What Is Grass Growth Regulator?

Plant growth regulators can affect multiple stages of plant growth and development. In actual production, plant growth regulators play specific roles including induction of callus, rapid propagation and detoxification, promotion of seed germination, regulation of seed dormancy, promotion of rooting, Regulate growth, regulate plant type, regulate flower bud differentiation, regulate floral nature, induce seedless fruit, preserve flowers and fruit, thin flowers and fruit, regulate fruit maturity, prevent fruit cracking, strengthen seedlings and seedlings, prevent lodging, improve stress resistance, and improve Crop quality, increase yield, storage and preservation, etc.The application effect of plant growth regulators is related to the specific application technology. For example, the use of auxin regulators at low concentrations can promote crop growth, while high concentrations can inhibit plant growth.Plant growth regulators have a wide range of applications, which can be divided into the following 6 areas:It is applied to field crops, such as rice, wheat, corn, rape, peanut, soybean, sweet potato, cotton and potato.Applied to vegetables, such as melons, beans, cabbage, cabbage, fungi, solanaceous fruits, onions and garlic, root vegetables, green leafy vegetables, etc.Applied to fruit trees, such as apples, cherries, grapes, bananas, citrus, ginkgo, peach, pear, etc.Used in forestry, such as fir, pine, eucalyptus, camellia, poplar, rubber tree, etc.Applied to special plants, such as aromatic plants, medicinal plants, sweet sorghum, sugar beet, sugar cane, tobacco, tea trees, etc.Applied to ornamental plants, such as herbal flowers, succulents, woody plants, etc.

Title: Plant Growth Regulators Category: Pesticide Sources: China Plantation Grand View · Pesticide Rolls Plant growth regulators are a class of substances that have similar physiological and biological effects as plant hormones.It has been found that substances regulating plant growth and development are amine fresh ester (DA-6), chlorpyrifos, sodium nitrophenolate, auxin, gibberellin, ethylene, cytokinin, abscisic acid, brassinolide. Salicylic acid, jasmonic acid, paclobutrazol and polyamines, etc., and used as plant growth regulators in agricultural production are mainly in the top nine categories.

1. The dosage should be suitable, and the dosage should not be increased arbitrarily. Plant growth regulators are a class of substances that have similar physiological and biological effects as plant hormones and cannot be used in excess. Generally only a few grams or a few milliliters per acre. Some farmers are always afraid that the amount of use is small, and there is no effect. If you increase the dosage or use the concentration at will, it will not promote the growth of the plant, but will inhibit its growth, and even lead to malformation, dryness, and death of the whole plant.2. Can not be mixed at will. Many vegetable farmers use the plant growth regulator to save time and often mix it with fertilizers, pesticides, fungicides, etc. Whether plant growth regulators and chemical fertilizers, pesticides and other substances can be mixed, must be carefully read and used after testing, can not be determined, otherwise it will not achieve the role of promoting growth or preservation of flowers and fruits, supplement fertilizer, but will be improperly mixed A phytotoxicity has occurred. For example, the ethephon solution is usually acidic and cannot be mixed with alkaline substances; the amine fresh ester is easily decomposed by alkali and cannot be mixed with alkaline pesticides and fertilizers.3. The method of use should be appropriate. Some vegetable farmers often do not read the instructions carefully before using the plant growth regulator, but use the plant growth regulator directly with water. Whether it can be directly watered must be seen clearly, because some plant growth regulators can not be directly dissolved in water, if not prepared into the mother liquor and then formulated into the required concentration, the agent is difficult to mix, will affect the use of the effect. Therefore, it must be diluted in strict accordance with the instructions for use.4. Growth regulators are not a substitute for fertilizer application. Growth regulators are not plant nutrients. They can only regulate growth and cannot replace fertilizers. In the case of insufficient water and fertilizer conditions, spraying too much plant growth regulator is harmful. Therefore, when plant growth is found to be poor, it is first necessary to strengthen the management of fertilization and watering, and on the basis of this, the growth regulator can be used to effectively exert its effects.5. Plant growth regulators are pesticide products. The product packaging must have a formal "three pesticides" and the labeling zone is yellow.6. Strictly follow the instructions and take protective measures to prevent the impact on people, livestock and water safety.

Switchgrass (Panicum virgatum) has become a high-value crop in recent years due to its role in bioenergy production, forage systems, and conservation planting. However, successful stand establishment and long-term productivity heavily rely on early and effective weed management. Annual grasses like crabgrass, foxtails, and barnyardgrass can severely outcompete young switchgrass seedlings, limiting biomass yields.
Quinclorac, a selective post-emergent herbicide, is widely used in turf and rice systems for its ability to control problematic grassy weeds. Increasingly, it is being evaluated and applied as a targeted herbicide in switchgrass fields to suppress weed pressure during the early growth stages.

