When a friend told me that she had picked 15 tomato hornworms off her tomato plants, I immediately went to my patch to see if I had missed something. I was relieved that I didn’t find any of the black fras (hornworm poop), any defoliated branches or any chewed fruit.

For those who haven’t had the experience, they are by my unscientific description those 3- to 4-inch, fat, freaky, prehistoric-looking caterpillars with five pairs of prolegs and a “horn” on the last segment and sporting a bright green color that matches the green of the plant.

The control is to pick them off and dispose of them in whatever manner guarantees they won’t procreate. For the weak of heart, use tongs to remove them from the plant. The exception would be if you found one with what are the cocoons of the parasitic wasp on its back, which would appear as white egg sacs. Allow the hornworms to eat until the wasps hatch inside. Now you have an army of free predators. Plant dill or fennel to attract parasitic wasps.

According to Whitney Cranshaw’s “Garden Insects of North America,” there are more than 120 hornworms, but only two are considered significant pests.

The majority live in shrubs and trees where damage is rarely noticed.

The adults are strong-flying, heavy bodied moths known as the sphinx or hawk moths. They feed on nectar from deeply-lobed flowers and at first glance could be mistaken for a hummingbird; they have also been dubbed the hummingbird moth.

I mention this now as a possible preventive measure. Tomato, pepper, potato and certain nightshade family weeds are the host plants. Full-grown larvae burrow 4 to 5 inches into the soil and create a cell in which pupation occurs. The pupae overwinter and emerge as the moth in mid to late spring. Eggs resemble small pearls and are laid singly on foliage. Through the course of a month, the newly hatched caterpillars will pass through four to five larvae stages. Then low and behold, about the time you are ready to eat a tomato, so are they. Needless to say, you are not the winner.

Knowing their life cycle helps us to practice some preventive measures. As you clean up your tomato patch, turn the soil at least 5 inches deep, and hopefully you will destroy any existing cells. It is worth the extra effort in the fall.

Have you looked at a tree or shrub in your landscape and discovered cobwebby, silken caterpillar nests totally encompassing a branch? Welcome to the world of the fall webworm.

These little hairy caterpillars work together diligently to make a communal home. The caterpillars are the larvae of a native species of tiger moth known as Hyphantria cunea. The adult tiger moth is large, silky white with black spots on its underside and flies in mid-summer.

Eggs are laid in masses on the underside of leaves, and the young feed together first skeletonizing the leaf and then incorporating leaves, droppings and cast skins into the silky tents.

Fall webworms have one of the widest ranges of host species of deciduous trees and shrubs. However, they seem to prefer cottonwoods, chokecherry, mountain ash, elm, willow and various fruit and nut trees. They grow to about an inch and a half and then overwinter as pupae in a brown cocoon in protected places such as in bark crevices or on the ground in litter or duff.

Fall webworms differ from the spring tent caterpillar by how they enclose themselves along with their food in their web. Tent caterpillars are found outside their much smaller web.

Fall webworms are more of a cosmetic nuisance than a serious threat to the landscape, as they rarely cause significant damage.

If the webworm tents become too bothersome, you can prune off the infested branches and destroy them. Trying to just remove the tents can be tricky. The caterpillars, when disturbed, often twitch in an effort to deter potential predators, so you run the risk of dispersing them to make more tents. Squirting them with a harsh jet of water is also a bad idea.

As you work through your fall checklist of chores, you might add one more to-do. That is to check your containers of insecticides for the ingredient Dinotefuran, which is believed to have caused the death of 50,000 bees as a result of a spraying. The list of products that contain Dinotefuran can be found at the Oregon Department of Agriculture’s website, http://j.mp/12mN0TE. The Oregon Department of Agriculture issued a ban restricting the use as of June 27 for at least 180 days from that date.