Aphids are one of the most destructive pests on cultivated plants in temperate region. They can cause yellowing, mottled leaves, stunted growth, curled leaves, browning, low yields and even death in plants. Hence, they are the fear among the growers. Leaf curl, is a common symptom of the aphid infestation. The leaves become useless to the plant. Some species also transmit viral disease of plants, causing serious damage to food crops like grains, apple, cabbage, corn root, alder and beech tree blights.
Aphids are tiny, about ½ inches but often invisible to the naked eye. They are in clusters, especially around stems and leaves. Aphids usually feed in large groups. However, they are seen in small numbers occasionally. They come in a wide variety of colors including green, yellow, black, red, grey and brown. They are soft bodied, and pear-shaped with long antennae. Another interesting fact is that adults are mostly wingless, but some do grow wings, especially when the population of aphids increases. The also secrete large amounts of sticky fluid known as honeydew.
The life cycle of the aphid is complicated. Overwintering eggs are hatched by wingless female aphids, known as stem mothers, in springs. These eggs take birth to many nymphs soon. These gradually increase in size and within a week they multiply into many nymphs. When the process is repeated several times, it results in huge population explosion. A few stem mothers develop wings and fly off to other host plants to start new colonies.
Aphis infestations destroy an entire plant and if left untreated, they can even spread to surrounding plants as well. The exploding population of aphids are mostly controlled by their natural enemies such as aphidlions, ladybird beetles and lacewings. When the aphids multiply in damaging numbers, they can be controlled by horticultural oils, insecticidal soaps, and other traditional insecticides. Remember, aphids do not respond well to insecticides. Therefore, pampering and nurturing their natural enemies is an excellent method to control them organically. Ensure not to plant mint, dandelions, fennel, dill, and yarrow, as they will help attract these insects to your garden. Controlling outbreak of aphid is difficult, but a combination of biological deterrents mixed with organic oils, sprays and soaps can regulate the outburst, especially if the infestation is still in its early stages.