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Herbicide active ingredients

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2,4-D (Amine 4, 2,4-D, Orchard Master CA, Saber, Unison, Weedar 64) 2,4-D is a selective herbicide that is effective on many annual and perennial broadleaf weeds when applied as a postemergence foliar spray. It is particularly effective in controlling dandelions on the orchard floor at minimal rates when applied in late fall. These materials should not be applied during the bloom period of fruit trees, i.e., from the time flower buds begin to expand until 4 weeks after bloom. Combinations of 2,4-D plus glyphosate have been effective in controlling many difficult perennial broadleaf weeds. Do not apply to bare ground or light, sandy soil. Be careful with herbicide DRIFT! Grapes, many flowers, and vegetable are very sensitive to 2,4-D drift.

Carfentrazone-ethyl (Aim 2EC, Rage) is a contact, post-emergent, desiccant herbicide for control of young broadleaf weeds only; it has no effect on grasses or sedges. Aim is most effective if used on weeds that are small (up to 4 inches high) in combination with glyphosate. Tank mix provides faster desiccation of weeds than glyphosate alone, but is not effective for long-term control of perennial weeds. Aim should always be mixed with crop oil concentrate or nonionic surfactant. Do not allow spray to contact green bark, fruit or foliage. Aim can be used for sucker control when tissue is soft and succulent.

Clethodim (Arrow, Clethodim 2EC, Prism, Select 2EC, Select Max, Shadow) controls most grass weed species, including certain hard to control grass weeds, such as small grain volunteers and cover crops, and perennials such as hard fescue, tall fescue, Bermudagrass, orchardgrass, quackgrass, Johnsongrass, and wirestem muhly. Use the lower rate to control annual grasses and the perennial grasses listed above. Repeat the application if regrowth occurs. Always add nonionic surfactant to be 0.25% of the spray solution.

Clopyralid (Spur, Stinger) is a selective, postemergence herbicide for control of some broadleaf weeds if applied while weeds are generally small and actively growing. Some of the weeds controlled include clover species, dandelion, nightshade, burdock, common groundsel, jimsonweed, horseweed, and many thistle species including Canada. Clopyralid is effective on clover (moreso than 2,4-D).

Dichlobenil (Casoron 4G or CS) volatizes rapidly under warm, moist soil conditions and must be applied in late fall or very early spring before the soil temperature exceeds 45°F to minimize such loss. It is absorbed principally by the roots of established and germinating weeds and rapidly translocated to growing points. This material is effective against a wide range of annual and established perennial grasses and weeds including nutsedge and quackgrass. Applications of 100 lb of 4G/A are effective on many annual grasses and broadleaf weeds, whereas 150 lb/A are usually required for control of most established perennials.

Diuron (Direx, Diuron, Karmex, Parrot) is effective against germinating annual broadleaf weeds and some annual grasses. It is absorbed by roots and translocated to the leaves where it interferes with photosynthesis. For best results it must be present in the soil before weed seeds germinate. Diuron is best used in combination with materials that are more effective on grasses. It is not effective on established perennial grasses or broadleaf weeds. Rates must be determined in relation to soil texture and organic matter content. Use is limited to APPLES, PEARS, and PEACHES. Labels do not recommend treatment of trees on full dwarf rootstocks.

Fluazifop-P butyl (Fusilade DX) is a selective postemergence herbicide effective on both annual and perennial grasses. Its best use is for control of grasses in newly planted orchards. Two applications are usually necessary with perennial grasses such as quackgrass. Spot treatments are suggested unless a severe grass problem exists. Inclusion of a nonionic surfactant enhances uptake by grass leaves. Can be used in STONE FRUIT ORCHARDS of any age and in NONBEARING APPLE and PEAR ORCHARDS.

Flumioxazin (Chateau WDG, Broadstar) is a herbicide with pre-emergent and postemergent activity, It provides residual control and will also enhance the activity of the burndown program with glyphosate or paraquat. It is readily absorbed by leaves, and quickly causes bleaching and wilting of weeds. It is effective for post-emergence control of many broadleaf weeds while they are small, 2-6 inches high, depending on the weed species. It also provides effective pre-emergent control of many broadleaf weeds and grasses. See label for application rates. If applied to trees established less than 1 year, the tree trunks must be protected with non-porous tree wraps. Label restricts application to between final harvest and pink bud on apples and budbreak on stone fruit.

Fluroxypyr (Starane Ultra) controls many annual and certain perennial broadleaf weeds in pome fruit only. Apply to the foliage of actively growing weeds. Starane Ultra will not control certain common annual broadleaf weeds, including common lambsquarter and pigweed sp. Tank-mix with 2,4-D to improve the spectrum of annual broadleaf weeds controlled, or with a glyphosate product to control emerged annual grasses and broadleaf weeds, and with residual herbicides for season long annual weed control. For established apples and pears ONLY and registered in MAINE ONLY.

