Ways to Control Mexican Bean Beetle

Mexican Bean Beetle Control-mexican-bean-beetle-insecct-pest — *Mexican bean beetle insects*

The Mexican bean beetle is one of the most destructive pests of the bean plant in the eastern United States and parts of the southwest, this garden insect pest is native to Mexico and belongs to the family Coccinellidae which includes the lady beetle that is a beneficial insect but unlike their family, the lady beetle the Mexican bean beetle as the names say does damage by feeding on bean plants where they cause server destruction.

Some plants that the Mexican bean beetle uses as a food source are lentils, lima beans, peas, soybeans, snap beans, and runner beans. If you’re having issues with the Mexican bean beetle, here is what you need to know to bring complete control.

Mexican Bean Beetle Identification

The adult beetle is oval-shaped, about 0.31″ long and 0.23″ wide at maturity, and orange to copper with 8 black spots on each wing. The larvae of the Mexican bean beetle are yellow, possess soft oval-shaped bodies, and are covered with six rows of dark, branched spines.

Signs or symptoms of the Mexican Bean Beetle

Bright yellow eggs are laid on the leaves’ undersides in clusters of about 40 to 60.
Larvae can also be seen feeding.
The mature larvae at the pupae stage are yellow to orange in color.
The adult and their larvae can be found feeding on the leaf’s undersides between the veins where the leaf’s lower epidermis is removed. The upper epidermis dies, followed by the production of a transparent, lacy appearance. Tissues that are damaged fall out, skeletonized leaves may curl and fall to the soil surface.

Mexican Bean Beetle Life Cycle

Overwintering Mexican bean beetles shelter under pine needles and leaf litter, in open fields, in wooded areas, and under plant debris. In spring, the adult beetles emerge and lay their eggs on the underside. Within two weeks, the larvae hatch and join their parents by feeding on the plant’s foliage.

Monitoring for the Mexican Bean Beetle

During early spring, inspect the undersides of your garden plants for clusters of oval-shaped yellow eggs.
Look for leaves that are wilted and discolored.
If Mexican bean beetles are present, you will see both the adult and their larvae.
The larvae that are yellow and spiny may be seen on the soil’s surface.
Leaves that are skeletonized with the veins and midribs remaining intact.

Biological Control

Introducing beneficial insects into your garden can help manage Mexican beetles and their larvae. Some beneficial insects include green lacewings, minute pirate bugs, ladybugs, stink bugs, assassin bugs, and damsel bugs.

Cultural Control of Mexican Bean Beetles

Remove all overwintering locations, such as leaf litter, bushes, and weeds, will expose beetles to freezing temperatures, killing them.
Small amounts of adult beetles and their eggs can be hand-picked and thrown into a container with soapy water, bringing the elimination of eggs and adult beetles can be crushed.
Planting early crops will help to prevent the second generation that emerges in midsummer.
Cover your entire bean crop with floating row cover, the row cover can remain on bean crops until harvest time.
Plants that are severely infested should be uprooted and placed in plastic bags and properly sealed. After about a week, the plants and the beetle can be used as compost.

The Use of Insecticides to Control Mexican Bean Beetles

Before using any insecticides, read and follow the manfacture’s directions on the label for the best results.

Neem oil can be applied to infected plants. Once applied, this oil will disrupt the Mexican bean beetles from being able to mate and feed. The application of neem oil also acts as a repellent.
Other insecticides that can be used are pyrethrum or spinosad.
Diatomaceous earth can be used to bring control; lightly and evenly sprinkle Diatomaceous earth over vegetable crops wherever insect pests are seen.
The use of harvest guard can be used as a physical barrier to discourage the beetles and their larvae from feeding on plants.
Safer soap, including insecticidal soap, will control beetles and their larvae. When applying, ensure to get both the top and the undersides of plant leaves.
Sevin^® Insect Killer Ready to Use, Sevin^® Insect Killer Ready to Spray, and Sevin^® Insect Killer Concentrate will bring control.

10 Frequently Asked Questions (FAQs)

1. What is a Mexican bean beetle and why should I be concerned?

The Mexican bean beetle is a yellow-orange insect that looks a bit like a ladybug, but don’t let its cute looks fool you! These pests love to munch on bean plants and can cause serious leaf damage. Left unchecked, they can ruin your entire bean crop. That’s why early detection and control are so important.

2. How can I tell if Mexican bean beetles are damaging my plants?

Look for yellowing leaves with a lacy or skeletonized appearance — that’s a telltale sign! You might also spot clusters of orange-yellow eggs on the underside of leaves or find the beetles themselves crawling around. The damage of these beetles are usually most visible in mid to late summer.

3. Are Mexican bean beetles harmful to all types of beans?

Yes, unfortunately, they’re not picky! They attack snap beans, lima beans, soybeans, and even cowpeas. If you grow any type of legume, you’ll want to keep an eye out for them. However, they tend to prefer green beans the most.

4. What natural predators help control Mexican bean beetles?

Ladybugs, parasitic wasps (like Pediobius foveolatus), and assassin bugs are your garden’s allies. These beneficial insects feed on beetle eggs and larvae, keeping populations in check. Encouraging biodiversity in your garden can make a big difference.

5. What are some effective organic control methods?

There are a few great organic approaches:

Handpick beetles and eggs off leaves.
Neem oil or insecticidal soap sprays can kill larvae without harming your plants.
Introduce beneficial insects, like parasitic wasps.
Use floating row covers early in the season to prevent beetles from reaching your plants.

6. When should I start looking for Mexican bean beetles in my garden?

Start scouting in late spring to early summer, especially if you’ve had problems with them in the past. The beetles overwinter in garden debris, so by the time the weather warms up, they’re ready to feed and lay eggs.

7. Will tilling my soil help reduce beetle problems?

Absolutely! Tilling during the fall months or early spring can disturb overwintering beetles hiding in plant debris. It’s a simple but effective cultural control method to reduce the number of pests emerging the next season.

8. Are there chemical options for controlling Mexican bean beetles?

Yes, but use them as a last resort. Products with pyrethrin, spinosad, or permethrin can work, but they may also harm beneficial insects. If you go this route, apply treatments early in the morning or late evening when pollinators are less active.

9. Can I grow bean varieties that are resistant to Mexican bean beetles?

While no bean variety is completely immune, some types tend to suffer less damage. For instance, pole beans and yard-long beans are less attractive to beetles than bush beans. Rotating your crops and choosing different bean types can help.

10. How can I prevent future infestations naturally?

A few prevention tips:

Rotate crops every year to avoid building up pest populations.
Cleaning up plant debris in the fall will help to eliminate overwintering sites thereby discouraging the presence of these beetles.
Plant trap crops for example early bush beans away from your prize or main garden to lure beetles there.
Encourage natural predators and avoid broad-spectrum pesticides that harm beneficial bugs.

Conclusion

The Mexican bean beetle can be controlled with the help of this guide; these beetles, if left unmanaged, can wipe out entire crops, so strike back by including these control measures. You will be happy with the results. Why should these beetles rob you of your harvest by destroying your crops?