There are many pests that can harm our cannabis plants. In today's article, we'll talk about caterpillars that can appear especially in outdoor cultivation, where countless insects can land and lay eggs without us barely noticing until the damage starts to show.
The key is observation: we need to closely observe our crop to be able to detect any possible pest and spot eggs of future parasites that could destroy our harvest.
What are caterpillars?
Caterpillars or worms are a pest that, if we act immediately, are very easy to eliminate. Most worms we can find on our plants come from moth larvae, that is, eggs from the typical hairy butterflies we can see flying at night.
Caterpillar life cycle
- The butterfly lays eggs on the highest parts of the marijuana plant, especially on flowers and buds
- Newly hatched worms find their food to survive and grow
- Depending on the type of butterfly, the worm can have a green, yellow, whitish tone... and they are small and round
- The worm hatches and starts eating, causing small holes in leaves or eating the edges
- In 2-4 weeks, it will have grown, changing color and looking for a place to build its cocoon
- From there, the butterfly emerges and the cycle starts again
Special attention during flowering: During the flowering period we must especially care for the buds, as their softer areas are the first that caterpillars will start devouring.
How to detect a caterpillar infestation in cannabis?
When the infestation is advanced, it will be quite evident and we'll quickly see how it devours our marijuana plant. But at the beginning of the cycle it won't be so easy, which is why we should be alert to these signs:
Early warning signs
- Presence of butterflies
- If you see them flying above your plants, try to keep them away and start observing that they haven't left eggs.
- Visible eggs
- You can find them on flowers or leaves, especially on the upper parts of the plant and in leaf areas closer to the stem.
- Holes in leaves
- If you have holes or leaves that are nibbled at the edges, it means the worms have already hatched from the eggs and are feeding on your plant while growing.
- Excrement
- Look for traces of droppings that the worm leaves behind as it passes. They are dark colored and can bring more problems by causing botrytis, among other fungi.
- Dark spots on the bud
- If the caterpillar takes over this area, we'll see how the flower has rotten and brown parts. Watch the flower and bud very carefully as it's the first thing they'll eat!
Tip: Observe at night, as that's when caterpillars are most active. During the day they camouflage and don't remain visible on the leaves.
How to eliminate a caterpillar infestation?
As soon as we detect that we have caterpillars, we must act with immediate speed if we don't want to be left without a plant.
Elimination methods
1. Manual removal
Removing them by hand is the first step. Although it may seem very obvious, it's very important since it may be that when we see them we don't have any specialized product at hand or we don't want to apply anything that could damage our plant. So you'll have to bite the bullet and remove all the ones you see on your cannabis plant.
2. Biological insecticides
These are the most recommended to avoid leaving chemical residues, especially in the flowering phase or close to it. We advise using biodegradable products that naturally attack worms and caterpillars:
- Bacillus Thuringiensis kurstaki (apply once a week for 3 weeks at 32%)
- Mittel
- Bio Thur
- Prirepot
Depending on how advanced the infestation is or how big the worms have gotten, some may work better for you than others.
3. Home remedies
- Pepper and garlic infusion
- Pyrethrum and rotenone mixture
4. Natural predators
Introduce these allies to your cultivation:
- Trichogramma wasp
- Apanteles
- Trichoderma Hamatum
- Podisus maculiventris
- Orius spp.
- Lacewings
Important precautions
Last days before harvest
Do not apply any product if you are in the last 15 days before harvesting. In that case, simply don't apply any insecticide and remove all possible caterpillars manually.
Post-harvest surveillance
Make sure that no trace of them remains. At the time of harvest and drying, when you hang the plant and it dries, the worms will no longer have fresh green food and will move away.
They will probably look for another space to build their cocoon and start the cycle again. Stay alert! We don't want cocoons or eggs in corners of your house that later become the next generation of devourers of your cannabis plant.
Remember: prevention and constant observation are the best weapons against caterpillar infestations in cannabis.