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There are a lot of plagues that can harm our cannabis plants. In today’s article we will talk about the caterpillars that can appear above all in outdoor growing operations, where there are often an infinity of insects who can lay eggs without us even realizing it until we notice the harm that they are doing. Because of this, we have to continue closely observing our crop in order to be able to detect any possible plague and pick out the eggs of future parasites that destroy your harvest.

Caterpillars and worms are a plague that, if you act immediately, are easily eliminated. The majority of worms that we find in our plants come from moth larvae, which is to say, that they are the eggs of typical fuzzy butterflies that we see flying around at night.


Oruga que puede afectar a nuestra planta de marihuana

Source: very interesting


Butterflies lay eggs on the top parts of our marijuana plant, in the flowers and on the buds where recently hatched worms can find food to survive and grow. According to the kind of butterfly, the worms can be greenish, yellowish or whitish… and they are small and round. The worm hatches and begins to eat, causing small holes in the leaves or eating its borders. In 2-4 weeks, it will have grown and changed color and it will look for a place to build its cocoon. From there, the butterfly emerges and begins the cycle again.

Above all, in the flowering time take special care of the buds since the softest areas are the first to be devoured by the caterpillars.


How do you detect a caterpillar plague?


Once the plague is advanced it is very evident and you will see how rapidly your marijuana plant is devoured. But at the beginning of the cycle, it’s not as easy to see and for that reason you have to keep in mind a few basic bits of advice:

  • Butterflies: if you see them fly around your plants, try to avoid them and begin checking to make sure that they haven’t laid eggs.
  • Eggs: you can find these on the flowers and leaves, above all on the upper parts of the plant and in the areas of the leaves that are closest to the stalk.
  • Holes on the leaves: if you have holes or the leaves are chewed around the borders. It means that the worms have already emerged from their eggs and they are feeding on your cannabis plant as they grow.
  • Excrement: Look to see if there is any evidence of defecation that the worm has left along the way. It is dark in color and can bring us even more problems like botrytis, among other fungi.
  • Dark marks on the bud: if the caterpillar is in this zone, you will see how the flower has rotten and brown parts. Keep your eye on the flower and the bud since it is the first that to get eaten in the blink of an eye.
  • Watch at night: since this is the time with the caterpillars are most active. During the day they camouflage themselves and they can’t be seen on the leaves.


Orugas en planta cannabis

Photographic source: Cannabis Cultura

How do you eliminate a worm plague?


As soon as you detect that you have caterpillars, you must act immediately if you don’t want to end up without a plant.

  • Remove them by hand: This is the first thing you need to do. Though it may seen very obvious it is very important since when you catch them you might not have any specialized products on hand, nor do you want to just spray anything that could hurt your plant. So, you need to bite the bullet and remove each one that you can see on your cannabis plant.
  • Biological insecticide: these are the most recommendable in order to avoid leaving chemical traces, above all in the flowering phase or close to it. We suggest that you use biodegradable products that attack worms and caterpillars in a natural way. For example, you can use Bacillus Thuringiensis (once a week for three weeks), Mittel, Bio Thur, Prirepot… According to how advance the plague is or how big the worms have grown, some products may be more useful than others.
  • Homemade remedies: pepper and garlic infusion can also be useful, as can a mixture of pyrethrum and rotenone.
  • Natural predators: such as the Trichogramma, Apanteles, Trichoderma Hamatum, Podisus maluliventris, Orius spp.y crisopas…


Note: it is important to not apply products if you are in the 15 final days before harvest. In this case, do not spray any insecticide and remove all of the caterpillars that you possibly can manually.. Another thing to keep in mind is to be careful that we don’t leave any trace of them. At the moment of harvest and drying, when you hang the plant upside down to dry, the worms will no longer have fresh, green food and they will leave. You can be sure that they will look for another place to build their cocoon and start their cycle over again. So, be careful to make sure that you don’t have cocoons or eggs in the corners of your house that could later turn into the next generation of destroyers of your cannabis plants.

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