Weed Management in Sweetpotato

Weeds compete with sweetpotato plants for nutrients, water, sunlight, and even space within the soil. During storage root initiation, which occurs three to four weeks after transplant, and storage root growth, weed competition can greatly impact the number of storage roots per plant and the size of storage roots. Removing or eliminating these weeds reduces the stresses and competition pressure on the sweetpotato plants, which allows the plants to maintain a high crop yield and high crop quality.

For many growers, the most effective and efficient way for eliminating weeds within their sweetpotato fields is the application of pesticides, particularly herbicides. Often, herbicide applications are focused on the first six weeks following transplanting, as weeds that emerge after six weeks (canopy closure) normally do not impact the quality or yield (Jennings et al., 2019). Additionally, herbicide applications are focused soon after transplanting because herbicide activity is often more effective when applied to young, actively growing weeds (Smith and Miller, 2007). However, it is important to still manage weed populations following this six-week period to prevent weeds from growing to maturity and producing seeds, which will grow the seed bank in the soil. Factors that are of great importance when discussing herbicide applications to sweetpotato fields include the herbicide’s mode of action, the weed species, the time of application, the application dosage, and the type of soil within the field.

Below are tables that detail herbicide application protocols specific to each state associated with the SweetARMOR project.

Additional avenues that growers may utilize in order to eliminate weeds within their fields include tillage or cultivation practices. For organic sweetpotato production, cultivation practices and hand removal of weeds are the most important strategies for effective weed management (Jennings et al., 2019). Additionally, for commercial growers, timely cultivation can effectively reduce weed populations in addition to herbicide applications. Cultivation begins soon after transplanting (10-14 days) and oftentimes multiple cultivations are required for the control of weed populations. Weeds that are not successfully removed via cultivation practices must be removed by hand. Hand removal of weeds before they become larger will prevent competition. Further, as stated above, the removal of weeds before they become larger and reach maturity prevents the addition of more weed seeds to the seed bank in the soil. Large weeds should be cut at the soil line or soil surface to further prevent the uprooting of the sweetpotato storage roots.

Further strategies that may be implemented for weed management in sweetpotato fields involve initial field selection, time of transplanting, cultivar selection, planting, and the use of crop rotation. As with field selection for nematode management, it is important to select fields, when possible, that do not currently have high weed populations or have a history of high weed populations. If there is a history of high weed populations, there may be issues further into the sweetpotato growing season as weed seeds within the soil seed bank begin to germinate, creating competition. If the use of a field with high weed populations cannot be avoided, it is best to transplant when the temperature is optimum for sweetpotato growth (Jennings et al., 2019). When transplanting, it is advantageous to utilize a cultivar with a bunch-type growth habit and further, it is advantageous to utilize a shorter row spacing, as these two strategies can decrease the time between transplanting and canopy closure (Jennings et al., 2019). Last, frequent crop rotations can be beneficial for weed management through the introduction of alternative herbicides, those registered for use with other crops, as it increases the number of targetted weed species (Smith and Miller, 2007).

North Carolina

Table 1. The below table has been adapted from the 2022 North Carolina Agricultural Chemicals Manual.

