The primary goal of weed management is to optimize yields by minimizing competition between the weeds and the crop. Weeds reduce yields by competing with the crop for water, space, light, and nutrients. Weeds also harbor insects and diseases and encourage vertebrate pests. Timely cultivation, wise use of herbicides, and never permitting weeds to go to seed are integral parts of a good weed management system. Many of the weeds found in crop fields are difficult-to-control perennial weeds that are not common in annual crop culture. New plantings usually have fewer perennial weed problems than older plantings. Annual and biennial weeds can also exist in these fields. Fields should be scouted at least twice a year (spring and fall) to determine specific weed problems. The selection of a weed management tool should be based on specific weeds present in each field. Several herbicides are labeled for use in this crop. A list of herbicides and their recommended uses is presented in Table 47.
Herbicides can be broadcasted or applied as a directed spray to the base of the crop. With a band treatment, only 1 to 2 feet on either side of the row is treated. The areas between the crop row are usually maintained with a mowed cover of sod, clover, weeds, or a combination of these. This cover is used primarily for erosion control and to improve trafficability in the field. With banding, less herbicide is needed in each acre. For example, a 3 foot band (1.5 feet on either side of the row) where rows are spaced 9 feet apart will require only one third the amount of herbicide normally required for a broadcast treatment.
Weeds can develop resistance to herbicides. The Weed Science Society of America (WSSA) developed a grouping system based on the mode of action of different herbicides. WSSA Group numbers can be used as a tool to choose herbicides in different mode of action groups so mixtures or rotations of active ingredients can be planned to better manage weeds and reduce the potential for resistant species.
Cultivation and mulching are sometimes used as weed management tools. All cultivations should be timely and shallow to minimize crop root injury, to minimize loss of soil moisture, and to avoid repositioning new weed seeds to the soil surface. Mulches that are free of weed seeds and placed thickly enough can be very effective at reducing or eliminating most annual weeds from the crop row. They are seldom effective on perennial weeds. If mulches are used in combination with herbicides, use the lowest recommended herbicide rate to avoid crop injury.
| Weed Problem | Herbicide | Rate/Acre | Comments and Limitations |
|---|---|---|---|
| TRANSPLANT YEAR | |||
| PREEMERGENCE WEED CONTROL | |||
| Annual grasses and small seeded broadleaf weeds | Group 0 (napropamide) Devrinol 50DF Devrinol 10G |
8 lb 40 lb |
Apply after transplanting to weed-free soil. Devrinol must be activated within 24 hrs by cultivation or enough water by irrigation or rainfall to wet the soil to a depth of 2 to 4 inches. The full rate may not be necessary at transplanting. |
| Group 3 (oryzalin) Surflan AS Surflan DF |
2-6 qt 2.4-7.1 lb |
Do not apply until soil has settled around the plants and no cracks are present. Irrigation or 1 inch of rain is needed within 21 days of application. Shallow cultivation will improve control. May injure newly planted tissue culture plants. | |
| Broadleaf weeds and some grasses | Group 5 (simazine) Princep 4L Princep Caliber 90 |
1-2 qt 1.1-2.2 lb |
Use to improve the broadleaf weed activity of Devrinol or Surflan. Consider applying half the maximum rate after planting and half in the fall before winter annuals emerge. Do not use on newly transplanted tissue culture plants. |
| Broadleaf weeds only | Group 29 (isoxaben) Gallery 75D |
0.66-1.33 lb | NON-BEARING USE ONLY. Do not apply within 1 year of the first harvest. Do not apply over the top of plants but as a directed spray to the base of plants after the soil had settled. Does not control emerged weeds. Controls many broadleaf weeds from seed. See label for a complete list. |
| POSTEMERGENCE WEED CONTROL | |||
| Emerged annual and most perennial grasses | Group 1 (fluazifop) Fusilade DX |
16-24 oz | NON-BEARING USE ONLY. See label for best times to treat specific weeds. Will not control broadleaf weeds or sedges. Do not apply to crops to be harvested within 1 year of application. Do not apply if rainfall is expected within 1 hour or if grasses are under drought stress. Must be used with a crop oil concentrate or non-ionic surfactant. |
