So... What are Harlequin Bugs?
The adult Harlequin bug, a shield-shaped bug with bright red, orange, and black markings, is generally about 3/8"-1/2" in length.
Nymphs look similar to the adults, but they are more roundish in shape and do not have wings.
Eggs are barrel-like in shape and are light yellow or gray. The eggs are deposited in clusters on the leaves of crucifers.
Reproduction Patterns of Harlequin Bugs
Harlequin bugs spend the winter hidden under plant debris, then, after emerging in the spring, females will lay their eggs. Eggs are laid in two-row clusters on the underneath parts of leaves. When she has finished, the female will have laid about 150 eggs. The female will fiercely defend her eggs from predators.
Within three weeks, the eggs will hatch and the emerging nymphs will begin feeding on the host plant. Nymphs feed for about two months and progress through five instars until they become adults. There are anywhere from 1 to 4 generations per year depending on the climate of a particular region.
Harlequin Bug's Habitat
Harlequins are found throughout the continental United States and reach southward through Mexico to its native countries in Central America. It can be found in agricultural fields as well as home gardens.
Its favorite foods include members of the cabbage family, including Brussels sprouts, broccoli, cauliflower, and kale. It also feasts on members of the mustard family, including wild mustard, peppergrass and watercress.
In a pinch, these injurious pests will also partake of corn, tomatoes, squash, asparagus and beans.
Symptoms of Harlequin Bug Damage
Harlequin bugs in both the adult and nymph stages drain the juices from leaves and stalks with their sharp needle-shaped mouths.
Symptoms of harlequin bug infestations include cloudy areas around the point of extraction, browning and wilting plants, and slower plant growth.
Results of a Harlequin Bug Infestation
Damage from an infestation of harlequin bugs includes stunted plant growth, wilting plants and dying plants.
Although older plants can withstand an attack better than younger plantings, the older plants may show slowed growth. Younger plants may be damaged so severely, they may end up dying.
Natural & Organic Controls
The combination of Insecticidal Soap and Botanical Pyrethrins will kill harlequin bugs on contact if they are spotted on your plants.
Insecticidal Soap (Potassium Salts of Fatty Acids) & Pyrethrin - combined are the organic equivalent of a one-two knockdown punch. The soap will penetrate the insect's shell enough to weaken and dehydrate the insect and allow the pyrethrin to absorb into the insect and do its job.
Pyrethrin is a powerful nerve agent and will paralyze and kill the insect on contact. Keep in mind this soap is not like dish detergent, it's a base from a blend of natural plant sources and pyrethrin oils and comes from the chrysanthemum flower. An effective and organic combination...
Use Insect Soap & Pyrethrin as a contact killer. Use in accordance with directions on the product label.
Safer® Brand offers a variety of harlequin bug control products to help control and eliminate this garden pest and revive your plants. Please check out our harlequin bug control products for more details about how they work and how, when, and where they should be applied.
If you are concerned about a plant or unsure of how it will react to these solutions, test an inconspicuous area and wait 24 hours before applying full coverage. As a general rule, much like watering, do not use any liquid insecticides in the peak of the day or when temperatures exceed 90°F.
Parasitic wasps and parasitic flies may be able to help control harlequin bug infestations.
Parasitic wasps and flies attack the eggs, nymphs and adults, paralyzing the harlequin bugs and laying their eggs inside of them. When the eggs hatch, the offspring will feed on the harlequin bug eggs, larvae or adults. Attract them by growing flowering plants, especially those that produce nectar or pollen.
Parasitic wasps can be attracted through the flowering plants or purchased through commercial growers. Purchases should be done as soon as possible once harlequin bugs have been spotted.
Most local greenhouses and garden centers can help you determine the right planting time for nectar and pollen producing plants to ensure that the pollen and nectar will be available when the wasps arrive.
Remove or till under any plant debris left over from the harvest to get rid of harlequin bugs. Removal of bordering weeds and vegetation is also an important step in controlling a harlequin bug infestation.
Planting resistant varieties of crops is another method of helping to control problems caused by harlequin bugs.
Remove and discard plant debris. This will help prevent the adult harlequins from finding a place to overwinter. Overwintering adults can also be eliminated by tilling under any plant debris after the harvest.
Remove any weeds or vegetation along the perimeters of the field or garden, where the harlequin bugs may hide for the winter.
Resistant varieties of crops or plants can be purchased at your local garden center, from garden catalogs, or on the Internet.
Remove or till under any plant debris left over after harvesting. Remove any weeds or vegetation along the perimeters of the field or garden throughout the growing season and after the harvest.
Plant the resistant varieties according to the temperature and your climate zone. The professional staff at your local garden center can advise you on when to plant.