What is the best medicine to spray at the seedling stage of watermelon? What herbicide is good to ap

The yellowing of watermelon may be related to low temperature and high soil moisture, and the yellowing of the roots of watermelon may be related to low temperature and high soil moisture. The safety of seedlings should be considered first, and it is generally recommended to apply 600 times of "75 Daknin wettable powder" to prevent diseases at the seedling stage. Because this medicine does not contain metal ions, it is safe at the seedling stage.

If the seedlings are yellow, it is recommended to increase the temperature and reduce the frequency and amount of watering.

Cataplexy is the most common disease at the seedling stage, the base or middle part of the embryo stem exposed on the soil surface at the seedling stage is soaked in water, and then becomes yellow-brown and shrinks, the cotyledons have not yet withered, and the seedlings suddenly fall suddenly, so that the seedlings are attached to the ground, and sometimes the cotyledons and cotyledons of the melon seedlings have been generally rotted, browned and died. The suitable ground humidity for cataplexy is 10, and low humidity is not conducive to the growth of watermelon, but the pathogen can still be active, especially the nutrients stored in the seedling cotyledons are used up, and the new roots are not yet solid before the susceptibility period. Use "Olik - R. solanacearum Rick" 500 times liquid + 1 package of wofengsu to irrigate the roots, 1 time in 5-7 days, and 2 times in a row.

Watermelon blight is mainly harmful to the base of the seedling stem or the underground roots, at the beginning of the oval dark brown lesion appears on the stem, gradually concave inward, the edge is more obvious, after the expansion around the stem, causing the stem to shrink and dry up, after the melon seedling dies, but not lodging, the disease has a wrinkle or arachnoid mold when the temperature is large, but it is not obvious, at the beginning of the individual melon seedlings wilt during the day, recover at night, and cataplexy is easy to mix. When the temperature of the seedbed is high, the plants grow long, which is easy to aggravate the spread of blight.

Prevention and control methods: the same as cataplexy prevention and control.

When anthracnose occurs in watermelon seedlings, the lesions at the base of the stem of the seedlings are dark brown fusiform depressions, causing the seedlings to die. Cotyledons are damaged, semicircular light brown lesions appear on the edges, and there are orange-yellow dot-like sticky substances on them, because anthracnose mainly relies on water flow to spread the disease, so the disease is more severe near the ground, and the base of the stem near the ground becomes yellow-brown, gradually shrinking, causing the seedlings to lodging.

Control method: 300-500 times of "Olik-Quick Clean" can be used to spray the leaves and stems at the base, once every 3 days, and 2 times in a row.

Most of the above diseases occur when the air humidity is high, and due to the cold weather, vegetable farmers set up multi-layer membranes in the shed for heat preservation. Especially after a period of grafting, in order to promote the healing of the grafting joint, the pumpkin is directly covered with mulch, and the temperature of the shed is extremely high, which creates an opportunity for the infection of germs. <>

First of all, for vegetable farmers who are ready to sow seeds, the seeds and seedbed should be treated before planting. Seed treatment can be carried out by means of chemical treatment and blanching. You can use 1500 times to soak the seeds, remove and wash them to promote germination; Alternatively, use 75-80 blanching for 3 to 5 seconds, then add cool water to bring the water temperature down to 55-60 and soak for 7-8 minutes.

The seedling soil used for sowing should also be treated, and the soil can be disinfected with 800 times the solution of "Olik-R. solanacear". This is an important step in preventing the occurrence of diseases.

Secondly, pay attention to adjusting the environment of the seedbed. In the case of ensuring the temperature of the shed, try to reduce the temperature to the minimum, after opening the curtain in the early morning, if you find that there is a large fog in the room, you should immediately carry out 5-10 minutes of small air outlet dehumidification, pay attention to cover the innermost membrane, discharge the moisture in the shed and the second film, and then close the air product, and then repeatedly put the small air to drain the humidity after the temperature rises to 28-30. In addition to the conventional air and moisture discharge, it can be supplemented with broken straw around the nursery to absorb moisture.

Stiff seedlings are the main physiological disorders at the seedling stage of watermelon. Once the watermelon seedlings are stiff, the recovery is very slow, which will delay the favorable growing season and seriously affect the yield and efficiency. The measures to control the stiff seedlings of watermelon seedlings are as follows:

Choose loose and well-aerated pastoral soil as nutrient soil, and try not to use river mud with heavy soil clay.