What Is Quinclorac and How Does It Work?
Quinclorac is a synthetic auxin herbicide (HRAC Group 4) that mimics plant hormones to disrupt cell elongation and growth. Its mode of action leads to abnormal growth, tissue distortion, and ultimately weed death, particularly in emerged annual grasses and some broadleaf weeds.
Key Features:


Chemical name: 3,7-Dichloro-8-quinolinecarboxylic acid


Formulations: 75% WDG, 20% SC, 25% WP


Weed targets: Crabgrass (Digitaria spp.), foxtail (Setaria spp.), barnyardgrass (Echinochloa spp.), clover, bindweed


Residual activity: Up to several weeks in soil, offering extended suppression


Rainfast: 6–8 hours after application



Is Quinclorac Safe for Switchgrass Fields?
Yes—Quinclorac can be used in switchgrass systems under certain conditions, especially as a post-emergent herbicide targeting grassy weeds without harming established switchgrass stands.
Crop Selectivity:


Switchgrass shows moderate to good tolerance to Quinclorac once it reaches 3+ tillers.


It is not recommended during seedling emergence or early establishment (within 2–4 weeks after seeding).


Registered Uses:


In some regions, Quinclorac is used off-label or under research permit in native grassland restoration and switchgrass biofuel programs.


Always check with local extension offices and label guidance before field application.



When and How to Apply Quinclorac in Switchgrass Fields
Best Timing:


Post-emergent: Apply when switchgrass is established and weeds are at 2–4 leaf stage.


Avoid applications during early emergence or drought stress to minimize crop injury.


Recommended Application Rates:




Formulation
Rate per Acre
Carrier Volume




75% WDG
0.67–1.0 lbs
15–40 GPA (ground)


20% SC
1.5–2.0 pints
10–40 GPA






Always add a methylated seed oil (MSO) or nonionic surfactant (NIS) for improved weed uptake.


Quinclorac is often tank-mixed with broadleaf herbicides (e.g., 2,4-D) for broader spectrum control.



Target Weeds Controlled by Quinclorac in Switchgrass Plantings




Weed Type
Examples
Control Level




Annual grasses
Crabgrass, foxtails, barnyardgrass
Excellent (post-emergent)


Broadleaf weeds
Clover, speedwell, black medic
Partial–Moderate


Perennial grasses
Johnsongrass, brome
Poor–Not labeled





Note: Quinclorac is most effective when used in conjunction with pre-emergent programs and cultural controls (e.g., mowing, timely planting).


Quinclorac vs. Other Herbicides in Switchgrass Systems




Herbicide
Mode of Action
Main Use
Crop Safety




Quinclorac
Synthetic auxin
Post-emergent grass control
Good in established stands


Pendimethalin
Cell division inhibitor
Pre-emergent annual grass
Safe pre-plant or pre-emergence


2,4-D
Synthetic auxin
Broadleaf control
Safe post-emergent in mature stands


Imazapic
ALS inhibitor
Broad-spectrum; some grasses
Selective; may suppress switchgrass at high rates





Practical Use Tips for Growers


Start clean: Control weeds pre-plant with glyphosate or tillage.


Monitor weed stage: Quinclorac is most effective on young, actively growing weeds.


Tank mix wisely: Combining with IGRs or compatible broadleaf herbicides improves spectrum.


Avoid replanting sensitive crops (e.g., legumes) for up to 12 months due to soil residue.


Follow re-entry and harvest intervals as indicated on the product label.



Frequently Asked Questions (FAQ)
Q1: Can I use Quinclorac on new switchgrass seedlings?
A: No. Wait until switchgrass is well established (typically 4–6 weeks post-planting) before applying.
Q2: Will Quinclorac control perennial grasses?
A: No. It is effective on annual grassy weeds, not perennials like johnsongrass or brome.
Q3: Can I tank mix Quinclorac with 2,4-D?
A: Yes, in many cases, this is recommended to broaden control spectrum. Always conduct a jar test and read both labels for compatibility.
Q4: Is Quinclorac safe near waterways or sensitive plants?
A: Like most herbicides, avoid drift to non-target species and buffer zones near aquatic areas.

Conclusion: Quinclorac is a Strategic Tool for Grass Weed Control in Switchgrass
When used appropriately, Quinclorac offers a targeted, post-emergent solution for controlling crabgrass and other invasive annual grasses in switchgrass production systems. While it is not a silver bullet, it can protect biomass yield, preserve soil cover, and support stand longevity when integrated into a broader weed management program.

Professional-Grade Quinclorac Solutions for Bulk Buyers
As a leading supplier of post-emergent herbicides, we provide:


Quinclorac 75% WDG / 20% SC / 25% WP


Custom packaging, labeling, and branding services


Regulatory documentation: COA, MSDS, SDS, and export support


Free samples available for product evaluation


We specialize in bulk agrochemical supply for biofuel programs, commercial growers, and distributors. Let us support your switchgrass weed control programs with reliable, field-tested solutions.
Contact us now to request a quote or sample pack.