Tomatillos are a vibrant, flavorful addition to the garden, prized for their unique, papery husks and tangy fruit used in authentic salsa verde. As relatives of the common tomato, pepper, and eggplant, they belong to the nightshade family and are susceptible to many of the same common garden pests. Successfully growing a healthy harvest requires vigilance, as an unchecked infestation can quickly compromise a plant’s health and fruit yield. Understanding which pests target these plants and how to manage them organically is the first step toward a successful growing season.
Key Pests That Target Tomatillos
The Tomato Hornworm is one of the most destructive pests, a large caterpillar that can reach up to four inches in length. This larva of the hawkmoth is bright green with white V-shaped markings, making it difficult to spot as it blends with the foliage. Hornworms rapidly consume entire leaves and stems, typically feeding on the upper parts of the plant.
The Three-Lined Potato Beetle is another common threat, appearing as a small, quarter-inch beetle with mustard-yellow wings marked by three black stripes. Its larvae are slug-like and often covered in a brownish “fecal shield” that helps deter predators. Both adults and larvae chew on the leaves, favoring nightshade plants like tomatillos.
Aphids are small, soft-bodied insects that cluster on new growth and the undersides of leaves and stems. They can be green, yellow, or black and reproduce quickly, creating dense populations in protected areas. Whiteflies are similarly small, yellowish insects that congregate on the lower surface of leaves and fly up in a cloud when disturbed.
Diagnosing Infestations by Plant Damage
Identifying the type of damage is often easier than spotting the pest itself, aiding in diagnosis. When large sections of leaves are completely eaten away, often leaving only the central leaf veins, the culprit is likely the Tomato Hornworm. The presence of large, dark green, pellet-like droppings, known as frass, on the leaves or the ground is a strong indicator of a caterpillar infestation.
Small, circular holes in the leaves that look like fine buckshot are characteristic of adult Flea Beetle feeding. This “shothole” damage is most severe on young seedlings. On mature plants, the Three-Lined Potato Beetle and its larvae may cause more angular, irregular holes along the leaf margins.
Pests that suck sap, such as Aphids and Whiteflies, leave behind distinct symptoms. These include yellowing, curling, or stunted leaves, as the removal of plant fluids weakens the tissue. A shiny, sticky residue called honeydew is secreted by these sap-suckers, which can lead to the growth of a black, velvety fungus known as sooty mold.
Effective Organic Control Measures
Once an infestation is confirmed, several organic methods can manage the pests. For large, visible pests like the Hornworm and Three-Lined Potato Beetle, manual removal is highly effective. Handpick them from the plant and drop them into a container of soapy water.
For smaller, soft-bodied pests like aphids and whiteflies, a forceful stream of water can dislodge them from the plant, especially the undersides of leaves. This technique works well for minor infestations but must be repeated every few days to manage new populations.
Applying insecticidal soap or neem oil provides organic control by targeting the pests directly. Insecticidal soap works by penetrating the insect’s outer shell, leading to dehydration, while neem oil disrupts their feeding and life cycle. Apply these sprays thoroughly to all plant surfaces, particularly the leaf undersides. Timing the application for early morning or late evening prevents leaf burn and protects beneficial insects.
Introducing beneficial insects, such as ladybugs, lacewings, and parasitic wasps, provides long-term biological control. Ladybugs are voracious predators of aphids. Tiny braconid wasps parasitize hornworms, their larvae consuming the caterpillar from the inside. If a hornworm has white, rice-like cocoons attached to its back, leave it alone; this indicates it has been parasitized and will soon release more beneficial wasps.
Preventing Future Pest Problems
Garden practices that improve plant health and disrupt pest life cycles are the best defense against future infestations. Crop rotation is a significant preventative measure, as many tomatillo pests overwinter in the soil or plant debris. Planting tomatillos in the same spot year after year allows pests to build up populations, so rotating them with non-nightshade plants is advised.
Proper plant spacing encourages good air circulation, which helps keep foliage dry and reduces fungal issues that stress the plant. At the end of the growing season, thoroughly clean the garden bed to remove all plant debris, including fallen leaves and fruit. This eliminates overwintering sites for many pests and their eggs. For young seedlings, using floating row covers acts as a physical barrier against adult beetles and moths, preventing egg-laying.