What are the watermelon cultivation and management models? Detailed explanation of pest and disease control methods
With the adjustment of agricultural planting structures in recent years, the optimization of cultivation facilities, and the bold practice of farmers, various watermelon cultivation models have been formed across the country that can extend the marketing period of watermelons, basically achieve year-round supply, and meet long-term consumer demand. So specifically, what are the watermelon cultivation and management models? How to control pests and diseases?
I. Watermelon cultivation and management models
1. Open-field direct seeding
After Qingming, it basically enters the frost-free period, and the temperature rises quickly. Open-field watermelons can be direct-seeded with dry seeds, or direct-seeded with large sprouted seeds after germination. This planting method does not seek early maturity and focuses on high-yield cultivation, generally selecting early-to-mid-maturing or mid-to-late-maturing high-quality large-fruit high-yield varieties.
2. Plastic film mulching cultivation
This is currently the most common planting method in China, with two approaches: “direct seeding followed by film covering” and “film covering followed by transplanting pre-grown seedlings.” At present, some places adopt the plastic film method of “covering the sky first, then covering the ground,” which works very well. Plastic film-mulched watermelons are generally planted after the frost ends in mid-April, and the harvest period is 7-15 days earlier than open-field direct seeding, with yields about 30% higher, generally mainly using mid-maturing or early-to-mid-maturing varieties.
3. Small arch shed cultivation
Built on the basis of plastic film mulching, generally an arch shed plus plastic film mulching. Most are first raised as seedlings and then transplanted, and can be transplanted in mid-to-late March. If straw mats are covered over the shed at night, the transplanting period can be advanced to early March, and they can generally be marketed in early June. Because they are marketed early, a second crop of melons can also be kept, resulting in relatively high economic benefits. This cultivation method mainly aims for early maturity and high selling prices, while also taking into account the yield of the second crop of melons. Therefore, it requires selecting varieties that are tolerant to low temperatures, early-maturing, and good for a second crop of melons.
4. Greenhouse cultivation
Greenhouses have good insulation effects, and watermelon greenhouse cultivation can be planted earlier and marketed early, fetching high prices. The seedling raising period for greenhouse watermelons is generally late December to early January, the transplanting period is early-to-mid February, and they are marketed from late April to early May, with a second crop of melons that can be harvested. Watermelons cultivated this way aim for high prices and high benefits, but due to unstable climate, the requirements for varieties are somewhat stricter.
II. How to control pests and diseases in watermelon cultivation?
1. Fusarium wilt
Commonly known as vine cutting disease and wilt disease, it is caused by infection with the watermelon-specialized form of Fusarium oxysporum. This pathogen can survive in the soil for 5-6 years and is prone to occur in old watermelon-producing areas and continuous cropping fields. When the disease occurs, plants wilt during the day and recover in the morning and evening, then die after 4-5 days. The cortex at the base of the plant splits longitudinally, and when humid, the stem base becomes water-soaked and rotted, with mold-like substances and exuding gum. A longitudinal cut of the diseased stem shows the vascular bundles turning yellow-brown, caused by the pathogen infecting the vascular bundles. This is one of the main diseases in old melon areas. Acidic soil, continuous cropping plots, low-lying terrain, flood irrigation, poor drainage, excessive nitrogen fertilizer, insufficient organic fertilizer, and weak plant growth all aggravate the occurrence of this disease.
Control measures:
(1) Implement crop rotation of more than 5-6 years, clean the field, and promptly pull out and burn diseased plants when found.
(2) Select disease-resistant varieties, such as Xin Jiyu, Yuyi Xin Quanwang, Longjuanfeng, Lv Zhi Xiu, Jingpin Huaguan 908, Yuyi 360, etc.; or use grafting cultivation to prevent the occurrence of this disease.
(3) Seed disinfection: soak seeds in 150 times dilution of 40% formaldehyde for 30 minutes.
(4) Reasonable fertilization: apply nitrogen, phosphorus, and potassium in combination, increase the application of fully decomposed organic fertilizer, and apply lime to improve acidic soil.
