Control of stem rot of orchids

Symptom

The disease mainly occurred on the new buds of orchids, followed by leaves. At the initial stage of the disease, a large spot of mung bean appeared at the base of the bud. After 2 to 3 days, it rapidly expanded upward and downward, becoming a dark green patch, extending to the outside of the bud and showing dark brown. When the new orchid bud fell ill, it was quickly transmitted to the orchid plant of the previous year. 1 to 2-year-old seedlings were prone to disease, and the pseudo-bulbs of the old seedlings had a high degree of Lignification and were not easy to occur.

Pathogenic bacteria

The pathogen is carrot soft rot Erwinia. The optimum temperature is 25 ℃ to 30 ℃. It can grow at pH 5.3 to 9.2, and pH 7.2 is the most suitable. The pathogen can infect many kinds of orchids.

Prevention and cure measures

In the period of high temperature, cooling measures should be taken to control the temperature of orchid cultivation place below 25 ℃; at the same time, reduce the amount of watering, reduce the water content of basin soil, reduce the times of water spraying, reduce the relative humidity in the air, and strengthen ventilation to create an environment that is not conducive to bacterial infection and reproduction.

Strengthen medicament prevention

Disease prevention: according to the author's investigation, if early measures are taken when the disease occurs in spring, autumn and winter, some orchid plants are expected to be preserved, but in hot summer, it is difficult to treat the disease. Therefore, it is very important to do a good job in drug prevention of the disease. The following agents can be used to prevent the disease: 53.5% can kill dry suspension 1000 times, 72% agricultural streptomycin wettable powder 800x, 50% soft humin powder 800x.

Usage: once every 7 to 10 days, use it for 2 to 3 times in a row, and then spray according to the situation.

Pest control: after pests in orchid garden or orchid pot, the pathogen invades the orchid and the orchid plant suffers. Therefore, it is necessary to prepare for pest control.

In short, in the prevention and control of orchid diseases, we must abide by the principle of prevention first and prevention as a supplement. Secondly, in peacetime management, it is necessary to create an environment suitable for orchid growth, so that orchids do not grow in a hot, humid and airtight environment. In the use of fertilizers, nitrogen, phosphorus and potassium should also be used together, and nitrogen fertilizer should not be applied partial to enhance the ability of disease prevention and disease resistance.