Sweetpotato, Preplant
Weed	Herbicide, Mode of Action Code, and Formulation	Amount of Formulation Per Acre	Pounds Active Ingredient Per Acre	Precautions and Remarks
Annual and perennial grass and broadleaf weeds, stale seed bed application	glyphosate, MOA 9 (numerous brands and formulations)	See labels	See labels	See comments on resistance management in TABLE 7-10. Apply to emerged weeds before transplanting. Perennial weeds may require higher glyphosate rates. Consult label for rates for specific weeds. Certain glyphosate formulations may require the addition of a surfactant. Adding nonionic surfactant to glyphosate formulated with nonionic surfactant may result in reduced weed control.
Broadleaf weeds and some annual grasses	caprylic acid, MOA (Homeplate)	See label	See label	May be applied prior to planting as a burndown treatment for emerged weeds, as a preemergence application after seeding but before emergence, as a directed or shielded application between rows, as a harvest aid or desiccant, or as a post-harvest application. Use 3 to 6% solution for weeds less than 5 inches tall; 3 to 6% solution for larger perennial weeds and grasses; 5 to 9% solution for tough to kill weeds, vines. Apply at 35 to 400 gallons per acre. Use higher spray volumes for high weed density and weeds larger than 5 inches. Coverage is important for acceptable weed control. May be tank mixed with other herbicides. See label for further instructions.
Suppression or control of most annual grasses and broadleaf weeds, full rate required for nutsedge control	metam sodium (Vapam HL) 42%	37.5 to 75 gal	15.7 to 31.5	Rates are dependent on soil type and weeds present. Plant back interval is often 14 to 21 days and can be 30 days in some environments. See label for all restrictions and additional information.
Palmer amaranth, redroot pigweed, smooth pigweed, Galinsoga sp., black nightshade, Eastern black nightshade, common purslane, partial control of yellow nutsedge	fomesafen, MOA 14 (Reflex) 2 EC	1 pt	0.25	This is a Section 24(c) special local needs label for sweetpotato in North Carolina. Growers must obtain the label at syngenta-us.com/labels/indemnified-label-login prior to making an application of Reflex. See label for further instructions.Carryover is a large concern; see label for more information. Apply prior to transplanting for preemergence control. May be tank-mixed with other herbicides registered for preplant application however do not tank mix with flumioxazin.
Annual broadleaf weeds including Palmer amaranth and other pigweeds, smartweed, morningglory, wild mustard, wild radish, common purslane, common lambsquarters	flumioxazin, MOA 14 (Valor SX, Chateau) 51 WDG	3 oz	0.094	Apply prior to transplanting crop. Do not incorporate. Movement of soil during transplanting should not occur or reduced weed control may result. Do not apply postemergence or serious crop injury will occur. Do not use on transplant propagation beds. See label for further instructions.
Sweetpotato, Preemergence
Annual grass and broadleaf weeds, Palmer amaranth, yellow nutsedge suppression	S-metolachlor, MOA 15 (Dual Magnum) 7.62 EC	0.75 pt	0.7 to 0.96	This is a Section 24(c) Special Local Needs Label. Growers must obtain label from syngenta-us.com/labels/indemnified-label-login. Apply over top of sweetpotatoes after transplanting but prior to weed emergence. Do not apply preplant. Do not incorporate after application. Injury potential is greatest when applied to sands or loamy sands especially if a heavy rainfall event occurs following application. See label for further information.
Annual grasses such as large crabgrass and broadleaf weeds including velvetleaf, purslane, prickly sida	clomazone, MOA 13 (Command) 3 ME	Up to 2 pt	Up to 0.75	Apply preplant or after transplanting prior to weed emergence for preemergence control. Weak on pigweed. The label allows up to 4 pt per acre. See label for other instructions and precautions.
Annual grasses including large crabgrass and broadleaf weeds including purslane, Florida pusley, common lambsquarters	DCPA, MOA 3 (Dacthal) W-75 (Dacthal) 6 F	8 to 10 lb 8 to 10 pt	6 to 7.5	Apply to the soil surface immediately after transplanting. May also be applied at layby for preemergence weed control late in the growing season. Do not apply in plant beds or crop injury will occur.
Annual grasses including crabgrass, foxtail, goosegrass, fall panicum and broadleaf weeds including pigweed, Florida pusley, purslane	napropamide, MOA 15 (Devrinol, Devrinol DF-XT) 50 DF (Devrinol, Devrinol 2-XT) 2 EC	2 to 4 lb 2 to 4 qt	1 to 2	Plant Beds. Apply to the soil surface after sweetpotato roots are covered with soil but prior to soil cracking and sweetpotato plant emergence. Does not control emerged weeds. Check label for more information. Production Fields. Apply to the soil surface immediately after transplanting. If rainfall does not occur within 24 hr, shallow incorporate or irrigate with sufficient water to wet the soil to a depth of 2 to 4 inches Check label for more information. See XT labels for information regarding delay in irrigation event.
Annual and perennial grasses only	clethodim, MOA 1 (Arrow, Clethodim, Intensity, Select) 2 EC (Select Max, Intensity One) 1 EC	6 to 16 oz 9 to 32 oz	0.094 to 0.25 0.07 to 0.25	Apply to actively growing grasses not under drought stress. See label for adjuvant and rate. Adding crop oil may increase the likelihood of crop injury at high air temperatures and high humidity. Very effective in controlling annual bluegrass. Do not apply within 30 days of harvest.
	fluazifop, MOA 1 (Fusilade DX) 2 EC	6 to 16 oz	0.1 to 0.25	Apply to actively growing grasses not under drought stress. Consult manufacturer’s label for specific rates and best times to treat and adjuvant and rate. Do not apply Fusilade on days that are unusually hot and humid. Do not apply within 14 days of harvest.
	sethoxydim, MOA 1 (Poast) 1.5 EC	1 to 1.5 pt	0.2 to 0.3	Apply to actively growing grasses not under drought stress. Adding crop oil to Poast may increase the likelihood of crop injury at high air temperatures and high humidity. Do not apply within 30 days of harvest.
Sweetpotato, Row Middles
Most broadleaf weeds less than 4 inches tall or rosettes less than 3 inches in diameter; does not control grasses	carfentrazone-ethyl, MOA 14 (Aim) 1.9 EW or 2 EC	Up to 2 oz	Up to 0.031	Apply post-directed using hooded sprayers for control of emerged weeds. If crop is contacted, burning of contacted area will occur. Use a nonionic surfactant or crop oil with Aim. See label for rate. Coverage is essential for good weed control. Can be tank mixed with other registered herbicides.
Most emerged weeds	glyphosate, MOA 9 (numerous brands and formulations)	See labels	See labels	See comments on resistance management in TABLE 7-10. Apply as a hooded spray in row middles, as shielded spray in row middles, as wiper applications in row middles, or postharvest. To avoid severe injury to crop, do not allow herbicide to contact foliage, green shoots, stems, exposed, roots, or fruit of crop. May cause cracking of sweetpotato storage roots if spray solution comes in contact with sweetpotato foliage. Do not apply within 14 days of harvest.

