Symptom Identification and Control Methods of Black Rot in Cauliflower

Cauliflower, also known as cauliflower, cauliflower, or cauliflower, is a cruciferous vegetable and a variety of cabbage. The head of cauliflower is a white inflorescence, similar to the head of broccoli. Cauliflower is rich in B vitamins and vitamin C. These components are water-soluble and easily decomposed and lost by heat, so cauliflower should not be cooked at high temperatures, nor is it suitable for boiling. It originated along the Mediterranean coast, and its product organ is a curd formed by the aggregation of pure white, shortened, plump and tender flower buds, flower branches, and flower stalks. It is a vegetable with low crude fiber content, fresh and tender quality, rich nutrition, and delicious flavor that people enjoy eating.

Cauliflower black rot is one of the main diseases of cauliflower, seriously affecting the overall benefits of cauliflower cultivation. Next, let us understand the symptoms and control methods of cauliflower black rot.

Symptoms of cauliflower black rot

When affected at the seedling stage, the cotyledons appear water-soaked, gradually turn brown, wither, and spread to the true leaves, with small streaks of uneven length appearing along the leaf veins; the disease is severe at the mature stage, mainly harming cauliflower leaves, mostly spreading inward from the leaf margin to form “V”-shaped yellow-brown lesions, after which the leaf veins turn black, black rot appears at the leaf margin, and a yellow halo forms at the edge, spreading to the stem and roots, causing the vascular bundles of the stem and roots to turn black, and the small curd to become gray-black and dry-rotted. In severe cases, the plant dies.

Control methods for cauliflower black rot

① Seed disinfection: Select disease-free seeds for sowing, soak the seeds in warm water at 50°C for 20 minutes, or soak them in a 200-fold solution of 50% amobam for 15 minutes, or soak them in a 1000-fold streptomycin solution for 2 hours, then wash and dry them before sowing;

② Seedbed soil disinfection: For every 1 sq m of seedbed, use 8 g of 40% quintozene powder and 8 g to 10 g of 40% thiram wettable powder, mix evenly with an appropriate amount of fine dry soil, first spread one-third on the seedbed surface, and keep two-thirds for covering the seeds when sowing;

③ Crop rotation: In heavily diseased land, rotate with non-cruciferous crops for 2 to 3 years, which can reduce field sources of the disease;

④ Control disease-transmitting pests: Timely control pests such as diamondback moth, cabbage caterpillar, beet armyworm, aphids, Phyllotreta striolata, and root maggots to avoid spreading the disease;

⑤ Strengthen management: Sow at the appropriate time and control seedling growth appropriately; drain promptly after rain to prevent waterlogging or excessive drought in the soil; strengthen field management, fertilize reasonably, and promote vigorous plant growth to improve disease resistance;

⑥ Clean the field: After harvesting cauliflower, promptly remove residual roots and fallen leaves, take them out of the field, and bury them deeply or burn them: plow the soil deeply, prepare the land, and sun the field to reduce sources of the pathogen;

⑦ Chemical control: In the early stage of the disease, spray any one of the following: 100-fold Nongkang 751 aqueous solution or 200-fold Fengling solution, 400-fold 14% copper ammonia complex aqueous solution, 500-fold 77% Kocide wettable powder, or 600-fold 50% zineb solution; or use 1000-fold 50% amobam aqueous solution, 4000-fold 72% agricultural streptomycin soluble powder, or Xinzhiomycin solution, spraying once every 7 to 10 days for 2 to 3 consecutive sprays. In heavily diseased fields, the number of sprays may be appropriately increased depending on disease development.