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Tomato pinworm infestation

Posted by teresa_in_md z7 MD (My Page) on
Sun, Oct 21, 07 at 14:28

I had a terrible time this year with tomato pinworms - almost every ripe tomato was affected by them and they hollowed out much of the foliage. I tried BT dust as well as insecticides with little to no success. Have others had any successful treatments they can share? I've already pulled my plants for the season but am worried about these pests over-wintering and being a problem again next year. Any and all suggestions are welcome. Thanks.

Teresa :)

Follow-Up Postings:

RE: Tomato pinworm infestation

Hi teresa - tomato fruitworms (aka corn earworms) overwinters in the soil as a pupa so tilling the beds can help. But the adult moth (tan-colored), lays eggs on the plants very early and you have to spray/dust with Bt early to get them before they burrow into the fruit.

Second generation moths start laying eggs the last of May and early June in our zone so you have to dust/spray again then to catch them as they are the ones that cause the most damage to tomatoes.

I dust with Bt every 7 days and after each rain right at first fruit set time and manage to get 90% of them. Cover the entire plant with a dust or spray.

Hope this helps.


RE: Tomato pinworm infestation


Thank you - your suggestions are helpful and I will certainly give them a try.

Just to be certain - are we talking about the same worm? The tomato pinworm was the pest I had last year. It is very tiny (about 1/8 of an inch) and gray. The adult moth is also very small and tan colored.


RE: Tomato pinworm infestation

Pinworms and fruitworms are two different pests. Actually, fruitworms are several different, but similar species. Fruitworms are considerably larger than pinworms. You can find a lot of info on both by Googling.


RE: Tomato pinworm infestation

I am having the same problem with tomato pinworms. Ruined all of my tomatoes. Have you found any addtional advice? Thank you

RE: Tomato pinworm infestation

um what is bt?


mato novice here forgive the ignorance! :)

RE: Tomato pinworm infestation

Bt is Bacillus thuringiensis, a bacterial strain that specifically affects caterpillars. It is considered an organic treatment. It stops infestations by causing young caterpillars to stop feeding, and the caterpillars die of starvation. It works best on smaller, younger caterpillar stages. You can buy Bt as Dipel or any of several other brands (no advertising plug intended). After using Bt, you may still see caterpillars on the plants for a few days. However, if they ingested the Bt, they will stop feeding and eventually curl up and die. They're sick.

Bt is a surface treatment, not systemic. It needs to be reapplied after rain or watering, and it does degrade over time with sunlight. It's harmless to pets, people, birds and other nontarget species.

Bt is best used when no rain is expected for a few days and if you can water from the bottom or at soil level instead of top-watering. It's good to apply Bt on cloudy days or in the evening, as it's degraded by sunlight. This gives the caterpillars an opportunity to eat the Bt-- they must ingest the bacteria; it's not a contact poison.

Make sure that you get Btk, the strain of Bt that gets caterpillars. There are other strains of Bt, such as Bti that kill mosquito larvae or other targets, but Btk is the one for plant-type caterpillars.

Note that Bt will also kill "good" butterfly caterpillars so use caution with it around butterfly host plants if you are intentionally raising BF's.

Oh, and spinosad also works for pinworms.

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