What are the natural enemies of aphids and the biological control methods?

Aphids are a pest that reproduces very quickly and can harm many cash crops such as cotton, tea, rice and wheat. Controlling aphids is a headache for almost every farmer. Biological control can reduce the use of pesticides and make crops safer, so what are the natural enemies of aphids? What are the biological control methods?

1. What are the natural enemies of aphids?

1. Ladybugs

Ladybugs are the general name for round, convex beetles of the family Coccinellidae in the order Coleoptera, often with red, black or yellow spots. Predatory ladybugs mostly feed on aphids. Many ladybugs live only in specific habitats, sometimes limited to a few kinds of plants in a particular habitat. In contrast, many species such as the harlequin ladybird and the striped ladybird are widespread, and their traces can be found in many habitats; when prey becomes scarce in a habitat they leave to look for food elsewhere.

2. Hoverflies

Hoverflies are effective natural enemies of aphids, scale insects, whiteflies, leafhoppers, thrips and small lepidopteran larvae. They are insects of the family Syrphidae in the order Diptera and are famous for their larvae preying on aphids. Adults range from small to large, with broad or slender bodies, either a single dark color or often with bright markings in yellow, orange, grayish-white and other colors, while some species have metallic colors such as blue, green or bronze, and resemble bees in appearance.

3. Parasitic wasps

Parasitic wasps refer to various insects of the families Pteromalidae, Ichneumonidae and Chalcididae in the Apocrita suborder of Hymenoptera that live by parasitism. There are many species, each parasitizing different developmental stages of the host. Common ones include chalcid wasps, ichneumon wasps, braconid wasps, trichogramma wasps and tetrastichus wasps.

4. Aphid midges

Aphid midges are insects of the family Cecidomyiidae in the order Diptera, distributed in Hubei and other areas. Their host insect is the cotton aphid. They overwinter as cocooned larvae in the surface soil around the host plants of aphids, pupate between March and April of the following year, and after emergence and mating lay eggs and reproduce on early-spring hosts such as weeds with aphids and hibiscus.

5. Crab spiders

Crab spiders are spiders of the family Thomisidae in the order Araneae. Not only do they look like crabs, they can also move sideways or backward like crabs. They have the spirit of taking on bigger opponents and will prey on insects much larger than themselves, such as butterflies, damselflies, mosquitoes and bees. They often prey on pests in flower and grass clusters or bean fields, or in cotton fields and wheat fields near bean fields.

6. Green lacewings

Green lacewings are a large family in the order Neuroptera of the class Insecta, with a great many species, distributed in most areas of China. They are important natural enemy insects of various aphids such as pine aphids, willow aphids, peach aphids and pear aphids as well as pine scale insects, and play an effective role in suppressing the rise and fall of aphid and scale insect populations in forest nurseries, orchards and farmland.

2. Biological control methods

The biological control of aphids mainly means protecting their natural enemies. There are quite a few natural enemies of aphids, including ladybugs, hoverflies, parasitic wasps, aphid midges, crab spiders, green lacewings and entomopathogenic fungi, and these natural enemies have a strong suppressive effect. Apply broad-spectrum pesticides as little as possible, and avoid applying them during the peak activity period of natural enemies. Where conditions allow, aphid natural enemies can be reared and released artificially.

3. Other control methods

1. Using natural enemies: The method of using natural enemies to control harmful organisms is the most widely applied, as natural enemies can effectively suppress the mass reproduction of pests.

2. Resistant crops: Resistant crops means breeding crop varieties with resistance to control diseases and pests, such as breeding potato varieties resistant to potato late blight.

3. Sterile control: Raising large numbers of harmful insects into sterile individuals and releasing them to mate with wild pests, so that the offspring lose their reproductive ability.

4. Genetic control: By changing the genetic makeup of harmful insects, their offspring's vigor is reduced, their fertility weakened, or genetic sterility appears.

5. Cultivation control: Cultivation control means changing the agricultural environment to reduce the occurrence of harmful organisms.

Biological control can effectively reduce the use of pesticides, so that the crops grown this way are safer to eat. We hope everyone can use biological control methods to effectively prevent aphids.