem becomes weak and breaks easily in case of wind.

Battle events:

  • Introduction of crop rotation
  • When harvesting corn, cut the plant as low as possible
  • Collection and burning of plant waste
  • Deep pruning of the plot after harvesting
  • Weeding
  • Installation of pheromones
  • Carrying out chemical treatment (it is important to determine the phase of development of the pest in order to correctly select the active substance to fight it)

For more information on these and other topics, see Agrocompany Baraka’s YouTube channel – https://www.youtube.com/@baraka.georgia2230