Control of diseases and insect pests in broccoli

Broccoli is a 2012 herb, originated in the eastern Mediterranean coastal area, a small amount of cultivation in China, mainly for Western food use. Broccoli is rich in nutrition, containing protein, sugar, fat, vitamins and carotene, ranking first among similar vegetables and known as the "vegetable crown". A variety of cabbage species of the genus Brassica in Cruciferae that uses green flower balls as products. Originated in Italy along the Mediterranean coast of Europe, it was introduced into China at the end of the 19th century.

The main diseases of broccoli at seedling stage are quenching and blight.

Symptoms of sudden collapse of broccoli

After the seeds were unearthed, there were many rotten seeds infected before they were unearthed, and after they were unearthed, they appeared water stains near the soil surface, softened, the epidermis was easy to fall off, the disease part constricted, expanded rapidly around the stem for a week, and the vegetable seedlings lodged, resulting in pieces of dead seedlings. Pathogen of quenching disease of broccoli

Pythiumaphanidermatum (Eds.) Fitzp. It is called Pythium of melon and fruit, which belongs to oomycetes. The mycelium grows luxuriantly, showing white cotton wool shape, and the mycelium is colorless and septum-free, with a diameter of 2.3 to 7.1 microns. There was no significant difference between hyphae and cyst peduncle. Sporangia filamentous or branched valvular, or irregularly dilated. The size is 63 ~ 725 × 4.9 ~ 14.8 microns. The vesicle is spherical and contains 626 zoospores. The egg organ is globose, 14.9 to 34.8 microns in diameter, and the male organ is bag-shaped to broadly clavate, homofilamentous or heterofilamentous, mostly 1. The size is 5.6 ~ 15.4 × 7.4 ~ 10 microns. Oospores globose, smooth, discontented, 14.0 to 22.0 microns in diam. The frequency of this bacteria is higher in the places with high annual average temperature, in addition, P.spinosumSaw. It is called Pythium spiniferum, which belongs to oomycetes. It is also the pathogen of the disease. There is no special shape on CMA. It was slightly radiate on PCA. The main hyphae are 8.0 microns wide and spread between or within cells: sporangia globose or subglobose, smooth or spiny, terminal or interspore, 14 μ m in size, 1 μ m in size, 3 germ tubes in germination, no zoospores; ovoid to subglobose, densely covered with finger spines of uniform thickness, different lengths and straight fingers, few or no spines, 17 μ m in size, terminal or interstitial. Male organ 1, typical homofilament stipitate, male organ born in egg organ stalk or main stem hyphae, size 12 ~ 32 × 3 ~ 5 microns: oospore full organ, even nearly full organ, oospore colorless, spherical, size 12 × 21 microns. According to the test in Ningxia, the seedling death rate of pepper cataplexy caused by this bacteria accounted for 83%, melon and fruit Pythium accounted for 84%, and the ultimate Pythium accounted for 80%.

Prevention and treatment of broccoli quenching disease:

(1) for the areas where P.aphanidermatum thermophilic bacteria mainly cause quenching disease, 0.2% of 40% seed dressing double powder can be used for seed dressing or soil treatment. The method of chemical treatment of soil is to cultivate strong seedlings to prevent quenching disease, cover with a layer of nutritious soil after sowing, cover with film to keep warm and moisturize, spray 0.2%-0.3% potassium dihydrogen phosphate 2 times 3 times after emergence, enhance disease resistance, if necessary, spray 800 times of 25% Riemerol wettable powder.

(2) for the quenching disease caused by A.brassicicola, it is recommended to use 0.2-0.3% 75% chlorothalonil wettable powder or 70% mancozeb dry suspension powder or 60% Fangmaibao (carbendazim hydrochloride) ultra-fine wettable powder. The control effect is better than that of soil treatment or irrigation. (3) irrigate 69% Anke manganese-zinc wettable powder 900 times if necessary.