Glufosinate-ammonium (Rely 280, Cheetah) is a non-selective herbicide for application as a directed spray labeled for control of a broad spectrum of annual and perennial grass and broadleaf weeds. Rootsucker control in APPLES is not allowed on the Rely 280 label. It has no residual activity. Avoid all contact with foliage and green bark tissue since injury to the trees can result, especially in young trees.

Glyphosate (Roundup, Makaze, many generics and brand names) is a nonselective broad-spectrum herbicide for controlling established annual and perennial grasses and weeds plus woody brush, vines, and trees. The best timing of applications varies with weed type but is usually after weeds have developed full foliage and/or have begun to flower. Greatest effectiveness against nutsedge is obtained after tuber formation begins. Inclusion of 2,4-D and/or a nonionic surfactant is suggested to increase effectiveness, particularly on perennial broadleaf weeds. Glyphosate is absorbed through foliage and bark and translocated throughout the plant. Glyphosate may be applied as a directed spray or by wiper in APPLE, PEAR, and CHERRY orchards. Do not allow contact with foliage or bark on trunks of young fruit trees. Root-suckers or low branches that might be contacted by glyphosate should be removed at least 10 days before the glyphosate application. In APRICOT, PEACH, NECTARINE, PLUM, or PRUNE plantings, use wiper applications only. PEACHES and PLUMS are EXTREMELY SENSITIVE to glyphosate, and ANY contact with leaves or small branches or trunks of young trees may result in severe damage or tree death.

Halosulfuron-methyl (Sandea) has has both pre and post-emergent activity on broadleaf weeds and nutsedge. It is absorbed through weed roots, shoots, and foliage and is translocated within the plant. Do not apply to trees established less than 1 year. Best results require application with a broad-spectrum burndown herbicide. Nutsedge control is best at 3-5 leaf stage for first germination flush, then followup again for the second flush. APPLE and PEAR only.

Indaziflam (Alion) is a pre-emergent herbicide with both broadleaf and grass weed control. It is labeled on pome and stone fruit, but not to be used unless trees have been established 3-years or more. Alion provides preemergence, residual control of weeds. Moisture is needed for activation. Alion controls weeds by inhibiting cellulose biosynthesis in plants. Do not apply within 25 feet of ponds, lakes, rivers, streams, wetlands, and habitat containing aquatic and semi-aquatic plants.

Isoxaben (Gallery, Trellis) provides pre-emergence herbicide for control of broadleaf weeds in NON-BEARING orchards. Do not apply Gallery to newly transplanted non- bearing fruit and nut trees or non-bearing vineyards until soil or potting media has been settled by packing and irrigation or rainfall and no cracks are present or plant injury may occur. GALLERY IS HIGHLY RECOMMENDED AS A POST-PLANT TREATMENT IN 1ST-LEAF ORCHARDS to control broadleaf weeds.

Lemon grass oil (Greenmatch EX) is a contact organic herbicide. Make application before weeds are less than six inches high.

Norflurazon (Solicam DF) at rates recommended provides control of most annual grasses and many annual broadleaf weeds plus suppression of quackgrass and nutsedge. It is absorbed by roots and translocated to growing points where it inhibits pigment formation. Solicam must be applied and moved into the soil by rainfall or irrigation before seed germination. Rates of application depend on organic matter and clay contents of the soil and crop. Norflurazon is most frequently used in tank-mix combinations that will increase effectiveness of broadleaf weed control. Established perennial weeds are not effectively controlled by norflurazon. Registered for use in APPLE, PEAR, APRICOT, CHERRY, NECTARINE, PEACH, PLUM, and PRUNE, depending on tree age.

Oryzalin (Oryzalin, Surflan) provides effective control of most annual grasses and some annual broadleaf weeds. It is not effective against established weeds or grasses. Oryzalin is absorbed by roots of germinating seedlings and interferes with cell division. To be effective, it must be applied and moved into the soil by 1/2 - 1 inch of rainfall-before seed germination. Oryzalin can be used in newly planted orchards as soon as the soil settles around the roots and no open cracks are present. Can be used in all tree fruit crops.

Oxyfluorfen (Goal 2XL, Galigan, GoalTender, or Collide) has preemergence and postemergence activity as a contact herbicide. Uptake can be through leaves, stems, or roots, but very little translocation occurs in the plant. Destruction of membranes occurs when treated plant parts are exposed to light. Oxyfluorfen is primarily effective against seedling broadleaf weeds. It does not control established perennial weeds or grasses and is best used in tank-mix combinations with other appropriate herbicides. Applications of oxyfluorfen must be made while trees are dormant, before buds begin to swell, to avoid possible damage from vapors. Registered for use on all tree fruit crops of any age.

Paraquat dichloride (Gramoxone Inteon or SL, Firestorm, Parazone) is a nonselective contact herbicide that is effective in killing emerged annual broadleaf weeds and grasses and top-kills and suppression of perennials. It is rapidly absorbed into foliage and green bark where it is effective in destroying cell membranes. Paraquat is strongly adsorbed onto soil colloids where it's degraded by microbial activity. Contact with foliage, branches, and green bark on trunks of young trees (particularly) can result in damage to the trees. Observe all worker safety cautions specified on labels when mixing, handling, or applying paraquat. KEEP OUT OF REACH OF CHILDREN. Registered for use on all tree fruit crops.