| Group 1 (sethoxydim) Poast |
1-2.5 pt | See label for best times to treat specific weeds. Will not control broadleaf weeds or sedges. Do not apply to grasses under stress (e.g., drought). Crop oil concentrate must be added to the spray tank. Do not cultivate 5 days before or 7 days after application. Do not apply more than 5 pints per acre per season. | |
| Most grass weed species | Group 1 (clethodim) Arrow 2EC Select Max |
6-8 oz 9-16 oz |
Use the lower rate to control annual grasses and the perennial grasses listed to the left. Repeat the application if regrowth occurs. Always add crop oil concentrate to be 1 percent of the spray solution, or a minimum of 1 pint per acre, to Select 2EC. Always add crop oil concentrate to be 1 percent of the spray solution, or a minimum of 1 pint per acre, or nonionic surfactant to be 0.25 percent of the spray solution to Select Max. Do not tank-mix with any other pesticide unless labeled. Do not apply within 1 hour of rainfall. Do not apply to grasses in drought, heat, cold, or any other stress condition. Select 2EC is currently labeled for nonbearing fields only. Do not apply within 12 months of harvest. |
| Emerged annual weeds and suppression of perennial weeds | (pelargonic acid) Scythe |
3-10% solution | Contact material for burn down only. See Scythe comments on page in Strawberry section. See label for complete instructions. |
| Emerged annual and perennial weeds | Group 9 (glyphosate) Roundup, Touchdown |
1 to 5 pt | Apply to actively growing weeds. Apply with a wiper or a shielded/directed spray. Do not allow the spray, spray drift, or mist to contact green foliage, suckers, open wound, or other green parts of the plant. Consult the label for rates for specific weeds and other precautions. Use with a surfactant or wetting agent. |
| Weed Problem | Herbicide | Rate/Acre | Comments and Limitations |
| ESTABLISHED PLANTINGS | |||
| PREEMERGENCE WEED CONTROL | |||
| Annual grasses and small seeded broadleaf weeds |
Group 0 (napropamide) Devrinol 10G |
8 lb 40 lb |
Apply in the early spring before seedling weeds emerge. Devrinol must be activated within 24 hours by shallow cultivation or with enough rainfall or irrigation to wet the soil to a depth of 2 to 4 inches. |
|
Group 3 (oryzalin) Surflan DF |
2-6 qt 2.4-7.1 lb |
Apply to weed-free soil in the spring. Irrigation or 1 inch of rainfall is needed within 21 days of application. | |
| Group 12 (norflurazon) Solicam 80DF |
2.5-5 lb | Apply in early spring when crop is dormant to clean and weed-free soil. May result in temporary bleaching or chlorosis of leaves from which the plant will recover. Do not use on nursery stock. | |
| NOTE: For broad spectrum preemergence weed control, consider applying one of the above four “grass” herbicides (napropamide, oryzalin, metolachlor or norflurazon) in addition to one of the following “broadleaf” herbicides (simazine, terbacil, mesotrione or dichlobenil). | |||
| Broadleaf weeds, some grasses, and suppression of some perennial weeds |
Group 5 (simazine) Princep Caliber 90 |
2-4 qt 2.2-4.4 lb |
Apply in the spring before bud break and before weeds emerge, or in the fall. Do not apply when fruit is present. For improved control as well as quackgrass suppression apply half in the spring and half after harvest. May injure ‘Royalty’ raspberries. |
| Group 5 (terbacil) Sinbar WDG |
1-2 lb | Apply in the early spring or in the fall as a directed spray to the base of the plants. Will also control small emerged weeds. Do not contact new shoots and avoid contact with bramble foliage. Spring application must be made before fruit set. Avoid application on plantings low in vigor. Planting must be at least 1 year old before application. Do not apply within 70 days before harvest. | |
| Group 29 (dichlobenil) Casoron CS Casoron 4G |
1.4-2.8 gal 100 lb |
Apply at temperatures below 40˚F, preferably just before rain or snow. Soil must be settled around established plants. Uniform application is essential. Do not apply during new shoot emergence. Effective on many perennial weed species. May reduce/delay new shoot emergence in plantings that are young or lacking vigor. There is a leaching risk with this product however both the granular (4G) and microencapsulated (CS) formulations have reduced leaching potential compared to the wettable powder formulation used previously. | |
