Prevention and control of orchid rot in high temperature and humid season

Orchid rot disease: this disease mostly occurs in humid summer and autumn rainy season, common black rot, soft rot and so on.

Black rot: caused by Phytophthora. It often occurs in the leaves, roots and growing points, and the disease initially appears translucent spots, then the spots expand, and the tissue blackens and decays.

Soft rot: caused by Erwinia and Pseudomonas bacteria. In the early stage of the disease, tiny brown water-immersed spots appear on the leaves, and then expand into gray, moist patches. The epidermis will rupture at the slightest touch, and foul-smelling bacterial pus will flow out. Prevention and control methods: first of all, to maintain plant ventilation, reduce humidity, the initial stage of the disease with 50% carbendan 500 times solution, 50% bacillus 1000 times solution, garlic water (garlic mash soak, take its filtrate) spray leaves or smear disease spots. Orchid rotten root: although the orchid likes to be wet, its fleshy root system is afraid of waterlogging, too wet or rain water is easy to rot the root, and easy to cause black spot disease. Therefore, the pot soil for orchid cultivation should not be too wet at ordinary times. In winter, orchids are in the dormant or slow growth stage, and the basin soil should be dry; spring and early summer are important periods for orchids to take root and draw leaves, and the basin soil should be moist; but if it is too wet for a long time, it is also easy to cause rotten roots and cause leaves to wither and yellow and even die. During the rainy or rainy season, orchids must take shelter from the rain. because of the long rain and humidity, black spots are most likely to occur on the new leaves, and the stamens often have "rotten clothes" phenomenon. Affect flowering and ornamental. However, if the basin soil is too dry, it is easy to make the false bulb dry or other tissues affect metabolism due to water loss, which will also lead to tissue weakness, poor plant growth, and even death. However, it is appropriate to be wet in autumn, because autumn drought will have an adverse effect on foliage and flowering in the coming year. Therefore, orchid farmers should know the secret of "not wet in winter, not dry in autumn". The above shows that orchids have different requirements for moisture (including humidity) at different times, so the amount of water for orchids should be strictly controlled. Improper fertilization of orchids, such as excessive fertilization, too thick, liquid fertilizer into the leaf sheath or splashed on the leaves is also easy to cause root rot, so fertilization should be applied along the edge of the basin.