Occurrence and Control of Common Diseases in the Middle and late growth period of Pinellia ternata

1. tuber rot

1. Etiology and symptoms: This disease occurs in high temperature, rainy season, excessive soil moisture for a long time, and the expansion period of tubers and bulbils. At the initial stage of infection, irregular black spots appeared around the tuber, which expanded rapidly around. After 3-4 days, many pathogenic spots joined together and continued to infect the tuber. At this time, the root system of Pinellia ternata began to atrophy, and the leaves of the aboveground gradually turned yellow and withered. A week later, pinellia tubers were round blisters, like ripe grapes, tubers were all black water, the whole plant died, and finally only thin skin remained. The spreading pathogen will quickly infect other tubers of Pinellia ternata, and in a short period of time, the whole plot will be infected and rotted, first rotting large tubers, then spreading to small tubers, and finally leaving only bulbils less than 1 cm. This disease is also the most common, difficult to treat, harmful and widespread disease of cultivated Pinellia ternata at present.

2. Prevention and control methods

(1) Pay attention to the selection of good seeds. Artificial planting Pinellia ternata, to choose strong disease resistance, vigorous growth of Pinellia ternata varieties, such as "narrow three-leaf","willow leaf" and other fine varieties of leaf shape.

(2) Disinfect the stems before sowing. Soak seeds with 50% carbendazim for 12 hours, 5% plant ash solution for 2 hours, 1 part of 50% carbendazim +1 part of 40% ethyl phosphorus aluminum 300 times solution for half an hour, 300 times vinegar and 50 ml/L potassium permanganate respectively to prevent rot and increase yield.

(3) Strict selection of soil and terrain. The soil must be medium loam or loam to ensure good drainage and permeability. The terrain should preferably have a slope of 10-25 degrees. If the terrain is flat, deep and densely packed seepage trenches should be dug.

(4) In case of continuous rainy weather and wet soil, as long as it can be cultivated in the field, it is necessary to carry out various forms and multiple times of cultivation to break the hardened layer of the soil, so that harmful gases in the soil can be eliminated, fresh oxygen in the air enters, and the gas exchange between the soil and the air is increased. This measure can effectively prevent and reduce the occurrence of rot disease. And timely spray fungicides or sprinkle 5kg/mu quicklime powder.

(5) timely control of underground pests grub and cutworm. A new pyrethroid pesticide containing 50 g/l cyfluthrin EC has activating effect, which can drive pests to climb out of caves, contact with the pesticide, and quickly act on the nervous system of pests to make them poisoned and die. It has been widely used in the field in the last two years, and the control effect is 100%.

(6) The rotten stems are harvested quickly. In the middle and late stages of Pinellia ternata growth, if continuous rainy weather and soil humidity are encountered, check the growth of Pinellia ternata frequently. If some Pinellia ternata plants are found to have rot disease, in this case, no matter whether it is harvest season or not, they should be harvested decisively in time without delay. Otherwise, tubers rot quickly, first rotten big ones, then rotten small ones, resulting in yield reduction or even no yield. Emergency harvest at the same time, from the wet mud in the planing of Pinellia tuber, should immediately peel processing, because at this time fresh tubers are still rotting inside, if not processed, most tubers will be 1-2 days later, but also rotten, please do not be careless.

II. Virus disease (leaf shrinkage disease)

1. Etiology and symptoms: This disease is Dasheen Mosaic Virus of potato Y virus group, namely DMV.

Mainly due to Pinellia seed stem with virus or aphids and other insect transmission virus. More in early summer, high temperature and rain, aphids occur and spread. After Pinellia ternata plant disease, normal growth leaves produce yellow irregular spots, so that the leaves become mosaic, shrinkage and distortion, roll up, plant dwarfing deformity, poor growth. The disease can also cause extensive rot during storage.

2. Prevention and control methods

(1) Select disease-free plots and areas for planting; strictly screen improved varieties of Pinellia ternata.

(2) Fermented and decomposed organic fertilizer is applied, and phosphorus and potassium fertilizer are appropriately applied.

(3) Timely and thoroughly eliminate or prevent the occurrence and spread of pests such as aphids.

(4) After Pinellia ternata emerges, it is necessary to continuously spray 40% dimethoate or 80% dichlorvos 1500 times, once every 7 days, and continuously spray 3 times.

(5) At the initial stage of the disease, new low-toxicity and low-residue drugs such as virus clearing, keduwei and poison tyrant were used for treatment once every 3 days and three times in a row.

III. Damping-off disease (leaf scald)

1. Etiology and symptoms: This disease is one of the most common main diseases in artificial planting of Pinellia ternata, and its cause is being studied and observed. In the high temperature rainy season, high humidity environmental conditions, the most likely to occur, especially in poor ventilation and light transmission, the disease is serious. At the beginning of the disease, irregular green spots appeared on leaves and petioles, and then the color of the spots deepened, the affected parts softened, and the leaves seemed to be scalded by boiling water, showing translucent drooping and sticking to each other. This disease is acute, infectious fast, once discovered, spread quickly, treatment trouble. The soil and air of the whole plot emitted a strong stench.

2. Prevention and control methods

(1) When selecting plots, the old vegetable fields without tomato, eggplant, cucumber and cabbage in the previous crop or the plots without damping-off disease in the previous crop should be selected for planting Pinellia ternata.

(2) In rainy season and high temperature season, attention should be paid to reducing soil moisture.

(3) After the soil is selected, winter tillage and sun-drying should be carried out in winter. No undecomposed fertilizer is applied, and nitrogen fertilizer in chemical fertilizer is appropriately applied or not applied.

(4) Prevention is primary. After high temperature and rain before onset, 75% chlorothalonil 800 times solution;50% thiophane methyl 1000 times solution; agricultural streptomycin, neophytin;300ppm chloramphenicol; once every 7 days, alternately sprayed 3 times. Attention must be sprayed evenly, do not re-spray, do not leak spray.

(5) Recently, 800 times of 66.5% Prik and 500 times of 72% DuPont were sprayed to control the disease, and the effect was also good.