01, citrus red spider
▲ Citrus red spider and its mite eggs
Red spiders feed on the young tissues of citrus.
There are many kinds of natural enemies of citrus red spiders, and nearly 100 species have been found, among which the occurrence of red spiders can have a significant control effect, including Nicholas blunt mites, Gangwon blunt mites, long-spined blunt mites, nodal long-whisker mites, round-fruit large red mites, grass-dwelling small black spiders, eight-spotted bulbous spiders, Jincao moths, Chinese grasshoppers, tower six-point thrips, deep-spot mite ladybirds, abdominal tube mite ladybirds, zoonotic algae bacteria, stubby mold and non-connotative viruses.
In orchards rich in natural enemies, red spiders can be naturally controlled, especially in the middle and late stages of the growing season. The most important way to artificially affect the red spider is through orchard medication, proper medication can make the red spider better controlled, and unreasonable frequent medication will kill a large number of natural enemies, making the occurrence of red spiders more rampant and showing a multi-peak state.
02, citrus rust ticks
▲ Citrus rust ticks and their harmful fruit performance
Rusty spiders, also known as rusty ticks, mainly harm leaves and fruits, and the fruit is more serious.
After the leaves are damaged, they seem to be water-deficient and slightly rolled upwards, and the back of the leaves is smoky yellow or rusty brown, which is easy to fall off, affecting the tree potential and yield; After the fruit is damaged, it flows out of the oil, and after oxidation by the air, it becomes black-brown, which is called "black peel fruit", which affects the quality and is not resistant to storage.
It is smaller than the red spider and can be seen under a magnifying glass. July to September is the peak period of harm, and it will be harmful before and even after harvesting. In the early stages of occurrence, the peel seems to be covered by a layer of yellow powdery dust, which is not easy to detect, and when the black peel fruit appears, even if the insect body is killed, the peel will not recover. Therefore, the key to prevention and control lies in early detection.
03. Citrus insect pests
▲Citrus mesenchyloxa, shield mesenchymal
Larvae, nymphs, and female adults use their needle-like mouthparts to pierce the leaves, branches, fruits, and other tissues of the navel orange and aspirate the sap. After the leaves are killed, they turn yellow and fall off; the branches are killed, the surface is very rough, so that they die, the fruit is killed, the fruit surface is spotted, cannot be colored normally, the peel is shrunk, the juice is small, and the flavor is light. The weakening of the damaged plants is easy to induce bituminous coal disease, and when severe, the plant will wilt and die.
04. Citrus leafminer moth
▲Leafminer moth larvae harm the leaves
The larvae feed on the citrus twigs and young leaves under the epidermis, forming a curved worm path, commonly known as "ghost drawing symbol". The damaged leaves curl and harden and fall off easily. Because of the wounds on the injured leaves, they are very susceptible to ulcer disease and anthrax. Therefore, in citrus canker disease areas, the pest of leafminer moths often leads to the occurrence of ulcer disease.
5. Citrus whitefly
▲ Citrus black bettore whitefly
▲ Citrus whitefly
It mainly affects the young leaves of spring, summer and autumn. The larvae are fixed on the back of the annual leaves for feeding, resulting in short and delicate branches, and the leaves induce soot disease due to the excretion of honeydew by the larvae, causing the branches and leaves to turn black, hinder photosynthesis, cause the tree to weaken, and the fruit to grow slowly, so that it falls off. The retained fruit is small, with a hard skin, dark color and sour taste, which reduces the value of the product.
1. Black spotted whitefly: nymphs gather on the back of the leaves, suck sap, yellow the damaged parts of the leaves, and can secrete honeydew, induce soot disease, black branches and leaves fall off, weaken the tree, and sharply reduce production.
2, citrus whitefly: gathered on the back of young leaves, sap sucking harm, inducing soot disease, seriously causing leaf deformity and leaf fall, causing dead shoots, slow fruit growth, so that it falls off.
Source of the article: Green Shengyuan Agricultural Science and Technology