South Carolina

Table 2. The below table has been adapted from the 2022 Southeastern US Vegetable Crop Handbook.

Weed	Herbicide, Mode of Action Code and Formulation	Amount of Formulation Per Acre	Pounds Active Ingredient Per Acre	Precautions and Remarks
SWEETPOTATO, Preplant
Annual and perennial grass and broadleaf weeds, stale seed bed application	glyphosate, MOA 9 (numerous brands and formulations)	See labels	See labels	Apply to emerged weeds before transplanting. Perennial weeds may require higher glyphosate rates. Consult label for rates for specific weeds. Certain glyphosate formulations may require the addition of a surfactant. Adding nonionic surfactant to glyphosate formulated with nonionic surfactant may result in reduced weed control.
Broadleaf weeds and some annual grasses	caprylic acid, MOA 26 (Homeplate)	See label	See label	May be applied prior to planting as a burndown treatment for emerged weeds, as a preemergence application after seeding but before emergence, as a directed or shielded application between rows, as a harvest aid or desiccant, or as a post-harvest application. Use higher spray volumes for high weed density and weeds larger than 5 in. Coverage is important for acceptable weed control. May be tank mixed with other herbicides. See label for further instructions.
Contact kill of all green foliage, stale bed application	paraquat MOA 22 (Gramoxone SL 2.0) 2 SL	1 to 2 pt	0.25 to 0.75	Apply to emerged weeds prior to transplanting sweetpotato. Paraquat product labels require applicators to take an EPA-approved training every 3 years to mix, load, and apply paraquat.
Suppression or control of most annual grasses and broadleaf weeds, full rate required for nutsedge control	metam sodium (Vapam HL) 42%	37.5 to 75 gal	15.7 to 31.5	Rates are dependent on soil type and weeds present. For nutsedge, use 75-gal per acre. Plant back interval is often 14 to 21 days and can be 30 days in some environments. See label for all restrictions and additional information.
Palmer amaranth, red-root pigweed, smooth pigweed, Galinsoga spp., black night-shade, Eastern black nightshade, common purslane, partial control of yellow nutsedge	fomesafen, MOA 14 (Reflex) 2 EC	1 pt	0.25	This is a Section 24(c) special local needs label for sweetpotato. Check to make sure reflex is registered for use in your state prior to making an application. See label for further instructions. See label for potential carryover to rotational crops. Apply prior to transplanting for preemergence control. May be tank-mixed with other herbicides registered for preplant application however do not tank mix with flumioxazin.
Annual broadleaf weeds including Palmer amaranth and other pigweeds, smartweed, morningglory, wild mustard, wild radish, purslane spp., eclipta, common lambsquarters	flumioxazin, MOA 14 (Valor SX) 51 WDG	3 oz	0.094	Apply prior to transplanting crop. Movement of soil during transplanting should not occur or reduced weed control may result. Do not use on greenhouse-grown transplants. Do not apply postemergence or serious crop injury will occur. Do not use on transplant propagation beds. See label for further instructions.
SWEETPOTATO, Preemergence
Annual grass and broadleaf weeds, Palm-er amaranth, yellow nutsedge suppression	S-metolachlor, MOA 15 (Dual Magnum) 7.62 EC	0.75 pt	1.0	This is a Section 24(c) Special Local Need Label. Check to make sure Dual Magnum is registered for use in your state. Apply over top of sweetpotatoes after transplanting but prior to weed emergence. Do not apply preplant. Do not incorporate after application. See label for further information.
