What are the key technical points for pest and disease control in Hami melon?
Hami melon is a variant of melon, with round or oval fruit, produced in **. It is not only delicious but also rich in nutrients and high in medicinal value, with excellent prospects for cultivation. It is widely grown throughout China. During production, bacterial leaf spot, gummy stem blight, fungal leaf blight and other diseases often occur. Let's take a look at the pest and disease control techniques for Hami melon!
Bacterial Leaf Spot
[Symptoms] In the early stage, water-soaked lesions appear near the veins on the underside of leaves. The lesions expand rapidly and merge together, with a yellow halo at the edges.
[Control Methods] In the early stage of the disease, spray the leaves with 77% Duoning at 500 times dilution or 3% Zhongshengmycin at 800 times dilution 2-3 times, once every 4-5 days.
Gummy Stem Blight
[Symptoms] It damages vines and leaves. The affected parts of the vines often split open, with dense small black spots on the surface. In severe cases, amber-colored gum oozes from the affected parts. When the average temperature is 18-25°C, soil moisture is high, and there is continuous cropping, poor drainage, or weak watermelon growth, the disease occurs more severely.
[Agricultural Measures] ① Strictly control soil moisture to avoid excessively high water content. ② Reduce wounds on melon plants to lower the chance of pathogen infection. ③ Avoid flooding irrigation in the field when the disease occurs.
[Chemical Control] In the early stage of the disease, spray the leaves with 25% Kairun emulsifiable concentrate at 1800 times dilution, or 32.5% Amisulbrom suspension concentrate at 1500 times dilution, or 24% Yingde at 2000 times dilution. The number of applications depends on the disease development, generally 2-3 times, once every 3-4 days.
Hami Melon Powdery Mildew
[Symptoms] The pathogen mainly damages leaves, and stems and petioles can also be affected. In the early stage, small round spots appear on the leaves. After the lesions expand, they merge into patches. In severe cases, both sides of the leaves, stems and petioles are covered with white powder, and the diseased leaves turn yellow, become brittle and curl. The pathogen overwinters in the soil as cleistothecia with plant debris. It spreads through airflow and rain. When the melon field has high humidity, dense plant growth and poor ventilation, the disease is severe.
[Control Methods] ① Strengthen field management, increase application of phosphorus and potassium fertilizers, prevent excessive vegetative growth and premature senescence due to fertilizer depletion, prune scientifically, improve ventilation and light penetration, and reduce humidity. ② In the early stage of the disease, apply 2-3 kg of 200-mesh sulfur powder per mu in the morning and evening when there is dew on the melon vines, or spray sulfur suspension concentrate at 200-300 times dilution, or 15% triadimefon wettable powder at 67 g, or 75% chlorothalonil wettable powder at 600 times dilution, or 70% thiophanate-methyl wettable powder at 1000 times dilution, once every 7-10 days, for 2-3 consecutive times.
Fungal Leaf Blight
[Symptoms] The disease occurs in July-August, mainly damaging leaves, and petioles, stems and fruits can also be affected. In the early stage, water-soaked brown small spots can be seen on the underside of leaves. The lesions gradually expand, and yellow-brown lesions can be seen on the upper side of leaves, slightly sunken, with water-soaked edges, becoming a chlorotic ring after drying, semi-transparent, with a grayish-white center. Under high temperature and high humidity, the concentric rings are more obvious. In the later stage, the lesions merge, and the leaves scorch as if burned, turning brown in large areas. In severe cases, it affects fruit quality and yield, and can even cause total crop failure. The pathogen overwinters in diseased debris and seeds. It spreads through wind, rain and insects. The disease is prone to occur under high temperature and high humidity during the fruit-setting period, especially during continuous rainy days with high humidity when the disease develops rapidly. Poor drainage, dense stems and leaves, poor ventilation and light penetration, and excessive nitrogen fertilizer application lead to severe disease.
[Control Methods] ① Strictly implement crop rotation of more than 5 years. ② Strengthen field management, increase application of phosphorus and potassium fertilizers, promote robust plant growth, enhance disease resistance, plant at reasonable density, prune in time, prevent excessive closure of stems and leaves, reduce disease occurrence, and promptly remove diseased leaves and bury them deep or burn them. ③ In the early stage of the disease, spray with 75% chlorothalonil wettable powder at 600 times dilution, or 70% mancozeb or 50% thiram at 500 times dilution, or 70% thiophanate-methyl at 700 times dilution, once every 7-10 days, for 3-4 consecutive times.
