Plant Growth Regulators:a Key Technical Tool in Green Plant Protection Systems

In the realm of plant protection, plant growth regulators (PGRs) primarily aid in the control of pests and diseases by modulating crop growth and development and enhancing stress tolerance; they constitute one of the pivotal technical tools within the "Green Plant Protection" framework. Rather than directly eradicating pests and pathogens, PGRs indirectly bolster a plant's resistance to diseases and insects by optimizing its physiological state, thereby reducing the reliance on chemical pesticides.

1. Regulating Growth and Enhancing Stress Tolerance
Plant growth regulators modulate hormonal balance within crops, thereby increasing their tolerance to abiotic stresses such as high temperatures, drought, and low temperatures. This, in turn, mitigates the incidence of diseases induced by adverse environmental conditions (e.g., viral diseases triggered by heat stress or spider mite outbreaks caused by drought).

Brassinolide: Activates the expression of stress-resistance genes in crops and enhances cell membrane stability, significantly boosting the crop's resistance to fungal diseases such as downy mildew and powdery mildew.

Abscisic Acid (ABA): Induces stomatal closure to minimize water loss, thereby maintaining plant vitality under drought conditions and lowering the risk of secondary infections.

2. Controlling Excessive Growth, Preventing Lodging, and Improving the Field Microenvironment
Excessive vegetative growth (etiolation) in plants can lead to canopy closure, poor ventilation, and insufficient light penetration within the field—conditions that foster the proliferation of pathogens (e.g., rice blast and gray mold). The application of growth-retarding regulators—such as Paclobutrazol (Paclo), Chlormequat Chloride, and Mepiquat Chloride—inhibits internode elongation and promotes a robust plant architecture, thereby reducing the probability of disease occurrence.

Application Example:Spraying Paclobutrazol during the late tillering stage of rice cultivation effectively suppresses the development of ineffective tillers, prevents premature canopy closure, and reduces the risk of sheath blight transmission.


3. Promoting Root Development and Enhancing Nutrient Uptake and Disease Resistance
A robust root system serves as the primary line of defense against plant diseases. Regulators such as Sodium Nitrophenolates (Atonik), Indole-3-Butyric Acid (IBA), and Gibberellins stimulate root growth and enhance the crop's capacity to absorb essential nutrients—including nitrogen, phosphorus, potassium, and various trace elements—resulting in healthier, more vigorous plants with heightened disease resistance. **Application Suggestion:** After transplanting, applying a combination of Brassinolide and a rooting agent can accelerate the recovery process (alleviating transplant shock) and reduce the risk of infection by soil-borne diseases such as root rot and damping-off.

4. Alleviating Herbicide/Pesticide Injury and Restoring Plant Health
During crop protection operations, the improper use of pesticides can easily lead to phytotoxicity (symptoms such as leaf curling, yellowing, and stunted growth). In such instances, spraying a mixture of Brassinolide and Monopotassium Phosphate can rapidly repair cellular damage, promote metabolic recovery, and minimize crop losses.

Emergency Protocol:Upon detecting symptoms of phytotoxicity, immediately spray a solution consisting of 0.01% Brassinolide (diluted 5,000-fold) mixed with 0.3% Monopotassium Phosphate. Apply this treatment twice, with a 5-day interval between applications, for highly effective results.

5. Synergistic Enhancement with Pesticides: Achieving "Multiple Benefits in a Single Spray"
Mixing plant growth regulators with fungicides and insecticides allows for the simultaneous achievement of a dual objective: disease prevention combined with the strengthening and robust growth of seedlings.