Common diseases and control of guava

Guava is a fruit tree growing in the tropics and subtropics, and it is one of the well-known fruits in the subtropics. Guava has strong adaptability to the environment, especially there is no requirement for soil, so it is easy to cultivate. But easy to plant does not mean that it is easy to yield, it will also encounter a lot of diseases and insect pests in the planting process, so the pest control of guava is very important. Next, I will talk to you about the common diseases and insect pests of guava.

1. Guava leaf blight

Leaf blight is mainly harmful to guava leaves, which produces brown irregular patches on the leaves at the initial stage, and gradually becomes light brown in the middle and later stage, and the boundary between the disease and the normal is obvious. In the later stage, the whole leaves were infected until withered, and the leaf blight was mainly caused by fungi spending the winter in the diseased body and soil, and began to propagate and spread in the rainy season, invading the leaves. It is necessary to clean up the orchard in time, concentrate the remains and burn them, and reduce the source of the disease. it is found that the disease can be sprayed with chlorothalonil wettable powder and other agents, once a week for a month.

2. Pseudosporium guava brown spot.

Pseudocercospora brown spot is mainly harmful to the leaves and fruits of guava, the leaves will produce brown irregular patches, the edge is not obvious, the back of the leaves produce gray mildew. Black dots will be produced on the fruit epidermis, the fruit will be sunken in the middle, and the sunken edge is reddish brown. This is mainly due to the spread of pseudocercospora in diseased trees and normal trees, and excessive humidity is the time with the highest incidence. Diseased leaves and fruits should be removed in time and destroyed centrally. Prune diseased branches, reduce the incidence of disease, spray carbendazim wettable powder and other agents to disinfect the orchard.

3. Guava sun fruit disease

Sun fruit disease usually occurs on the sunny side of the fruit, starting with small spots like water stains on the fruit, and then turning into brown patches, a little sunken. In the later stage, all the plaques will spread to form a large plaque, which is not caused by fungal pathogens, but mainly begins to be burned by the sun to the sun, causing the bacteria to invade. It mainly occurs in the high temperature season at 7: 00 or 8: 00 in summer, when the bacteria lurking in the diseased body and soil invade the burned fruit and cause disease. Remove the diseased body from the orchard, protect the fruits exposed to the sun, disinfect the orchard and reduce the source of the disease.

4. Guava root knot nematode disease

Root-knot nematode disease is mainly due to the invasion of root-knot nematode larvae into the roots of guava, causing the root tip to bend and gradually expand to form an oval shape, fewer whisker roots, unable to absorb and transfer nutrients normally. The control methods can choose the areas without root-knot nematodes and fertile soil to build gardens, select disease-resistant varieties, improve soil, and reduce the existence of root-knot nematodes.

For non-disease-resistant varieties are more prone to disease, every day carefully observe the changes of guava trees, find anything abnormal, immediately identify the types of disease, so that we can prescribe the right medicine in time. Preventive measures should be taken in the daily management, the disease does great harm to crops, which can lead to serious yield reduction or even no yield.