Control of black root disease of lotus root

Lotus roots originated in India and were introduced into China very early. In the Northern and Southern Dynasties, lotus roots were planted quite widely. Lotus slightly sweet and crisp, raw food can also be cooked, and medicinal value is quite high, its roots and leaves, flowers and fruits, all for treasure, can be nourishing medicine. Lotus root powder, can digest diarrhea, appetizing heat, nourishing, prevent internal bleeding, is a good liquid food and nourishing treasure for women and children, weak and sick people, in the Qing Xianfeng years, it was appointed as imperial tribute.

Lotus roots are suitable for growing in hot and rainy seasons. Most of them are planted in the south of Yangtze River from March to early April, and in Beijing area in early May. Lotus field selection soil deep, rich in organic matter slightly acidic or nearly neutral clay soil. Lotus seed should select the female lotus or fully mature son lotus with the characteristics of the variety, plump lotus head, complete nape bud, enlarged lotus body, small lotus node, thick fat and bright color. Sowing methods should be dug, selected, planted, or planted after germination.

Lotus field generally keep 5-6cm shallow water in the early stage to promote germination and leaf extraction, and the water depth in the middle stage is 15- 16cm; in the later stage, shallow water is put again to facilitate lotus formation. In the process of growth, oxygen in the air combines with iron in the soil to produce reddish brown rust spots of iron trioxide attached to the lotus skin. When the lotus leaves wither, lotus breathing slowed down, rust due to reduction, and gradually reduced. Therefore, picking leaves before harvest, rust spots are easy to wash away. Leaf hilum, petiole and underground stem are connected by aerenchyma, so petiole should not be broken, lest water causes plant decay.

Black root disease of lotus root is an important physiological disease of lotus root, which occurs in all planting areas. Generally, the loss is 20%-30%, and the loss of serious plots is about 80%. So how do you prevent and treat lotus root black root disease?

Symptoms of Black Root Disease:

The disease mainly shows that stem nodes are damaged, and after the disease, stem nodes are brown to black-brown, and later spoilage and deterioration cannot be eaten. Upward leaves, green at the beginning of the veins, turn brown or purple-brown later, extend inward from the leaf margin, and eventually die.

Causes of Black Root Disease:

Black root is mainly due to too much late pressing green, high temperature, application of undecomposed organic fertilizer, so that lotus physiological obstacles occur. Usually rice fields are planted with lotus roots, which are seriously ill due to high temperature in summer and autumn.

Black root disease control methods:

1. In winter, keep deep water bubble field and apply fully decomposed organic fertilizer.

2. Scientific management of water. 37 500 kg/ha green pressing is suitable, no later than the fourth leaf extension stage.