Garden Bugs
Your garden would not be complete without bugs in the soil, on the plants, and in the air. Many bugs actually help gardens grow and produce vegetables and fruit. Earthworms eat decaying plant matter releasing nutrients into the soil. Bees and some ants pollinate your garden. Lady bird beetles (ladybugs) and other beetles, assassin bugs, and green lacewings eat garden pests and their eggs. Braconid wasps, trichogramma wasps, and tachinid flys lay their eggs on the eggs and larvae of pests, preventing those pests from ever being able to chow on your plants.
There are some simple ways to make these do-gooder bugs feel at home in your garden. First, avoid garden-wide use of pesticides as they can be harmful to both the bugs you want to keep out and the bugs you want to invite in. Provide food sources such as dill, parsley, yarrow, milkweed, angelica, and wild carrot. These plants have small flowers that provide nectar and pollen for your helper bugs. Finally provide shelter for the bugs by including a few perennials within your garden.
There are some other preventative measures to keep your garden from becoming a pest motel. Plant a wide variety of vegetables, fruits, shrubbery, and trees. This makes your garden less attractive to pests that like to munch on a particular type of plant. Make sure you have rich soil — healthy plants are less susceptible to pests and diseases. Take care not to water your garden too much. The proper amount of water can also make plants stronger and better able to stand up to pests.
Once the pests have found your garden, you will need to know what they are and what you can do about them if you're going to prevent them from enjoying your veggies before you do. Below is a list of the most common bugs in Boston-area gardens, their favorite vegetables, and how best to "ask" them to leave.
If you see one aphid, their friends and family probably aren't far away. Aphids are tiny but make up for their small size in numbers — there might be twenty or more generations in one growing season. Spray the aphids with water or a mild, non-toxic soap mixture.
Keep them away by installing a floating row cover. When you find them, pick them off by hand and remove them from your garden.
Hand pick Colorado potato beetles and their orange-colored eggs from your radishes. Moving the radish plot yearly won't keep these pests at bay because they can fly long distances. If you have trouble with Colorado potato beetles, consider planting radishes only every other year.
Keep these beetles from ever finding your cukes by using row covers, cultivating the soil, and planting resistant varieties, or plant "trap crops" a few weeks before your actual crop. Any pests will be attracted to the first crop, which you can then destroy if necessary. Not only do these pests eat the roots, stems, leaves, and fruits of your plants, they also carry diseases like bacterial wilt and squash mosaic virus. Prevent the spread of these diseases by removing the affected plants.
The term cutworm refers to the larvae of certain types of moths. Cutworms chew away at your plants eventually "cutting" them down. Again, prevention is key. Cultivate the soil well, rotate your crops, and use paper collars around the plant. When you find cutworms, remove them from your garden.
Clean up plant debris at the end of the growing season. Place floating covers over seedlings and check leaves for masses of yellowish eggs. Hand pick adult Mexican bean beetles.
Place cheesecloth around the base of your squash plant to prevent these pests from burrowing into the stem, which will cause your plant to rot and wilt. If you find a hole where a squash vine borer has entered, slit the stem, remove the pest, and then cover the stem with soil.
The term "leaf miners" is used to refer to the larvae of many types of moths and flies, as well as some wasps and beetles (like the leaf miner beetle shown here) that eat the leaves of plants. Leaf miners can be fooled by "trap crops" (See the Cucumber Beetle description above). Remove affected leaves as you find them.
Slugs and their eggs spend the winter in your soil, so prevent as many as possible from coming back next year by removing plant debris from your garden each year. You might choose to mulch around your plant with a gritty material like sand or set "traps" for the slugs overnight. Set out wooden boards and melon rinds and remove the slugs that hide under them early each morning.
Onion smut is actually a fungus that affects the seedlings of onions. Black, blistery growths appear on the seedlings and the seedlings usually don't produce fruit. When the growths burst, spores are released into the soil, so if you experience onion smut, do not plant your onions in the same part of your garden next year.