(5) Chemical control: Use “Guakuning,” “Bacillus cereus,” and “Diwang” mixed into medicinal soil at a 1:50 ratio, and apply in holes at transplanting; or at transplanting, dip the roots in a plug tray with “11% Yingdun (mefenoxam · hymexazol · azoxystrobin) 600 times dilution + 20% hymexazol 1500 times dilution + active root-promoting agent 600 times dilution” for 30 seconds before transplanting, or after transplanting use the above agents made into a medicinal solution to irrigate the roots 1-2 times, which has a very good control effect on Fusarium wilt. In the early stage of disease occurrence, irrigate the roots with the above agents at an interval of 3-5 days, using continuously 2-3 times, and the treatment effect is relatively good.
2. Viral disease
Also known as little leaf disease and mosaic disease, it has two types: mosaic and fern leaf. It is caused by infection with multiple viruses, mainly including watermelon mosaic virus, melon mosaic virus, cucumber mosaic virus, and tobacco mosaic virus.
Control methods:
(1) Soak seeds in 10% trisodium phosphate solution or 1% potassium permanganate solution for 20 minutes for seed disinfection.
(2) In the Huang-Huai River basin, around late May to early June each year before and after wheat harvest, focus on controlling aphids and red spiders on wheat that migrate to watermelons and transmit the virus.
(3) 10-15 days before disease onset, spray the leaf surface twice with “Jianzhibao 500 times dilution + zinc fertilizer,” which can better prevent large-scale occurrence of viral disease.
(4) In the early stage of disease onset, use “Kangrun No. 2 2 tablets + Wanshuai No. 1 30g + Jianzhibao 30ml” or “Qianduling + Yunda 120 + Haishengsu” mixed with 15kg of water, and spray the whole plant once every 4-5 days, using continuously 3 times, with very good results.
3. Anthracnose
Also known as black spot disease, it is caused by infection with Deuteromycetes, and the pathogen is on diseased residues in the soil or on seeds. In the early stage of disease onset, slightly sunken water-soaked round light yellow spots form on the surface of stems and leaves, then turn brown and black, with concentric rings appearing. When dry, the lesions are easily broken and perforated; when humid, pink sticky substances form. After the lesions on the vines expand and encircle the stem, the whole plant dies.
Control methods:
(1) Seed disinfection: soak seeds in 500 times dilution of 50% carbendazim for 1 hour, which can kill anthracnose pathogens on the seed surface.
(2) Implement crop rotation, and deep furrows with high ridges are beneficial for drainage; increase the application of phosphorus and potassium fertilizers to improve plant disease resistance, and promptly prune branches and vines to ensure good ventilation and light transmission in the field
(3) Chemical control: Spray once every 5-7 days with “Haoyi + Jianzhibao” 500 times dilution, or 70% Duobaojing 600 times dilution, which is a sure trick for preventing this disease; in the early stage of disease onset, promptly use 30% Tonghao 1500 times dilution, or 10% Shize 1500 times dilution, or 30% Daikeli 2000 times dilution, or 10% prothioconazole 1000 times dilution, 25% Longzonghao 500 times dilution and other agents for control.
4. Mole crickets and white grubs: Use trichlorfon mixed with roasted wheat bran to make poison bait for trapping and killing. Trichlorfon:water:bait = 1:5:300, scatter on the sowing bed surface or in the field after transplanting. Use about 2-3kg of poison bait per mu in the field.
5. Root maggots: For the organic fertilizer in the nutrient soil, during the decomposition process use 50% phoxim, or 90% trichlorfon, combined with 10% Jinzhangmen to kill insect eggs. If root maggots are found damaging seedlings, promptly spray the root and stem parts of the seedlings with 2.5% Huisuling 800 times dilution + 2.5% deltamethrin 800 times dilution, or 90% trichlorfon 1000 times dilution.
6. Aphids: Spray for control with 10% Mada (nitenpyram) 800 times dilution, 20% Nuoyi (acetamiprid) 1000 times dilution, 70% imidacloprid 3000 times dilution, 2.5% Huisuling (lambda-cyhalothrin) 500 times dilution and other agents. For greenhouse watermelons, 10% Yansheng (isoprocarb smoke agent) can be used to fumigate the shed.
7. Red spiders: Control with Huiguang insecticidal element (1.8% abamectin) 500 times dilution, 15% Shuangman (abamectin · spirodiclofen) 800 times dilution, 5% Huiguang Manwang (fenpyroximate suspension concentrate) 700 times dilution.