Every year sees new insect pest control chemicals at the garden center, and new articles about concerns over chemicals in our environment, our food supply, and on ourselves. Chemical garden treatments come with one price tag in dollars, and another in worry. Before reaching for the spray, at least try hand picking.
Know the enemy, and the allies. Learn about good and bad bugs on your flowers and crops.
You often catch bad bugs in the act of damaging your plants. Insects, as adults or as young caterpillars or grubs, may eat leaves or suck plant juices. Holes plus bugs usually equals "bad bugs," but how do you know for sure? Many bad bugs are named for their favorite foods: cucumber beetles, squash bugs, rose chafers are a few of those. That helps, but these so-named bugs can be just as damaging to plants other than their favorites. Potato and bean beetles can be seen on squash; cucumber beetles and squash bugs can plague other kinds of cucurbit (squash, cuke, pumpkin, gourd.) Be suspicious of any bugs you see becoming numerous in the garden, especially if you see them lounging about on damaged plants. When in doubt, submit a picture and description to Dave's Garden Insect and Spider Identification Forum.
Familiarize yourself with common "beneficial insects" (good bugs) too. They are your allies in the garden. Beneficial insects, like ladybugs and wasps, are usually few in number, unlike the alarming swarms of bad bugs. By avoiding chemicals, you are also allowing those allies to help you. You will never find all the bad bugs. Those you miss are a constant lure for the good guys. The beneficial insects stay on duty long after human gardener has gone in for a glass of lemonade.
What if you haven't seen ANY bugs, just chewed leaves? Small holes in leaves, skeletonized leaves, and ragged edged leaves are usually the work of some insect (mammals tend to eat whole leaves or take large bites). The insect might be feeding at some other time of day, like the nocturnal Asiatic garden beetle.
Learn the enemy's habits and strategies.
Bad bugs might be easy to spot, or elusive. Some only feed at night, leaving you scratching your head over holey leaves with no culprit in sight. Walk the garden at different times of day, and at least once in the dark, to learn when the bugs are active. Be carefully observant; some insects are superbly camouflaged, like the perfectly cabbage-leaf-hued caterpillar of the imported cabbageworm. Pests may feed during daylight but hide underneath leaves to avoid detection. Young squash bugs are devilish at hiding in clusters under wilted leaves.You might learn that certain beetles lounge in pollen-filled flowers in the morning and are easy picking there. Other beetles might spook easily and are hard to catch, requiring more stealth.
Choose your method of execution. Some strong stomached gardeners simply crush the offenders in their fingers. That's certainly a lethal and satisfying, even mercifully quick, death to the bad bugs. Wear gloves if this method is just too icky. For extended campaigns of handpicking, use drowning. Insects will sink and drown when tossed in soapy water. (They can often float and climb out of clear water.) Carry a large cup or a bowl of water, with a few drops of soap added, into the garden.
You may have to grab or catch the bugs, then drop them in the cup. Try holding the cup in one hand, under the bug, as you knock the offender off with the other hand. Watch for the jumpers; "flight risks" like pigweed flea beetles are quick to hop away at the slightest disturbance. Cup your hand to cut off the escape route, and and brush that pest into the "death bowl".
Some bugs feed only at night. Get a headlamp from the camping and outdoors store. The headlamp lights the way while leaving you both hands free for bug gathering.
Fuzzy caterpillars can sometimes bear stinging hairs. Wear gloves, or use a tool to move them. Leaf miners make squiggly tunnels inside leaf tissues. FInd the worm and squash it, or pick and destroy any tunneled leaves.
Insect pests may go through several generations during a growing season. Be persistent with handpicking. Leave a death bowl or two in the garden. Pick bugs anytime you stroll the yard. Observe and admire any beneficial bugs along the way. Your persistent, frequent attacks on bad bugs may keep their numbers under control. Healthy plants often cope well with a small amount of insct damage.