Annual grasses such as large crabgrass and broadleaf weeds includ-ing velvetleaf, purslane, prickly sida	clomazone, MOA 13 (Command) 3 ME	Up to 2 pt	Up to 0.75	Apply preplant or after transplanting prtior to weed emergence for preemergence control. Weak on pigweed. The label allows up to 4 pt per acre. See label for other instructions and precautions.
Annual grasses includ-ing large crabgrass and broadleaf weeds including purslane, Florida pusley, common lambsquarters	DCPA, MOA 3 (Dacthal) W-75 (Dacthal) 6 F	8 to 10 lb 8 to 10 pt	6 to 7.5	Apply to the soil surface immediately after transplanting. May also be applied at layby for preemergence weed control late in the growing season. Do not apply in plant beds or crop injury will occur.
Annual grasses including crabgrass, foxtail, goosegrass, fall panicum and broadleaf weeds including pigweed, Florida pusley, purslane	napropamide, MOA 15 (Devrinol, Devrinol DF-XT) 50 DF (Devrinol, Devrinol 2-XT) 2 EC	2 to 4 lb 2 to 4 qt	1 to 2	Plant beds. Apply to the soil surface after sweetpotato roots are covered with soil but prior to soil cracking and sweetpotato plant emergence. Does not control emerged weeds. Check label for more information. Production fields. Apply to the soil surface immediately after transplanting. If rainfall does not occur within 24 hr, shallow incorporate or irrigate with sufficient water to wet the soil to a depth of 2 to 4 in. Check label for more information. See XT labels for information regarding delay in irrigation event.
SWEETPOTATO, Postemergence
Annual and perennial grasses only	clethodim, MOA 1(Arrow, Clethodim, Intensity, Select) 2 EC (Select Max, Intensity One) 1 EC	6 to 16 oz 9 to 32 oz	0.094 to 0.25 0.07 to 0.25	Apply to actively growing grasses not under drought stress. See label for adjuvant and rate. Adding crop oil may increase the likelihood of crop injury at high air temperatures and high humidity. Very effective in controlling annual bluegrass. PHI = 30 days.
	fluazifop, MOA 1 (Fusilade DX) 2 EC	6 to 16 oz	0.1 to 0.25	Apply to actively growing grasses not under drought stress. Consult manufactur-er’s label for specific rates and best times to treat and adjuvant and rate. Do not apply Fusilade on days that are unusually hot and humid. PHI = 55 days.
	sethoxydim, MOA 1 (Poast) 1.5 EC	1 to 1.5 pt	0.2 to 0.3	Apply to actively growing grasses not under drought stress. Adding crop oil to Poast may increase the likelihood of crop injury at high air temperatures and high humidity. PHI = 30 days.
SWEETPOTATO, Row Middles
Most broadleaf weeds less than 4 in. tall or rosettes less than 3 in. in diameter; does not control grasses	carfentrazone-ethyl, MOA 14 (Aim) 1.9 EW or 2 EC	Up to 2 oz	Up to 0.031	Apply post-directed using hooded sprayers for control of emerged weeds. If crop is contacted, burning of contacted area will occur. Use a nonionic surfactant or crop oil with Aim. Coverage is essential for good weed control. Can be tank mixed with other registered herbicides.
Most emerged weeds	glyphosate, MOA 9 (numerous brands and formulations)	See labels	See labels	Apply as a hooded spray in row middles, as shielded spray in row middles, as wiper applications in row middles, or postharvest. To avoid severe injury to crop, do not allow herbicide to contact foliage, green shoots, stems, exposed, roots, or fruit of crop. May cause cracking of sweetpotato storage roots if spray solution is exposed to sweetpotato foliage. PHI = 14 days.

