How to Keep Caterpillars Off Your Cannabis Plants

Caterpillars are voracious pests that can wreak havoc on your cannabis plants, leaving holes in the leaves and damaging the stems, ultimately affecting the overall health and yield of your crop. In this comprehensive guide, we'll discuss the various types of caterpillars that can infest your cannabis plants, how to identify them, and the various ways to prevent and treat caterpillar infestations. By following these tips and techniques, you can ensure a successful and healthy cannabis harvest.

Understanding Caterpillars​

Caterpillars represent the larval stage in all moth and butterfly species. Researchers estimate there are over 175,000 species of caterpillars worldwide. These soft-bodied insects range in size from 1mm to 14cm in length. While the majority are herbivorous, a carnivorous and cannibalistic minority exists.

Caterpillars are differentiated from other larval species based on specific anatomy. Their key features include:

• Maximum of five pairs of legs
• Twelve stemmata (simple eyes)
• The presence of crochets on the prolegs (limbs that allow them to climb well)
• "Y" or "V" shaped cleavage lines on the front of the head

Though they contribute to the biodiversity of any garden by eventually transforming into pollinating butterflies, caterpillars pose a threat to cannabis plants due to their insatiable appetite for plant matter.

Signs of Caterpillar Infestation​

A caterpillar infestation can range from a few inconvenient holes in the foliage to total devastation of a specimen, resulting in a significant loss of yield. Keep an eye out for the following symptoms indicating a caterpillar infestation:

• Irregular holes: Caterpillars will leave oddly shaped holes in your fan leaves, ranging in size from several millimeters to several centimeters across.
• Stem damage: Species such as the Eurasian hemp borer target the stems and branches, boring through the tissue and compromising the plant's structural integrity.
• Chewed flowers: Some caterpillars burrow into your buds, feeding on the resin and precious phytochemicals. This can lead to wilting and death of the flower.
• Leaf yellowing: Damage to your plants, particularly the stems, can affect water and nutrient transportation, leading to yellowing leaves.
• Stunted growth: Caterpillar damage can stress plants out, reducing their size and productivity.

Preventing Caterpillar Infestations​

Prevention is better than cure when it comes to caterpillar infestations. Implementing the following measures can help you avoid infestations in the first place:

Introducing Beneficial Insects​

Introducing insects such as parasitic wasps, praying mantises, and ladybugs early in the growing season can help keep caterpillars at bay. These predatory insects will naturally control caterpillar populations, protecting your cannabis plants.

Barrier Fabrics​

Setting up a wooden frame and fabric layer around your crop can prevent caterpillars from physically reaching your plants to feast and lay eggs. While not visually appealing, this method is highly effective in keeping caterpillars away.

Neem Oil​

Derived from the South Asian Neem tree, neem oil serves as a natural pesticide. It contains phytochemicals that deter insects when administered as a soil drench or foliar spray.

Identifying and Removing Caterpillars​

If you suspect a caterpillar infestation, follow these steps to confirm their presence and remove them from your cannabis plants:

Physical Removal​

Caterpillars are visible to the naked eye and relatively easy to spot. If you're dealing with a small number of specimens, simply pick them up, place them in a jar, and relocate them to a nearby natural setting. Many species are nocturnal, so be prepared for some nighttime hunting.

Parasitic Wasps​

Parasitic wasps, such as Trichogramma wasps and Podisus maculiventris, can help control caterpillar populations. These wasps prey on caterpillars and use their bodies to lay their eggs, effectively eliminating the caterpillar population.

Praying Mantises​

Praying mantises are stealthy predators that patiently wait underneath leaves, hidden in flowers, and behind stems until their prey makes the first move. These efficient insects can significantly reduce caterpillar populations.

Bacterial Sprays​

Bacterial sprays, such as those containing Bacillus thuringiensis, can harm caterpillars without posing a risk to cannabis plants or the people who consume them. Avoid administering these sprays too close to harvest time.

Treating Caterpillar Infestations with Homemade Insecticides​

In addition to the methods mentioned above, you can also use homemade insecticides to control caterpillar infestations. Some effective options include:

• Pepper and garlic spray: A homemade blend of pepper and garlic can repel caterpillars when applied to your cannabis plants.
• Pyrethrum spray: This quick-acting spray stuns caterpillars, causing them to fall off the plant immediately.
• Bacillus thuringiensis: This biological insecticide is the most effective method for treating caterpillar infestations, as it harms caterpillars without posing a risk to cannabis plants or humans.

Post-Harvest Caterpillar Precautions​

After harvesting your cannabis plants, it's essential to hang them upside down for proper drying. This will cause any remaining caterpillars to leave your plants as they dry up, searching for a new food source.

Inspect your harvested plants carefully, removing any caterpillars or signs of infestation. Failure to do so may result in the caterpillars completing their life cycle and creating chrysalises in unexpected corners of your home, leading to a never-ending cycle of infestation.

The Bottom Line on Caterpillars and Cannabis​

Caterpillars are a potential threat to your cannabis plants, but with proper prevention and treatment strategies, you can protect your crop and ensure a successful harvest. By utilizing barrier fabrics, beneficial insects, and natural pesticides, you can keep these hungry pests at bay while maintaining a healthy and thriving garden. Always be vigilant, regularly inspect your plants for signs of infestation, and act quickly if you spot any caterpillars to minimize damage and maintain the overall health and yield of your cannabis crop.