Aphids attack in swarms, attaching themselves to flower and vegetable plants. Swarms of aphids in your vegetable garden cause considerable damage as they weaken plants. Aphids live and thrive throughout the world, in wet and cold regions as well as dry, arid desert regions. With 4,400 different species of aphids continually reproducing, it's likely at some point in your gardening experience you will encounter these pests feasting on your vegetable plants.
Aphids are small insects. Their bodies are soft and may be black, brown or green in color. Some varieties are winged while others are wingless. All types of aphids work in large swarms to cover plant leaves and stems. They may appear as a few spots at first, but within a few days they may cover all but the flowerings of the plant.
Aphids serve no practical function to you the gardener in regard to pest control; the aphid feeds only on your plants, not other pests. They also spread disease from plant to plant. Aphids are food for birds, ladybugs, wasps and ants, however, and so function ecologically as a part of the food chain.
Aphids weaken your plants by sucking the interior nutritional juices. They sink their tiny mouth fangs into the plant and, as a swarm, suck the plant dry. They leave behind a sticky substance known as honeydew that may attract other pests or turn to mold.
This results in a weakened plant. Leaves curl and the plant produces small fruits if it produces at all. Aphids enjoy preying on young plants, resulting in stunted growth and sparse foliage.
Though most species of aphids attack the leaves and stems of the plants, some are soil dwellers, such as the lettuce root aphid. This species attacks the roots of lettuce causing the leaves to wilt before harvest. The woolly apple aphid infests apple tree roots and causes the decline of the orchard over time.
You may wish to practice organic or biological methods to prevent and control aphid infestations. Onions and garlic, chives and coriander or cilantro repels aphids. Plant these throughout your vegetable garden.
Encourage predators such as wasps and ladybugs in your garden. Ladybugs use rosemary as an egg-laying shelter; plant this herb on the border of your garden. Use sunflowers and Queen Anne's lace, as well as parsley, to attract wasps to your garden.
Use aluminum foil mulches around your plants. The aluminum foil repels the plant-sucking pests and provides additional solar energy for plant growth.