Lettuce is a common vegetable in life, economical and delicious, and is favored by people. Stem rot and rust are common diseases that are harmful to the growth of lettuce. This article will introduce the prevention and control measures of lettuce stalk rot and rust.
Lettuce stalk rot
A fungal disease caused by the infection of the melon of the genus Basil, which is a genus of Rhizoctonia solani. Generally, the disease occurs first in the petiole near the ground. The diseased part is brown necrotic spot at the beginning, and then spreads to the entire petiole. When the humidity is high, the diseased part overflows the dark brown juice; when the weather is dry, the diseased part is limited to one brown. Depression spots.
When the conditions are appropriate, the leaf ball is damaged, resulting in the whole leaf ball being wet and rotted. The diseased part often produces reticular mycelium or brown sclerotia. The pathogens are used in the soil, and the hyphae are in contact with the host and invade through the stomata for initial infection and reinfection. When the average daily temperature in the shed is above 20 °C, and the humidity is high, the disease is prone to epidemic.
Control methods: strengthen cultivation management, rational close planting, maintain ventilation and light transmission in the field, avoid excessive environmental humidity; combined with other diseases, spray 4000-5000 times solution of streptomycin sulfate or 72% streptomycin sulfate in the early stage of the disease Soluble powder 3000-4000 times liquid, etc., spray once every 5-7 days, continuous control 2-3 times. The medication was stopped 3 days before harvesting.
Lettuce rust
A fungal disease caused by the infection of the lettuce rust fungus of the genus Basil. Mainly harming the leaves, many fresh yellow to red cap-shaped rust spores are produced on the leaf surface at the beginning of the disease, and bulges are formed on the corresponding parts of the back of the leaves. Many cap-shaped rust spores gather together to form about 1.5 cm in size. Disease spots. After the rupture of the epidermis, a dark brown powder, that is, the teliospores of the pathogen, is released, and the diseased leaves are yellowed and dead.
In the northern part of the country, winter spores overwinter on the diseased body. When the conditions are suitable, the burden and the basi spores are generated. The spores invade the host to form the rust cavity stage. The resulting rust spores infect the host and produce the urediospores, and the spores are released. After re-infestation, the spores invade by the epidermis or stomata after germination, the temperature is 16-26 ° C, easy to onset when rainy and high humidity, low temperature, insufficient fertilizer and poor growth.
Control methods: 2-3 years of rotation with non-composite crops; apply organic fertilizer, increase phosphorus and potassium fertilizer, improve the disease resistance of the host; strengthen cultivation management, planting density should be appropriate, not too dense, try to reduce the shed Humidity prevents moisture from stagnation. At the beginning of the disease, the following agents are sprayed: 65% Dyson zinc wettable powder 600 times solution, or 70% mancozeb wettable powder 500 times solution, or 80% New Wansheng wettable powder base 600-800 times solution, or 80% Dasheng M-45 wettable powder base 600-800 times liquid, or 12.5% ​​speed Baoli wettable powder 2000-2500 times liquid, or 40% DuPont new star emulsifiable oil 9000 times liquid, or 6% Lebeng ploughable wet powder 1000 -l500 times liquid, or 10% Yiduowei emulsifiable concentrate, etc., every 10 days or so, continuous control 2-3 times. The medication was stopped 5 days before harvesting.
Silicone Oven Mitts,Best Oven Mitts,Silicone Oven Gloves,Funny Oven Mitts
YANGJIANG VOSSEN INDUSTRY AND TRADE CO.,LTD , https://www.cnvossen.com