**Tarnished Plant Bugs** (*Lygus lineolaris*) are highly polyphagous (feeding on many plants) insects and a major economic pest across North America. The conflict is severe, diverse crop damage: they feed by inserting their sharp mouthparts into tender plant tissue (buds, flowers, young fruit), **injecting toxins** that cause the tissue to **shrivel, distort, or die**. This results in **”cat-facing”** (deformed fruit), **ragged holes in leaves**, and **bud abortion**, leading to significant yield loss in strawberries, cotton, vegetables, and ornamentals.
Taxonomy and Classification
Tarnished Plant Bugs belong to the order Hemiptera (True Bugs), family Miridae (Plant Bugs). They undergo simple metamorphosis. Both the adult and the nymph (immature stage) are destructive feeders.
Physical Description
Adult Bugs are small, 1/4 inch long.
- **Appearance (Key ID):** Mottled brown/green/yellow body. Key feature is a distinct **yellowish triangle** (scutellum) between the wings. They have long legs and antennae and are quick to fly or drop when disturbed.
- **Nymph (Key ID):** Bright green, resembling an aphid but moving much faster. Late-stage nymphs have distinct **black spots** on the thorax.
- **Damage Sign (Key ID):**
- **Bud Drop:** Flowers or buds shrivel and drop prematurely.
- **Deformation:** “Cat-facing” (puckered, scarred areas) on mature fruit (especially peaches and strawberries).
- **Stunting:** Damage to the apical bud, causing the plant to branch excessively and become stunted.
- **Conflict:** Diverse crop damage and yield loss across many commodities.
Distribution and Habitat
Tarnished Plant Bugs are widespread across North America. Their habitat includes alfalfa fields, weedy areas (especially pigweed and curly dock), and cultivated crops during the susceptible growth stages.
Behavior and Conflict
The conflict is high mobility and broad host range.
- **Migration:** When their preferred wild hosts (weeds) or hay crops are harvested, they migrate rapidly into high-value cultivated crops, causing sudden, significant damage.
- **Toxic Feeding:** The toxic saliva injected during feeding causes damage that is disproportionate to the small size of the insect.
Management and Prevention
Control is integrated pest management (IPM), relying on monitoring and timely intervention.
- **Sweep Netting:** Use sweep nets in alfalfa and weedy areas to monitor populations and predict when migration pressure will begin.
- **Trap Crops:** Plant highly attractive crops (like alfalfa) around the cash crop to serve as a **trap crop**, concentrating the population for easier, localized control.
- **Weed Control:** Manage weeds (especially the preferred host weeds) near the crop.
- Apply a registered insecticide only when monitoring indicates populations exceed established economic thresholds, focusing the application on the plant part most susceptible to feeding (e.g., flower buds).
Conservation and Research
Tarnished Plant Bugs are managed as high-priority agricultural pests. Research focuses on host-plant resistance, optimizing sweep net thresholds, and developing biological controls (e.g., specialized parasitic wasps) that target the adult or nymph stages.