Louisiana

Table 3. The below table had been adapted from the 2022 Louisiana Suggested Chemical Weed Management Guide.

Active Ingredient and Rate	Formulated Product and Rate	Weeds Controlled	Remarks and Precautions
PREPLANT:
flumioxazin @ 0.063 – 0.079 lb./A	Valor SX @ 2-2.5 oz/A	Smellmellon, prickly sida, copperleaf, pigweeds May suppress annual sedges	Apply before transplanting to a clean seed bed. Do not apply post-transplant as foliar burn will occur.
POST-TRANSPLANT:
clomazone @ 0.5-1.0 lb./A	Command 3ME @ 1.33-2.33 pt/A	Annual grasses and broadleaf weeds	Apply after transplanting before weeds emerge. Do not apply within 1,200 feet of sensitive areas; consult label. Sedges may become more problematic when Command is used. 125 days to harvest. Consult label for recrop intervals.
S-metolachlor @ 1.0-2.0 lbs./A	Dual Magnum @ 1.0 pt/A on light soil 1.33 pt/A on med-heavy soil	Many small-seeded grasses, yellow nutsedge, pigweed, carpetweed	Apply after transplanting before weeds emerge. Do not incorporate. Injury potential increases on sandy or loamy sand soils, especially if heavy rainfall occurs shortly after application. If irrigation is used, don’t apply more than 1/2 inch of water following a Dual Magnum application.
fluazifop @ 0.094-0.375 lb./A	Fusilade DX @ 0.375-1.5 pt /A Apply with COC @ 1-2 pt/25 gal or NIS @ 0.5-1 pt/25 gal	Annual and perennial grasses	Apply to actively growing grasses before they exceed the labeled growth stages. Use sufficient volume (5-40 GPA) and pressure (40-60 psi) to ensure complete coverage. Apply at least 55 days before harvest. Maximum season use rate is 48 oz./A.
sethoxydim @ 0.1-0.3 lb./A	Poast @ 0.5-1.5 pt/A Apply with COC @ 2 pt/A Pump up sprayer: 1.3-2 oz/gal Poast + 1.3 oz/gal COC	Annual and perennial grasses	Apply actively growing grasses before they exceed labeled heights; consult label. Adjust pressure (40-60 psi), volume (5-20 GPA) and boom height to ensure thorough coverage. Don’t apply more than 2.5 pt./A per season. COC should be used with caution because of potential leaf injury when temperature exceeds 90 degrees and the relative humidity is 60% or higher or anytime the temperature exceeds 100 degrees. Rainfast in 1 hour. Apply at least 30 days before harvest.
clethodim @ 0.1 - 0.125 lb./A	Select, Arrow, Intensity, Clethodim @ 6 - 8 oz/A Select, Arrow, Intensity, Clethodim Max @ 9-16 oz/A Apply with COC at 1 gal/100 gal Pump up sprayer: 0.33 to 0.66 oz/gal Select, Arrow, Intensity, Clethodim + 1.3 oz/gal COC	Annual and perennial grasses	Apply to actively growing grasses. Rates vary by grass species and stage; consult label. Rainfast in 1 hour. Apply at least 30 days before harvest.

