Marengo is a preemergence herbicide specific to the Production Ornamentals industry. Its active ingredient, indaziflam, is unlike any other preemergence herbicide active ingredient currently on the market. Marengo is long-lasting and provides effective control for up to eight months.
Unlike DNA (dinitroaniline) herbicides (e.g., Barricade®, Pendulum®), which are well known for their control of grassy (monocotyledon) weeds, Marengo also controls a broad spectrum of broadleaf (dicotyledon) weeds. Unlike Gallery®, noted for its broadleaf weed control, Marengo controls a wide number of grassy weeds as well.
Marengo even controls certain sedges (Cyperaceae family) from seed. Indaziflam is a high active herbicide, meaning it provides effective weed control with low use rates of grams per acre. Other herbicide chemistries can require multiple pounds of active ingredient per acre.
Marengo is available in two formulation types, a Suspension Concentrate (SC) –‘Marengo FLO’, EPA Reg. No. 432-1518 – and a granule – ‘Marengo G’, EPA Reg. No. 432-1523. Marengo FLO is applied via sprayer as a directed application – treat the ground around and up to the plant trunk/stem(s).
Marengo G, on the other hand, is applied over-the-top with a spreader. The unique Verge® carrier used in Marengo G is designed to roll off plant foliage, minimizing the potential for foliar injury. It is important to always make certain the soil around plants has settled prior to making any Marengo application. This is to ensure the product does not move in soil cracks, crevices, holes, etc. directly down to the ornamental roots.
After application, indaziflam should be ‘activated’ within three weeks by light irrigation or rainfall. Indaziflam has physical and chemical properties of moderate water solubility (2,040 –18,300 mg/L at pH 7-9, respectively) and moderate soil adsorption (Koc <1000) allow it to move with water and bind at the upper soil profile.
As weed seedlings germinate within the treated zone, their roots take up the herbicide transporting indaziflam within the plant to growing points, such as root tips. Through this process, weed seeds germinate but fail to emerge from the soil.