Prevention and Control Methods for Pepper Flower and Fruit Drop in Spring

Because spring temperatures vary greatly and remain unstable, peppers at the flowering and fruit-setting stage are easily affected by environmental conditions, leading to flower and fruit drop. There are many causes of pepper flower and fruit drop, including physiological ones and pathological ones. Peppers prefer an environment with dry air and moist soil. If the temperature is too high (above 35 degrees), pollination and fertilization are affected, or if there is prolonged cloudy and rainy weather, causing insufficient light and a temperature drop (below 15 degrees), both will affect pollination and pollen tube elongation, leading to flower drop.

Soil drought, insufficient water, and high air evaporation will also inhibit the plant's demand for fertilizer and water, causing flower and fruit drop. Excessive water and poor permeability will obstruct root respiration and growth and development, and can even cause root rot, which will also cause flower and fruit drop.

Fertilizer application should provide comprehensive nutrients, with nitrogen, phosphorus, and potassium applied in combination. Too much or too little nitrogen, or a lack of phosphorus and insufficient potassium, will make fertilizer application unbalanced and the supply of various nutrients uncoordinated, causing flowers and fruits to drop due to insufficient nutrients or nutritional disorders.

Planting too densely leads to poor ventilation, insufficient light, weakened photosynthesis, and poor male flower development, making the flowers on the first and second layers prone to dropping. The prevention and control measures are as follows:

1. Practice crop rotation. Select disease-resistant and tolerant varieties, plant strong seedlings free of pests and diseases, do not plant seedlings with damaged roots or broken leaves, plant at a reasonable density, and improve ventilation conditions so that the plants have a good growing environment.

2. Strengthen temperature and humidity management. During the flowering and fruiting stage, ventilation should be increased. Keep the daytime greenhouse temperature at 20-27 degrees. When the nighttime temperature is not lower than 15 degrees, ventilation can be carried out day and night. Only with good ventilation can the plants grow vigorously and the fruit-setting rate be high.

3. Strictly control fertilizer and water, and fertilize reasonably. Before fruit set, watering and topdressing may be omitted, thereby controlling vegetative growth and promoting reproductive growth. When topdressing, increase the application of phosphorus and potassium fertilizers and reduce the amount of nitrogen fertilizer. When entering the full flowering stage and fruit-setting stage, the fruits expand rapidly and require large amounts of nitrogen, phosphorus, and potassium fertilizers.

4. Control soil moisture. Peppers generally require air humidity of 55%-65% and soil moisture of about 15%. If it is higher than 18%, it will affect root development and plant growth, but during the full fruiting stage the soil should be kept moist.

5. Prevent and control diseases. The main diseases of peppers include viral disease, anthracnose, and cottony leak. Viral disease can also cause plants to become stunted and unable to branch and grow, seriously affecting yield. Viral disease caused by aphids should be thoroughly and early controlled, eliminating them at the spot and patch stage. Imidacloprid, dimethoate, and dichlorvos can be used for control; for pupae, moth-killing agents or lime sulfur mixture can be used. For viral disease, virus A, plant disease spirit, and others can be sprayed.

For other diseases, agents such as propamocarb, metalaxyl, procymidone, iprodione, carbendazim, thiophanate-methyl, and others can be selected for control.

In addition to the above measures, hormone treatment can also be used, such as 2,4-D or fruit-setting hormone, both of which can play a role in preventing flower drop.