Aphids, also known as greasy insects and honey worms, are a class of plant-eating insects that include all members of the Aphid family (also known as Aphididae, scientific name: Aphidoidea). Aphids have been found in a total of about 4400 species in 10 families, most of which belong to the aphid family.
Aphids are also one of the most destructive pests on the planet. About 250 of these are pests that are seriously harmful to agroforestry and horticulture. Aphids vary in size and range in length from one to ten millimeters.
Aphids' natural enemies are ladybirds, aphid-eating flies, parasitic wasps, aphid midge larvae, crab spiders, grasshoppers, and insect pathogenic fungi (containing green zombie fungi).
Aphids are widely distributed worldwide, but are mainly concentrated in temperate regions. In addition, species diversity is much lower in the tropics than in temperate zones. Aphids can migrate remotely, mainly by spreading in the form of winds; for example, lettuce aphids are thought to have spread from New Zealand to Tasmania in this way. And some human activities can also help with the migration of aphids, such as the process of transporting plants attached to aphids.
Aphids have tubular protrusions (abdominal tubes) in their abdomen, aphids have a pair of abdominal tubes for the discharge of a defense fluid that can harden rapidly, the composition is triglycerides, the abdominal tubes are usually tubular, often larger than wide, the base is thick, sucking plant sap, and is a plant pest. It not only hinders plant growth, forms galls, spreads viruses, but also causes flower, leaf, and bud deformities. Life history is complex, with wingless females (stem mothers) in the summer camp parthenogenesis, oviparous birth, and juvenile aphids. When the aphids on the plant are too dense, some grow two pairs of large membranous wings in search of a new host. Female and male aphids appear at the end of summer, and after mating, the female aphids lay eggs, overwinter with their eggs, and eventually produce a dry mother. There may be no egg stage in warm areas. Aphids have wax glandular secretions, so many aphids look like white wool balls.
Most of the species in the family are oligo-eating or monophagous, a few are polyphagous, and some species are important pests of economic plants such as grain, cotton, oil, hemp, tea, sugar, vegetables, tobacco, fruits, medicines and trees. Because the migration of flying spreads to find the host plant to repeatedly transfer and taste, it can spread many kinds of plant virus diseases, causing greater harm. These include important pests such as wheat tube aphid, wheat aphid, cotton aphid, peach aphid and radish aphid.
Aphids are very fertile, can reproduce 10 to 30 generations a year, and the phenomenon of generation overlap is prominent. Female aphids are born to give birth. And aphids do not need males to conceive (i.e. parthenogenesis).
Aphids and ants have a harmonious symbiotic relationship. Aphids with small needles with a suction mouth can pierce the epidermis layer of the plant and absorb nutrients. Every minute or two, these aphids will their abdomen and begin to secrete honeydew containing sugar. The worker ants came and scraped the honeydew off their jaws and swallowed it into their mouths. A worker ant shuttles back and forth, approaching an aphid and licking honeydew like a milking operation on a dairy farm. Ants provide protection for aphids and drive away predators; aphids also provide honeydew to ants, a cooperative and beneficial trade.
The aphid's soft body cannot protect it from predators and diseases. As a result, aphids have developed a variety of self-protective defenses. Some species of aphids can interact with plant tissues, causing plants to form a gall (an abnormal proliferation of plant tissue), and aphids can live in galls, thus protecting it from predators. Many of these gall-inducing aphids are able to alienate some defensive "soldier" aphids to protect the galls. For example, Alexander's horned aphid is a class of soldier aphids that have a hard exoskeleton and mouthparts similar to crayons. Chinese bran aphid (Melaphis chinensis) can create a special kind of gall. This gall is used to make the Chinese medicine pentagram to treat cough, diarrhea, dysentery, night sweats, and to stop intestinal bleeding and uterine bleeding. In addition, this gall is also an important raw material for the production of tannic acid.
There are also aphids (kamino aphids) that secrete a layer of fluffy wax covering the body surface for protection. Brevicoryne brassicae is able to store and release chemicals that react violently and produce a strong mustard oil odor to scare off predators. Aphids can also protect themselves by attacking aphid cocoons by kicking and other movements.
The abdominal canal is generally thought to be the organ that secretes honeydew. But in reality, honeydew is secreted from the anus of an aphids, while the role of the abdominal canal is to secrete chemical defense substances such as wax. There is also evidence that in some cases, abdominal canal waxes are able to attract aphids as natural enemies.
Prevention and control methods
1. Drug prevention and treatment
When a large number of aphids are found, timely spray pesticides. Spray plants 1 to 2 times with 50% marathon emulsion 1000 times liquid, or 50% borer pine emulsion 1000 times liquid, or 50% anti-aphid moisture powder 3000 times liquid, or 2.5% cypermethrin emulsion 3000 times liquid, or 2.5% antiscapermide emulsion 3000 times liquid, or 40% imidacloprid water solvent 1500 to 2000 times liquid, prepare chili water (about half an hour to cook) in the ratio of 1:6-1:8, or spray with 1:20-1:30 ratio. Or use the ratio of 1:20:400 to prepare laundry detergent, urea, water mixed solution spraying, continuous spraying of plants 2 to 3 times; for peach powder aphids themselves covered with wax powder, when applying any agent, 1% soapy water or laundry detergent should be added to increase adhesion and improve the prevention and control effect.
2. Artificial control
In autumn and winter, brush white at the base of the trunk to prevent aphids from laying eggs; combine pruning, cut off the damaged branches and residual flowers, burn them centrally, and reduce the mouth of the overwintering insects; scrape or brush off the dense overwintering egg blocks on the bark in winter, clean up the dead branches and leaves in time, and reduce the overwintering insect eggs; when a small number of aphids are found on the flowers in the spring, you can use a brush dipped in water to clean, or tilt the potted flowers under tap water to rotate and rinse.
3. Protect predators
There are many natural enemies of aphids, including ladybirds, grasshoppers, aphid-eating flies and parasitic wasps, which have a strong inhibitory effect on aphids. Minimize the application of broad-spectrum pesticides, avoid applying drugs during the peak period of natural enemy activity, and conditionally raise and release aphid natural enemies.