Pests, Diseases and Control Measures

Common Bean Pests

These little guys will probably visit your beans. Several types exist that attack both below and above ground. They fly in from everywhere and are born pregnant, so you might want to start control soon or you will be having lots of fatherless aphids looking for a free meal. Luckily, they are probably one of the easiest to control. Seaweed sprays alone are often enough to dislodge them. The seaweed also seems to attract ladybugs to the yard, which like to chow down on aphids.

If seaweed doesn’t do the trick, try a soap product such as Organic Insecticidal Soap or an organic control like Bug-a-Tak Organic Insecticide.

Cutworms and other Destructive Caterpillars
These can be easily controlled with a BT (Bacillus thuringiensis) application of Dipel dust or Thuricide spray. You can also control these critters naturally with the release of parasitic wasps.

Photo courtesy of jason riedy at

Mexican bean beetle
These ravagers look like harmless orange ladybugs with black spots (about 16 spots), until they strip your leaves down to its skeleton! They live just about everywhere a bean is, or can be, grown. These little terrors come in cycles. If you can figure out the time of arrival in your area, you may be able to avoid them, but don‘t count on it. You will have to talk to a local expert or an extension agent to figure this out. They seem to especially enjoy soybeans, so planting soybeans near other beans as a trap crop can help you reduce the spraying to the soybeans when the beetles attack. Pyrethrum can also control the beetles, as can Citrus, Orange or Neem oil. Parasitic wasps may be affective at controlling them.

Spider mites
These tiny red mites mottle foliage and young growth. They’re almost always associated with water- or temperature-stressed plants. You can usually control these by maintaining good moisture levels in the soil. If they get a little out of hand, seaweed or soap sprays (see above) will usually eradicate them.

Chances are you’ll need a microscope to see these pests. Unfortunately their damage is easily visible. Control can be achieved with products that contain crab or shrimp meal, which have large quantities of an enzyme that digests chitin, which, happily, these critters are made of. Orange peel, ground and applied to the surface, or tilled in between rows, can also provide control, although this is best done as a pre-treatment before planting.

Rabbits and other rodents
For rabbits in the city, we recommend catch and release traps and fences to exclude the furry terrors. Attracting birds of prey is another way to control rodents of all kinds, but if you use this method, you’ll want to keep your cats and small dogs inside. Shake Away Organic Rodent Repellent, Shot Gun Repels-All Animal Repellent Granules, and Garden Guard Pest Repellent (a cement block infused with rodent repelling scents) are also great environmentally friendly ways to keep destructive rodents away from your bean garden.

{ 2 comments… read them below or add one }

nancy utter 08.07.09 at 4:49 pm

I have very healthy vines and no flowers. They are growing with
corn and summer squash.They have had lots of water and this
summer a great deal of sun.

Has it been hot where you live? Beans seem to lose blooms, not produce flowers, or flower and not set a bean pod when it’s hot.

Mack 07.04.10 at 12:32 pm

Every time we plant beans as they pop up through the ground they die off no leaves… and most don’t even pop up? any suggestions?

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