Green corn rootworm

Systematic position. The green corn rootworm (Diabrotica viridula) belongs to the order Coleoptera and the family Chrysomelidae. This species is a significant agricultural pest, closely related to other rootworm species that pose a constant threat to maize production across various temperate and subtropical regions.

Host plants and damage potential. The primary host for this pest is maize (Zea mays). Both larvae and adults contribute to the economic damage of the crop. Larval feeding on the root system weakens the plant's ability to absorb water and nutrients, while adult feeding on foliage and reproductive structures can significantly impede pollination and seed set, leading to substantial yield losses.

Biology and life cycle. The insect undergoes complete metamorphosis: egg, larva, pupa, and adult. Eggs are typically deposited in the soil near the host plant's roots. Larvae emerge and immediately start feeding on roots. The duration of each developmental stage is heavily influenced by soil temperature and moisture levels, which determine the timing of emergence and the overall severity of the infestation.

Character of damage. Typical symptoms include irregular chewing damage on leaves and visible root pruning. In severe cases, extensive larval feeding leads to lodging, where plants lean or fall over, making them difficult to harvest mechanically. Adult feeding on silks can result in poor ear fill and reduced grain quality, directly impacting the final marketable harvest.

Control measures. Integrated Pest Management (IPM) is essential for controlling this beetle. Crop rotation is the most effective cultural practice, as it denies larvae a food source. Chemical control involves the use of insecticidal seed treatments or the application of soil insecticides at the time of planting. Regular scouting using sticky traps or pheromone lures helps determine the need for foliar insecticide applications during the adult activity season.