Auxin Training and Use Requirements

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It is essential to follow appropriate guidelines and label requirements when applying auxin products to ensure that no damage occurs to nearby sensitive crops. Too, for many, these products and the crop tolerant trait offer a viable weed management tool that we need to protect from further weed resistance development. As such, below are some highlights of some of the more recent label changes, training requirements and guidelines.

  • Make sure you have the right active ingredient! The term “auxin herbicide” describes many different herbicides. Both 2,4- D and dicamba are auxin herbicides but they are not the same herbicide and cannot be used interchangeably. So, whether making a burn-down application prior to planting or an over-the-top application, make sure the crop being treated and nearby crops are tolerant to the active ingredient used. Otherwise, severe damage may occur.
  • Use only new products. Older formulations of auxin products are on the market but these products are more prone to off-target drift or volatilization. As such, damage to nearby crops or sensitive areas may results. Too, use of these products on auxin tolerant crops is illegal.
  • Attend training. All new 2,4-D and dicamba products require that all applicators attend training each year. Furthermore, beginning in 2019, dicamba products will be labeled as Restricted Use Products. As such, within North Carolina (NC), only licensed individuals may purchase or use the product. This means anyone applying a dicamba product must also have a NC Private Pesticide Applicator license.
  • Be aware of crops and areas that are especially sensitive to these products. A complete list is provided on the label but within Eastern NC, tobacco, cotton, soybeans, grapes, sweet potato, peanuts, beans, tomatoes, fruit trees, flowers, ornamentals, most garden plants, pumpkin, and watermelon. The exceptions to this would include crops specifically bred to tolerant application of these products and most grass crops.
  • Prove that you consulted sensitive crop registries. Within NC, DriftWatch serves as a public registry of sensitive crop and/or beehive location. Visit the site and print the report for your field or fields.
  • Monitor wind speed and buffer requirement. The maximum wind speed allowed for application of any of these products is 10 mph. Wind speed and direction change rapidly within this area so monitor closely. There continues to be a 110 feet downwind buffer requirement for all applications. However, new buffers have been added for many counties. (See below).
  • Endangered Dicot Vegetation Species Buffer is now required. New label requirements mandate an added 57 feet when applied to areas where endangered dicot species exists. Thus, the 110 feet downwind buffer still applies but a 57-foot buffer must exist on all other sides of the field. Within the coastal counties, most from Martin County and south to the NC State Border have endangered plants with the exception of Jones, Pamlico, Duplin, and New Hannover. View a complete listing of endangered plants or search by county.
  • Application timing is limited by crops. Over the top application of dicamba products is limited to 45 days after planting for soybean and 60 days after planting for cotton.
  • Limited applications allowed for over-the-top application within cotton. Past applications allowed for up to four applications to cotton. New changes restrict over-the-top application for cotton and soybeans to two per year.
  • Time of application and spray volume is restricted. All application must be made with a minimum volume of 15 GPA and can only be made 1 hour after sunrise and must cease 2 hours before sunset.
  • Watch rainfall projections! No application can be made if the anticipated 24-hour rainfall amount will exceed soil field capacity.
  • Monitor spray solution pH. Recent evidence shows solutions with low pH may increase the volatility of these products. Whether the low solution pH is due to added products or naturally occurring low pH water source, test frequently and aim to buffer when needed to maintain a pH of 5.0 or higher.

This is simply a partial list of requirements. More information on record keeping and other updates will be provided at annual training sessions.