|
Group 2 (rimsulfuron) Matrix SG |
4 oz | Apply as a directed spray to the base of the crop prior to bud break in the spring. Applications should be made either pre-emergence or early post-emergence to weeds. May be applied twice per year with at least 30 days between applications. Crop should be at least 1 year old. MAINE ONLY. | |
| Broadleaf weeds and nutsedge |
Group 2 (halosulfuron) Sandea |
0.5-1 oz | Applications should be made prior to primocane emergence or after cane burning. Avoid contact with canes. Contact will result in temporarty chlorosis of treated leaves. Use of a shield is recommended. |
| POSTEMERGENCE WEED CONTROL | |||
| Emerged annual grasses and broadleaf weeds. Suppression of emerged perennial weeds. |
Group 22 (paraquat) *Firestorm |
2-4 pt
1.3-2.7 pt |
Restricted-use pesticide. May be fatal if swallowed or inhaled. Applicators must complete an EPA-approved paragquat training listed at the following website: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators. Burndown contact herbicide with no soil activity. Use with a non-ionic surfactant. Apply as a coarse directed spray to wet the weeds. Apply before emergence of new canes or shoots to avoid injury. Use of a shield is highly recommended. |
|
Group 14 (carfentrazone) Aim EC |
1-2 oz | Apply as a directed spray to the base of the crop to burn down emerged weeds including morning glory, nightshade, bedstraw and ferns. Do not use more than 6.1 oz/year. Contact with the crop will cause damage. Requires a non-ionic surfactant or crop oil concentrate. | |
| Emerged annual and most perennial grasses | Group 1 (sethoxydim) Poast |
1-2.5 pt | See label for best times to treat specific weeds. Will not control broadleaf weeds or sedges. Do not apply to grasses under stress (e.g., drought). Crop oil concentrate must be added to the spray tank. Do not cultivate 5 days before or 7 days after application. Do not apply within 45 days before harvest in brambles. Do not apply more than 5 pints per acre per season. |
|
Group 1 (clethodim) Select Max |
9-16 oz | Apply as a directed spray to the base of the crop and to actively growing grasses. Grasses under drought stress will not be controlled. Do not apply more than 64 oz/acre/year. Do not repeat applications within 14 days. | |
| Emerged annual weeds and suppression of perennial weeds. |
Group 0 (pelargonic acid) |
3-10% solution | Contact material for burn down only. See Scythe comments in Strawberry section. See label for complete instructions. |
| Emerged annual and perennial weeds | Group 9 (glyphosate) Roundup Ultra, Touchdown |
1-5 qt | Apply to actively growing weeds. Apply with a wiper or a shielded/directed spray to the base of the plants. Do not permit herbicide solution to contact desirable vegetation, including green shoots, canes, or foliage. Do not cultivate within 7 days after application. |
| Broadleaf weeds and Nutsedge |
Group 2 (halosulfuron) Sandea |
0.5-1 oz | Applications should be made prior to primocane emergence or after cane burning. Avoid contact with canes. Contact will result in temporarty chlorosis of treated leaves. Use of a shield is recommended. |
|
†Where brand names for chemicals are used, it is for the reader’s information. No endorsement is implied, nor is discrimination intended against products with similar ingredients. Please consult pesticide product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks. OMRI listed for organic production. |
|||
| Year | Month | Herbicide Options | Non-herbicide Options |
|---|---|---|---|
| Planting year | |||
| Fall prior to planting | Glyphosate for emerged perennial weeds. | Frequent tillage | |
| April-early May | Surflan or Devrinol before weed seedlings emerge. Till or water in within 24 hours | Plant sod in row middles. Use mulch in planting rows for 1st year. Handweed | |
| Mid-June after planting | Fusilade, Poast, Select or Arrow for perennial grasses before 6” of growth | Cultivate/handweed/mulch; mow row middles and borders | |
| Mid-July | Glyphosate spot treatments | Cultivate/handweed; mow row middles and borders | |
| October | Princep at low rate | Cultivate/handweed; mow row middles and borders | |
| Late November | Casoron for grasses and broadleaf weeds. Read label carefully for specific application requirements | Handweed if needed | |
