Popular science of pest control in autumn: what are the beneficial insects in the field? Are all insects harmful?

In the primeval forest, the vegetation is luxuriant and there are many kinds of insects, but it is rare to see a large number of insect pests, even rampant. The reason is that in such an environment, although there are many kinds of insects, they are also divided into camps, and they struggle with each other and depend on and restrict each other, forming a state of relative balance. Today, the editor will introduce to you the natural enemies of several kinds of pests. Don't accidentally injure the "friendly forces" when you usually see them.

I. on natural enemies and insects

Insect pests are a major hidden danger to the healthy growth of crops, such as eating plant organs, spreading viruses, creating favorable conditions for the invasion of diseases and so on.

However, among crop pests, the real harm is great, causing economic losses all the year round, and there are not many insects that need to be controlled frequently, accounting for only 1% of the total number of insects. In fact, there are several or even dozens or hundreds of natural enemies of each kind of pest, such as rice planthopper and leafhopper, which fully shows the abundance of natural enemy insect resources in nature.

II. Main species of natural enemy insects

According to the mode of killing insects, the species of natural enemies can be divided into predatory natural enemies and parasitic natural enemies.

1. Predatory natural enemy

There are many kinds of predatory natural enemies, the most common are dragonflies, mantis, assassin bugs, stinging bugs, flower bugs, lacewings, ladybugs, pedestrians, insectivorous gadflies, aphid flies, wasps, mud wasps, spiders and predatory mites.

These natural enemies generally have a large amount of prey, and in the process of their growth and development, they may need to eat several, dozens or even thousands of insect bodies in order to complete their growth and development. According to the way of eating, it can be divided into chewing type and piercing type, and so on. The following are briefly introduced:

01. Mantis: it can prey on more than 40 kinds of pests, such as flies, mosquitoes, locusts, moths, butterflies and their larvae, exposed pupae, crickets and other small insects, as well as cicadas, migratory locusts, katydids and other large insects.

02. Predatory ladybug: preys on aphids, scale insects, whitefly, leaf mites, etc.

03. Predatory mites: it covers a wide range of mites, including red mites, large red mites, velvet mites, long beard mites and phytoseiidae. It is a kind of omnivorous beneficial mites with red spider, rust tick and other plant leaf mites as the main food.

04. Lacewings: can prey on a variety of pests. Such as whitefly, red spider, all kinds of aphids, in addition, it also likes to eat the eggs of many kinds of pests, such as cotton bollworm, ground tiger, Spodoptera litura, wheat moth and small bridge worm, which are all within its food range.

05. Bugs: bugs of Pentatomidae, Miridae and Pentatomidae can prey on leafhoppers, planthoppers, aphids, thrips, cotton leaf mites and cotton lacewing eggs and other pests.

06. Aphid flies: larvae mainly prey on aphids and are effective natural enemies of aphids, shell insects, whitefly, leafhopper, thrips, Lepidoptera larvae and other pests.

two。 Parasitic natural enemy

Parasitic natural enemies are insects parasitic in insect pests, which feed on pest body fluids or internal organs, and are mainly represented by parasitic wasps and parasitic flies.

01. Trichogramma: egg parasite that can parasitize the eggs of many Lepidoptera pests such as corn borer, armyworm, striped borer, cotton bollworm, Spodoptera litura and ground tiger.

02. Cocoon wasp: parasitic on a variety of moth and butterfly larvae, plays a certain role in controlling the number of its occurrence.

03. Parasitic flies: most of the larvae of Lepidoptera and leaf wasps can be parasitized, as well as longicorn beetles and bark moth larvae living in the stems of plants, beetle larvae living in soil, and adults such as beetles and bugs.

III. Utilization of natural enemy insects

1. Recognition

In order to use natural enemy insects for biological control, excellent natural enemies must be selected, that is to say, the dominant species that play an important role in a region or community must be selected.

The necessary conditions for good natural enemies are: strong ability to find hosts, consistent with or closely cooperate with the life history, world algebra and number of hosts, strong diffusion ability, strong adaptability to the environment, strong selectivity to hosts, easy to reproduce in large numbers, and so on.

two。 Protection

After pests live in an area for a long time, they are bound to be accompanied by a certain species and number of natural enemies. However, due to the limitations of various living conditions, the number of natural enemies is often not enough to control insect pests. At this time, appropriate measures can be taken, such as protecting natural enemies safely through the winter, rational use of chemical pesticides, avoiding damage to natural enemies, and promoting the reproduction of natural enemies to control the occurrence and harm of pests.

3. Release

Natural enemy insects in nature and their hosts or prey host insects often follow, not only the occurrence time lags behind, but also the number is much lower than that of pests. At this time, artificial feeding or direct purchase of corresponding products can be considered, and pest control can be released to the field when pests first occur.

There are not only pests in the field, but also beneficial insects. Remember to distinguish between the good and the bad when preventing pests.