It’s August and everybody’s vegetable gardens crank out delicious organic food. Yum-oh! But sometimes gardeners find holes in the middle of the leaves of their vegetable crops. Large holes. Many of them. Who’s the culprit? Caterpillars? Grasshoppers? Beetles?  Or maybe snails!

Snails and slugs both glide through your garden on a ribbon of slime, the shiny, sparkly stuff the snail in the photo above is leaving behind. At bottom left you can see the slime glistening on the ground. These animals are mollusks, related to oysters, clams, and octopus.

A trail of dried slime across the large hole in this green pepper is the definitive clue. A snail or slug definitely made this hole. Anytime you find holes in the leaves or fruit of your vegetable plants look for slime. Slime, this incontrovertible evidence tells you who to blame. And then you know how to fix it.

If you catch the buggers red-handed in the act of destroying your produce you don’t even have to search for evidence. This slug has just devoured the side of a friend’s tomato. Yuk!

But often, you can’t catch them in the act because they hide in the heat of the day. They come out at night, on overcast days, during rain storms, or when the sprinklers come on. They like it cool and wet and they hide under boards and pots – in any cool, shady, damp place where they can survive the mid-day sun and heat.

You can go out into the garden at night with a flashlight and hand pick snails easily. Just pick them up by the shell put them in a brown paper bag. Then you can step on it to crush the critters and bury it in your compost. Slugs, however, have no shells and are too slimy to pick up. Because slugs and snails hide during the day you can also make traps for them and that way you don’t have to go out at night with a flashlight. Put upside-down flower pots around your garden. They’ll hide inside them where you can easily harvest and destroy them in daytime comfort.

Iron phosphate controls these mollusks in the garden. You’ll find it under the brand name Sluggo. Iron phosphate is not toxic to pets, children, or birds. It also has no effect on insects. It kills mollusks and only mollusks. Slugs and snails eat it and they die.

 Older style, toxic, non-organic slug bait uses a poison called metaldehyde. Metaldehyde is poisonous to your pets, your kids, and wildlife. Avoid it.

 Some people swear by beer to kill slugs and snails. You’re supposed to put a shallow bowl of beer out in the garden, the slugs and snails are attracted by the odor, crawl into the beer and drown. Maybe I just don’t do it right but it’s never worked for me. 

Tiz the season . . .  for squash bugs to attack. They’ll torment any member of the squash family, especially winter squash, summer squash, and pumpkins. But they also go after cucumbers, cantaloupe (including other melons like honeydew), and watermelon. Like all true bugs (see our blog More Bugs That Suck) squash bugs have needle-like mouth parts. They stick their sharp little beaks directly into your plant’s veins and suck the life out of it.

 The damage they do kills your plants!

An infestation of these bugs causes the leaves of your squash plant to turn yellow. The whole plant slowly turns brown and dies.

If you think you have squash bugs, look on the underside of the leaves for clusters of tiny, brown, football shaped eggs. These eggs can be anywhere on the plant (leaves, leaf stalks, stems) but they won’t be on the upper surface of the leaf where you can spot them easily. You have to turn the leaves over and look on the underside. Look all along the stalks and stems as well. When you find eggs, destroy them. Remove the leaf tissue with the eggs on it and crush the eggs. Or just smash them in place with your thumb.

When the eggs hatch, the baby squash bugs look a bit like aphids except that they move around fairly quickly and aphids don’t. Babies of true bugs are called nymphs. They look somewhat like the adult squash bugs except that they don’t have wings. Squash bugs, like grasshoppers, aphids, and stink bugs have incomplete metamorphosis from egg to nymph to adult. The baby insects in this group look like miniature adults in most cases. (On the other hand, insects that experience complete metamorphosis, like butterflies, bees, and flies grow from egg to larva to pupa to adult. A baby butterfly, a caterpillar, looks nothing at all like the winged adult.)

As squash bug nymphs grow they get bigger and easier to spot. They crawl all over your plant. Like all insects, the nymph has to molt (break out of its hard exterior shell, its skeleton) as it grows. You may find some left-behind shells stuck to your plants. Eventually, the nymphs reach their maximum size. Then they are ready to become adults.

The winged adult squash bug flies swiftly. Moving fast, they can be difficult to catch. Sometimes you can catch them in the morning before the day gets hot. Insects become more active in heat, less active in cold. Carry a jar of soapy water with you and dump all the bad bugs you catch into the soapy water. They die quickly (which is very satisfying!). Because the adults are good fliers they fly into your garden from your neighbor’s garden.