Pelargonic acid (Scythe) and is a contact herbicide with moderate burn-down action (depending on rate) on annual and perennial broadleaf weeds and grasses. Somewhat effective at burning leaves on rootsuckers, and only herbicide specifically labeled for rootsucker ‘control.’ Use higher rates for greatest effect, however, quite expensive at higher rates.

Pendimethalin (Acumen, Pendimax, Pendulum, Prowl) is effective in controlling most annual grasses and some annual broadleaf weeds when used in preemergence applications. Primary mode of action is through root uptake and subsequent inhibition of cell division. Pendimethalin can be used in newly planted orchards. Combination with a contact herbicide is necessary to control emerged or established weeds. The lower the rate, the shorter the weed control duration. It is effective for pre-emergent control of many grasses as well as some broadleaf weeds such as pigweed and lambsquarters. Best on grasses.

Pronamide (Kerb) is effective in controlling winter annual and perennial grasses and chickweed. It is absorbed by roots and translocated throughout the plant. Pronamide must be applied in late fall when temperature does not exceed 55 F. but before soil freeze-up, and moved into the soil by rain to be effective. The range of activity on broadleaf weeds is limited, requiring additional measures for their control. Rates of application are determined by the type of grass being controlled and by soil texture.

Pyraflufen ethyl (Venue) is a PPO inhibitor that is a nonselective contact herbicide for post-emergence control of broadleaf weeds in tree fruit crops. It is often tank mixed with other herbicides such as glyphosate, paraquat or glufosinate to speed up the burndown of weeds to cause rapid plant desiccation. The addition of a chemical with a different mode of action appears to improve weed kill and helps avoid development of weed resistance to herbicides. Venue is most effective when the weeds are small, 2-4 inches height. Venue is labeled for use on all POME and STONE fruits. A supplemental label allows use on rootsuckers, but otherwise avoid contact with green trunk bark (young trees).

Rimsulfuron (Matrix, Pruvin, Solida) controls certain broadleaf weeds and grasses in stone and pome fruit established for at least 1 full growing season. Matrix is absorbed through roots and leaves inhibiting growth of susceptible leaves. Matrix is most effective if half an inch of rainfall or irrigation occurs within 2 weeks of application. Matrix is mainly a pre-emergent herbicide but can provide some post-emergent control if weeds are still in seedling stage; but Matrix applications should include a burndown herbicide such as glyphosate, paraquat, or glufosinate. Reduced weed control may result if applied to heavy weed residue, limiting even distribution of Matrix to the soil surface.

Saflufenacil (Treevix) is a post-emergent burndown for broadleaf weeds but must be tank mixed with a grass herbicide or broad-spectrum post-emergent herbicide such as glyphosate for improved control of marestail. Tank mixing with paraquat is not recommended; it may reduce the efficacy of TreeVix. TreeVix requires the use of MSO (methylated seed oil) as an adjuvant for best results.

Sethoxydim (Poast) is a selective grass herbicide for use in controlling established annual and perennial grasses. It does not control broadleaf weeds or sedges. A crop-oil concentrate must be used with sethoxydim. Suggested rates depend on height of grasses being treated.

Simazine (Princep, Sim-Trol, Simazine) is effective in controlling a wide range of annual broadleaf weeds and grasses. It does not control established perennial weeds or grasses. Simazine is taken up by roots and translocated to the leaves where it interferes with photosynthesis. It must be applied and moved into the soil before weeds germinate to be most effective; therefore, late fall or very early spring applications are suggested. (Note that some formulations of simazine have a 150 day PHI in pome fruit, which limits spring applicatiom.) Activity is reduced in soils of low pH. Resistant weeds such as pigweeds and lambsquarters have been found where simazine has been the principal herbicide used. Control of these weeds has been achieved by using tank-mix combinations with other pre-emergent herbicides. Rates of simazine application and crop tolerance depend on soil texture and organic-matter content as well as crop and tree age.

Terbacil (Sinbar) is effective in controlling most annual grasses and broadleaf weeds and in providing partial control or suppression of such perennials as quackgrass, horsenettle, and nutsedge. Terbacil is absorbed by plant roots and is translocated to the leaves where it interferes with photosynthesis. Residual activity of terbacil in the soil is relatively long-lived. This material is frequently used in tank-mix combinations with diuron or simazine. Application rates and crop tolerance depend on soil texture and organic-matter content as well as crop and tree age. Terbacil is also registered for newly-planted fruit trees after the soil has settled and young and non-bearing apple, peach, plum, apricot and cherry trees at reduced rates.

Trifluralin (Snapshot, Treflan) is a pre-emergent herbicide for use in non-bearing orchards only. It controls both broadleaf weeds and grasses.