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Caterpillars On Marijuana Plants

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 breakdown.

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

Signs of caterpillars

Signs caterpillars cannabis

All it takes is about five to ten caterpillars to demolish your plant. What’s even worse is that the hole Corn Borers carve into the stems creates an open doorway for other pests that will complete suck the life out of your marijuana plants. Hemp Borers will damage the buds (see picture).

You can easily identity their damage by the chew marks left on the leaves.

Download my free marijuana grow guide at this link for more growing tips

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. 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.

Not sure if caterpillars are causing the damage to your marijuana plants? Check the article Marijuana pest and bug control for a list with pictures of all pests and bugs

How to get rid of caterpillars

Get rid caterpillars weed

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.

Download my free marijuana grow guide at this link for more growing tips

A commercial product like Bug Blaster will always to the job. If you want to be sure to kill them all buy something like Bug Blaster.

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 good.

Making your own neem oil spray is easy, just pour 1 to 1 ½ teaspoons 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

- 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.

Remember that plants with strong genetics have less change of getting sick and are less vulnerable for pests and diseases. So make sure you buy your weed seeds from a trusted seed bank.

Thanks for reading. Please leave comments or questions below and don't forget to download my free grow bible


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Comment Section

17 thoughts on “Caterpillars On Marijuana Plants

By John on 17 September 2015

My plant is infested with baby caterpillars. They are eatin my crops & idk what to do.

By Mike Cicchino on 20 September 2015

Hey john, my plants were hit by caterpillar's as well! It has been a nightmare on the east coast this year, we are down about 7 inches of rain. We had many day's of temps in the mid to high 90's here in the Carolina's.

By Luv2gro on 20 September 2015

I have had a terrible time with caterpillars in the past. This year I have been using Safer brand caterpillar killer...bacteria BT that targets only caterpillars. I apply in evening apx every 10 days...not a single caterpillar this season!!

By latewood on 21 September 2015

Best thing to do about "Caterpillars"; Immediately remove by hand. In some cases an insecticidal soap can work to stifle the production of further generations. It may take 2-3 applications, spread out over 304 weeks to catch up with larvae, or hatchlings; Etc.

Using an garden duster to apply Food grade CODEX Diatomaceous Earth will also eradicate these pests, and any other pests with a soft exoskeleton.

By Art on 6 July 2016

Last year I lost all four of my plants due to caterpillars damage. So this year I brought a mosquito netting to cover my plants. All six of my plants are budding nicely and no sign of caterpillars. YEAH!!!!!

By Darcy on 23 September 2016

Is it ok to use spinosad on flowering plants about to be harvested?

By latewood.ILGM on 24 September 2016

Spinosad is an ingredient in approximately 80% of all pesticides. When using a produvt such as Spinosad; It is advisable to read and follow the directions on the bottle. Each pesticide is different.

If you cannot figure out from the label instructions as to whether it is safe to use on plants you plan to ingest; You are advised to call the manufacturer of the product..

On the label. Find out what it says about eating produce treated with Spinosad. Many products used on produce contain Spinosad.

By J.Sr on 30 December 2016

I had a bad problem with those bud eating caterpillars they got inside the biggest buds I have ever grown 19inch buds and when I noticed some parts of the buds didn't look right i touched it to feel it and it just crumbled and so did my heart!! That's when I found them and became a surgeon dissecting every bud removing the worms by hand, them worms destroyed at least 3oz worth!! By the time I was done my plants looked like they had a kemo treatment...

By Roy ILGM on 30 December 2016

Ouch that's harsh, sorry to hear J!

By MAGGIE on 19 May 2017

Does anyone know if the birch borer will attack marinara plants? I have a lovely birch that I suspect may be infected and it is pretty close to where I would plant my plants outside

By latewood.ILGM on 25 May 2017


Best thing you can do is to monitor the plants and be ready with insecticidal soap or some other safe option. Happy growing 🙂 – I❤️GM

By latewood.ILGM on 25 May 2017


You could also be proactive by dusting the area with Food grade CODEX Diatomaceous Earth. – I❤️GM

By Jeff Jackson on 28 August 2017

Is there any guides just for pray mantas

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