How to prevent and control common pests and diseases of pistachio trees

The pistachio tree is a slow-growing plant with a relatively long lifespan, taking six years from planting to fruiting. The dried fruit made from its nuts is very popular in China and is not cheap. In addition, the pistachio tree is also a tree species that is relatively beneficial for soil and water conservation. During the cultivation of pistachio trees, they are also attacked by pests and diseases. Let us take a look below at common pest and disease prevention and control techniques for pistachio trees.

The main diseases of pistachio include root rot, leaf spot, gummosis, rust, and branch blight. The main pests include the green peach aphid, the brown scale insect (Eulecanium tiliae), and the hawthorn spider mite.

1. Root rot

Root rot is a soil-borne disease. The occurrence and spread of root rot are mainly related to the moisture in the soil and the activity of pests and diseases, for example, related to factors such as root-knot nematodes, soil pathogens, soil moisture, soil temperature, and agricultural operations.

At present, chemical agents are one of the most important methods for controlling root rot, mainly adopting a scheme of early-stage protection plus later-stage treatment.

Seed treatment: seed dressing is the most commonly used method of seed treatment and is also one of the important ways to prevent seedling-stage diseases. Commonly used agents mostly adopt 62.5% metalaxyl-M and fludioxonil, with a dosage of 3-4ml/kg of seeds. In addition to having a good preventive effect on root rot, it also has a good control effect on other seedling-stage diseases such as fusarium wilt and bakanae disease.

Seedbed treatment: before raising seedlings, sterilize the seedbed to prevent root rot. 50% carbendazim is mostly used for seedbed treatment, with a dosage of 400-500g per mu, applied by flushing with water. After application, cover with plastic film for 5-7 days, which can achieve a very good sterilization and disinfection effect.

For biological agent control against crop root rot, Bacillus amyloliquefaciens + Bacillus subtilis can be used for biological control. In the early stage of disease onset, it is recommended to apply 150-200g per mu by flushing with a small amount of water. When the disease is severe, it is recommended to use 10-15g diluted in 15kg of water for root irrigation. If the root rot is relatively severe, it is recommended to apply another root irrigation treatment at an interval of about 7 days.

Grafting is one of the effective methods for controlling root diseases. Choosing rootstocks with well-developed root systems can, to a large extent, prevent the effects of continuous cropping diseases. After watering or heavy rain, loosen the soil in time, which on the one hand helps with moisture loss and on the other hand helps the root system breathe. However, care must be taken not to damage the crop root system.

2. Leaf spot

It is a general term for various shaped spot diseases caused by local infection of leaf tissue. When leaf spot occurs in clusters, it can cause leaf blight, defoliation, or perforation, and in severe cases cause branches to die, or even lead to the death of the entire fig tree.

Use disease-free plants for cultivation, apply fertilizer and rotate crops reasonably, and maintain an appropriate planting density to facilitate ventilation and light penetration and reduce temperature. Pay attention to the watering method and avoid sprinkler irrigation. Thoroughly remove diseased fallen leaves and dead diseased plants and burn them in a centralized manner.

3. Green peach aphid

According to the outbreak time of the green peach aphid, carry out prevention and control in advance, and choosing the right symptomatic pesticide is key. The first three applications of chemical pesticides are particularly critical, and a combination of fast-acting and long-lasting effects must be considered. Once the leaves curl, the difficulty of control increases.

First control timing: when flower buds show red, which is the peak hatching period of the first generation of nymph aphids from overwintering eggs.

Second control timing: after flowers fall, when new leaves begin to grow. If pesticide spraying is not carried out promptly for control, once leaf curling occurs, the difficulty of control increases. Third control timing: the young fruit stage, at an interval of 10 days after the second application.