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How to Get Rid of Lygus Bugs

June 11th, 2009 Posted in Ornamental & Lawn Pests

The Lygus bug, or the tarnished plant bug, affects a wide variety of plants including herbs, vegetable crops, commercial flower plants, fruit trees and nursery stock. Hardly any plant is safe from the lygus bug.

They have such a wide appetite – it is known to eat over half of the cultivated plant species grown in the United States. However, they primarily feed on agricultural crops such as alfalfa, cotton, conifers and fruits and vegetables.

This article will teach you about:

• Lygus bug appearance
• Plant damage
• Tips on Getting rid of and Managing Lygus Bugs
• Organic control

Appearance

Lygus bugs are approximately 5-6 mm in length and 2-3 mm in width with a yellowish brown head. Their bodies are oval and somewhat flat with yellow and brown markings. In the center of their backs is a small yellow or pale green triangle that distinguishes them from other insects.

Newly hatched lygus bugs are yellowish green in color and are about 1 mm long. As they age, they will develop 5 black spots on their bodies–two on the segment right behind their head, two on the next segment and one in the middle of the abdomen.

Plant Damage

Lygus bugs have a needle-like mouth that they use to puncture the plant to eat the plant’s juices. Because the Lygus bug feeds off of a large number of plant species, the damage to the plant changes in different species.

These symptoms will appear within a few weeks of the lygus bug feeding:

• Leaf Damage–Ragged leaves, sometimes discolored brown or yellow, premature leaf dropping, leaf crinkling.
• Bud or Flower Damage– Ragged buds, discoloration of buds, flowers don’t develop from buds.
• Conifer Seeding Damage– needles thicker and shorter, and the tip of the needle is often curled which gives the tree limb a bushy appearance.
• Stem or Branch Damage– there may be lesions, or cuts, on the stems or branches caused by the enzymes the lygus bugs injects into the plant to help digestion.
• Lygus bugs may also cause abnormal branching patterns.

• Fruit– Fruit might appear irregularly shaped, or what is referred as cat-faced.
• The development of fruit may stop on strawberries.
• The lygus bug punctures the seeds causing the seeds to be large hollow and yellow in color.
• These signs on strawberries is a good indication of a lygus bug problem.

Tips on Getting Rid of and Managing Lygus Bugs

Lygus bugs lay eggs in weeds over the winter. Common weeds that lygus bugs lay their eggs on are butterweed, fleabane, goldenrod, vetch, dock, Russian thistle, black mustard, London rocket, wild radish, goosefoot and dog fennel. Management and destruction of weeds over the winter and early spring (March) can reduce the number of lygus bugs that pop up in the spring months.

Make sure you get rid of these weeds before they are fully grown adults. The adults will move from the weeds over to your plants.

Many insecticides are helpful in killing young lygus bugs, but early spring detection of young lygus bugs is extremely important because insecticides are not very effective on the larger adults. You may assume you’ve beaten the adult lygus with pesticides, but often the adult lygus migrate for a while after pesticides are applied, and then return later.

Parasitic wasps can be purchased commercially online. These wasps attack the lygus bug’s eggs. Be aware that these wasps do not kill the lygus bug, just their eggs, so if you already have a problem with lygus bugs on your plants, buying these wasps will do nothing. Use these wasps as a preventative measure in March before spring hits and the eggs hatch.

Bug-vacs or suction devices have been shown to reduce adult populations by 75% and in younger populations by 9-50%. These numbers vary depending on the machine you use. However, if you have a large number of lygus bugs, only using a vacuum will not reduce your damage. Also, vacuums have been known to cause other problems such as powdery mildew and gray mold by spreading the pathogens that cause these diseases. They may also remove an unhelpful amount of the lygus bugs’ natural predators causing your lygus problem to get worse. For the small scale gardener, this method is probably unnecessary, but it may be helpful to a nurseries, greenhouses, or commercial fruit growers.

Organic Control

Natural Predators

Lygus bugs have several natural predators that can help you fight an outbreak:

• Big-eyed bugs
• Damsel bugs
• Minute pirate bugs
• Several species of spiders

Organic Method for Controlling Lygus Bugs

To naturally get rid of these pests, try EcoSMART an organic pesticide that is safe for you, your children and your animals. Not to mention it’s eco-friendly too.



Christine Hellberg