Author: Thierry Besancon
Alion® for Pre-Emergence Weed Control in Vineyards
There have been numerous questions recently from growers about the use of Alion® (active ingredient: indaziflam) herbicide as they are planning their dormant-season herbicide program. Therefore, it may be useful to review some of the information about the use patterns of Alion® for weed control in grape, especially since a few changes have occurred in the last two years.
Alion® was first registered with the U.S. Environmental Protection Agency in 2012 by Bayer CropScience. It works as a pre-emergence (PRE) herbicide for annual grasses and broadleaf weeds, including glyphosate, triazine and ALS resistant weeds. Its new mode of action inhibits cellulose biosynthesis and prevents weeds from emerging by inhibiting the growth of the developing radicle (early root) in the seed germination zone. Alion® also provides growers flexibility as it can be tank-mixed with other burndown herbicides to control emerged weeds or other PRE herbicides for broadening the weed spectrum and managing the selection of herbicide resistant weeds. The most compelling characteristic of Alion® is its VERY long weed control period. Bayer indicates in their literature that weed control can be achieved for up to 6 months with this product.
Unfortunately, Alion® has some severe LIMITATIONS that may prevent or limit its use in vineyards:
- Alion® can only be applied in vigorous grapes that have been established for a minimum of three years after transplanting.
- Alion® can only be used in grapes that have at least 6 inches of soil barrier between the soil surface and the major portion of the root system.
- Alion® cannot be used on soils with 20% or more gravel content or on sand or loamy-sand soils.
- Do not apply Alion® prior to any type of soil disturbance, including hilling/dehilling operations, and only apply the herbicide after the soil settles.
- Do not allow spray or spray drift to contact crop foliage, green bark, roots or fruit of the crop being treated as it may cause localized crop injury or death
- Maximum use rate per application now has a restriction based on soil organic matter (OM) content: if soil contains less than 1% OM, maximum rate is 3.5 oz/A (0.045 lb ai) and if over 1% maximum rate is 5 oz/A (0.065 lb ai). In any case, maximum use rate cannot exceed 5 oz/A (0.065 lb ai) per year or in a 12 month period.
- No irrigation can be applied within 48 hours following Allion® application. This is designed to ensure crop safety by giving the herbicide enough time to bind to surface soils before rainfall or irrigation to ensure proper activation of Alion® by allowing weed seeds or seedlings to come into contact with the herbicide.
Bayer Cropscience has also listed some guidelines for use of Alion® that will ensure efficient weed control:
- Use the highest rate for local conditions for best performance.
- Soil should be free of debris, clumps or cracks at application time to ensure best weed control performance and prevent the herbicide from reaching the grape roots (this is true for best performance of ANY of our PRE herbicides).
- For best weed control, dry soil surface for 48 hours followed by rainfall or sprinkler irrigation within 3 weeks is ideal. If irrigation is used to activate, 0.5 inch of water is ideal (the idea is to incorporate the herbicide into the surface an inch or so, where the weeds germinate, but not go too deeply. This is also pretty true for all PRE herbicides).
Please, always take the time to consult the Alion® label on your favorite herbicide label source.