Citrus scale insect symptoms, prevention period and method

Morphological characteristics and harmful symptoms of citrus scale insects

The common feature of citrus-mediated pests is that they are male and female. Females have well-developed mouthparts, wingless, tough or soft body walls, and are covered with wax powder or a hard waxy shell to protect the body. Generally, it is damp and wet, and most of it is parasitic in the back of the leaves or branches and leaves, and the air is not circulating. The worms are small, dense, and very harmful. Such as blowing cotton, nymphs and females damage trunks, branches, leaves, etc., can induce serious bituminous disease, so that the tree is weak, branches and leaves fall, and even the whole plant is dead; Yajisuke, 糠片介, 黑点It is caused by adult and young insects that are parasitic on citrus shoots, leaves and fruits. After the victim, the branches of the victim are withered, the leaves are curled and dried, and the tree is in decline. The fruit is in a green state, the quality is deteriorated, and the yield is reduced. In recent years, Yajimi has been intensified in the citrus orchard. 90% of the results of the 10-year-old tree are endangered. The light-branched leaves of the damaged plants are yellow and yellow, and the whole plant is dead. The fruit of the victim is covered with media, the appearance is damaged, the quality is inferior, the value of the commodity is lost, and the economic benefits are directly affected.

Citrus scale insect control period

There are many kinds of scale insects on citrus. Commonly, there are scorpion scorpions, red wax mites, etc., all of which suck the juice with a sucking mouth device to cause damage to crops. These scale insects have different occurrence rules. The difficulty of prevention and treatment is very different because there are no nymphal peaks in different types of scale insects, strong nymphs have strong protective wax, etc., and there are naturally different requirements for the selection of pesticides.

Scale insects are sensitive to a variety of organophosphorus, pyrethroid and buprofezin, imidacloprid and other drugs. The difficulty in prevention and control is that the scale insects can occur many times a year, the middle and later generations overlap, and the older nymphs and adult bodies have protective layers. It is difficult for drugs to penetrate this layer of substance to exert a contact effect. In general, the first generation of scale insect nymph hatching peak is more obvious, is the key generation of drug control, and the overlapping of generations is more serious, it is difficult to achieve good results with contact drugs. When the body surface of the newly hatched nymphs has not formed a good protective layer, it is sensitive to drugs and is a critical period for drug control.

Quinthine is one of the commonly used drugs used in the production of citrus to control scutellaria and red wax mites. It can be seen from the characteristics that the drug has no systemicity and short duration of action. The drug and its compounding agent with pyrethroid pesticides are mainly suitable for use during the peak period of scale insect nymph hatching. Missing this opportunity, after application It is difficult to achieve good results. In the field, the overlap of scale insects in the field is more serious, and when various insect states are present, it is advisable to use imidacloprid, buprofezin, acephate and other drugs and other compounding agents for prevention and treatment.

Control measures for citrus scale insects

First of all, it is now the citrus fruit preservation period, and it is also the old spring ripening and small fruit turning green period. It is preferable to use agricultural measures and chemical pesticides with higher safety. 1. Lightly cut off the insects, leaves and closed branches of the past years, which is favorable for ventilation, light transmission and uniform spraying. The pruning method is mainly based on sparse. 2. Cooperate with the fruit-preserving measures to speed up the spring shoots. Available Jinyunda-120+九二O+potassium dihydrogen phosphate+amino acid to protect the first fruit, use the whole tree fruit + calcium phosphate magnesium zinc micro-fertilizer to protect the second fruit. 3. Prevention and treatment of the combination of the first and second instar larvae and the suppression of eggs. It can be sprayed alternately with cyanobacteria or imidacloprid and stone sulphur mixture to prevent insects and disease, and to inhibit eggs. 4, the prosperous tree in the spring shoots old and mature, only cut the fruit, and often observe the ring cutting mouth to see if there is a scale insect to swim, promptly spray with the medicine.

Secondly, the second, third and fourth generation larvae are controlled during the fruit expansion period and the autumn shoot. During the fruit enlargement, due to the relatively high temperature, the scale insects occur faster, and it is difficult to control with chemical pesticides. The effective method is to combine natural enemies and sprays. 1. In the early stage, pyrethroids, highly toxic organophosphorus pesticides, and diesel engine oil acaricides are not required to ensure the time for natural enemies such as ladybugs to reproduce. 2, do not eradicate weeds in the orchard, so that natural enemies have breeding grounds. 3, pay attention to observe, grasp the time rule of the scale insects in their own orchard, and focus on the larvae spraying control. The selected agents are cyanobacteria, imidacloprid and speed culling.

Third, try not to use the ring cutting measures to promote flowers in winter, so that it will not cause the scale insects to multiply in winter. In winter, the orange tree should be supplemented with enough fertilizer and nutrients to control the winter shoots, and the flower bud differentiation will proceed normally.

Fourth, pay attention to the winter clearing. Cut off the pests and branches, withered branches, remove the weeds in the orchard, and spray with the stone sulfur mixture and beta-cypermethrin + trichlorfon.