Caterpillar, Four String Farm

With this beautiful warm weather comes caterpillars.  Caterpillars do not come all at once, although sometimes, to the gardener, it may seem that way.  Caterpillars come in continual waves throughout the spring and summer.  It is best to have a plan to manage for caterpillars, because they can do a lot of damage to the garden.

It is not a good idea to use chemical pesticides to treat for caterpillars.  An application of chemical pesticide may kill active caterpillars in the garden; however, it also kills beneficial predators and the healthy microbes and bacteria in the soil.  That is why pest problems always return after an application of chemical pesticide , and usually worse than before.

Fuzzy Black Caterpillar, Four String Farm

Not only that, chemical pesticides are expensive, take a lot of time to go the store and buy, and then to apply.  Chemical pesticide residue is bad for the health of the humans who eat it in their garden produce–not to mention the impact of chemicals on the taste of the produce.  This is a steep price for something that actually makes the problem worse in the long run.

Following are safe and chemical-free solutions to caterpillars that we use on our farm.  Of course, our gardens are invaded every year by caterpillars, just like everyone else’s.  However, because of these methods, we spend very little time treating for caterpillars, and they do little damage in our gardens.

1) To prevent caterpillars before they become a problem, try companion planting.  Plant marigolds around your tomatoes; nasturtiums around the squash; and plant basil, dill, and cilantro throughout your vegetable 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.

2) When caterpillars do arrive, try using the highly effective “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 out of your reach.  To save yourself a great deal of time and work, get an inexpensive hiker’s headlamp, that 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 pinch away most of your pest problems in one or two short sessions of night pinching.

Four String Farm

3) You can also spray Bt, or Bacillus thuringiensis, an effective organic pesticide.  Bt is a naturally occurring bacteria that paralyzes the digestive system of caterpillars, but does not affect other insects, plants, or humans.  When caterpillars ingest Bt, they immediately stop feeding and eventually die.  Spray the tops and undersides of leaves until dripping with Bt, only at dusk, because sunlight kills the good bacteria in Bt, and you want the Bt on the leaves at night, when caterpillars are most active.

4) The best 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 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.

Caterpillar, Four String Farm

5) 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. If you have the weakest plants in your neighborhood, the caterpillars will visit your garden first.  If you have a healthy garden, the caterpillars will start with the weakest plants, giving you time to find them and treat for them.  Also, healthy plants resist bugs and disease extremely well, and recover quickly after an attack.  The healthier your garden soil, the healthier your plants, and the less you will need to treat for pests.

Let us know how these techniques work in your garden.  I invite you to send us your chemical-free tips, as well, on how to treat for caterpillars.

Caterpillar, Four String Farm