Hello, if the dead seedlings of guava are caused by root-knot nematodes, it is suggested that growers should not only choose healthy and strong seedlings, strengthen fertilizer and water management, cut off diseased plants, disinfect the soil, but also use nematicides to control nematodes. Before transplanting guava, applying Yinghui insecticidal granules in ditch, hole or whole field can control nematodes for 2-3 months. If guava is seriously damaged during its growth, irrigate the root system with Ying Hui blue root sand and clear water, and slowly apply it.

Extended data:

1. Land reclamation and land preparation: firstly, remove the weeds in the orchard in the planning, and then carry out comprehensive reclamation. The depth of land reclamation is 40 cm, so that the soil is fully exposed, and then ploughing is carried out to make the soil fine and loose. Flat land planted in single or double rows.

2. Before sowing 1 month, dig a pit and apply base fertilizer, and dig a big pit according to the plant spacing. The hole is 80 cm wide and 60 cm deep. During the crystallization period, * *, the nest exposure began to return to *, and it took about 15 days to return to half of the first hole that * * came back, and then each hole was filled with 15 kg of rotten organic fertilizer (such as cow, pig and chicken manure), and then returned to the hole with table *, and then returned.

3. sow all the year round. It can be planted in spring, summer and autumn, but spring is the best. After transplanting in spring, the temperature gradually rises, the light is not strong, the rain gradually increases, the survival rate is high and the growth is fast. Generally, the plant spacing is 2.5 meters and the row spacing is 3.5 meters, with 76 plants. Before planting, the seedlings should be disinfected and frosted. Then dig a hole about 20 cm deep in the first planting hole, evenly sprinkle 30-50g of 3% Dong Hao granules in the hole (to prevent young trees from being damaged by root-knot nematodes), cover with a little *, and finally sow. It is suitable to cover the original nutrition bag with water for planting depth.

4. Post-planting management Fertilization management can be carried out one month after planting. It is better to apply humic acid powder fertilizer once a month, once 10- 15 kg. When the seedlings grow to a height of 60cm, cut off the trunk about 45cm from the ground to promote the germination of new buds, and then keep 4-6 branches evenly distributed. When the branches grow to more than 70 cm, artificially pull the branches to about 45 degrees to promote the germination of the lower branches. When the new shoots grow to about 30 cm, remove the tips to promote the early green shoots to germinate and germinate again. The main pests and diseases of saplings are Fusarium wilt and root-knot nematodes, which should be sprayed once a month after planting to prevent the occurrence of diseases. If nematodes are found, they should be prevented in time and weeding should be done well to ensure the normal growth of seedlings.