Aphids, also known as plant lice, are small sap-sucking insects and members of the super family Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions. They are capable of extremely rapid increase in numbers by asexual reproduction. The damage they do to plants has made them enemies of farmers and gardeners around the world. About 4,400 species of aphids are known, all included in the family Aphididae. Around 250 species are serious pests for agriculture and forestry as well as an annoyance for gardeners. They vary in length from 1 to 10 millimeters. Aphids are small, soft-bodied, pear-shaped insects that are frequently found in large numbers. Their bodies may be translucent, but are usually various shades of green, brown, yellow, or white, sometimes blending in with the plant on which they are feeding. Many aphid species have two tube-like structures, called cornicles, which extend from the back and secrete a defensive fluid. Adult forms may be winged or wingless, depending upon their stage of development during the season. Winged forms have four membranous wings that rest upright above the body.
A generation of aphids survives the winter as eggs, which allows them to withstand extreme environmental conditions of temperature and moisture. In spring the eggs on the plant hatch, leading to the first generation of aphids. All the aphids born from the winter eggs are females. Several more generations of female aphids are born during the spring and summer. A female can live for 25 days, during which time she can produce up to 80 new aphids. Spring and summer reproduction occurs asexually. In these cases, the resulting aphids are basically clones of the mother. In addition, the young are born live rather than as eggs. When the fall approaches, there is a generation that grows into both male and female individuals. Females fertilized by the males lay winter eggs on the plant where they are, closing the cycle.
Aphid damage is usually most noticeable on shade trees and ornamental plantings. Leaves, twigs, stems, or roots may be attacked by aphids, whose mouthparts are designed for piercing the plant and sucking the sap. Aphids attack nearly all species of plants. When leaves are attacked by aphids, damage often appears first as spotty yellow discolorations, usually on the undersides of leaves; the leaves may later dry out and wilt. Some aphid species form galls or cause distorted, curled, or deformed leaves. The galls are swellings of plant tissues that are usually globular or spindle shaped, with mouth-like openings. Many galls turn brown and are considered unsightly. Each gall or deformed leaf may contain numerous aphids in all stages of development. Aphids attached to other plant parts such as stems or twigs may cause stunted growth, early leaf fall, or twig mortality. Many aphid species secrete honeydew from the anus; this sweet, sticky substance consists mainly of excess sap ingested by the insect and contains sugars and waste materials. At times, enough honeydew may be secreted to cover not only the aphid infested foliage but also objects below the affected tree or shrub. After a time a black, sooty fungus that grows on honeydew and gives everything it has covered a dirty gray appearance. Because of its sweetness, the honeydew attracts other pests such as flies, wasps, and especially ants, whose presence may be the first visible sign of an aphid infestation.
Let us look at some news articles pertaining to the damage caused by aphids.
Aphids seen at threshold level in southwest Missouri wheat
March 23, 2017, USA
Jill Scheidt, agronomy specialist with University of Missouri Extension, scouted fields west of Lamar and near Iantha for the March 1 crop scouting update.
Wheat was found to be in the tillering stage.
“Wait to apply nitrogen until just before jointing stage, when nitrogen is most efficiently used. Early nitrogen applications should only be made if tiller count is below 60 tillers per square foot,” said Scheidt. “This avoids overly lush growth, which can make wheat susceptible to disease, aphids, lodging and late freeze damage.”
Aphids damage early crops
August 6, 2013
There has been significant aphid damage to early sown crops, particular in central NSW.
Pest Facts reported there were many accounts of damage in the Central Tablelands region around Mudgee, NSW.
The damage began in July once the resistance imparted by seed treatment wore off.
Oats have been one of the worst impacted crops.
Oat aphid, corn aphid and rose grain aphid favor barley, but are found in all cereal crops. Heavy infestations of these sap sucking insects cause the crop to turn yellow, be stunted and generally appear unthrifty.
All three aphids can damage crops by feeding on them and in some instances by spreading barley yellow dwarf virus.
According to a recent study by researchers at Iowa State University aphids has become a threat to soybean in the recent years because they possess a unique ability to block the genetic defense response of soybeans and may open the door for other pests to do even more damage to the crops. Their research further made significant contribution as the scientist stated that Aphids emerged as a serious threat to Iowa soybeans around 2000. The insects are native to Asia and most likely came to the United States via international travelers or plants brought into the country. In the years since, aphids have caused soybean farmers major headaches, reducing yields in affected fields by up to 40 percent, a scientist said.
These creatures thus cause a lot of damage in the agricultural sector. Also they invite more pests like the ants to the plants further endangering them. Conventional methods used to combat them include the use of toxic pesticides which are extremely hazardous to the environment. New methods need to be developed to do away with aphids for good. The method used should be 100% effective and should not endanger the environment in any way whatsoever.
Termirepel™ is a non-toxic, non-hazardous insect and pest repellant. It can be best described as a termite aversive. It is effective against a multitude of other insects and pests like weevils, beetles, bugs, aphids etc. It works on the mechanism of repellence and therefore does not kill the target as well as non-target species. Being non-toxic, it does not harm the soil and environment. Termirepel™ can be added to a thin agricultural film to protect plants and crops from insects like aphids. It can also be incorporated in irrigation pipes to ward of pests.