Aphidius wasps, the natural enemies of aphids, can they control aphids?

For grower friends, aphids are the most troublesome pest. How to eliminate aphids? Who are aphids most afraid of? Nowadays aphids are becoming increasingly difficult to control, especially in April and May, which is the peak period for aphids. Below let us take a detailed look at what the natural enemies of aphids are. Do Aphidius wasps control aphids?

I. What are the natural enemies of aphids?

Aphids have many natural enemies, including ladybugs, hoverflies, Aphidius wasps, parasitic wasps, aphid midges, crab spiders, green lacewings, and entomopathogenic fungi. Among them, Aphidius wasps have the highest hit rate, with some tests showing it reaches as high as 98%. In modern agriculture and forestry, Aphidius wasps have been widely introduced for pest control, and they have become a powerful force in eliminating aphids.

Aphidius wasps are insects of the family Aphidiidae in the order Hymenoptera, and all species in this family are endoparasitic wasps of aphids. Aphidius wasps mainly subdue aphids with their eggs. Each year during the egg-laying season, females begin to mate with males, but females can lay eggs whether or not they have mated. When laying eggs, the female pierces her ovipositor into the dorsal side of the aphid's abdomen and deposits eggs inside the aphid's body, so the Aphidius wasp eggs become parasitic inside the aphid. The eggs parasitic inside the aphid develop into larvae there. They stimulate the aphid, causing it to eat more, gain weight, and swell abnormally, eventually turning into a grain-shaped yellowish-brown or reddish-brown motionless mummified aphid. There is also another situation: some wasp larvae secrete insect hormones inside the aphid's body. Excessive hormones affect the aphid's normal development, causing abnormal metamorphosis, either premature death, or failure to ever grow properly, ultimately dying young. One Aphidius wasp can lay several hundred eggs, and each egg is a “bullet” fired at an aphid, and almost “never misses”.

II. Do Aphidius wasps control aphids?

1. What are Aphidius wasps?

Aphidius wasps are a type of parasitic wasp. Simply put, they grow on others and absorb their nutrients. Parasitic wasps are the most common type of parasitic insect, and their main hosts are aphids. Scientific use of Aphidius wasps can efficiently control almost all types of aphids, including cabbage aphids, green peach aphids, soybean aphids, and wheat aphids.

2. Why control aphids

Aphids are the fastest-reproducing insects on Earth, able to reproduce 10-30 generations per year, and a single aphid could multiply into 1 billion aphids. Female aphids can reproduce as soon as they are born, and aphids do not need males to become pregnant. Aphids are one of the most destructive pests in the world, threatening not only tobacco leaves but also various plants such as vegetables and fruit trees!

3. How do Aphidius wasps control aphids?

Adult female Aphidius wasps lay eggs inside aphids. After the Aphidius wasp eggs hatch, they feed on the tissues and organs inside the aphid's body, and the aphid becomes mummified, forming a mummified aphid (the aphid has already died). The Aphidius wasp larva bites a small hole on the ventral side of the mummified aphid and secretes a sticky substance from its silk gland to glue the mummified aphid to the plant. Then, inside the body cavity of the mummified aphid, the larva uses fine protrusions on its body surface to rotate and spin silk to form a cocoon and pupate. Finally, the young Aphidius wasp emerges as an adult and flies out to continue searching for aphids to parasitize.

A mature female Aphidius wasp carries several hundred eggs in her body, and before her life ends she will find a suitable “home” for the eggs. During egg-laying, the female crawls while gently tapping the plant surface with her antennae, using the olfactory receptors on the antennae to search for the scent left by aphids, and follows the scent trail until she finds an aphid.

Although Aphidius wasps are very strong in their ability to control aphids, attention should also be paid to adopting the method of releasing small amounts many times continuously when releasing Aphidius wasps to control aphids. At the same time, releasing Aphidius wasps when aphids first appear gives the best effect. If aphids appear in large numbers, chemical control is recommended.