What are the control methods for zucchini viral disease?
Zucchini, also known as eggplant melon, bear (male) melon, white melon, wo melon, small melon, foreign melon, horn melon, xun melon, etc. Zucchini is an annual trailing herbaceous plant, with three main strain types: dwarf, semi-trailing and trailing. Most varieties have obvious main vine dominance. It is nutritious and contains a variety of vitamins, and both the elderly and children like to eat it.
Growth habits of zucchini
Temperature
Among cucurbit vegetables, it is the type that is relatively cold-tolerant but not high-temperature-tolerant. The most suitable temperature during the growing period is 20-25°C; below 15°C growth is slow, and below 8°C growth stops. Above 30°C growth is slow and diseases are very likely to occur. The suitable temperature for seed germination is 25-30°C; at 13°C it can germinate, but very slowly; at 30-35°C germination is fastest, but it easily causes excessive vegetative growth. The flowering and fruiting period requires a relatively high temperature, generally maintaining 22-25°C is optimal. Early-maturing varieties have stronger low-temperature tolerance. The minimum temperature for root elongation is 6°C, and the minimum temperature for root hair formation is 12°C. When the night temperature is 8-10°C, fertilized fruits can develop normally.
Light
The light intensity requirement is moderate, and it is relatively tolerant of weak light, but insufficient light easily causes excessive vegetative growth. In terms of photoperiod it is a short-day plant; long-day conditions favor stem and leaf growth, while short-day conditions make the fruiting period earlier.
Humidity
It likes moisture and is not drought-tolerant, especially during the fruiting period the soil should remain moist in order to obtain high yield. Under high-temperature and drought conditions, viral disease easily occurs; but high temperature and high humidity also easily cause powdery mildew.
Soil
It has no strict requirements for soil; sandy soil, loam and clay can all be used for cultivation, and deep loam soil easily achieves high yield.
Pollination and fruit setting
Zucchini is a crop with separate male and female flowers, and under greenhouse cultivation conditions, artificial pollination is required. 1. Pollination should be carried out at 9-10 a.m. every day. When pollinating, pick male flowers that open on the same day, remove the corolla, and gently smear the stamens of the male flower onto the stigma of the female flower to pollinate; each male flower can pollinate 5 female flowers. 2. Using Little Angel for foliar spraying is sufficient, replacing manual flower dipping and fruit smearing, safe and unaffected by temperature; at present the main domestic manufacturer is Nangong Huayang Chemical.
Fertilizer requirement
The fertilizer requirement is relatively large; to produce 1000 kg of marketable melons, the fertilizer requirement is equivalent to 3.9-5.5 kg of nitrogen, 2.1-2.3 kg of phosphorus pentoxide, and 4-7.3 kg of potassium oxide.
How is zucchini viral disease controlled?
Causes of zucchini viral disease
Too high temperature, scarce rainfall, dry air, and severe outbreaks of pests such as aphids and whiteflies cause severe occurrence of viral disease. In some cases, many weeds around the greenhouse, proximity to diseased crops, excessive application of nitrogen fertilizer, excessive vegetative growth of plants, continuous cropping, and lack of attention to disinfection during manual operations and other factors aggravate the occurrence and spread of the disease. Because most plants have been infected by the virus, even now, in greenhouses with relatively high temperatures, symptoms still appear, affecting yield.
Control methods for zucchini viral disease:
1. Disease-resistant varieties: use disease-resistant and disease-tolerant varieties as much as possible.
2. Seed treatment: to eliminate the virus carried on the seeds, seed treatment can be carried out. Warm water soaking: place the seeds in warm water at about 50°C and soak for 15-30 minutes. Trisodium phosphate soaking: place the seeds in 10% trisodium phosphate solution and soak for 20-30 minutes, then remove and rinse clean with water. Potassium permanganate soaking: soak the seeds in 1% potassium permanganate solution for 10-15 minutes, then rinse clean with water. Dry heat disinfection: place dry seeds in a constant-temperature chamber, maintain 75°C conditions, and treat for 72 hours.
