Camellia Leaves Developing Black Spots: Cause Analysis and Prevention Methods

As one of China's famous flowers, the camellia also ranks among the top in international floriculture. The camellia's flower colors are very beautiful, and because there are so many varieties of camellia, the flower colors come in all kinds of shades, making it deeply loved by people. It is generally grown mostly in the south, but the camellia's survival rate is not high, and growing it also requires skill. When it is infected by some pests and diseases that cause black spots on the leaves, what is the reason? What should we do? Below, Shuaishuai will tell everyone!

I. Leaf Spot Disease

1. Causes

Black spots appearing on camellia leaves may mean it has been infected with leaf spot disease. Leaf spot disease is also a problem that many growers have encountered. This is a disease that specifically harms plant leaves. The symptoms in the early stage of the disease are black-brown spots appearing on the leaves, which then slowly increase and spread outward, and finally become more and more numerous, covering the entire leaf, causing the leaf to die and fall off, and then infecting other leaves. Some lesions also appear gray-brown and gray-white. The reason camellias become infected with leaf spot disease is mostly because the air is too hot and humid and not ventilated, giving the pathogens conditions to breed. Overwatering is also one of the reasons. Once water accumulates, it causes the root system to rot, and at this time the pathogens take the opportunity to invade and infect the plant. These pathogens can spread through many channels, causing more leaves and plants to become infected with leaf spot disease.

2. Solutions

If your camellia has become infected with leaf spot disease, you need to pay attention to these points. When watering, do not splash water onto the leaves, as this will worsen the condition. If there is water on diseased leaves, it will provide nutrients for the pathogens. In addition, before overwintering, first cut off all infected leaves, then spray with lime sulfur mixture for treatment. During this period, take care to protect the leaves from sunburn and frostbite, control the temperature variation range of the surrounding environment, and it is best to move it back indoors to grow under scattered light. In daily care, we can buy chemicals for spraying, which can supplement nutrients and prevent diseases, reducing the camellia's disease rate.

II. Sooty Mold

1. Causes

Sooty mold is very similar to leaf spot disease, and the symptoms are also very similar. If a camellia suffers from sooty mold, black spots will form on the surface of the leaves. These lesions are also gray-brown in the early stage of the disease, but in the later stage they are different, eventually turning from gray-brown to black, then slowly expanding the range of the pathogens and harming the entire leaf and other leaves. The conditions for the growth and infection of sooty mold are a high-temperature, high-humidity, unventilated environment, and a fungal infection contracted through damage by aphids and scale insects. The higher the humidity and temperature in the ambient air, the faster sooty mold develops, and the black spots will affect the plant's photosynthesis, causing the plant's chlorophyll synthesis and other aspects to be damaged, which is very unfavorable to the growth of the camellia.

2. Solutions

First, prevent and control it from the root. We first adjust the growing environment of the diseased plant, move the plant to an environment with air circulation and moderate light for cultivation, then wipe all the diseased leaves of the plant with clean water, wiping away the lesions and some pathogens. Then you can buy some chemicals on the market for controlling aphids and scale insects and spray them, which can prevent the infection rate of pest damage. Usually, once pests are found, they can be wiped away with a cloth.

The above are the causes and solutions for black spots on camellia leaves. Generally, the reasons causing black spots on camellias are leaf spot disease and sooty mold. These two pathogens specifically harm plant leaves, so during the growing process we must disrupt the growth conditions of the pests, not give them conditions to reproduce, inhibit their spread, and then do some prevention work and spray chemicals.