Improve the seedling environment, use the ground ** or plastic film to cover the seedlings, increase the ground temperature, cultivate normal growth, good root development, and moderate seedling age (from the root seedlings 30-35 grafted seedlings for 40-45 days). <

Apply well-rotted organic fertilizer to the seedbed, lightly apply compound fertilizer away from the roots, or spray foliar fertilizer to prevent root damage.

Watering at the right time and in the right amount so as not to reduce the temperature of the seedbed and the ground temperature, which is not conducive to the growth of the root system.

When planting, high furrows and deep furrows are used to strengthen drainage, and hole fertilizer (rotten organic fertilizer or chemical fertilizer) is appropriately applied to promote root growth. Pay attention to refining seedlings before transplanting. Timely planting, to prevent the impact of low temperature after planting, choose a cold tail warm head sunny day planting.

How to control the temperature of watermelon planted in greenhouses at the seedling stage? What drugs are used to prevent disease?

Personally, I like to use pyrazole mibris, which has a good control effect on wilt.

After watermelon seedlings, 48% fluorinal emulsifiable concentrate, 33% weeding emulsifiable concentrate, etc., and 35% emulsifiable concentrate can be used to stabilize the emulsifiable concentrate, 20% Napnet EC, Cover Grass EC or 10% Grass Gram EC spray weeding the soil.

Watermelon field management technology: in the watermelon and the whole growth process needs to be watered about five times, the first time is after sowing, the second time is after the melon seedlings break through the soil, the third time is when the seedlings are fertilized, that is, when the melon seedlings grow to forty or fifty centimeters long, and the fourth is the flowering period.

This watering is very important, it is related to the success rate of the fruit, so the watermelon will be watered through, the last time is when the watermelon grows to the size of a palm, this watering must be watered enough, to ensure that its water can ** to the watermelon ripe, at the same time the last water can not be too much, the watermelon needs to accumulate sugar, if the water is too much, the ripe watermelon will not be sweet.

Watermelon management techniques.

Watermelon needs to be fertilized at least four times from planting to maturity, an average of two thousand catties of farmhouse fertilizer is needed as base fertilizer per mu, and secondly, if it is in the countryside, top dressing can be used in the manure of livestock is human manure and urine water, such fertilizer is the best absorption of watermelon, but if it is greenhouse planting or soilless cultivation and so on, it needs to use an appropriate amount of chemical fertilizer.

For example, nitrogen fertilizer is not more than 10 catties each time, potassium fertilizer is not more than 100 catties, phosphate fertilizer is not more than 50 catties and compound fertilizer is not more than 45 catties.

Gram (paraquat) and glyphosate are both biocidal herbicides. The former is the destruction of chlorophyll, which leads to the death of the green organs of weeds or plants. The latter is caused by weeds or other plants absorbing active substances through stems and leaves, and then transporting them to the root system, inhibiting the synthesis of root proteins and causing the root system to die, and eventually causing the aboveground organs to wither.

In addition, after the above two herbicides come into contact with the soil, they will be passivated by the metal ions in the soil and become ineffective. Therefore, neither of the above herbicides can be mixed with pre-emergence or pre-emergence herbicides.

For the selection of herbicides, one is to look at the proportion of weeding objects, such as the proportion of gramineous weeds and broad-leaved weeds, if grasses are the majority, then choose herbicides with higher activity to grasses. Second, it is necessary to choose the herbicide according to the safety of the crop. It is recommended to choose 72 metolachlor (Dur), which is effective for both grasses and broadleaf weeds.

Poaceous weeds are mainly poisoned through bud sheaths, while broad-leaved weeds are mainly poisoned through young grasses and young roots. The use method is generally soil spray before seedlings after sowing, when the soil organic matter content is below 3, the concentration is about 300 times the solution, and when the organic matter content is above 3, it is about 250 times the concentration of the solution.

2 to 3 days before transplanting watermelon seedlings, 48% fluoralin EC, 48% dilometin EC, 50% Dool EC, etc. can be used. After watermelon transplanting, before weeds emerge, 48% fluoralin EC and 33% herbicide EC can be used. During the growth period of watermelon, 35% emulsifiable concentrate, 20% napsunet emulsifiable concentrate, 12 5% caocan emulsifiable concentrate, 10% grass gram emulsifiable concentrate, etc.

I used the melon and melon of Korean agriculture last year, but the watermelon needs to grow to 20 cm before it can be used, and the effect is not bad, and the fragrant aconite can also be removed.

Watermelon field herbicide.

