Identification and control of diseases and insect pests of Schisandra chinensis

Disease 1. Leaf blight

1. Symptoms. Caused by the infection of Schisandra chinensis leaf blight pathogen, it is a common disease. It is easy to occur when it is hot, rainy and unventilated from late May to early August. First from the leaf tip or leaf edge to start the disease, the emergence of dark brown spots, gradually expand downward to spread to the whole leaf, and finally make the whole leaf become dark brown dry and fall off. Then the fruit shrinks and becomes the early fruit drop.

two。 Prevention and treatment. One is to choose a well-ventilated plot. The second is to strengthen field management and prune reasonably to avoid excessive overlap of branches and leaves and excessive closure. Create good ventilation and light transmission conditions, reduce field humidity and improve the microclimate among plants. The third is to find the central diseased plant, remove the diseased leaves and reduce the source of infection. Fourth, after the onset of the disease, 50% methyl topiramate 1000 times, 80% mancozeb 800 times, 80% mancozeb 1000 times solution spray, once every 7 days, spray 2 times 3 times.

2. Root rot

1. Symptoms. It is a common disease caused by the infection of root rot pathogen of Schisandra chinensis. The disease occurred during the rainy season from early July to mid-August, and the disease was serious in waterlogged depressions, low-lying lands and plots with poor permeability. After the disease, the leaves of the aboveground plants wilted and drooped, and black spots appeared at the junction of the root and the ground, which gradually spread upward and downward, so that the roots blackened and rotted, the root bark fell off, and the plant died a few days later.

two。 Prevention and treatment. One is to choose the land with high terrain, good drainage and strong permeability to plant Schisandra chinensis. Avoid waterlogging depression, low-lying land. Second, stagnant water in the rainy season should be eliminated in time to prevent waterlogging. Third, after the onset of the disease, 50% carbendazim 1000 times solution, 50% carbendazim 1000 times solution rhizosphere spraying.

Third, powdery mildew

1. Symptoms. Caused by Schisandra chinensis powdery mildew pathogen. It happens in individual years. Summer is dry and muggy, and it is easy to occur when the temperature is 25-28 ℃. In the early stage of the disease, the leaf color faded green or showed gray-white patches, covered with a layer of white powder, the leaf surface was uneven, and the outline of the disease spot was not clear. in severe cases, the white powder covered the whole leaf, and the diseased leaf gradually curled, withered and fell off.

two。 Prevention and treatment. First, strengthen field management, tie vines in time, trim auxiliary shoots, make branches evenly distributed on the shelf surface, and maintain ventilation and light transmission. Second, reasonable close planting, planting should not be too dense, nitrogen fertilizer should not be too much, nitrogen, phosphorus and potassium should be fertilized together to prevent leaf vines from growing. Third, cut off diseased branches in winter, sweep away diseased leaves and fruits, and concentrate on burning. Fourth, after the onset of the disease, use 25% of the powder, 50% of methyl topiramate 1000 times of the solution, 80% of mancozeb 1000 times of the solution spray. Spray every 7 days, 2x 3 times.

Downy mildew

1. Symptoms. Caused by downy mildew of Schisandra chinensis. It is easy to develop disease from July to August when it is high temperature and rainy in some years. The leaf front produces a large reddish spot, round or nearly round, and also a small polygonal spot, which gradually turns yellow or reddish brown, and the back of the leaf produces white mildew and gradually withered.

two。 Prevention and treatment. First, remove fallen leaves, cut off diseased branches, remove diseased leaves and fruits, and reduce the source of disease. The second is reasonable pruning, improving ventilation and light transmission conditions, timely elimination of stagnant water, increasing the application of phosphorus and potassium fertilizer, and enhancing disease resistance. The third is to spray the same amount of Bordeaux solution before the disease to control the disease. After the onset of the disease, 50% methyl topiramate 1000 times solution, metalaxyl manganese zinc 800 times solution spray, every 7 days, spray 3 times 4 times.

Drug damage

1. Symptoms. Schisandra chinensis is sensitive to any herbicide, especially to ethyl mixture. In the upper wind, the herbal medicine Yi A mixture is used to seal the weeds, and the fog droplets float with the wind to Schisandra chinensis within 200 meters downwind, and can still be damaged by medicine. On the day of administration, the whole leaves of Schisandra chinensis appeared water-immersed patches, spread the whole leaf, and gradually dried up. The light growing point can continue to germinate and form new leaves, while the heavy growing point can not germinate when it dies.

two。 Prevention and treatment. When choosing Schisandra chinensis plots, stay away from corn and soybean fields. Or corn and soybean fields do not apply closed herbicides. The selection of land should be continuous, or close to grape fields, vegetable fields, medicinal plots and other crops that cannot apply herbicides, so as not to cause drug damage and affect the growth of Schisandra chinensis. After the emergence of drug damage, it is necessary to fertilize in time to promote growth.

Insect pest

Black velvet beetles

1. Hazard. Adult damage, Coleoptera, Scarabaceae, is an early pest of Schisandra chinensis. The adult is 7-8 mm long and 4-5 mm wide, with dark brown and glossy protuberance on the back, with 9 raised lines on both wing sheaths. In the first 5 days of May, the daily average temperature was more than 10 ℃, and a large number of adults were unearthed, which was seriously damaged by windless and warm weather. The critical period is from early May to late June. Schisandra chinensis, which sprouts and spreads leaves from late April to early May, is the earliest crop to serve and spread leaves in farmland. After the adults are unearthed, they eat the leaf buds of Schisandra chinensis, leaving woody stems; on the edge of the field, they also eat dandelion, iron slices, borage pods, and tender buds of elm, poplar and willow.

two。 Prevention and treatment. One is manual capture. The black velvet beetle only crawls but does not fly within a few days, and a small number of insects can be caught manually. The second is chemical prevention and control. When the density of insect population is high and it is difficult to capture manually, chemical control can be carried out. Methods during the peak period of adult unearthed at 2 ~ 4 o'clock in the afternoon, 20% cypermethrin 1000 times, 4.5% cypermethrin 1500 times and 80% dichlorvos 1000 times were sprayed. The third is to trap and kill adults. Before the adults appear in the afternoon, soak the sprouting branches of elm, poplar and willow with 40% dimethoate EC 50 times, insert them into the areas where the adults are concentrated, and insert one for every square meter to trap and kill the adults.

2. Leaf curl (soybean borer moth)

1. Hazard. The larvae are harmful and belong to the family Lepidoptera. From July to August, the first instar larvae feed on the tender leaves, and after the 3rd instar, they roll up the leaves and feed on the mesophyll in the rolled leaves, which harms the leaves, affects the fruit development, and even drops the fruit.

two。 Prevention and treatment. The larvae were sprayed with 4.5% cypermethrin 1500 times and 80% dichlorvos EC 1000 times before rolling leaves. Spray 50% zinc parathion EC 1500 times after rolling leaves.