The Latest Control Methods for Carrot Black Rot

Carrots are very rich in vitamins and have excellent benefits for human health. Black rot is the most common disease of carrots, directly affecting carrot quality and yield and harming growers' interests. So how should we control carrot black rot? Below I will introduce black rot and its control measures.

1. Affected regions

Carrot black rot is mainly a fungal disease caused by certain fungi, and it is also the most common carrot disease. 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 damage is relatively severe, and in recent years the degree of damage has been increasing. The disease 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 emergence stage can cause damping-off in seedlings that have not yet emerged from the soil. Older leaves at maturity are also relatively susceptible, forming small black spots on the leaf stalks that then spread across the entire leaf, causing the whole leaf to die. In severe cases it can spread all the way to the crown of the carrot, rotting it black. An overly humid storage environment can also trigger it.

3. Timing of the disease

This disease is mainly caused by pathogens on infected seeds and diseased plant debris serving as the source of invasion; these pathogens can survive in diseased plant debris 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 areas 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. Seed coating, clearing away diseased plant debris and disinfecting the field are the most effective methods for preventing black rot. After harvest and before storage, infected roots should be washed clean and the black rot parts cut away, and the temperature and humidity of the storage room should be kept from getting too high. Spray chlorothalonil suspension concentrate and similar products for prevention some time before the disease period arrives, once a week for about one month. If infected roots are found, they should be pulled out immediately, the field disinfected, and chemicals such as uniconazole suspension concentrate sprayed, once a week for one month.

Black rot is a rather troublesome disease in carrots; once it occurs it is not easy to bring under control, so preventive preparations should be made before sowing and during the disease period. Disinfecting the storage room before storage and controlling the storage environment well can also greatly reduce the chance of the disease occurring. Alright, the above is a brief introduction to black rot. To learn about other carrot diseases, please continue to follow Qinnong Web!