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. 

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. 

Most of these “bugs” have mouthparts like a hypodermic needle. They stick their needle-like mouth parts into the veins of plants and suck out the nutrient rich sap. As their populations build they can seriously impact the energy budget of your vegetable plants and limit your crops. Also, just like a mosquito sucking the blood from your arm to give you malaria, these insects can transmit serious diseases to your plants.

Very familiar to most gardeners, aphids (aka green flies in the U.K.) attack almost all vegetable crops. There are thousands of different species in different colors (green, black, gray, yellow or reddish-brown). Sedentary, they don’t move around much. They just sit still and suck. Some species transmit mosaic virus diseases.

Tiny thrips on an onion plant. They have rasping mouthparts. They file away the soft tissue from leaves and flowers causing silvery discoloration. Active flyers, thrips transmit tomato spotted wilt virus.

Mealybugs don’t even look like insects. They look more like q-tips in the leaf axils and undersides of leaves. They are sedentary. They transmit mealybug virus to pineapple plants.

Leafhoppers come in an astonishing array of colors, and some are quite pretty. Common garden variety leafhoppers are generally pale green, wedge-shaped, and jump away when disturbed. These are active flyers with sharp little beaks. They transmit aster yellows (a serious mollicute disease) and viruses like beet curly top and yellows virus.