Disease and Pest Control of Rhododendron australis

Main diseases

Leaf swell

There are three main diseases that may occur in this flower. First, let’s talk about leaf swelling. This disease is not very common. You will know it from the name. The general symptoms are that the front of the leaf first becomes a light yellow transparent texture, and then slowly turns yellow and sinks. The whole leaf becomes fat and thick, and finally slowly becomes the shape of a biscuit. In severe cases, the petiole will also change. Once this situation is discovered, it must be dealt with as soon as possible. If the disease has not yet occurred, spray it with Bordeaux mixture of appropriate concentration. If the disease has already occurred, first remove the diseased leaves, and then spray mancozeb of appropriate concentration.

Leaf spot

There is another disease called leaf spot, which is very common. If you don't want the disease to develop too seriously, spray more ferrous sulfate. Don't take it lightly even before the symptoms are found. You can choose a certain concentration of thiophanate-methyl, oxycarboxin, and mancozeb in May-August. Doing this once every ten days can effectively prevent the occurrence of this disease.

Main pests

Crowned web bug

This kind of insect does not appear very frequently. They mainly gather together and eat the juice on the back of the leaves. At this time, there will be traces on the back of the leaves as if they were splashed with dirty water. This is the most obvious characteristic of this pest. Once discovered, measures must be taken immediately and a certain concentration of cypermethrin can be used for prevention and control.

Red Spider

This kind of pest is very common. After absorbing the juice, the leaves will be stained with grayish-white spots. In more serious cases, the entire leaf will turn yellow or even fall off. This disease and pest is more likely to occur in drier weather and will be alleviated in heavy rains. It is best to start prevention and control in winter, using Emperor Star emulsion of appropriate concentration.