1. They are a pest

Many plants are targeted by caterpillars – and they can have a devastating impact. A field of yellow desert marigolds, for example, will be nothing but bare stems where caterpillars have eaten away every leaf. This type of defoliation can also happen in wildflowers and in some vegetable crops.

The caterpillars of some species eat their host plant completely, leading to severe weed suppression and reduced yield. In the home garden, they can destroy flowers and vegetables like broccoli, kale, and collards.

Caterpillars can be controlled by hand picking, spraying with a biological insecticide such as Bacillus thuringiensis (Bt) or a synthetic home garden product, or by releasing predatory insects. In turf grass, sprinkling soapy water over the surface of affected foliage irritates them and makes them easier to pick up and to kill with a broom or rake. It is important to note, however, that if you use pesticides it is always important to read and follow label directions.

2. They eat plants

The larvae (caterpillars) of some butterflies and moths eat plants. But they only eat those plants that evolved alongside them. According to Tallamy, native plants that grow in the same soil and ecoregion as a species of butterfly or moth provide nearly all of its caterpillars’ food.

The caterpillars of the Gulf Fritillary butterfly, for example, eat passion flower vine, and the caterpillars of the Monarch butterfly eat milkweed. Some of these plant species also create toxic or bad-tasting chemicals that deter predators, such as the cardiac glycosides in swan plant leaves that kill or make animals sick that eat them.

https://peaksfabrications.com/aftermarket-caterpillar-parts-debunking-misconceptions.html Look for signs of caterpillar damage on plants: chewed leaves, rolled or tattered foliage, egg clusters and newly hatched caterpillars. Minimize the use of pesticides that pollute waterways, and instead opt for nonchemical control measures if possible. Examples include removing webbed or rolled leaves, pruning out caterpillars and their nests, handpicking them from plants, and using natural enemies such as birds, assassin bugs, lacewings, and predaceous ground beetles to keep their numbers down.

3. They are dangerous

Many caterpillars are venomous and can cause painful bites. Some have stinging spines, such as the saddleback caterpillar, and others, like the pine processionary moth, release a protein from their hairs that can irritate skin, eyes, throat and mouth.

A few caterpillars secrete toxic chemicals that can kill them if they are touched. The solitary genus Bombardier beetle, for example, releases a liquid that causes chemical burns when pinched or crushed, while predatory true bugs such as assassin bugs and giant water bugs shoot toxins into the air to poison prey or attack enemies.

However, caterpillars are not generally dangerous to people unless they come into contact with a venomous species such as the saddleback or the processionary. Even then, bites are rare and usually only very painful. It is much more common for humans to experience insect stings from social wasps, bees and hornets, or from arachnids such as spiders. Pets may also be harmed by a caterpillar’s tiny hairs, which can stick in their mouth or throat.