carfentrazone-ethyl (Aim EC, 2 lb ai/gal, 40% WDG or several trade names)
Rate 3.2 to 5.8 fl oz/A of the EC, 2 to 3.6 oz/A of the WDG (0.05 to 0.09 lb ai/A). Do not exceed 7.2 oz/A EC or 11.6 oz/A WDG (0.018 lb ai/A) per crop season as a desiccant.
Time For best results, apply when potato crop is in early stages of natural senescence. Desiccation generally is adequate within 14 days after initial treatment. If potato crop vegetation is actively growing when desiccation begins, two applications may be required to desiccate leaf and stem tissue. If a second application is necessary, wait 7 to 14 days after the first application.
Application methods Ground or aerial. It is essential to thoroughly cover the potato plant. Use enough water to thoroughly cover potato leaves and vines. Do not apply this product through any type of irrigation system.
Ground: Apply in at least 20 gal/A of water using 80 or 110 flat-fan nozzles. Vary spray volume and spray pressure according to density of potato canopy and vines to assure thorough spray coverage. Increase spray volume and pressure if potato canopy is dense or if weather is cool, cloudy, or dry. Increased spray volumes enhance performance. Apply with a crop oil concentrate (COC) at 1% v/v or with a methylated seed oil (MSO) at a minimum of 1 quart/A or 1% v/v when applied in volumes of more than 20 gal/A.
Aerial: Apply with aerial equipment 5 to 10 gal/A of water using higher volumes on dense potato canopies and vines. Apply 10 ft or less above potato canopy and use low drift nozzles.
Remarks Dense potato canopy, large plant size, and environmental conditions not conducive to product absorption or activity will reduce initial application efficacy and increase the need for a second application. Use higher rate during cool or cloudy weather or when vine growth is heavy. Do not use high rate if soil moisture is low or temperatures are high, or stem ends may discolor. When carfentrazone-ethyl is applied alone, grazing and hay operations may proceed with no restrictions.
Caution Do not exceed 0.181 lb ai/A total product per crop season. This total allowable usage applies to all applications made to the field per calendar year including burndown treatments and vine kill. Do not exceed 0.018 lb ai/A per crop season as a desiccant. Preharvest interval is 7 days. Personal protective equipment must be worn for handling and application; see label.
Tank-mixtures Carfentrazone-ethyl may be applied in a tank-mix or as a sequential application with other potato desiccants. Refer to the other product's label for restrictions on tank-mixtures, and observe all label precautions, instructions, and rotational cropping restrictions.
Rotational cropping restrictions Following an application of carfentrazone-ethyl, a treated field may be rotated only to a registered crop (registered crop may be planted at any time). All other crops may be planted after 12 months.
Site of action Group 14: protoporphyrinogen oxidase (Protox) inhibitor
Chemical family Triazolinone
diquat (Reglone Desiccant or several trade names, 2 lb diquat cation/gal)
Rate 1 to 2 pints/A (0.25 lb ai/A to 0.5 lb ai/A) in a single application. May be applied in two applications, but do not exceed a total of 4 pints/A (1 lb ai/A) per season before harvest.
Time Preharvest interval is 7 days. Do not exceed 0.5 lb ai/A (2 pints/A) in a single application. A 5-day interval between sequential applications is recommended.
Application methods Ground or aerial. Apply with a nonionic surfactant at 0.5 to 4 pints/100 gal spray mix. Do not apply through any type of irrigation system.
Remarks Do not apply in full sunlight; early-morning or later afternoon/early evening time is best. Do not apply to drought-stressed potatoes. Diquat is rainfast 30 minutes after application. Cool, cloudy weather slows activity but will not affect performance.
Caution A moderately toxic herbicide that requires protective gear for handling and application. Follow all use restrictions and precautions on label. Make last application at least 7 days before harvest. Do not feed forage from treated potatoes to livestock. Avoid applications in extremely dusty conditions because dust coating the plant surface can reduce desiccant activity.
Tank-mixtures Diquat can be applied in a tank-mixture at time of potato desiccation with fungicides listed on the supplemental (2ee) label and a nonionic surfactant (NIS) to facilitate harvest. Otherwise, no tank-mixtures (or tank-mixture restrictions) are listed on label.
Rotational cropping restrictions None listed on label.
Site of action Group 22: photosystem I electron diversion
Chemical family Bipyridilium
glufosinate-ammonium (Rely 280 or several trade names, 2.34 lb ai/gal)
Rate 21 fl oz/A (0.38 lb ai/A) in a single application only; do not split application.
Time Beginning of natural senescence of potato vines.
Application methods Apply in 20 to 100 gal/A of water by ground or 5 to 10 gal/A by air. Use enough water to thoroughly cover potato vines. Spray coverage on dense crop canopy will be better with higher water volumes.
