What are the control methods for carrot black rot?

Carrots contain very rich vitamins and have very good effects on the human body. Black rot is the most common disease of carrots, and it directly affects the quality and yield of carrots, harming the interests of fellow growers. So how should we control carrot black rot? Below I will introduce black rot and its control measures.

1. Areas where the disease occurs

Carrot black rot is a fungal disease mainly caused by certain fungi, and it is also the most common disease of carrots. It occurs in carrot-growing regions all over the world. In China, the main affected areas are Anhui, Fujian and other eastern regions, where the disease is more severe, and in recent years the degree of damage has been increasing. It can occur at every stage of carrot growth.

2. Causes of the disease

First, it may be due to the seeds themselves carrying the fungal virus, which begins to cause disease after emergence, leading to infection. Infection during the seedling stage can cause damping-off in seedlings that have not yet emerged. Old leaves at maturity are also relatively susceptible, forming small black spots on the leaf stalks, which then spread across the entire leaf, causing all the leaves to wither and die. In severe cases it will develop all the way to the head of the carrot, rotting it black. A storage environment that is too humid can also trigger it.

3. Timing of the disease

This disease is mainly caused by pathogens on infected seeds and diseased plant residues serving as the source of invasion. These pathogens can survive in diseased residues and soil for more than 5 years. They can spread through soil, wind and other means, and infection is also likely when temperature and humidity are too high. In North China the usual disease period is from July to September, with the highest incidence in August. Around June 2012, large-scale rainfall occurred nationwide, causing carrots in some regions to develop the disease early, and severely affected areas were not spared.

4. Reasons for control

When selecting seeds, choose disease-resistant seeds. Continuous cropping is not recommended. Methods such as seed coating, clearing diseased residues and disinfecting the field are the most effective ways to prevent black rot. After harvest and before storage, infected roots should be washed clean and the black rot parts cut off, and the temperature and humidity of the storage room should be kept from getting too high. Some time before the disease period arrives, spray chlorothalonil suspension concentrate and similar products for prevention, once a week for about a month. If infected roots appear, they should be pulled out immediately, the field disinfected, and pesticides such as tebuconazole suspension concentrate sprayed, once a week for one month.

Black rot is a rather troublesome disease in carrots. Once it occurs, the condition is not easy to control, so do a good job of preventive preparation before sowing and during the disease period. Before storage, the storage room should also be disinfected and its environment well controlled, which can also greatly reduce the chance of disease. Alright, the above is a brief introduction to black rot. If you want to learn about other carrot diseases, please keep following Qinnong Web!