To prevent caterpillars before they become a problem, try companion planting; this is the pairing of two or more plants that mutually benefit one another. Plant marigolds around your tomatoes; nasturtiums around the squash; and plant basil, dill, and cilantro generously throughout the garden. These companion plants repel or confuse pests, to keep them off of your vegetables, and they add a great deal of color, fragrance, and beauty to the garden.
When caterpillars do arrive, try using the effective and inexpensive “pinch method”. Simply pinch the caterpillar between your thumb and index finger, and work through the garden until the pests are gone. If you don’t want to squash the caterpillars, drop them into a bucket of soapy water, or simply relocate them a safe distance from your garden.
The pinch method works best at night. During the day, most garden pests hide in the soil, and when they see you coming, they are very good at scampering away. To save yourself a great deal of time, wear an inexpensive hiker’s headlamp, which allows you to shine the light, hands free, wherever you look.
At night, all the pests of your garden are active, and they will come to the tops of the plants and fight to get into the light. You can rapidly solve most of your pest problems in one or two short sessions of night pinching.
A wonderful long-term solution for caterpillars is your native population of beneficial predators. These are the birds, wasps, frogs, toads, lizards, lacewings, dragonflies and many other friends of the garden that eat caterpillars and other pests. Once beneficial predators are established in your garden, you will rarely need to treat for caterpillars.
To attract beneficial predators, create for them a safe habitat, or sanctuary, to protect them. A hummingbird or butterfly garden, or any dense thick planting with a lot of flowers and ground cover gives the predators a place to hide when they are not hunting your garden pests.
Finally, the best pesticide of all is healthy soil. Caterpillars attack the weakest plants first; it is nature’s way of eliminating weak plants from the gene pool. The healthier your garden soil, the less you will need to treat for pests.