Remarks Potato varieties with heavy or dense vines may require an application of another desiccation product to complete desiccation.
Caution Do not apply to potatoes grown for seed. Preharvest interval is 9 days.
Tank-mixtures No tank-mixtures or tank-mix restrictions on label.
Rotational cropping restrictions Wait at least 30 days (formerly, 70 days) after application to plant wheat, barley, buckwheat, millet, oats, rye, sorghum, and triticale. Wait at least 120 days after the last application to plant rotation crops other than those listed. Corn and soybeans may be planted any time after application.
Site of action Group 10: glutamine synthase inhibitor
Chemical family Phosphinic acid
paraquat (Firestorm, 3 lb paraquat cation/gal)
Note: Gramoxone SL or Inteon are currently not labeled for use as a potato desiccant.
Rate 0.7 to 1.3 pints/A (0.26 to 0.49 lb ai/A). Use two applications of 0.6 pint/A if vine growth is dense. Use 1.3 pints/A where quick vine kill is desired.
Time Begin application when leaves turn yellow. Immature potato foliage tolerates Gramoxone Max. Make split applications at least 5 days apart.
Application methods Ground application only, plus a nonionic surfactant with 75% or more surface-active agent at 0.125% v/v (1 pint/100 gal spray mix) or crop oil concentrate at 1% v/v (1 gal/100 gal spray mix).
Remarks For fresh-market potatoes only. Do not use in potatoes that will be stored or used for seed.
Caution Do not apply to drought-stressed potato vines. Potatoes must be harvested promptly after desiccation, and consumed or processed immediately. Do not pasture livestock in treated potato fields. Do not exceed 2.7 pints/A per season. Do not use on muck or peat soils.
Tank-mixtures No tank-mixtures or tank-mix restrictions are listed on the label.
Rotational cropping restrictions All rotational crops may be planted immediately after the last paraquat application.
Site of action Group 22: photosystem I electron diversion
Chemical family Bipyridilium
pyraflufen-ethyl (Vida or several trade names, 0.208 lb ai/gal)
Rate 2.0 to 5.5 fl oz/A (0.00325 to 0.00894 lb ai/A) in a single application. May be applied sequentially, but do not exceed two applications or a total of 11 fl oz/A (0.0179 lb ai/A) per season before harvest.
Time For best results, apply when potato crop is in early stages of natural senescence. A second application of this or another desiccation product may be needed under certain climatic conditions to ensure complete desiccation. Make one to two applications using ground equipment at a minimum 7-day interval.
Application methods Ground or aerial. Apply in at least 5 gal/A spray mix by air or 20 to 50 gal/A using ground equipment. Use an approved agricultural buffering agent buffering to less than pH 5 or less if using Vida in a water source of ≥ pH 5. Always buffer the water source before adding pyraflufen-ethyl. High temperatures and sunlight following application generally will enhance performance and speed desiccation. Do not apply through any type of irrigation system
Remarks A repeat application of pyraflufen-ethyl or another desiccant may be needed under certain climatic conditions to ensure complete desiccation. Pyraflufen-ethyl is rainfast within 1 hour after application. Do not apply within 7 days of harvest.
Caution A corrosive product that can cause irreversible eye damage; requires goggles or a face shield and other protective gear for handling and application. Follow all use restrictions and precautions on label. Do not exceed 2 applications or a total of 11 fl oz per acre per season for potato desiccation.
Tank-mixtures Pyraflufen-ethyl may be applied in tank-mixtures or sequentially with other desiccant/harvest aides such as diquat for improved desiccation. Weather, crop conditions, or the presence of certain weeds, crop damaging insects, or diseases will indicate the inclusion of other products in desiccation Tank-mixtures. Read and follow label directions and restrictions for each tank-mix product.
Rotational cropping restrictions Do not plant any rotational crops except corn, soybean, or wheat for 30 days after the last pyraflufen application.
Site of action Group 14: protoporphyrinogen oxidase (Protox) inhibitor
Chemical family Phenylpyrazole
sulfuric acid (93%)
Rate 17 to 28 gal/A
Time Repeat application after 5 days if vines are not completely desiccated. Preharvest interval is 5 days.
Application methods For retail sale and use only by certified applicators or appropriately licensed persons directly under their direct supervision. Apply undiluted sulfuric acid product.
Remarks This material is not as dependent on temperature or other environmental conditions as most other desiccants.
Caution A restricted-use herbicide. Sulfuric acid is very caustic. Requires protective clothing, including dust/mist filtering respirator, chemical-resistant headgear, protective eyewear, chemical-resistant boots, and waterproof gloves. Applicators must use a closed system/enclosed cab meeting Worker Protection Standards for agricultural pesticides. Adequate supply of water should be immediately available for drenching.
Tank-mixtures None on label.
Rotational cropping restrictions None on label.