CATDOLL : CATDOLL: There are red spider mites on the melon seedlings planted at home. Is there any simple way to prevent and control them?

1. There are red spider mites on the melon seedlings planted at home. Is there any simple way to prevent and control them?

(1) The symptom of the damage is that the adults and nymphs gather on the back of the melon leaves to suck the leaf juice. In the early stage of the damage, small yellow-white spots appear on the leaf surface, which later turn into red spots. In severe cases, the back of the leaves, the leaf surface, and the stems are covered with silk webs, and the leaves turn green and yellow until they die.

(2) Prevention and control methods

a. Clear weeds and dead branches and leaves in and around the melon field to reduce the number of red spider mites overwintering.

b. Pesticide control: If red spider mites are found, spray pesticides in time. Common pesticides include 1000 times diluted 80% dichlorvos, 2000 times diluted cypermethrin, 2000 times diluted 20% cypermethrin, 2000 times diluted 73% cypermethrin emulsion, 1000 to 1500 times diluted 50% bromocriptine emulsion, etc.

2. When is the best time to fertilize papaya? How to apply compound fertilizer? Do you still need to spray after flowering?

Basal fertilizer: Apply when deep plowing the orchard in late September, mainly with manure and human feces and urine, mixed with fast-acting nitrogen fertilizer. Apply 15-30 kg of basal fertilizer per young tree and 30-50 kg of basal fertilizer per large tree.

Topdressing: Before budding (late March to early April), apply 130 grams of urea and 400 grams of triple compound fertilizer to each plant in holes or furrows. Spray a mixture of 0.3% urea, 1% superphosphate, and 0.3% potassium sulfate once every two weeks before and after flowering to promote fruit cell division; spray 0.2% boric acid or 0.3% borax during the flowering period to facilitate fruit setting. In mid-to-late May, apply 100-250 grams of urea to each fruiting tree, either by spreading in a ring or in furrows. After the fruit is harvested, apply 0.5 kg of compound fertilizer mainly composed of nitrogen fertilizer to each plant.

Combined with water management, generally water thoroughly once before and after the flower buds sprout. Appropriate watering should be done during the fruit expansion period and the new shoot growth period. Before winter, antifreeze water should be applied once in combination with the application of base fertilizer. At the same time, papaya is afraid of waterlogging, so drainage should be carried out in time.

Pest and disease control: Papaya has very few diseases, the main ones are insect pests, which mainly include aphids, papaya borers, red spiders, etc.

(1) In May, for pests such as aphids, spray 10% imidacloprid at 5000-6000 times, once every 15 days, for 2-3 times in a row.

(2) In mid-June and late July, use Tao Xiaoling or Tao Xiaojing at a concentration of 1500-2000 times to control papaya borer.

(3) Red spider mites can be controlled with 2000 times of Metsol.

3. I planted a new papaya tree this year, but now the leaves are starting to wither. What disease is this? I need an expert to answer this question.

It's hard to say without a picture. There are many reasons. It could be red spider mites caused by poor ventilation, leaf rot caused by fungi due to the humid climate, or even root rot caused by too much watering and fertilizer. It's best to control water, prohibit fertilizer, maintain air circulation, and let it rest for a while.

4. How to prevent and treat papaya virus disease?

1. Virus disease (II) Symptoms: Yellowing of new leaves followed by yellow-green evenly spaced stripes, leaf deformation, premature withering and falling, slow growth of plants, oily streaks on stems, petioles and petals, easy flowering, round or oval continuous or continuous round spots, concave and convex surface, poor quality, low sugar content and commercial value (III) Prevention and control: A. Select disease-resistant varieties such as Hongfei and Nongyouhao; B. Plant corn between the rows of papaya in February to prevent aphids from flying directly to papaya plants and spreading viruses; C. Avoid intercropping with host melons; D. Cover the seedbed with nylon yarn to prevent aphids from spreading diseases; E. Surround the planted plants with transparent plastic bags to prevent aphids from spreading diseases; F. Cover the bed with a silver-black double-sided film to reflect light and drive away aphids; G. Change the medicine every 10-20 days and spray the aphid-killing medicine; H. Pay attention to cultivation and management to make papaya strong and increase disease resistance; I. Apply organic fertilizer to enhance plant health and improve crop immunity; II. Damping-off of seedlings (Yi) Symptoms: Dark brown spindle-shaped spots appear at the base of the stems of seedlings. As the disease progresses, the spots become sunken and constricted. The seedlings dry up and die. (II) Prevention and control: A. Use old seedbeds with high sustenance and good drainage. Vegetable plots that have not been planted should be used. The soil of the seedbed must be disinfected. B. Strengthen the management of the seedbed and control watering to avoid the soil for seedlings being too wet. Pay attention to ventilation and light transmission to prevent rain from wetting. C. At the early stage of the disease, remove the diseased seedlings and spray 50% fungicide 600 times diluted and other pesticides to control the spread of the pathogen. D. Use the seedling medium - Zhuang Miao Hao for seedling cultivation. III. Powdery mildew (Yi) Symptoms: Leaves and petioles have micro-granular protrusions followed by white powdery spores that make the leaves wither and turn yellow. (II) Prevention and control: A. Pay attention to ventilation and drainage; B. Spray 50% triadimefon 500 times diluted, etc. C. Reasonable close planting to enhance ventilation and light transmittance to change the hot and humid climate in the field. IV. Diseases seen: blight, anthrax, boron deficiency 5. Pests seen: red spiders, leaf miners, scale insects, snails, etc. Image class=ikqb_img_alink