Mississippi

Table 4. The below table has been adapted from the MSU Extension Weed Control Guidelines for Mississippi (2022).

Herbicide	Broadcast rate per acre	Weeds controlled	Time of application	Limitations, remarks
carfentrazone-ethyl Aim EC	0.031 lb ai 2 oz	Emerged weeds.	At least 7 days preplant — burndown.	Applications must include a nonionic surfactant (2 pints per 100 gallons) or crop oil concentrate (1 to 2 gallons per 100 gallons).
clethodim SelectMax	0.07 to 0.125 lb ai 9 to 16 oz	Annual and perennial grasses.	Post.	Use nonionic surfactant at 0.25% v/v. Do not apply within 30 days of harvest.
clomazone Command 3 ME	0.48 to 1.25 lb ai 1.33 to 3.33 pt	Annual grasses and certain broadleaf weeds.	Immediately prior to or after transplanting.	Do not apply within 95 days of harvest.
DCPA Dacthal W-75	4.5 to 10.5 lb ai 6 to 14 lb	Germinating grasses, purslane, wild verbena, and chickweed.	At transplanting or up to 6 weeks after transplanting.	Apply to weed-free soil. Thorough agitation is required.
fluazifop Fusilade DX	0.094 to 0.25 lb ai 6 to 16 oz	Grasses.	After grass emergence.	Add either crop oil concentrate at 1% or nonionic surfactant at 0.25%. Do not harvest within 55 days of application.
flumioxazin Valor SX	0.032 to 0.08 lb ai 1 to 2.5 oz	Certain broadleaf weeds.	2 to 5 days prior to transplanting.	Do not apply over the top of sweet potatoes. Do not use greenhouse-grown transplants. Tank-mix with Command only if applied pretransplant.
fomesafen Reflex	0.25 lb ai 1 pt	Most broadleaf weeds, including nonresistant PPO Palmer amaranth. Partial control of yellow nutsedge before emergence and desiccation of top growth if emergence has already occurred.	Before transplanting as a soil-surface application.	Do not apply more than 1 pint of Reflex per acre per year. Do not make more than one Reflex application per year. Do not apply Reflex within 70 days of harvest. Do not apply Reflex and Valor to the same field. Growers can obtain this label only by going to the Syngenta-sponsored website and registering as a user. Register once every calendar year. Do not distribute the label. Growers/users must have the label in their possession at the time of application. https://www.syngenta-us.com/labels/indemnifiedlabel-login
glyphosate Several formulations	0.375 to 1.5 lb ae Consult label for specific use rates.	Annuals at lower rates; perennials at higher rates.	Apply to weeds before or after planting, but before crop emergence.	Rate should be adjusted to weed species at the time of application. Avoid contact with desirable plants. For spot applications, use a 2% by volume solution. Refer to specific product label to determine the need of an adjuvant. Allow 3 days between treatment and planting (if planting has not occurred).
metolachlor Dual Magnum 7.62 EC	0.95 to 1 lb ai 1 to 1.33 pt	Annual and yellow nutsedge, annual grasses, and some broadleaf weeds.	Posttransplant to slips and preemergence to weeds.	Use only on field-grown ‘Beauregard’ transplants. There is a risk of injury to transplants if heavy rainfall occurs shortly after application. Do not apply so that the herbicide is allowed to be concentrated over the transplant row. Do not incorporate after application. Do not apply in irrigation water. Make only one application to sweet potatoes per growing season. NOTE (State Label 24c)
sethoxydim Poast	0.28 to 0.46 lb ai 1.5 to 2.5 pt	Grasses.	After grass emergence.	Use 2 pints of crop oil concentrate per acre. Do not apply within 30 days of harvest.

