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Pea Weevils – The Ugly Truth

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Are pea weevils ruining your peas & beans?

Have you been noticing notching on the leaves of some of your pea plants. Or perhaps some of your bean crops have munches leaves. This could be the work of pea weevils.

Pea Weevil Damage on Snow Peas

Pea Weevil Damage on Snow Peas

Or is it just birds doing the damage?

Often birds will sit on pea trellises and peck at the edges of pea leaves. And when they do this, they can do quite a bit of damage. In fact, they’ll eat an entire crop of young pea sprouts sometimes. But if you’re noticing very uniform notching on pea or bean leaves. And, if it’s only on the leaves, the issue may very well be pea weevils.

So are bean weevils the same as pea weevils?

Sharon Collman Teaching

Sharon Collman teaching her Bugs & Blights class

As with botanical plant names, the “bean” and “pea” weevil terms are often used interchangeably.

Fortunately, WSU Entomologist Sharon Collman helps clear things up. And she’s helped put together an IPM program to help deal with pea weevils.

When I asked Sharon if I could share this information, her response was fantastic:

“My goal is to teach people and the more people that pass on information the more people learn.”

That’s a statement after my own heart. So here’s how we drilled down on the problem together:

First, Sharon she clarified these are two distinct insects

According to Sharon, bean weevils aren’t even true weevils. However, they are closely related. But, that’s all we need to know about these critters if we’re dealing with this pea issue.

Next, she asked if the leaf notches were on newly germinated peas.

Because the notching was on young, new leaves of peas and beans, she was able to confirm this was pea weevil damage.

Sharon went on to explain:

“If (you’re seeing notching on young leaves)  I’ve seen them in the daytime though I think they may do the notching at night. They are small and I think a bit striped.”

So, how do you get rid of these garden pests?

Sharon tells us we don’t need to do a lot to get rid of pea weevils:

“…Once the peas reach 6 leaves apparently they won’t cause significant damage to the peas. These do not infest the peas in the pod but rather the larvae feed on root nitrogen fixing bacterial root nodules. Plants of the family Leguminosae (legumes) are the major food of the adult weevils. The larvae feed only on Rhizobium sp. nodules of these plants.”

Finally, Sharon’s final bit of insight…

“I guess if (the weevils are) really abundant they might cause some stunting but usually in home gardens if the plants make it to 6 leaves, the plants will do fine. If your population is too high you may have to pick off some, or I guess spraying is an option. Some people grow peas in a gutter inside then slide the pea plants into the furrow so that they have a head start on the season and maybe on the weevils which have an annual life cycle….Pea leaf weevil is probably the least of a garden’s worries. It’s a once a year thing so once you get through the spring you are good to go till next year.”

Tiny, Adult Weevil

Weevil (not ID’d as pea weevil)

If you have them, plan to rotate your crops going forward.

So if you have current infestation, you may still get a decent harvest from your growing crop. But, don’t plant to grow any legumes in those areas again for at least a few years. That’s because this will break the life cycle of this annoying pest. So that means no peas, not pea family cover crops and no beans in that part of the garden for at least 3 years.

And, if you need ideas for new food garden designs, join our online Academy where you’ll receive printable garden design plans with your membership.

And when you do harvest your infested crops…

You may find larvae feeding on the root nodules. So, all parts of the finished plants should be removed and disposed of. But, don’t put this into your compost or you may perpetuate the problem in your garden.

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