by: Kristen Obeid, OMAFRA Weed Management Specialist- Horticulture
Some growers who are pulling out orchards or individual trees are wondering what they can plant if they applied Alion® herbicide the previous year. If you are replanting the odd tree (or an entire block for that matter) it’s okay to have used Alion the previous year (12 months prior). For example: if you used Alion last May, you can put in new trees no issue, now. However, IF you just applied Alion this April (April 2019) and need to replace some trees you CAN but need to remove the soil from the transplant hole and plant into fresh soil.
Also, remember you can only apply Alion to trees that are a minimum of three years old since planting or transplanting, grape vines a minimum of five years and bushberries (subgroup 13-07b, except lowbush blueberries) and caneberries (subgroup 13-07a) a minimum of one year. So, once you replant you will have to wait to apply Alion in the areas where the new trees, vines or berries were planted.
If you are planning to take out an entire orchard and plant a crop that is not listed on the Alion label, Bayer recommends to NOT use Alion the last year in your orchard (in order to give a 24-month timeline, assuming Alion is applied in the prior spring). For example: If you applied Alion in April 2018 and pull out your orchard after the 2019 growing season you could plant crops that are not on the label in April 2020.
Alion stays absorbed to soil particles and can prune roots of subsequent crops, resulting in the potential for stunting of plants if proper re-cropping guidelines are not followed.
Alion Herbicide Label
Only crops listed on this label may be replanted within 24 months after the last application of Alion [pome fruit, stone fruit, grapes, bushberry subgroup 13-07b (except lowbush blueberries), caneberry subgroup 13-07a, hops, and tree nuts]. Individual plants within an orchard may be replanted anytime by removing all treated soil from the transplant hole and refilling around the plant with soil that has not received any application of Alion. Allow at least 12 months between the last application of Alion and replanting an orchard or vineyard with labeled tree or vine crops. Treated soil must be thoroughly mixed to a depth of at least 15 cm prior to planting. This may be accomplished through any combination of tillage operations such as ripping, disking, or plowing.