Intensity Herbicide is a selective, post-emergence product designed to control broadleaf weeds that have already sprouted without harming certain established grasses. Its primary use is in agricultural settings where desirable grasses need protection from competing weed species. The herbicide works on contact and is absorbed by the plant, moving through it to disrupt its growth processes.
Active Ingredients and Mode of Action
This herbicide’s efficacy comes from two active ingredients: dicamba and thifensulfuron-methyl. Each component targets weeds through a different biological pathway, creating a comprehensive method of control. This dual-action approach helps manage a wider spectrum of broadleaf weeds, including those that might be tolerant to a single-ingredient product.
Dicamba is classified as a Group 4 herbicide, which functions as a synthetic auxin. When absorbed by a susceptible plant, it mimics the plant’s natural growth hormones, causing rapid and uncontrollable cell division and elongation. This unnatural growth leads to twisted stems, cupped leaves, and eventual plant death. Thifensulfuron-methyl is a Group 2 herbicide, functioning as an acetolactate synthase (ALS) inhibitor. This enzyme is necessary for producing specific amino acids required for cell division and plant growth. By inhibiting ALS, thifensulfuron-methyl effectively halts the growth of the weed.
Controlled Weeds and Labeled Crops
The combination of active ingredients allows for the control of a wide array of annual, biennial, and perennial broadleaf weeds. It is particularly effective against troublesome species such as kochia, Russian thistle, and various pigweeds, including amaranthus. The herbicide also manages mustards, wild buckwheat, and prickly lettuce, which are common issues in grass cultivation. Additionally, it provides reliable control of several thistle species, including variegated and spear thistle, as well as broadleaf and curled docks.
This product is specifically labeled for use in established perennial grasses grown for seed production. These include grass varieties cultivated in agricultural settings where seed purity and yield are the primary goals. It is not intended for use on residential lawns, general pastureland for grazing, or other turf applications unless specified by the label. Using it on non-labeled crops can result in significant damage.
Application Guidelines
Application rates range from 0.5 to 1.0 pints per acre, depending on the target weed species and their size. Smaller, actively growing weeds require a lower rate, while larger weeds may need a rate at the higher end of the range. Application during drought or extreme temperatures can reduce effectiveness, as plants are less likely to absorb the herbicide.
Timing is a significant factor in the successful use of this herbicide. It should be applied when broadleaf weeds are young and actively growing, usually when they are less than four inches tall. For the crop, the application should occur after the perennial grasses are well-established, having reached at least the two-leaf stage, but before they enter the boot stage. Applying the product outside of this window can lead to reduced weed control or potential injury to the grass crop.
To ensure the active ingredients effectively penetrate the leaf surface of the target weeds, the use of an adjuvant is required. A non-ionic surfactant or a crop oil concentrate should be tank-mixed with the herbicide according to the manufacturer’s directions. These agents help the spray droplets spread and stick to the waxy cuticle of the weed’s leaves, facilitating better absorption of the dicamba and thifensulfuron-methyl. Without an adjuvant, the performance of the herbicide can be significantly reduced.
Use Restrictions and Rotational Limitations
Following an application, there are restrictions for livestock use. Treated fields cannot be grazed or harvested for hay for a designated period. This interval is between 7 and 45 days, depending on the application rate and local regulations. This waiting period is necessary to prevent herbicide residues from entering the food chain.
This herbicide has rotational limitations due to the soil residual activity of its active ingredients. Certain sensitive broadleaf crops cannot be planted in the same field for a specified time after application. The rotational interval can range from a few months to over a year, depending on the crop, rate used, and environmental factors like soil type and rainfall. For example, planting sensitive crops like soybeans or canola requires a longer waiting period than planting cereals.