In addition to the herbicide varieties such as dichlor, metolachlor, sec-butyl, quinoxalin, and high-efficiency flupyrimethoxalin, other herbicides such as amide butachlor, diphenyl ether ethoxyflufen, dinitroaniline pendimethalin, cyclic imine oxamine, triazine prometrine, carbamate grass, phenoxy pyrofluxafen, etc., are all available for weeding in watermelon fields. Among them, butachlor has become the first choice for weeding in most watermelon fields due to its relatively wide herbicidal spectrum, high safety and low cost.

Use herbicides registered on watermelons and follow the instructions for use. At the same time, it is necessary to select appropriate agents according to different cultivation methods and weed species. Weeding in watermelon field is mainly soil closure treatment, and pesticides are generally applied before seedlings or transplanting after sowing. After seedlings, it is advisable to use drugs to control gramineous weeds, such as quinoxalin, high-efficiency flupyrethoxalin, etc.

In areas with more rain or poorly drained fields, drugs such as metolachlor are recommended to be used in low amounts. Due to the high temperature of the watermelon field in the greenhouse and small arched shed, the liquid medicine is easy to volatilize, so it is necessary to lift the film in time and ventilate in time to avoid the pesticide damage caused by the high temperature in the shed, and the dosage should be used on the premise of ensuring safety. Mulch watermelon is generally limited to spraying the cover film part, rather than applying the whole field.

If there is any disease to hit the corresponding pesticides, you can't fight indiscriminately, and there are diseases in other plots, so you should take precautions.

Microbial preparations and plant-derived pesticides are more reliable, and organic pesticides are also easy to use.

Is it insect removal, or acid leaf blight, or powdery mildew, or mite pest.

1. Planting watermelon does not need to be deliberately medicated, and if it is a disease, it needs to be properly medicated. If it is downy mildew and anthracnose, it can be sprayed with zeb, usually at intervals of 7-10 days.

2. Mancozeb is also a commonly used fungicide, which can well prevent and control leaf spot, blight, black spot disease, etc., and the interval time is about a week. When actually taking the drug, the type of drug should be selected according to the situation.

1. Water management.

The watermelon seedling stage is a more important stage in the growth of watermelon, and the water requirements are relatively large during the whole seedling stage. Sufficient water is sufficient before sowing to meet the germination needs of the seeds, and if there is a lack of water, then we should choose to water in the morning on a sunny day. But don't do it in the afternoon, because the temperature has gradually decreased, the air is relatively humid, and watering is easy to cause pests and diseases.

And we should pay attention to all kinds of ventilation after watering to prevent excessive humidity in the seedbed and reduce the resistance of seedlings.

2. Ventilation management.

Proper ventilation is the key to ensure the healthy growth of seedlings, and ventilation can effectively improve the environment of the seedbed. After the emergence of seedlings, ventilation is required every morning when the temperature gradually rises. When the temperature starts to drop, the ventilation can be stopped, and the ventilation is opened according to the wind direction.

The size and duration of the vent are mainly determined by the surrounding weather, air volume and other factors. The air volume should not be too large, and the vent soil should not be closed at the end of ventilation to prevent seedlings from being uncomfortable. The vent should not be in the same place for a long time to prevent the growth of the tuyere seedlings.

3. Temperature management.

When a watermelon seedling grows a true leaf, it grows at its fastest rate, and at this time we need to control the temperature and reduce the temperature appropriately. To prevent the phenomenon of tall seedlings due to low temperature, the temperature is controlled at about 22 degrees during the day and appropriately reduced at about 16 degrees at night. When the hypocotyl stops growing, the temperature can be increased a little, and the temperature can be increased by 3-5 degrees.

When the seedlings are successfully cultivated and ready for transplanting 7 days ago, it is necessary to cool down appropriately to enhance the environmental adaptability of the seedlings. Improve the survival rate and yield of seedlings.

4. Light management.

Light is an essential external factor for every crop, and watermelons are no different, because watermelons are inseparable from light for photosynthesis. If there is not enough light time and intensity at the seedling stage, it is very unfavorable to the growth of the seedlings, and the seedling stage will be sluggish or even die. So we must control the light of the seedbed.

<> main diseases of watermelon at the seedling stage are blight, cataplexy and leaf diseases (such as anthracnose, vine blight and bacterial leaf spot). The prevention and control of blight can be sprayed with Ruimiaoqing, the prevention and control of cataplexy can be sprayed with Pulik, and the seedlings can be mixed in advance in the soil, and the prevention and control of leaf diseases can be used with amimiaoshu (azoxystrobin or difenoconazole), agricultural streptomycin, amisida (azoxystrobin), Shigao (difenoconazole) and copper succinate fertilizer.