Identifying: Aphids have tiny, pear-shaped bodies with long antennae; the nymphs look similar to adults. Most species have two short tubes projecting from their hind end. Various species can appear to be white, black, brown, gray, yellow or light green. Adults may or may not have wings.
Damage: Nymphs and adults feed on plant juices. They attack leaves, stems, buds, flowers, fruit, and/or roots, depending on the species. Look for misshapen, curling, stunted, or yellowing leaves and new buds that are deformed. Be sure to check the undersides of leaves; aphids love to hide there. If the leaves or stems are covered with a sticky substance, that is a sign that aphids may have been sipping sap.
Control:
Water- Wash them off under running water, monitor the plant and repeat if necessary.
Biological control- Chrysopa carnea, Aphidius colemani- natural enmey of aphids.
Ethanol spray- Make a spray mixture (75 percent of alcohol (ethanol 40%) and 25 percent of water).
Neem oil - It inhibits insect nutrition and fertility, therefore life cycle will be disturbed. Follow package instructions for diluting the oil in water and spray the affected areas, repeat if necessary. Although neem oil is of natural origin, wait a few days after spraying before eating your plants.