Six common diseases and control methods of green beans in greenhouses (二)

4. Carob root rot

Main symptoms: Root rot causes dead beans and dead vines. The pathogen of root rot is called Fusarium solani and Phaseolus vulgaris, which can infect carob and Phaseolus vulgaris. Generally, the early symptoms are not obvious until the plants are shorter when they bloom and set pods, and the lower leaves of the diseased plants start to turn yellow from the edge of the leaves, and slowly wither, generally do not fall off, and the diseased plants are easy to pull out. The underground part and main root of the stem turned reddish-brown, the diseased part was slightly sunken, and some cracked deep into the cortex, the lateral roots fell off and rotted, and even the main root rotted completely. The pathogenic bacteria live in the soil with mycelium, chlamydospores, etc., which are left with the diseased remains. They have strong saprophytic properties and can survive for many years in the soil and manure. It is mainly spread by rainwater, irrigation water, tools and bacteria-carrying fertilizers, and invades from root wounds and causes cortical rot. Generally, the disease is more serious in continuous cropping ground with heavy soil quality, excessive moisture, acidity, insufficient fertility and extensive management.

Prevention Methods

Try to avoid continuous cropping of beans and kidney beans. It is better to implement 2-3 years of crop rotation, and pay attention to selecting more disease-resistant and disease-resistant varieties. Timely remove and burn sick and stubborn plants. Compost and barnyard manure should be fermented and rotted thoroughly. The use of enzyme bacteria fertilizer also helps to inhibit and eliminate pathogenic bacteria in the soil. Select plots with higher terrain and better hydrophobicity, deep trenches and high borders, and appropriate amount of lime to prevent flood irrigation and timely drainage after rain. When sowing seeds, use thiophanate-methyl or 50% carbendazim wettable powder to form a 1:50 medicinal soil hole or furrow application.

5. Carob leaf mould

Main symptoms: Leaf mold is mainly leaf leaves, stems and pods. In the early stage of the disease, purple-brown spots appeared on both sides of the leaves, and after enlargement, they became nearly circular dark brown spots, 1-2 cm in diameter, with inconspicuous edges. Gray-black mold can be seen on the back of the leaf when it is wet.

Prevention Methods

After harvesting, remove sick bodies in time, burn them or bury them deeply, and clean the fields; keep the fields ventilated and light to prevent excessive humidity. In the early stage of the disease, the diseased leaves should be removed in time, and timely spraying can be used for prevention and treatment. Use 50% carbendazim wettable powder 500 times, or 75% thiophanate methyl wettable powder 800 times, or 25% difenoconazole 2000 times Liquid, spray once every 7-10 days, 2-3 times in a row.

6. Carob virus disease

Main symptoms: The leaves appear dark and light green mosaics. The green parts of the mosaics are protruding or recessed to form a bag shape. The leaves are usually bent downwards. Some varieties become deformed after being infected. The susceptible plants are dwarfed or not dwarfed, and flowering is delayed, and in severe cases, the yield will be reduced.

Prevention Methods 

① General bacterial diseases, viral diseases, etc. are suitable for growth under neutral or alkaline conditions. Spraying appropriate fungicides can effectively prevent virus diseases and increase production by more than 30%.

② In the early stage of viral disease, spray 40 kg of 0.5% vinegar solution to prevent and control viral diseases, with an effective rate of over 80% and an increase of about 25-30%.

③ Seed disinfection. Soak the seeds in clean water for 3-4 hours, soak them in 10% sodium phosphate for 20-30 minutes, then rinse them with water, or soak them with 0.1% potassium permanganate for 30 minutes, and then rinse them with water.

④ Strengthen field management. Sowing early in the right season, do not crop continuously, apply more organic fertilizers, increase the application of phosphorus, potassium, calcium, etc., and do not apply nitrogen fertilizer. Clean the garden, reduce the source of bacteria, take the previous crops out of the field, concentrate on processing, and dig deep burials.

⑤ Kill aphid and prevent virus disease. During the occurrence of aphids and planthoppers, foliar spraying with 10% imidacloprid is more effective.

⑥ Spray chlorobromoisocyanuric acid + sodium nitrophenolate 1000 times solution twice in 4 days at the beginning of the disease.

Zhengzhou Delong Chemical CO., Ltd. is the production base of plant growth regulators in China, which established in 2009, specializing in offering plant protection products. If you have any question, contact us any time.