How to control white spot of balsam pear

Balsam pear, also known as cold gourd, is a cucurbitaceae plant, is an annual climbing herb, edible, has high value, stems, branches, petioles and pedicels covered with pilose, axillary tendrils. Leaves 3 to 12 cm in diameter, 5 to 7 palmately parted, lobes oval, outer margin serrated. Blossoms at the turn of spring and summer, monoecious and yellow. The fruit is long oval, with most irregular tumor-like protuberances on the surface. The seeds are hidden in fleshy fruit and are wrapped in red sacs when ripe. Balsam pear is a favorite vegetable, the origin is not clear, but it is generally believed to be native to the tropics. It is widely cultivated in South Asia, Southeast Asia, China, and the Caribbean Islands.

Requirements for growth environment of balsam pear

Temperature: temperature control, balsam pear like temperature, more heat-resistant, not cold-resistant. The germination of seeds is suitable for 30 ~ 35 ℃. When the temperature is below 20 ℃, the germination is slow, but it is difficult to germinate below 13 ℃. At about 25 ℃, the seedlings with 5 true leaves can be bred in about 15 days, and if it is about 15 ℃, it takes 20 to 30 days. Balsam pear plants grew slowly at 10-15 ℃, but grew poorly when the temperature was below 10 ℃. When the temperature was below 5 ℃, the plants were significantly damaged. However, with slightly lower temperature and short sunshine, the node of the first female flower occurred earlier. The flowering and fruiting period is more than 20 ℃, and the suitable period is about 25 ℃. The higher the temperature in the range of 15-30 ℃, the more beneficial to the growth of balsam pear-early fruit, high yield and good quality. However, more than 30 ℃ and less than 15 ℃ were disadvantageous to the growth and fruit of balsam pear.

Light: balsam pear is a short-day plant, like the sun but not shade-tolerant. However, after long-term cultivation and selection, the requirements for the length of light are not too strict; however, if the light is not enough at the seedling stage, it will reduce the resistance to low temperature. Balsam pear in winter and spring in northern Hainan is affected by low temperature, overcast and rainy weather, the growth of seedlings is weak, the resistance is poor, and it is often vulnerable to freezing injury. The flowering and fruiting period needs strong light and sufficient light, which is beneficial to photosynthesis and improve the fruit setting rate; otherwise, it is easy to introduce falling flowers and fruits.

Moisture: suitable soil balsam pear prefers wetting to waterlogging. 85% of the air relative humidity and soil relative humidity are needed during the growth period. The weather was dry, the water was insufficient, the plant growth was hindered and the fruit quality decreased. But it is not suitable for stagnant water, the stagnant water is easy to retting the root, and the leaves are wilted. If it is light, it will affect the result, and if it is serious, the plant will die.

Nutrients: balsam pear has a wide range of adaptability to soil, from sandy soil to light clayey soil. Generally speaking, it grows well and has high yield on the loam which is fertile and loose, water and fertility is strong. Balsam pear has higher requirements for fertilizer, if sufficient organic fertilizer, strong plant growth, luxuriant stems and leaves, blossom and fruit, melons are also fat, good quality. Especially in the later stage of growth, if there is not enough fertilizer and water, the plant will be weak, the flowers and fruits will be few, the fruit will be small, the bitterness will increase, and the quality will decline. Balsam pear needs more nitrogen fertilizer, but can not be partial application of nitrogen fertilizer; otherwise, stress resistance is reduced, so that the plant is vulnerable to bacteria infection and cold damage. In the fertile and loose middle loam, the application of phosphorus and potassium fertilizer can make the plant grow healthily and bear melon for a long time.

How to prevent and cure white spot of balsam pear?

What is balsam pear white spot disease? What are the symptoms?

Balsam pear white spot is a fungal disease caused by Cercospora balsam pear. The main damage to the leaves, the early emergence of small round spots of chlorosis and yellowing, gradually expanded into a near-round or irregular type, about 1-4 mm in diameter of grayish brown to brown spots, the edge is more obvious. The disease spot is gray-white in the middle, polygonal or irregular, sparse, light black, mildew, easy to see when wet. It is often easy to cause plaque perforation.

The disease overwintered with mycelium or conidia on the remnant of the disease and was the source of infection in the following year. Through the airflow or Rain Water spread to the balsam pear leaves infection, causing the disease. The conidia produced on the disease spot continue to spread and infect. The melon fields with high temperature and rainy season, lack of organic fertilizer, excessive application of chemical fertilizer and soil consolidation are more serious. Prevention and control of white spot of balsam pear:

First, we should do a good job in field cleaning, remove and destroy diseased and residual plants, and reduce the accumulation of disease sources in the field.

Second, it is necessary to apply enough organic fertilizer to improve soil quality, enhance fertility, ensure deep roots and strong plants of balsam pear and improve disease resistance.

Third, topdressing balsam pear in the first round to ensure adequate nutrition for both vegetative growth and reproductive growth, apply foliar fertilizers such as green Fenwei, Bashi or Lvfengsu to supplement necessary trace elements, and properly pick lateral buds to ensure that the leaves of new shoots are thick and green.

Fourth, regularly spray fungicides to prevent disease. You can choose Alcidol or Ammeto (70% WP) 800-1000 times, Xinerpu or Fengling (65% WP) 400,500X, chlorothalonil or chlorothalonil (40% suspension) 600,700x, generally sprayed once every 7-10 days, 2-3 times in a row.