Symptoms of blight of broccoli

Broccoli stem blight, also known as black root disease, is an important seedling disease of broccoli. At the initial stage of the disease, the rhizome of the seedlings became black or constricted, and gray-white mildew appeared on it when it was moist. After the plant was infected, the leaves wilted and withered within a few days, resulting in the death of the whole plant. It generally stops expanding after planting. However, individual fields continue to die. In addition, the disease can also be characterized by sudden collapse or leaf ball decay. Pathogen of broccoli blight

RhizoctoniasolaniK ü hn is called the fusion group of AG2~1 and AG-4 hyphae of Rhizoctonia solani, which belongs to half-known fungi. The characteristic is Thanatephoruscucumeris (Frank) Donk. It is called Cucurbitaceae, which belongs to basidiomycetes. Before fusion, hyphae often induce each other to form three fusion states: complete fusion or incomplete fusion and contact fusion. More than ten mycelium fusion groups have been found and established in China, among which AG-4 is the dominant bacteria causing cucumber, wax gourd and maize sheath blight. It has a wide range of hosts, causing a variety of crop diseases. According to the morphology of sclerotia and the homology of nitrogen base sequence of deoxyribonucleic acid, the strains of AG-4 mycelium fusion group were divided into two subgroups: AG-4HG-I and AG-4HG- Ⅱ. The former formed dark brown sclerotia on PDA medium, while the latter formed gray to white-brown sclerotia. Rhizoctonia solani can be divided into three groups, one group is multinucleated Rhizoctonia solani, with 3 or more nuclei, the hyphae are large, about 6 μ m in diameter, and their behavior is Thanatephoruscucumerls (Frank) Donk. A thin layer of waxy or white pink reticulate to omentum-shaped solid layer is formed in the soil, and the basidium is barrel-shaped to subcylindrical, slightly wider than the hyphae supporting the basidium, and the basidium has 3-5 small stalks bearing basidiospores; the basidiospores are oval to broadly rod-shaped, and the base is wide, with a size of 7.5-12 × 4.5-5.5; microns, basidiospores can germinate repeatedly and form 2 basidiospores on the basidium. Rhizoctonia solanacearum is formed by dense branches at the tip of a single hyphae or mycelium knots formed by a dense tip and hyphae. Different mycelial fusion groups are different in morphology, pathology, physiology and ecology. The pathogenicity specificity of each fusion group, the internal relationship between them and their role in nature need to be further clarified.

Prevention and control of broccoli blight:

The main results are as follows: (1) the varieties which are not sensitive to low temperature in the early growth stage should be selected for spring cultivation. Such as Green Ridge, Green Emperor, Green Green, Zaosheng Green, Bisong, Jasmine, Luhua No. 2, normal Saline, Shanghai No. 1 and so on.

(2) Brassica oleracea seeds were coated with film. 0.1% oxytetracycline or 3% 75% chlorothalonil was added to the film-forming solution, stirred evenly, mixed according to the proportion of 30 parts of seeds and 1 part of medicine solution, and used after drying, which could prevent and cure the disease caused by bacteria in cabbage vegetable seeds.

(3) sowing at the right time should not be too early or too late.

Diseases during the growing period include downy mildew, virus, Sclerotinia sclerotiorum, black rot, soft rot and so on. Agricultural control methods are as follows: 1. Select disease-resistant varieties. 2. Apply fully mature organic fertilizer to balance the application of nitrogen, phosphorus and potassium. 3. Clean the fields in time after harvest, remove the plant remains and fallen leaves, and take them out of the field for deep burial or burning. Chemical prevention and control methods are as follows: 1. Downy mildew: at the beginning of the disease, 15 kg of water is sprayed with 15 kg of ethyl manganese 50 muri 75 g water or 15 kg of Ruidu 15 Rue 20 g water or 60% methamphetamine or 64% antidote alum or 58% Redomir or 72% Kloe 500 ~ 600 times spray. 2. Virus disease: the prevention and control effect is better with 15ml 20g water 15kg solution, such as virus net, virus death and so on. 3. Sclerotinia sclerotiorum disease: spray with 1000 times of 50% paracetamol or 1500 times of 50% acetaminophen in early onset and rainy days. 4. Black rot and soft rot can be killed 500 times or 47% plus Ruinong 800 times with 80% necessary 500 times or 77% after transplanting.

The main pests of cauliflower are aphids, cauliflower and so on, which can be controlled alternately by chlorpyrifos, chlorpyrifos, trichlorfon, insecticidal king, etc.