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tomatoman_gw

The Mighty Weevil

tomatoman
18 years ago

For the past several years my tomatoes have started to decline just as the tomatoes are maturing, and then the plant slowly died.

I have posted on several garden sites, contacted my local ag agent, and had numerous suggestions from all over the country, and up until this week was unable to identify this serious culprit in my garden. After several years of frustration, I have finally identified the culprit. Thanx to a gentleman from the England, it turns out to be the vine weevil. He also suggestion a cure, a beneficial nematode that kills the destructive larva.

Since I only use BT & neem oil, neither of these have had any effect on the vine weevil larva. The larva enters the plant below ground, and works it's way up the stem, eating the inside, and leaving a hollowed stem, unable to sustain the plant. When the larva mature, they exit the stem, and repeat the cycle.

From previous posting, I believe there are others with the same problem. Hope this helped some of my fellow tomato growers

Comments (3)

  • jean001
    18 years ago

    I never saw your original posts, thus cannot even guess at what might have occurred.

    But when it comes to blaming the "vine weevil," maybe, maybe not.

    After searching on google.com, the references to "vine weevil" I could find apparently (both in the UK and US) refer to the black vine weevil.

    As it turns out, this particular weevil doesn't hollow out stems. Instead, the larvae "worry" the basal portion of stems and will eat new roots. The adults damage leaves.

    So, the gent in the UK needs to supply the scientific name of the beetle he is referring to so that you/we can verify if his critter is in the US.

    Beyond that, did you ever find any weevils or other critters which were the potential damagers? Without a critter in hand, and/or without typical damage produced only by one critter, it's folly to blame damage on a critter you only suspect.

  • tomatoman
    Original Author
    18 years ago

    "Beyond that, did you ever find any weevils or other critters which were the potential damagers?"

    Thanx for your inciteful reply to my post Jean. You are quite right in your questioning a diagnosis of black vine weevil, but there are many insects in the Otiorhynchus species. I don't believe my pest is the black vine weevil, but another vine weevil species, that I lack the expertise to correctly identify. I tried to take pictures of an adult, but they were so small that my pictures, even on a macro setting they were not clear enough to send for identification.

    I have seen the larval grubs in various stages almost to an adult ready to exit the vine, several times. Their appearance is almost exactly like the black vine weevil, but I believe smaller.

    I am hopeful that the biologic agent (nematodes) I obtain, will control my weevils.

    If you have any other comments or questions, please let me know.

    Ron

  • jean001
    18 years ago

    Good to hear that you saw the critter.

    And yes, troublesome sorts of weevils exist which are quite small.

    If this is a current problem -- if not, then if the critters return during another growing season -- collect several of the adults and take them to your county's Extension Service office. Even if no one in the office has enough experience and/or training to ID the critters, the critters can be submitted to the entomologist for ID.

    Hope this helps you find an answer.

    And if you do, please come back to telll us.