1, phytotoxicity: vegetable seedlings tender, poor drug resistance, improper use of pesticides, easy to produce phytotoxicity. In the event of a phytotoxicity, the leaf blades of the vegetables are distorted or the leaf margins are gradually becoming dry and the growth is blocked or even died. The main cause of phytotoxicity is improper selection of pesticides, high concentration, unequal preparation, improper spraying time, and excessive application amount. The method of preventing drug injury is to prescribe the right medicine according to different pests and diseases, and the concentration should be appropriate. When mixing, it should be well-mixed and evenly sprayed. The spraying point should be fine and uniform, and it can't focus on the local place for spraying for a long time. If it is found that the spray concentration is too high, spray water immediately to avoid phytotoxicity. The spraying time should be carried out after 1-2 hours of ventilation in the morning. It is strictly forbidden to spray the medicine when it is in the shelter. 2, fertilizer damage: fertilizer damage is due to improper preparation of nutritious soil, adding excessive nitrogen fertilizer or organic fertilizer is not enough maturity, or high concentration of top dressing caused. The phenomenon of deciduous roots was observed when vegetable seedlings were damaged. The nutritious soil should be reasonably prepared, and organic fertilizer should be used. The nitrogen, phosphorus and potash fertilizers should be properly mixed and evenly mixed. When dressing fertilizers outside the roots, the fertilizer concentration should be properly formulated. Top dressing should be done 1-2 hours after sunny morning ventilation. Immediately ventilate and apply moisture after dressing. In case of fertilizer damage, spray water immediately and ventilate and dehumidify. 3, grass damage: As the seedbed environment is warm and moist, bed soil fertile, seedbeds easy to grow weeds. On the one hand, weeds compete with vegetable seedlings for seedbed nutrients; on the other hand, they bring pests and diseases to vegetable seedlings. To prevent weeds, nutrient soils should be strictly piled up to make weed seeds die during composting; manual weeding can be performed when weeds occur.