3. Land selection: continuous cropping should be avoided, deep plowing should be carried out, sufficient organic fertilizer should be applied, and phosphorus and potassium fertilizer should be increased to promote robust plant growth and improve disease resistance. Before planting, spray 200 g/mu of no-deep-plowing soil conditioner to make the deep soil loose and permeable, which is beneficial to root growth and development.
4. Seedling raising: the temperature during the seedling stage should be suitable; leggy seedlings are easily susceptible to disease. When transplanting, damage as few roots as possible, which can promote seedling recovery and reduce disease occurrence.
5. Field management: when planting, select disease-free strong seedlings and eliminate diseased and weak seedlings. During field operations such as pruning and harvesting, frequently wash hands with soapy water for disinfection, and minimize human sap transmission. Tobacco carries viruses, so smokers are forbidden to enter. Clean the field in time and pull out diseased plants. Diseased plants should be deeply buried or burned to reduce sources of disease. After planting and seedling recovery, do not exercise the seedlings excessively. In hot and dry seasons, appropriately irrigate with small amounts of water frequently, keep the field moist, and lower the soil temperature. Apply topdressing in stages, increase phosphorus and potassium fertilizer, and spray a 1:10000 solution of natural brassinolide every 20 days, which can improve plant disease resistance.
6. Control whiteflies and aphids: control whiteflies and aphids in time, which can reduce virus transmission vectors and avoid the occurrence of disease. In addition to chemical control, gauze netting can also be used for shading.
7. Chemical control: attenuated vaccine N14 and satellite virus S52 can stimulate plants to develop disease resistance after application. Common methods include: root-dip inoculation, that is, lift out small seedlings with 1-2 leaves, wash off the soil, soak in a 100-fold vaccine solution, and after 30-60 minutes remove and transplant; spray-gun inoculation, in 100 ml of 100-fold vaccine solution, add 0.5 g of 400-600 mesh carborundum, shake well, and use a spray gun to spray-inoculate seedlings at the 1-3 leaf stage. Passivating substances: use high-protein substances such as soybean milk, milk and fish blood, diluted 100-fold with clean water, once every 10 days, spraying 3-5 times consecutively, which can form a film on the leaf surface, weaken the virus's infection ability, and reduce its sharpness.
In addition, there is also plant virus passivator-912: add a small amount of water to a 75 g bag of powder to make a paste, then add 1 kg of boiling water, soak at 100°C for 12 hours, stir well, let cool, then add 15 kg of water, and spray once each in the morning and evening after planting, at the early fruiting stage, and at the full fruiting stage. Protective substances: use 200-500-fold solution of high-lipid film and spray on the leaf surface before disease onset, once every 7-10 days, spraying 3-4 times consecutively, which can form a thin film on the leaf surface to prevent and reduce virus invasion. Resistance-enhancing substances: 83 resistance enhancer can improve plant disease resistance, prevent virus infection, and reduce the speed of virus spread in the plant body. Use 7.5 kg of stock solution per hectare plus 750 kg of water, and spray once each at the 2-3 leaf stage of small seedlings, 1 week before transplanting, and 1 week after planting and seedling recovery. In addition, there are also 20% Dukexing 400-500-fold solution, antiviral agent No. 1 300-400-fold solution, 25% antiviral soluble powder 400-600-fold solution, 20% Bingdujing 400-600-fold solution, and Bingduning 500-fold solution. Use one of the above chemicals, once every 7 days, spraying 2-3 times consecutively. All the above chemicals have a certain preventive effect, but the therapeutic effect is not significant.
In addition, for plants with severe viral disease, they should be pulled out immediately and deeply buried. For those not severe, management can be strengthened to promote fruiting, and they can be pulled out in February next spring.