When is the best time to apply plant growth regulators to different crops?
The optimal timing for applying plant growth regulators centers on critical growth stages. Based on the characteristics of major crops in the Zhengzhou, Henan region, the specific application times are as follows:
I. Optimal application timing for staple crops
Wheat:Spray brassinosteroids once each during the jointing, heading, and grain-filling stages to enhance stress resistance and increase the thousand-kernel weight; avoid spraying during the flowering stage to prevent interfering with pollination.
Corn: During the milk stage (early to late), combine application with "one spray, multiple effects" operations by mixing the regulator with foliar fertilizers, insecticides, and fungicides to prevent lodging and promote grain filling and weight.
Rice:Spray regulators from the booting/heading stage to the early grain-filling stage to enhance stress resistance, promote grain filling, and improve the seed-setting rate and thousand-kernel weight.
Soybeans: Spray once each during the initial flowering stage and the early pod-setting/seed-swelling stage (with a 7–10 day interval) to reduce flower and pod drop and lower the rate of shriveled or empty pods.
II. Optimal application timing for cash crops
Peanuts:Spray regulators during the pegging and pod-expansion stages to increase the rate of fully filled pods and reduce the incidence of empty shells.
Fruit trees: Apply regulators one week before flowering to promote abundant blooms; apply when 80–90% of petals have fallen to preserve flowers and fruit; apply during the young fruit stage to promote fruit expansion; and spray 15–20 days before coloring to promote uniform coloration.
Solanaceous vegetables (e.g., tomatoes, peppers, eggplants): Apply regulators during the flowering/fruit-setting and fruit-expansion stages; reduce the concentration during the seedling and young fruit stages to avoid phytotoxicity.
III. General precautions regarding application timing
Preferably spray on sunny days between 8:00–11:00 AM and 3:00–6:00 PM; avoid the midday period of intense sunlight and high temperatures to prevent rapid evaporation of the solution, which could cause phytotoxicity. If rainfall occurs within six hours of spraying, a follow-up application of half the dosage is required to ensure full efficacy.
Do not apply the product during high winds or when rain is forecast within one hour, in order to prevent loss of the chemical and waste caused by drift.
I. Optimal application timing for staple crops
Wheat:Spray brassinosteroids once each during the jointing, heading, and grain-filling stages to enhance stress resistance and increase the thousand-kernel weight; avoid spraying during the flowering stage to prevent interfering with pollination.
Corn: During the milk stage (early to late), combine application with "one spray, multiple effects" operations by mixing the regulator with foliar fertilizers, insecticides, and fungicides to prevent lodging and promote grain filling and weight.
Rice:Spray regulators from the booting/heading stage to the early grain-filling stage to enhance stress resistance, promote grain filling, and improve the seed-setting rate and thousand-kernel weight.
Soybeans: Spray once each during the initial flowering stage and the early pod-setting/seed-swelling stage (with a 7–10 day interval) to reduce flower and pod drop and lower the rate of shriveled or empty pods.
II. Optimal application timing for cash crops
Peanuts:Spray regulators during the pegging and pod-expansion stages to increase the rate of fully filled pods and reduce the incidence of empty shells.
Fruit trees: Apply regulators one week before flowering to promote abundant blooms; apply when 80–90% of petals have fallen to preserve flowers and fruit; apply during the young fruit stage to promote fruit expansion; and spray 15–20 days before coloring to promote uniform coloration.
Solanaceous vegetables (e.g., tomatoes, peppers, eggplants): Apply regulators during the flowering/fruit-setting and fruit-expansion stages; reduce the concentration during the seedling and young fruit stages to avoid phytotoxicity.
III. General precautions regarding application timing
Preferably spray on sunny days between 8:00–11:00 AM and 3:00–6:00 PM; avoid the midday period of intense sunlight and high temperatures to prevent rapid evaporation of the solution, which could cause phytotoxicity. If rainfall occurs within six hours of spraying, a follow-up application of half the dosage is required to ensure full efficacy.
Do not apply the product during high winds or when rain is forecast within one hour, in order to prevent loss of the chemical and waste caused by drift.
