Comprehensive control of downy mildew of spinach

Spinach (Spinacia oleracea L.), also known as Persian food, red root vegetable, parrot vegetable, etc., belongs to spinach of subfamily Chenopodiaceae of amaranth family, and is an annual herb. Plants up to 1 meter tall, roots conical, reddish, less white, leaves hastate to ovate, bright green, entire or with a few dentate lobes. There are many kinds of spinach, which can be divided into two varieties: thorn species and non-thorn varieties according to the seed morphology. Spinach originates from Iran and is widely cultivated in China. It is one of the most common vegetables.

The growing environment of spinach

Temperature

Spinach is a cold-tolerant vegetable, the seeds can germinate at 4 ℃, the optimum temperature for vegetative growth is 15-20 ℃, the growth is poor above 25 ℃, and the aboveground can withstand the low temperature of minus 6-8 ℃.

Sunshine

Spinach is a long-day crop, which is easy to sprout and blossom under the condition of high temperature and long sunshine, and can be intercropped with high-stem crops.

Moisture content

Spinach has large leaf area, tender tissue and high requirement for moisture. It has plenty of water, thick meat when growing vigorously, high yield and good quality. Under the conditions of high temperature and long sunshine and drought, the vegetative growth is inhibited, the reproductive growth is accelerated, and the immature bolting is easy.

Soil

Spinach has strong adaptability to soil, but it is still better to preserve water and fertility in fertile soil. Spinach is not acid-resistant, and the suitable pH is 7.3 Murray 8.2. Spinach is a leafy vegetable, which needs more nitrogen fertilizer and appropriate phosphorus and potassium fertilizer.

Comprehensive control of downy mildew of spinach

Spinach downy mildew is one of the main diseases of spinach, which seriously harms the planting benefit of spinach, so how to control spinach downy mildew comprehensively?

What is spinach downy mildew?

The disease is caused by a fungus called spinach downy mildew. The main damage to the front of the leaf, disease spot yellowish, irregular shape, different sizes, diameter 3mur17mm, the edge is not obvious. After the disease spot enlarged, it connected with each other and became brown and withered in the later stage, and the gray-purple mildew layer was produced on the disease spot on the back of the leaf. The disease gradually developed from the outer leaves to the inner leaves and extended upward from the lower part of the plant. The diseased leaves withered and yellow during drought, rotted when the humidity was high, and the serious leaves of the whole plant turned yellow and died.

The comprehensive control methods of spinach downy mildew are as follows:

First, strengthen cultivation management: reasonable close planting, scientific irrigation, reduce field humidity.

Second, select disease-resistant varieties: sharp-leaf varieties can be selected, or seeds can be collected on disease-free land or disease-free plants.

Third, chemical seed dressing: seeds with bacteria, can be used before sowing with 50% Fumishuang wettable powder, the dosage is 0.4% of the seed weight.

Fourth, pull out the diseased plant: if the diseased plant is found in the spinach field in early spring, it should be pulled out in time and burned out of the field.

Fifth, chemical prevention and treatment: spray 25% Ruidu wettable powder or 25% metalaxyl wettable powder to water 600 times, or 75% chlorothalonil wettable powder to water 500 times, or 64% disinfectant alum wettable powder or methyl frost manganese zinc to water 400 times 500 times. The above drugs are used in rotation, spraying once every 5 to 7 days for 3 times.