Starting your squash plant seedlings under row covers of light weight fabric that lets in sunlight, air, and water but keeps bugs out will protect them from the adult squash bugs and give them a good start in life. Eventually though you have to lift the covers to allow the bees to pollinate the flowers or you’ll have no fruit. You can hand pollinate the flowers yourself and keep the plants under cover if you wish. Even so, many squash plants get huge and are hard to contain under cover.  

 Go out into your garden every day, search for squash bug eggs, and crush them. Since the nymphs don’t have wings they can’t get away from you very fast so knock them into your soapy water or smash them with your hands. You can also squirt them with insecticidal soap but be careful because squash plants are sensitive to soap and you can damage your plants. If you make your own soap spray, be sure to use a genuine soap, not a detergent.

We recently visited two side-by-side gardens in Albuquerque, New Mexico. One garden, where the green peppers and other vegetables are thriving, is all organic. Every morning the organic gardener goes out to inspect her squash plants, and she finds and crushes all the squash bug eggs. There are no squash bugs on her plants and her plants are healthy.

The neighbor is not organic and uses any harsh chemical he can find. Most of these photos of problems came from the non-organic garden. Because the ecology of the non-organic garden has been completely disrupted by the indiscriminate use of broad-spectrum insecticides, the predators have been killed. As a result, the non-organic garden has many more problems than the organic garden.

True bugs. Forewings cover half of the abdomen (aka backs) of true bugs. They are in the order Hemiptera, which means half wing. Many other insects are often called bugs, the lady bug for example, which is actually a beetle (a lady beetle). But the only actual bugs are insects in the order Hemiptera.

 All of the true bugs have piercing-sucking mouthparts like hypodermic needles. The bugs that damage our vegetable gardens are ones like stink bugs, squash bugs, harlequin bugs, and tarnished plant bugs. But there are also good bugs, beneficial predators, like minute pirate bugs, that use their needle-like mouth to stab other insects and suck the life out of them. Aside from the bugs you find in your garden there are also bugs like bed bugs and kissing bugs, ones that feed on us humans by sucking our blood.

This green stink bug has its needle-like mouth parts inserted into a flower bud and is busy sucking nutrients out of the plant. You can clearly see that the hard forewings (green with yellow dots) only cover half the bug’s back. The membranous hindwings stick out from underneath the forewings and are easily visible to the naked eye. Stink bug feeding leaves Yellow spots of damaged tissue on developing fruits are the tell-tale clue that stink bugs leave behind.

This insect is a spotted asparagus beetle, not a bug and not a lady beetle. Like all beetles, the hard, colorful forewings (red with black spots in this example) completely cover the abdomen and the membranous hindwings are not visible. Beetles have chewing mouthparts, unlike bugs. This pest lays eggs on asparagus plants, and its larvae eats the asparagus berries.

All of the true bugs have incomplete metamorphosis where their babies (nymphs) look like the adults but without wings. The bug nymph shown here on an asparagus plant has very rudimentary wings and strongly resembles the adult bug. When it reaches maturity it will have well developed wings like the green stink bug in the first photo shown above.

The squash bug feeds on squash plants and their relatives. It, like the stink bug, is a true bug. The adults and the babies (nymphs) stick their sharp little beaks into the leaves and suck out the nutritious sap. They can seriously damage your summer and winter squash, and pumpkins, but they will also feed to a lesser extent on any other member of the cucurbit family. The nymphs look a bit like gigantic gray aphids clustered on the undersides of the leaves. When they reach adulthood they have well developed wings and are swift flyers.

In contrast to insects that have incomplete metamorphosis, those that have complete metamorphosis, like butterflies, have babies (larvae) which do not look anything like the adult. The butterfly larva is a caterpillar, a very different creature from the adult. The fly larva is a maggot, also very different from the adult.

 Effective organic controls for pesky true bugs in the vegetable garden include hand-picking where you grab them and dump them into a jar of soapy water. Insecticidal soap is also safe and easy to use. Just be sure that the bug you spray is actually a pest and not a beneficial insect because the soap will kill pests and beneficials alike. If you are plagued by bugs in your vegetable garden this year, think about putting up some row covers next year to exclude the bugs completely.

 Be careful and think twice before using any chemicals to control insects in your vegetable garden. Remember, you’re growing food that you intend to eat. Never spray your food with poison.