There are many reasons for tomato leaf curling. How to control tomato leaf curling?

No matter planting tomato in greenhouse or open field, leaf curling phenomenon with different symptoms caused by different causes is easy to occur under high temperature and drought. The main causes and symptoms of tomato leaf curling are as follows:

Tomato leaf rolls

First, the harm of virus disease: tomato leaves are curled and clustered, and in serious cases, only veins without mesophyll can be seen. The virus is transmitted by contact with aphids, whiteflies and juices, and has a high incidence under high temperature and drought. Control measures: selecting disease-resistant tomato varieties; implementing crop rotation to reduce the source of primary infection; spraying 1000 times of potassium permanganate solution at the initial stage of virus disease; killing virus-borne aphids and whitefly 1500-2000 times.

Second, physiological curling leaves: before and after tomato harvest, the leaves of the first ear are slightly curled, or the leaves of the whole tomato are curled into a barrel and become brittle, which is caused by high temperature and drought and stomatal closure. Control measures: tomato fruit after timely watering and fertilization, and cover the sunshade net, sunny day cover, night cover, cloudy day does not cover.

Third, element deficiency: tomato leaves are purple-red on the back, with brown dots, the lower leaves are rolled up, the curly leaves turn yellow, and the tips of the leaves are black and brown and die. Reliable soil phosphate fertilizer, or foliar spraying 0.3% potassium dihydrogen phosphate solution. Magnesium deficiency showed that during the expansion period of the first inflorescence tomato, the lower gray leaves lost chlorosis, yellowing appeared between the veins, and then expanded upward to form yellow spotted leaves. In severe cases, the tomato leaves were stiff or curled at the edge, and there were necrotic spots or brown bands between the veins. The leaf roll of magnesium deficiency in tomato can be solved by applying all-element fertilizer or spraying 100-fold solution of magnesium sulfate on the leaf.

Fourth, hormone drug damage: in the prevention and control of tomato falling flowers and fruits with plant hormones, such as accidentally dipping it into the young leaves or growth points of tomatoes with 2meme4murD, the leaves or growth points may bend, the new leaves may not be able to unfold normally, and the leaves will be green twisted. Prevention and control measures: when hormone is used, choose the appropriate concentration, generally use the concentration of 15-20 mg / kg, when the temperature is high, the concentration is lower. When in use, avoid dipping the liquid into the tender leaves or growing points, and never spray it. After the occurrence of drug damage, you can apply some nutrient solution to promote the growth of tomato, such as spraying natural brassine, love more harvest and so on.