How to identify ginger plague? How to prevent it?

Ginger rot, also known as ginger blast, is the most common and widespread destructive disease in ginger production. The yield of diseased plots is generally reduced by 10% ~ 20%, and in severe cases by more than 50%, or even completely reduced, which poses a serious threat to ginger production.

(1) symptoms

After plants are invaded by pathogens, symptoms will appear in stems, leaves and rhizomes. At the beginning of the disease, the rhizome was soaked in water, yellow-brown, and lost its luster. After that, the internal tissue gradually softened and rotted, leaving only the outer skin. When squeezing the affected part, dirty white rice juice can flow out, giving off an unpleasant smell. The roots were killed, yellow-brown, and eventually all rotted. The stems on the ground are dark purple, the internal tissues are brown and rotten, and there are fiber residues. The leaves withered, turned yellow from bottom to top, and the edges curled, and finally the whole plant drooped and died.

(2) pathogens

Ginger rot is a bacterial disease, and its pathogen is Pseudomonas solanacearum, which not only infects ginger, but also infects tomato, eggplant, pepper, potato and other solanaceae crops.

(3) the route of transmission and the conditions of onset

Pathogens mainly overwinter in rhizomes and soil, and generally can survive in soil for more than 2 years. Ginger with bacteria is the main source of initial infection, which can be spread over a long distance by means of ginger seed regulation, and ginger seedlings with bacteria will get sick. In addition, in the diseased ginger field, the soil was infected by bacteria because the diseased plants were left in the field. For example, continuous cropping often leads to early diseases and serious harm. Even if the disease-free ginger is planted in the soil with bacteria, it will cause disease, so the soil with disease is also an important source of infection of ginger rot. The more the old ginger area, the continuous cropping of disease stubble and the accumulation of bacteria year after year, which leads to the aggravation of the disease year by year. In addition to diseased ginger and diseased soil, if manure made of diseased body or diseased soil is used in ginger field, it will also bring germs to the field and cause diseases. Irrigation water and rainwater are also vectors for spreading germs. Especially at the peak of the disease, if the water source is polluted, germs will flow with the water and cause diseases. In severe cases, bacteria will spread everywhere and diseases will spread rapidly.

The occurrence and spread of ginger rot are affected by many factors such as temperature and humidity. The suitable temperature for pathogen development is 26 ~ 365438 0℃. The higher the temperature, the shorter the incubation period and the faster the disease spreads. Especially in hot and rainy weather, a large number of bacteria spread with water, causing repeated reinfection, which often leads to a large number of plants dying in a short time. The severity of the disease is also related to the rainy season and rainfall. Early rainy season, early emergence of central disease strains and early onset provide opportunities for repeated reinfection. Heavy rainfall provides convenient conditions for the spread, invasion and reproduction of pathogens. Therefore, in high temperature and rainy years, diseases often occur in a short time, which is very harmful; In years with little rainfall and low temperature, the illness is generally mild. Sandy soil with high terrain, dryness and good drainage is generally mild; Ginger fields with low terrain, poor drainage, heavy soil, stagnant water in the field or partial application of nitrogen fertilizer are more serious.

(4) Prevention and control methods

Ginger rot has many transmission routes, long onset period and difficult control. At present, there are no ideal fungicides and disease-resistant varieties, so agricultural control measures should be given priority to, supplemented by chemical control, in order to cut off the transmission route and control the occurrence and spread of diseases as much as possible.

① Soil disinfection. Fumigating the soil with 25 ~ 35 kilograms of chloropicrin every 667 square meters. The specific application method is as follows: about 30 days before sowing, use a special applicator to apply the liquid medicine into the soil layer with a depth of 15 ~ 25 cm, with a spacing of about 30 cm, and inject 2 ~ 3 ml at each point, then cover it with plastic film for 3 ~ 5 days, and prepare for sowing after 15 ~ 20 days. Chloropicrin is highly toxic and volatile, so it must be operated by professionals when smearing. It can also be fumigated with methyl bromide, and the specific method refers to chloropicrin.

In addition, lime nitrogen can also be used for soil treatment. Lime nitrogen is a kind of green fertilizer with long fertilizer effect, which has the functions of killing insects, sterilizing, weeding, raising ground temperature, adjusting soil pH, accelerating root rot of residual plants in soil and inhibiting nitrification. There are two ways to use it: soil disinfection and ditching and sowing. Soil disinfection can be carried out by mixing 50- 100 kg of lime nitrogen with enough organic fertilizer or chopped crop straw every 667 m2 20-30 days before ginger planting, applying it in the field and watering it, and then covering it with plastic film 15-20 days to prepare the soil for sowing. Ditching and sowing: evenly mix and sow 50 kilograms of lime nitrogen and organic fertilizer in the ditch every 667 square meters, fully mix with the soil, and then water and sow. The effect of soil disinfection is closely related to temperature. Generally, the effect is better above 20℃, but worse below 15℃.

② Crop rotation. Because the pathogen of ginger rot can survive in the soil for more than 2 years, rotation is the main way to cut off the spread of soil, especially in the affected plots, ginger can only be planted at intervals of 3 ~ 4 years. The field where ginger was planted in the past should be a plot where food crops were planted. As for the vegetable garden, onion stubble and garlic stubble are better. Tomato, eggplant, pepper, potato and other solanaceae crops have been planted, especially in the plots where bacterial wilt has occurred, which is not suitable for planting ginger. Practice has proved that more than four years of rotation and the use of disease-free ginger seeds combined with fine management have remarkable effects on controlling the occurrence of ginger rot.

③ Strictly select disease-free ginger to prevent ginger from spreading diseases. Before harvesting ginger, seeds can be strictly selected in disease-free ginger fields, stored in ginger storage pits, and strictly selected before planting in the following year to eliminate the hidden dangers of planting ginger.

④ Land selection and preparation. Jiangtian should be selected in a plot with high and dry terrain and good drainage. When preparing the soil, the ground should be flat, and the ginger ditch should not be too long, preferably not more than 20 meters. In order to prevent water accumulation in rainy season, Jiangtian should set up drainage ditches.

⑤ Apply net fertilizer. The fertilizer used in the ginger field should be as free from germs as possible. It is not allowed to use diseased ginger, diseased plants or soil with bacteria as soil miscellaneous fertilizer, and farmyard manure can only be used after it is decomposed.

⑥ Clear water. It is best to irrigate ginger fields with well water to prevent water pollution. It is forbidden to throw diseased plants into canals and wells. Plastic hoses can be used for irrigation if conditions permit. When watering, you should control the amount of water, and you must not drown it.

⑦ Find the diseased plant and eradicate it in time. When a diseased plant is found in the field, not only the central diseased plant should be removed in time, but also the healthy plants within 0.5 meters around it should be removed together, and the soil with bacteria should be dug up, lime should be sprinkled in the diseased hole, and then it should be buried with clean sterile soil.