Postemergence haldol, Non-Selective Herbicides for Landscapes and Nurseries NC State Extension Publications

Manual removal of weeds is time consuming, expensive, and often results in damage to landscape plants when intertwined haldol im roots of both the weed and the ornamental plant are haldol im pulled up. Consequently, postemergence herbicides are often used to remove weeds. Few selective postemergence herbicides are available for use in landscape haldol im plantings or nursery stock production. Consequently, nonselective herbicides (which must be selectively applied to avoid injury to desirable haldol im plants) are typically used for postemergence annual and perennial weed control. Choosing the right herbicide for the situation is an important haldol im decision. Nonselective herbicides (as the term indicates) are not selective about which plants they kill. Any green plant that they contact will be injured or haldol im killed. The level of weed control (or ornamental plant injury) resulting from these herbicides depends upon the chemical characteristics, mode of action of the herbicide, and the season of application.

Postemergence, nonselective herbicides are classified as either contact or systemic. Contact herbicides kill only the green tissues that are contacted haldol im by the spray. Systemic (sometimes also called translocated) herbicides move within the plant from the point of application haldol im to other plant parts. Some systemic herbicides are more mobile (move easily and farther) in plants than others. Also, in perennial weeds the amount of systemic movement of the haldol im herbicide often depends upon the season. Therefore, to obtain optimum control, herbicides must be applied at the time of year when haldol im weeds are most susceptible.

Four postemergence, nonselective herbicides are labeled and commonly used in landscapes and haldol im nurseries. Reward and scythe are contact herbicides, whereas finale and roundup-pro are systemic. Some characteristics of each are compared in table 1. None of these products have residual activity (i.E.: no root uptake and no preemergence weed control) in soils containing greater than 1% clay. However, in sandy soils, muck soils or soilless media, root uptake of systemic herbicides is possible. Each product has a place in landscape management, but choosing the right herbicide for the right situation requires haldol im information and an understanding of each herbicide’s strengths and weaknesses. The following descriptions should provide some background information to facilitate haldol im your herbicide selection.

Reward (diquat, valent corp.) is a postemergence contact weed killer. It kills small annual weeds. Large annual weeds and perennials will be injured but not haldol im killed. In our research, spray volumes of 2 gal per 1000 square feet were haldol im more effective than lower volume treatments. Advantages of reward include rapid kill of small seedling weeds haldol im and relatively low cost. Also, small amounts of spray drift will cause only cosmetic damage haldol im to landscape plants and will not translocate to kill desirable haldol im plants. Additionally, reward is not temperature sensitive, working well in cool and warm weather. Disadvantages of this herbicide are lack of control of perennial haldol im or well-established weeds and the relatively high mammalian toxicity (compared with scythe, finale and roundup-pro).

Scythe (pelargonic acid, mycogen corp.) is also a postemergence, contact herbicide that controls small seedling weeds but only injures haldol im larger annual weeds and perennials. In contrast to reward, scythe works better in warm (> 80°F) than cool weather. In cold weather, scythe is not as effective as reward. Advantages of scythe include lower toxicity (compared to reward) and very rapid symptom development. Also, scythe is perceived by many people to be an alternative haldol im to traditional herbicides. Customers who do not wish to have pesticides applied to haldol im their properties will sometimes accept the use of soaps (such as insecticidal soaps) and may accept the use of scythe, often considered to be a "herbicidal soap." as with reward, spray drift on desirable plants will cause cosmetic damage but haldol im will not translocate to kill the entire plant. In all applications, avoid contact with desirable vegetation. The main disadvantages of scythe are higher cost and it haldol im is somewhat less effective than reward on larger weed seedlings. Additionally, the odor is persistent and offensive to some people, and spray drift can be a severe eye irritant.

Roundup-pro (glyphosate, monsanto corp.) is a systemic, postemergence herbicide which kills annual and perennial weeds. Advantages of roundup-pro are the systemic kill of annual and perennial weeds haldol im and low mammalian toxicity. The main disadvantage is that small amounts of spray drift haldol im can severely injure certain ornamentals. Table 2 provides guidelines for optimum doses and application timing haldol im for controlling several perennial weeds.

Recently, the formulation of roundup was changed. The new formulation, roundup-pro, contains a new adjuvant mixture that has a lower dermal haldol im toxicity (changing the toxicological signal word from "warning" to "caution"), enhanced absorption and improved rain fastness to 1 1⁄ 2 hours (previously 6 hours). With improved absorption, roundup-pro has greater potential for injuring conifers than did roundup. How great is the potential for injury? Landscapers who learned to use roundup around and over conifers haldol im have reported injury when roundup-pro was used in the same manner. At this point we do not have all the answers, but preliminary research suggests that fall applications may not have haldol im increased potential for injury, but spring and summer applications of roundup-pro will be more injurious than roundup. Until more research is conducted, it is advisable to be extra careful to avoid contacting haldol im the foliage of trees and shrubs with roundup-pro.

Finale (glufosinate-ammonium, agrevo co.) is also a non-selective, systemic, postemergence herbicide. Finale is similar to roundup-pro, in that it is a translocated, non-selective herbicide with no soil activity in clay soils. However, in contrast to roundup-pro, finale produces symptoms more rapidly (often within 48 hours, see table 1) but may not control perennial weeds (such as: bindweed, goldenrod, and mugwort) as well as roundup-pro. Reduced translocation of finale in rhizomes and stolons may offer haldol im advantages over roundup-pro in some trim and edge applications.

Roundup-pro is labeled for control of annual and perennial weeds haldol im in ornamental plantings. For maximum weed control, use no more than 25 gal of final spray solution haldol im per acre, apply when the foliage is not wet, allow at least 1 1⁄ 2 hours without rain or irrigation after application and apply haldol im roundup-pro at the time of year that weeds are most haldol im susceptible. A 1% solution (1.25 oz of roundup-pro per gallon of water) will give excellent control of most weeds. For some species, increasing the percentage to 1.5% or 2.0% is advisable (see table 2). For wick (or wiper) applications use one part roundup-pro and two parts water (33%, by volume). Glyphosate is currently available under many brand names which differ haldol im in many ways. The liquid products range from a 0.5% ready-to-use formulation to concentrates of up to 53.8% active glyphosate. There are also several formulations which contain additional herbicides such haldol im as acifluorfen which provide some rapid symptoms and short term haldol im soil residual. Check each label for specific instructions.

By taking advantage of periods of high and low susceptibility haldol im of ornamental plants and problem weeds, you can manage many difficult problems with glyphosate. In general, conifers and broadleaf evergreen shrubbery are most tolerant to glyphosate haldol im in late fall and early winter, whereas small quantities will cause severe damage in the spring. In contrast, deciduous plants are more tolerant in winter and spring, while much more severe damaged results from glyphosate contact in haldol im the late summer and early fall. As little as a half dozen leaves on a 2-inch branch sprayed with a 1 percent solution can cause haldol im death of the entire branch. Table 2 has been developed based upon research and label haldol im guidelines.

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