What Is a Genista Caterpillar?
- Genista caterpillars feature small patches of white hairs and dark spots on orange or green bodies.They reach up to one inch when fully mature. Often confused with the fall webworm, genistas have less hair and lack a double row of black dots on each body segment. Genistas prefer Texas laurel, crape myrtle, honeysuckle Sophora secundiflora and Laburnum as host plants.
- Moths feature four life stages. The genista caterpillar, or larvae, emerge from cream-colored eggs deposited on the underside of leaves. They then go through several feeding stages on the host plant before reaching the pupal stage. During this time, they form silk webs on the host plant. Genista caterpillars spend the winter months in the pupal stage, emerging as moths during the early spring, according to Texas A&M AgriLife Extension. Southern parts of the United States may see two full life cycles per year.
- Genista caterpillars are most active during daytime hours, but moderate weather conditions may encourage night feeding. Young larvae prefer to feed in groups, with older caterpillars becoming solitary as they mature. As they mature, the caterpillars spread throughout the entire plant, occasionally moving to surrounding plants and buildings. Generations overlap, often resulting in all stages of the life cycle evident on a single plant.
Damage first appears on the new plant growth in the spring time. Young genista caterpillars cause small tracks and pin-holes on leaves, while mature caterpillars feed on the edges of leaves. Over time, webbing becomes apparent. Damage by genistas usually results in damaged leaves that drop from the plant over time. While usually not fatal to the mature plant, large numbers of caterpillars may cause the plant to become stressed and vulnerable to infection. - The University of Arizona, Maricopa County Cooperative Extension recommends protecting young or newly installed plants against genista caterpillar damage. Small gardens may benefit from handpicking and disposing of caterpillars. Bacillus thuringiensis (BT) also may be applied to new growth and young plants to control genista damage. Only effective on young caterpillars, BT must be reapplied regularly to control new generations of genistas.