What are the causes of cotton square and boll shedding?

1. Physiological shedding

Physiological shedding accounts for about 60-70% of total square and boll shedding, mainly caused by improper management and damage from pests and diseases, which leads to nutrient imbalance in the plant and insufficient nutrients for squares and bolls. There are mainly the following three aspects:

1. Poor root development, insufficient absorption of water and nutrients, stunted, yellowed and weak cotton plants, or damage from cotton aphids and red spiders, resulting in less nutrient production by leaves.

2. Improper density and management, intensified conflict between the population and individual plants, shaded cotton fields, poor ventilation and light penetration, affecting the photosynthesis of leaves.

3. Imbalance between vegetative growth and reproductive growth, excessive vegetative growth, causing severe insufficient nutrients for vegetative organs, thus forming “tall, big and empty” plants.

2. Mechanical shedding

Square and boll shedding caused by wind, hail, insect bites, and mechanical damage during field management.

3. Failure to fertilize

Rain during flowering prevents fertilization, or temperatures above 36.5 degrees C damage pollen grains and affect fertilization.

The main measures to reduce square and boll shedding include: timely prevention and control of pests and diseases, strengthening cultivation management, coordinating fertilizer and water supply, strictly preventing shading in cotton fields, and improving ventilation and light penetration conditions in cotton fields.