| Fruiting years | |||
| March-April | Princep or Sinbar for broadleaf weeds. Devrinol, Surflan or Solicam for annual grasses. Poast or Select for perennial grasses. Poast or Select may need to be reapplied in 14 days or can be substituted with a cultivation if possible. | Handweed rows and mow row middles and borders | |
| Early May | Aim, Gramoxone or Scythe before new cane emergence. | Handweed and mow row middles and borders | |
| Mid-Summer | Poast or Select on actively growing grasses | Handweed and mow row middles and borders | |
| September to October | Sinbar, Devrinol, Solicam, Surflan, Princep. See labels for restrictions. | Handweed and mow row middles and borders | |
| November |
Casoron if needed for grasses and broadleaves. See labels for restrictions. |
||
NOTES
Chateau EZ (flumioxizin) - Other formulations are available; check label to verify specific use directions prior to applying. Use 6 oz/acre, not to exceed 24 oz/acre per season. Allow at least 30-day interval between applicatoins. Take care when using near desirable vegetation. Irrigate after application to activate herbicide and reduce wind displacement of soil. 7-day PHI.
Alion (indaziflam) - Use preemergence. A dry soil surface at time of application and 48 hours after application is optimum for binding the active ingredient to soil particles and preventing its downward movement to the crop’s roots. Moisture is needed for activation of Alion Herbicide. Dry soil conditions following the initial 48-hour period after application of Alion may result in reduced weed control. Controls selected broadleaves and grasses. Exercise caution with this product around or near water bodies.
Callisto (mesotrione) - May be used as a pre-bloom directed spray. May be applied at a rate of up to 6 oz/acre. If using split applications, use up to 3 oz/acre. Use of a crop oil concentrate at the rate of 1% v/v is recommended. Will control a variety of broadleaved weeds; control will be improved when applied to small young weeds. Several formulations and many generics of this herbicide are available. Please read the label of the purchased product prior to application to verify proper use rates and recommendations.
QuinStar (quinclorac) - A systemic herbicide with plant uptake occurring through both the foliage and roots. Resultant herbicide symptoms on susceptible plants include twisting, stunting, reddening and chlorosis. For annual plants, symptoms may take up to two weeks after application to develop with death occurring in about three weeks. For perennial weeds, symptoms may not be evident for several weeks after application and full effect may not be evident for 3 to 6 months. May affect desirable nearby species; check label.
Weeds Controlled: Field bindweed, hedge bindweed, barnyardgrass, Canada thistle and large crabgrass. For the first application, apply up to 12.6 fluid ounces per acre (0.375 lb ai/A) of QuinStar® 4L at the end of dormancy, prior to budbreak. Apply as a banded, soil application on each side of the caneberry plants. A second application may be made up to 30 days prior to harvest. Apply up to 12.6 fluid ounces per acre (0.375 lb ai/A) of QuinStar® 4L as a banded, soil application on each side of the caneberry plants. A crop oil concentrate at a rate of 2 pints per acre may be included in the spray mixture.
Zeus/Spartan (sulfentrazone) - a selective soil-applied herbicide for control of susceptible broadleaf, grass and sedge weeds. Adequate moisture of at least 0.5 inch is required within 14 days of application for optimal control. Should be applied as a uniform braodcast soil application to ground or as a uniform band application directed to the base of the trunk. For best control, apply when no weeds are present. If weeds are present, mix with a postemergence herbicide. For flowable forumations, use 8-12 oz/A not to exceed 12 oz/acre per 12-month period.
Suppress EC - nonsystemic, nonselective postemergence foliar burndown herbicide for control of annual and perennial broadleaves and grasses. Best on newly emerged plants, less than 6 inches in height. OMRI-approved product.
Axxe - nonsystemic, nonselective postemergence, foliar burndown herbicide. Use higher rates on bigger plants. Very toxic to fish and invertebrates. Do not contaminate water resources during use. Eye irritant. OMRI-approved product.