Fungal Leaf Blight
[Symptoms] The disease occurs in July-August, mainly damaging leaves, and petioles, stems and fruits can also be affected. In the early stage, water-soaked brown small spots can be seen on the underside of leaves. The lesions gradually expand, and yellow-brown lesions can be seen on the upper side of leaves, slightly sunken, with water-soaked edges, becoming a chlorotic ring after drying, semi-transparent, with a grayish-white center. Under high temperature and high humidity, the concentric rings are more obvious. In the later stage, the lesions merge, and the leaves scorch as if burned, turning brown in large areas. In severe cases, it affects fruit quality and yield, and can even cause total crop failure. The pathogen overwinters in diseased debris and seeds. It spreads through wind, rain and insects. The disease is prone to occur under high temperature and high humidity during the fruit-setting period, especially during continuous rainy days with high humidity when the disease develops rapidly. Poor drainage, dense stems and leaves, poor ventilation and light penetration, and excessive nitrogen fertilizer application lead to severe disease.
[Control Methods] ① Strictly implement crop rotation of more than 5 years. ② Strengthen field management, increase application of phosphorus and potassium fertilizers, promote robust plant growth, enhance disease resistance, plant at reasonable density, prune in time, prevent excessive closure of stems and leaves, reduce disease occurrence, and promptly remove diseased leaves and bury them deep or burn them. ③ In the early stage of the disease, spray with 75% chlorothalonil wettable powder at 600 times dilution, or 70% mancozeb or 50% thiram at 500 times dilution, or 70% thiophanate-methyl at 700 times dilution, once every 7-10 days, for 3-4 consecutive times.
Hami Melon Red Pink Disease
[Symptoms] Red pink disease is a relatively common disease of Hami melon, occurring from time to time in various regions, seriously affecting the yield and quality of Hami melon. On nearly mature or mature Hami melon fruits, nearly round to irregular lesions appear, with indistinct edges, light brown. On the lesions, initially white, later pink mold-like substances grow, which are the conidiophores and conidia of the pathogen. The flesh under the lesions becomes bitter and inedible. It is one of the important diseases during storage and transportation.
[Control Methods] ① Harvest at the appropriate time, not too late, to reduce various wounds. ② Control temperature and humidity well during storage and transportation. Hami melon at 3-9°C, honeydew melon at 5-8°C, relative humidity should not exceed 85%, and pay attention to ventilation to remove moisture.
Root-knot Nematode Disease
[Symptoms] Root-knot nematode disease is an important disease of Hami melon, occurring and distributed in some areas. It can occur in protected cultivation and open fields, with more severe occurrence in autumn. Infection at the seedling stage has a great impact on production. After the disease occurs, the diseased plant rate often reaches more than 60%, significantly affecting Hami melon production. It mainly damages the root system, producing many milky white root knots of varying sizes on the main root and lateral roots. When the root knots are cut open, white semi-transparent pear-shaped nematodes can be seen. In the later stage of the disease, the diseased roots darken in color and eventually rot. The aboveground parts of the plant or seedling gradually fade in leaf color as the disease develops, wilting from bottom to top until completely dead.
[Agricultural Control] Raise seedlings in disease-free soil. In areas where the disease commonly occurs, use insect-free soil or field soil for seedling raising, apply organic fertilizer that does not contain diseased debris or is fully decomposed, or use substrate for seedling raising, and also pay attention to preventing human transmission. After harvest in heavily diseased plots, thoroughly remove diseased root debris, deep plow the soil 30-50 cm, and carry out solar high-temperature disinfection and pest elimination in late spring and early summer. That is, after pulling up the previous crop, apply quicklime and chopped rice straw at 4.5-7.5 tons/hectare respectively, plow and mix evenly, then dig trenches and form ridges or make beds, fill with water, cover with plastic film and press firmly, then seal the greenhouse for 10-15 days, which can kill all nematodes, pathogens and weeds in the soil. After treatment, pay attention to increasing application of biological bacterial fertilizer.
[Chemical Control] Before sowing or transplanting, treat the soil according to the nature of the pesticide. You can choose 1.8% abamectin emulsifiable concentrate at 10-15 L/hectare, mix with water and apply evenly to the seedbed, or apply to the transplanting ditch or transplanting hole before sowing or transplanting. You can also use 98%-100% dazomet microgranules at 75-120 kg/hectare, broadcast evenly or apply in furrows in the top 20 cm of soil. After application, immediately cover with soil, sprinkle water to seal or cover with film for 7-12 days, then loosen the soil to release gas for 3-10 days, and then sow or transplant. You can also use 3% milbemycin granules at 22.5-30 kg/hectare applied evenly in the transplanting ditches and holes.