Insects are attracted to specific crops and seem to know the minute you've planted those seeds in the soil. They lay their eggs on the vegetable plants, as well as in the soil and in surrounding garden debris, and once the eggs hatch, the larvae become eating machines. To thwart them, plant flowering herbs to encourage predatory ladybirds and lacewings to your garden. Rotate crops so they never grow in the same place twice in a row.
Insect eggs are usually small --less than 1/8 inch -- and are laid in clusters. The eggs are often red, orange, yellow, grey or white. They may have a shiny, glistening appearance. They are usually hard to detect because of their size. The appearance of adult insects in the garden usually means insect eggs, as well. When the larva first emerge from the eggs, they often bear little resemblance to adult insects. For example, most worms found in the garden, such as the cabbage looper that feeds on cabbage and broccoli, and the tomato hornworm, that feeds on tomatoes and peppers, are actually the larva of moths. Hand pick them or control them with Bacillus thuringiensis.
Insects lay their eggs in protected areas, such as the undersides of leaves, or under bark or debris in the garden. Some insects, such as flea beetles and grasshoppers even lay their eggs in the soil. Nearby weeds and grasses can harbour insect eggs, as well as old stumps, baskets or even paper. Be especially vigilant about looking for insect eggs if you notice adult insects in the garden. For example, leafhoppers and aphids suck the juice from plants, causing the leaves to wilt and yellow. They are especially damaging because they proliferate quickly. Control them by spraying the leaves with a stream of water or insecticidal soap, and be on the lookout for their small yellow, green or orange eggs. Spray the eggs with a stream of water, as well.
Insects hatch from eggs from early spring to early summer, depending on the insect, although some insect species may produce more than one generation per season. Pay attention to when insects emerge, and plant crops accordingly. For example, squash vine borers hatch in late spring or early summer. By planting squash and other cucurbits a few weeks later, you may thwart them.
Till the soil in the fall or early spring to destroy adult insects overwintering there before they have the chance to lay eggs. Inspect the undersides of leaves and look at the base of the plants for signs of eggs. Handpick eggs and drop them in a bucket of soapy water or spray them with a pesticide. Not all eggs are affected by pesticides, though. Remove weeds, garden debris and sticks and logs to limit breeding places. Place floating row covers over crops immediately after planting in the spring to exclude pests, such as squash vine borers, stink bugs and cucumber beetles. Remove the row covers when plants begin flowering so bees can pollinate them.