Growing green - Caterpillars: Garden friend or enemy?It seems that those of us with gardens or flowers to keep luscious and healthy throughout the growing season are always dealing with some sort of garden pest. Why is it that the tastiest snack has to be the most gorgeous or best producing plant in the yard?
By: Janelle Lanoue, U of M Extension intern, Alexandria Echo Press
It seems that those of us with gardens or flowers to keep luscious and healthy throughout the growing season are always dealing with some sort of garden pest. Why is it that the tastiest snack has to be the most gorgeous or best producing plant in the yard?
Because we usually associate bugs with garden destruction, it seems as soon as we see one, we’re always eager to figure out how to get rid of it. What we do not consider is that some bugs are beneficial!
In the past couple of weeks, we have had several calls about caterpillars. These critters are large enough for us to see and can munch away an entire row of the garden in one afternoon. However, not all caterpillars are the same – some may be just friendly garden visitors! It is very important to know the difference between garden friends and enemies and the proper way to control the curious guests.
Caterpillars are actually immature moths and butterflies, which go through several stages of development (egg, larva/caterpillar and pupa) before the winged adults emerge. The larva/caterpillar stage of development is called the “feeding stage.” These critters are constantly munching on leaves and plants and grow very rapidly before entering the cocoon or pupa stage where they transform into their adult selves.
The most interesting critter sighting around the area this summer has been the white-lined sphinx moth. This moth is commonly misidentified as a hummingbird at first glance. They hover over flowers with a fast wing beat pattern, uncoil and inject their long sucking mouthparts into the nectarines of plants.
The caterpillars of the sphinx moths are extremely large. At maturity, the caterpillars measure about three inches in length. They are commonly green in color but, in rare occasions, may be black. Though many caterpillars, including the white-lined sphinx, enjoy a snack full of green leaves and flowers, they rarely occur in large enough numbers to do any destruction.
Control of unwanted garden company seems to take priority over considering if it is just a friendly visitor. Most of the time, we just start spraying! Before you do anything about your caterpillars, you should answer a couple of questions:
--What kind of caterpillars do you have? Helpful caterpillar identification guides can be found at www.butterfliesandmoths.org/identification_tools.
--Are they doing any serious damage to your garden? If not, it is suggested to leave them be. The caterpillars will soon spin their cocoons and settle in. If they are munching away at your prize winning tomato plant, consider just picking them off and moving them onto something less valued.
--If they are damaging your harvest or seriously injuring ornamental plants, there are a couple of natural options available. You can buy a product called Bacillus thuringiensi – or BT. It’s a natural bacteria that is toxic to caterpillars, but does not affect any other insects, animals or humans. The one thing to consider about BT is that it kills all caterpillars. If you wish to just get rid of the destructive ones, consider picking them off and putting them into a bucket of soap and water. This way, you have more control over which caterpillars will be eliminated.