California

Table 5. The below table has been adapted from information provided by Dr. Scott Stoddard.

Weed	Herbicide and Formulation	Amount of Formulation Per Acre	Timing of Application	Precautions and Remarks
Perennial and annual grasses	fluaziflop (Fusilade)	See label.	Postemergence.	A crop oil concentrate is often required to maximize effectiveness. Annual and perennial grasses should be the proper size and actively growing for good control. Consult your farm advisor or PCA for details and follow label directions regarding chemical use restrictions.
	sethyoxydim (Poast)	See label.	Postemergence.
	clethodim (Select)	See label.	Postemergence.
Broadleaf and grassy weeds down the drip line (between rows)	glyphosate (Roundup)	2 – 4 qts/A, or a 2 - 4% v/v solution. The addition of AMS improves efficacy.	Postemergence, shielded sprayer.	Directed sprays with shielded sprayers can provide effective control of most weeds down the drip line, and eliminates the need to move the drip tape. Chemical contact with crop foliage should be minimized to avoid damage to desirable root development.
Broadleaf weeds (between rows)	carfentrazone-ethyl (Aim, Shark)	2 oz/A	Postemergence, shielded sprayer.	Directed sprays with shielded sprayers can provide effective control of broadleaf weeds down the drip line, and eliminates the need to move the drip tape. Chemical contact with crop foliage should be minimized to avoid damage to the crop.
Broadleaf weeds (between rows)	capric and caprylic acids (Suppress)	6 – 9% v/v.	Postemergence, shielded sprayer.	More effective on broadleaf weeds than grasses or sedges. OMRI certified. Chemical contact with crop foliage should be minimized to avoid damage to the crop.
Broadleaf and grassy weeds	napropamide (Devrinol)	4 lbs/A	Post plant and pre-emergence to weeds (first cultivation)	Not effective on emerged weeds. Apply to clean cultivated bed 2 – 4 weeks after transplanting and mechanically incorporate to 2 – 4” depth. Effective in the hotbeds. Apply immediately after covering roots with soil and incorporate with ½ - 1” water.
Broadleaf and grassy weeds	flumioxazin (Valor, Chateau)	1.0 oz/A	Hotbeds: broadcast immediately after covering roots and incorporate with water.	Effective in the hotbeds at reduced rates (1 oz/A). Apply immediately after covering roots with soil and incorporate with ½ - 1” water. Valor has not been effective in drip irrigated production fields due to lack of water incorporation. See label for use in sprinkler irrigated fields.
Broadleaf and grassy weeds, yellow nutsedge	methyldithiocarbamate (Metam sodium, metam potassium)	42 – 45 gpa. See label for specific guidelines. 60 to 75 gpa	PRE: At least 2 weeks before planting.	Shank applications permitted. 9” row spacing at 3”, 6”, and 12” depth into moist soil, followed by soil sealing with light disc or ring-roller. May be applied through sprinklers. Water seal required. Flood applications may use highest rates and provide best overall weed control.

The use of brand names in this publication does not imply endorsement by NC State University or N.C. A&T State University of the products or services named nor discrimination against similar products or services not mentioned.

Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance in North Carolina, contact your local N.C. Cooperative Extension county center.