Gray mold of tomato mainly occurs at flowering and fruiting stages, and can harm flowers, fruits, leaves and stems. Flowering period is the peak of infection. The disease can occur from the beginning of flowering to fruit setting. The harm is serious in years with low temperature and continuous rainy weather.
Gray mold of tomato occurs early, lasts long, and mainly damages fruit, so it causes great loss.
1、Symptoms
Stems, leaves, flowers and fruits can be harmful, but the main harm to the fruit, usually the green fruit disease is more serious.
The leaf disease usually starts from the tip of the leaf and spreads inward along the branch veins in a “V” shape.
At first, it is watered-like, and after development, it is yellowish-brown, with irregular edges and alternating dark and light wheel markings.
The boundary between diseased and healthy tissues is obvious, and a small amount of gray and white mold is produced on the surface.
When the stem is infected, it begins as a small water-soaked spot, and then expands into an oblong or irregular shape, light brown. When humidity is high, there is a gray mold layer on the surface of the spot, and in serious cases, the stem and leaves above the disease part die
Fruit disease, the residual stigma or petals are first infected, and then spread to the fruit or stalk, resulting in the peel is gray, and there is a thick gray mold layer, like water rot.
control method
Agricultural control
- Ecological control
Timely ventilation in the morning on sunny days, especially in the solar greenhouse with water irrigation, the second to third days after irrigation, open the tuyere for 15 minutes after opening the curtain in the morning, and then close the vent. When the temperature in the solar greenhouse rises to 30 ° C, then slowly open the tuyere. The high temperature above 31℃ can reduce the germination rate of spores and reduce the occurrence of diseases. During the day, the temperature in the solar greenhouse is maintained at 20 ~ 25 ° C, and the vent is closed when the temperature drops to 20 ° C in the afternoon. The night temperature is kept at 15 ~ 17℃. On cloudy days, according to the climate and cultivation environment, the wind should be properly released to reduce humidity.
- Cultivation for disease control
Promote the cultivation of small and high cardigan mulching film, carry out drip irrigation technology, reduce humidity and reduce disease. Watering should be carried out in the morning on sunny days to prevent excess. Moderate watering at the beginning of the disease. After watering, pay attention to letting out the wind and removing humidity. After the disease, remove the sick fruit and leaves in time and properly deal with them to prevent the spread of germs. After fruit collection and before seedling planting, the disease residue is removed to clean the field and reduce the infection of bacteria.
- Physical control
The use of summer and autumn high temperature, closed solar greenhouse for more than a week, the use of sunlight to make the temperature in the greenhouse rise to more than 70 ° C, high temperature disinfection.
Chemical control
According to the characteristics of gray mold of tomato, it is necessary to choose suitable kinds of medicine to control it scientifically. When the tomato is dipped in flowers, in the prepared dip flower diluent, 50% of the amount of saprophyticus wettable powder, or 50% of doxycarb wettable powder, etc., is added to prevent bacterial infection. Before planting, tomato should be thoroughly disinfected with 50% carbendazim wettable powder 500 times liquid, or 50% Suacrine wettable powder 500 times liquid spray once to reduce the number of pathogenic bacteria. At the beginning of the disease, 2000 times liquid of 50% Suk flexible wettable powder, 500 times liquid of 50% carbendazam wettable powder, or 1500 times liquid of 50% puhain wettable powder were used for spray prevention and control, once every 7 to 10 days, for 2 to 3 consecutive times. Can also choose 45% Chlorothalonil smoke agent or 10% Sukline smoke agent, 250 grams per mu greenhouse, closed greenhouse after 7 to 8 places in the evening to light smoke prevention. When the disease is serious, after removing the diseased leaves, fruits and stems, the above agents and methods are taken to alternately prevent and cure 2 to 3 times.
Post time: Jul-06-2023
