Mexican Bean Beetle

*Epilachna varivestis*

Content coming soon for this insect guide.

Insect Profile

Beneficial Rating

-5 Pest

Active Months

JanFebMarAprMayJunJulAugSepOctNovDec

US Distribution

NortheastSoutheastMidwestWestPacific Northwest

Habitat Preferences

gardensmeadowsagricultural fieldswooded areas

Taxonomic Group

Beetle

Order

Coleoptera

Family

Coccinellidae

Lifecycle

The Mexican bean beetle undergoes complete metamorphosis with four distinct life stages: egg, larva, pupa, and adult. The adult beetles overwinter in plant debris or other sheltered locations and emerge in the spring. Females lay bright yellow eggs in clusters of 40-75 on the undersides of bean leaves. The eggs hatch in about a week to two weeks, and the larvae emerge. The larvae are yellow, spiny, and feed voraciously on the undersides of leaves for two to four weeks, passing through four instars. After the larval stage, they pupate on the leaves, and the pupal stage lasts for about a week to ten days. The entire life cycle from egg to adult takes approximately 30 to 40 days in the summer, and there can be one to three generations per year, depending on the climate.

Overwintering Strategy

Adults overwinter in plant debris, under brush or leaves, in open fields, or in wooded areas.

Native Range

Southern plateau region of Mexico

Attracted By

lima beanssnap beanscowpeassoybeansalfalfacloversChinese wisterialupines

Repelled By

garlicmarigoldsnasturtiumrosemarysummer savorypotatoes

Organic Control Methods

There are several organic methods for controlling the Mexican bean beetle. Hand-picking the eggs, larvae, and adult beetles from the plants is an effective, albeit labor-intensive, method. Floating row covers can be used to create a physical barrier to prevent the beetles from accessing the plants. The parasitic wasp *Pediobius foveolatus* is a natural enemy of the Mexican bean beetle and can be released to control their populations. For more severe infestations, organic insecticides such as neem oil, pyrethrum, or spinosad can be used. Trap crops, such as an early planting of beans, can be used to attract the beetles, which can then be destroyed before they move to the main crop.

Companion Planting

Companion planting can be an effective strategy to deter the Mexican bean beetle. Plants with strong scents, such as garlic, rosemary, and summer savory, can help to confuse the beetles and make it more difficult for them to locate their host plants. Marigolds and nasturtiums are also known to repel Mexican bean beetles. Additionally, planting potatoes near beans is a classic companion planting technique, as the potatoes are said to repel the bean beetles, while the beans repel the Colorado potato beetle.