Caterpillars on marijuana plants

Caterpillars love marijuana plants! Corn Borer and Hemp Borer are the two most destructive caterpillars. These pests will diminish the strength of your plant by eating away at the marrow inside the stalk causing stem cankers to form. If the plant is really infested it will break down.

Read this article and learn how to identify caterpillars on your marijuana plants and how to get rid of them.

Signs of caterpillars

All it takes is about five to ten caterpillars to demolish your plant. You can easily identity their damage by the chew marks left on the leaves. Observe the plants stems to see if there are holes with brown trails around them. If you notice visible holes on your plant, then you most likely have a problem.

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    What’s even worse is that the hole Corn Borers carve into the stems creates an open doorway for other pests that will completely suck the life out of your marijuana plants. Hemp Borers will damage the buds (see picture).

    Effect stem boring caterpillars marijuana plant
    Effect stem boring caterpillars marijuana plant

    Stem boring caterpillars do their damage from the inside of the plant so, they can go undetected until it’s too late and the harm is done.

    Also read Marijuana pests & bugs – Control and identification

    How to get rid of caterpillars

    You can simply rely on nature to eradicate caterpillars by having parasitic wasps around. Mostly likely they will come all on their own as soon as the sense caterpillars are nearby. These wasps will lay eggs on the caterpillar’s body and when they hatch, the caterpillar becomes food for them.

    Another way nature can assist you with this is the praying mantis. These insects love eating caterpillars and will remain until all of them are fully devoured.

    When it comes to stem borers the only way to really get rid of them is to cut them out of the plant. If the plant doesn’t revive itself, then completely remove it by doing a clean cut at the bottom of the train. This will guarantee no further damage.

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    Neem oil spray is excellent for caterpillar control. Use this once the sun has gone down or on an overcast day. The sun will make the solution useless. Spraying the tops and base of the plants. Don’t overdo it, just cover it really well.

    Making your own neem oil spray is easy, just pour 1 to 1 ½ teaspoon liquid dish soap into one gallon of warm water. Pour in one ounce of neem oil and shake well. This concoction will lose its strength after 4-8 hours, so it’s pointless to keep what you don’t use. Do this once a week until all caterpillars are gone. You can buy neem oil at a nearby garden center or get it online at this link here.

    List of marijuana plant symptoms

    How to recognize marijuana plant symptoms caused by caterpillars:

    • Holes with brown trails around them
    • Chew marks on the leaves
    • Yellowing on the top leaves
    • Holes and damage to the stems

    Remember caterpillars are marijuana lovers! If you see any signs of these, you definitely want to do something about it immediately. These pests will destroy and potentially suck all the life out of your plant.

    Marijuana plant symptoms
    Marijuana plant symptoms

    Plants with strong genetics have less chances of getting sick and are less vulnerable to pests and diseases. Make sure you buy weed seeds from a trusted seed bank.

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    FAQs about caterpillars on cannabis plants

    What are some ways to eradicate caterpillars on cannabis plants?

    Having parasitic wasps or a praying mantis around the plant, cutting the affected stems, or spraying with neem oil are some effective ways to deal with caterpillars on your weed plants.

    How many caterpillars does it take to take down a marijuana plant?

    All it takes is about five to ten caterpillars to demolish your plant.

    What plant symptoms should I look out for to know that my plants have been infested with caterpillars?

    Some of the most common caterpillar symptoms include chew marks on the leaves, holes and damage to the stems, and yellowing on the top leaves.

    Practice and learning are all you need to grow marijuana like a pro! Let my blog help you get started.

    Have you had caterpillars on your marijuana plants? Please share your experience or leave questions in the comments.

    Happy growing!


    Avatar for Robert Bergman

    Robert Bergman

    Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing led him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]


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