**Tomato Fruitworms** (*Helicoverpa zea*), also known as Corn Earworms or Cotton Bollworms, are the destructive larvae (caterpillars) of a generalist moth. The conflict is severe **fruit destruction**: the larvae feed on the foliage and bore into the **ripening or green tomato fruit**, where they feed and leave behind copious amounts of frass (feces), leading to contamination, rot, and complete loss of market value for the infested fruit.
Taxonomy and Classification
Tomato Fruitworms belong to the order Lepidoptera (Moths and Butterflies), family Noctuidae. They undergo complete metamorphosis. They are highly polyphagous, attacking corn (ear), cotton (boll), soybeans, and numerous vegetable and weed hosts.
Physical Description
Adult Larvae are medium-sized, 1 to 1.75 inches long.
- **Larva (Key ID):** Color varies widely (green, pink, brown, yellow) but often has faint stripes running down the body and a rough, textured skin.
- **Adult Moth:** Tan to yellowish-brown moth with a dark band near the edge of the hindwing.
- **Damage Sign (Key ID):**
- **Hole:** A clean, round entry hole (often near the stem end) on the tomato fruit.
- **Internal Rot:** Internal feeding cavity filled with moist, reddish-brown frass.
- **Foliar Feeding:** Minor damage to leaves (ragged holes) before the larva bores into the fruit.
- **Conflict:** Fruit destruction, contamination, and economic loss.
Distribution and Habitat
Tomato Fruitworms are found across the Americas. Their habitat is the foliage and fruit of their host plants.
Behavior and Conflict
The conflict is mobility and the difficulty of internal control.
- **Host Switching:** Larvae often feed on corn first, and as the corn matures, the moths lay eggs on tomatoes, leading to severe, late-season damage.
- **Protected Feeding:** Once the larva is inside the fruit, it is protected from most topical insecticide treatments, making timely application critical.
Management and Prevention
Control is integrated pest management (IPM), relying on monitoring and careful timing.
- **Pheromone Traps:** Use pheromone traps to monitor adult moth flight density, informing the exact timing of chemical application (when moth populations are high and fruit is setting).
- **Bt:** Apply the biological insecticide *Bacillus thuringiensis* (Bt) to the foliage, targeting newly hatched larvae before they bore into the fruit.
- **Chemical Sprays:** Use registered insecticides timed specifically when the most vulnerable stage (newly hatched larvae) is present.
- Planting **trap crops** (e.g., specific corn varieties) early to lure the initial generation of moths away from the tomato crop.
Conservation and Research
Tomato Fruitworms are managed as high-priority agricultural pests. Research focuses on developing genetically modified crops with inherent resistance (*Bt* corn, cotton), improving monitoring thresholds, and enhancing natural enemy populations.