Tarnished plant bug

📖Overview

Lygus lineolaris, the tarnished plant bug, is a widespread hemipteran pest in North America. Adults and nymphs feed by piercing plant tissues and sucking sap, causing deformities, stunted growth, necrotic spots and reduced yields on a very wide range of host plants. They are highly mobile, can move between wild hosts and crops, and often build up on weed hosts before moving into cultivated fields.

Tarnished plant bugs overwinter as adults in leaf litter and field margins. In spring they become active, lay eggs inserted into plant tissue, and produce several generations per year depending on climate. Control is typically integrated: sanitation and weed management reduce populations, and insecticide applications or biological controls are used when economic thresholds are exceeded.

🔍How to identify a tarnished plant bug

Adults are 4.5-6.5 mm long, elongate-oval true bugs with a somewhat flattened body. Colouration is variable — mottled brown, green and yellow with darker markings across the back. The wings lie flat over the body; between their bases sits a small triangular scutellum, often marked with a pale yellowish V or Y. Nymphs are wingless, similar in shape to adults but smaller and often greener; later nymph instars begin to show wing pads. Eggs are tiny, elongate and laid inserted into stems, buds or leaf tissue.

1. Adults 4.5-6.5 mm long, elongate-oval, mottled brown-green with pale yellow patches
2. Small triangular scutellum between the wing bases, often with a pale yellowish V or Y mark
3. Nymphs are wingless, smaller, and often greener; later instars have visible wing pads
4. Variable markings — identification to species may require examination of subtle markings or expert confirmation for some Lygus species

Lookalikes

↻Life cycle

1. 🥚

   Egg

   Small, elongate eggs laid into stems, buds or petioles. Eggs hatch in about 1-3 weeks depending on temperature.

2. 🐞

   Nymph

   Several nymphal instars over 2-4 weeks; nymphs are wingless and feed like adults on plant juices. Multiple generations occur per year in warm areas.

3. 🐞

   Adult

   Overwinters as an adult in leaf litter and field edges. Becomes active in spring, mates and females insert eggs into plant tissue.

🍃Diet and predators

🌱Effect on plants and gardens

Feeds on a very broad host range: fruit and vegetable crops (strawberry, apple, peach, cotton, alfalfa, beans, tomatoes), ornamentals and many weeds. Feeding causes bud and fruit deformities, necrotic spots, failure of fruit set and reduced quality.

How to get rid of tarnished plant bugs

Use integrated pest management: remove or mow weedy field margins and flowering weeds that host juveniles, use row covers for small plots or young plants, monitor with sweep nets or sticky traps and apply insecticides only when economic thresholds are met. Encourage natural enemies (predatory bugs, lacewings, spiders, parasitic wasps). In commercial crops consult local extension guidelines for appropriate insecticides and timing to target vulnerable nymph stages.

📍Where and when to find it

Sweep or beat flowering weeds, alfalfa, clover and crop canopies to find adults and nymphs. Overwintering adults hide in leaf litter and field margins.

✨Fun facts

• Tarnished plant bugs feed on hundreds of plant species and are considered one of the most polyphagous agricultural pests in North America.
• They overwinter as adults and can rapidly recolonize crops in spring from nearby weedy habitats.
• Damage is often most evident as distorted fruit or aborted buds rather than visible feeding holes.

?Frequently asked questions

📷Photos of the tarnished plant bug