5. A small red spider

This is red spider, also known as cotton spider, commonly known as big spider, big dragon, sand dragon, etc., scientific name spider mite, my country's species are mainly cinnabar spider mites, belonging to Arachnida, Acarina, Tetranychus. Widely distributed, with a variety of diets, it can harm more than 110 species of plants.

Additional information

It mainly harms many vegetable crops such as Solanaceae, Cucurbitaceae, Leguminosae, and Liliaceae.

Pest spider shape

There are many types of red spider mites on jujube trees. The dominant species in jujube orchards with intercropping of dates and crops is the truncate spider mite, which parasitizes a wide range of plants, including jujube trees, cotton, corn, beans and a variety of weeds and vegetables.

Red spiders lay about 100 eggs once a year, which begin to hatch a month later. The mother spider waits day and night and is willing to be the first food for her children, teaching them how to hunt but at the cost of herself.

There are 13 generations in a year. They overwinter as eggs. The overwintering eggs usually begin to hatch in early March and are all hatched in early April. After overwintering, the first to third generations mainly reproduce and cause damage on ground weeds. After the fourth generation, they cause damage to jujube trees, intercrops and weeds at the same time.

The hibernation period begins in mid-to-late October. The eggs mainly hibernate in the cracks of the jujube tree bark, the cracks in the ground, and the base of weeds. After the hibernating eggs hatch in early March, they leave the hibernating sites and move to the weeds that sprout in early spring. The longest distance that the newly hatched mites can crawl within 2 days is about 150 meters. If they cannot find food within 2 days, they will die of starvation.

In late April, when the jujube trees sprouted, some red spider mites on the ground weeds began to move to the trees to harm them, and the main way of transfer was to crawl up along the trunk. All active insect stages of the red spider mites can be transferred.

References Red Spider_Sogou Encyclopedia

6. What should I do if papaya has mosaic disease?

Virus disease (ringspot mosaic): generally called mosaic disease, it is fierce, spreads quickly, causes great harm, and is a devastating disease. It can be spread through aphids, friction, wind and other ways; the virus can also be left in the garden and parasitic belts around the garden, and then transmitted to the plants. The fruit quality of the diseased fruit is extremely poor and loses its commercial value. Symptoms: In the early stage of the disease, water spots appear between the stems, veins and branches of young leaves, followed by mosaic symptoms of yellow-green or dark green and light green on the young leaves; water-soaked round spots (ring spots) also appear on the epidermis of the infected fruit, and several round spots can be combined into irregular shapes. During the low temperature period, most of the leaves of the diseased plants fall off, and the young leaves become deformed. The pathogens of papaya virus disease include papaya mosaic virus, papaya ringspot virus and papaya deformed leaf virus. The natural transmission medium is peach aphid and cotton aphid, and the transmission rate is very high. Friction is very easy to transmit the virus, and the leaves of the diseased plants in the field can be transmitted by contact and friction with the leaves of healthy plants.

Prevention and control methods: There is no radical cure at present, but comprehensive prevention and control measures based on cultivation measures are adopted. ① Select disease-resistant varieties. ② Strengthen cultivation management, improve cultivation management measures, and enhance the resistance (tolerance) of plants to diseases. ③ Dig out diseased plants in time. ④ Eliminate the source of disease and isolate appropriately. ⑤ Kill aphids with pesticides. Spray pesticides in time during the peak period of aphid migration, especially in the dry season. At the same time, pay attention to clearing the weeds that aphids like to inhabit around the orchard. The drugs can be 2% Haopu 800 times solution, 2% Junke Du Ke 250 times solution, Virus Ling or Ke Du Bao or Plant Disease Ling 1200 times solution, 3.85% Virus Bike 800 times solution. Generally, spray twice a month, and spray three times a month during the peak period of viral diseases from April to May and October to November. Choose one each time and use them alternately. Spray Tianfengsu 4000 times solution, salicylic acid 7500 times solution plus zinc sulfate 1000 times solution once a month to enhance tree vigor and improve resistance. At the same time, combine the prevention and control of aphids and red spiders to reduce the transmission of viruses. I hope this helps you.