New 2,4-D formulation offers greater safety for berries, tree fruit and nut tree crops

A 2,4-D choline formulation is now available for controlling or suppressing broadleaves weeds in pome and stone fruits, tree nuts and and various berry crops.

Blueberry plant showing leaf curling
Blueberry plant showing leaf curling and epinasty typical of non-lethal, 2,4-D damage. Photo by Mark Longstroth, MSU Extension.

The phenoxy herbicide 2,4-D is one of the oldest herbicides used in America. It has been used since the 1940s to kill broadleaf weeds. The major drawback of this effective herbicide is its ability to volatize and drift as a vapor injuring or killing broadleaf crop plants. A less volatile formulation of 2,4-D is now available.

The U.S. Environmental Protection Agency (EPA) has registered the choline salt formulation of 2,4-D for use in pome (including apple and pear) and stone fruits (both sweet and tart cherries, peaches), tree nuts, highbush blueberries, cranberries and established strawberries plantings. Embed and Embed-Extra from Corteva Agriscience have the new 2,4-D choline salt formulation. These herbicides are labeled for use in pome fruit, several stone fruit, strawberries and some new berry crop uses.

The 2,4-D choline salt is an auxin-disruptor in the Group 4 herbicides based on Weed Science Society of America (WSSA) site of action classification and acts in plants similarly to endogenous plant auxins. After exposure, susceptible plants show epinasty (drooping leaves) symptoms within 24 hours followed by chlorosis, leaf/stem malformation and growth inhibition. Susceptible plants die within a month. The choline formulation of 2,4-D is not as volatile and drift-prone as other 2,4-D formulations such as amine and ester formulations and should be safer to use. However, it can still cause off-target injury if not applied in accordance with label recommendations. There are label restrictions to avoid potential volatility and drift issues. See the Embed and Embed-Extra Section 3 labels for those restrictions.

Both products control many broadleaf weeds, both annual (common lambsquarters, common chickweed, common ragweed, horseweed, pigweeds, nightshades and mustards etc.) and perennial (dandelion, field bindweed, wild carrot, horsenettle, vetches and common milkweed) broadleaf weeds. For optimum control of annual weeds, the best application timing is when weeds are small (less than 3-4 inches) and actively growing. For perennial weeds, the best application timing is from early shoot growth to bloom. It may require higher rates and repeated applications for hard to control perennial weeds such as Canada thistle and field bindweed.

Embed 3.8L has 56.3% 2,4-D choline salt and is registered to use in orchard floors including pome and stone fruits and tree nuts. Apply 1 to 4 pints Embed 3.8L (0.46 to 1.9 pounds active ingredient) per acre and no more than 8.42 pints per acre per year when weeds are growing actively. Applications should not be made when trees are blooming or on orchard sites with light sandy soils.

The pre-harvest interval (PHI) is 14 days for pome fruits, 40 days for stone fruits and 60 days for tree nuts. Avoid spray drift contacting the foliage, fruit, stem, trunk or exposed roots. To prevent soil uptake by the crop roots, do not make any application immediately before or after irrigation and withhold irrigation for two days before and three days after any application. Because newly established and young trees are more susceptible to 2,4-D injury, use Embed only on trees that have been planted for at least one year.

Embed-Extra has 55.7% 2,4-D choline salt and is registered for use in high bush blueberries, cranberries and established plantings of strawberries along with pome, stone and nut orchard floors. This is the first time any 2,4-D formulation has been labeled in blueberries, which are sensitive to 2,4-D. Due to the low volatility and drift properties of 2,4-D choline salt, it is registered for use in blueberries. The blueberry label requires the use of directed or shielded application equipment to avoid direct contact with blueberry plants to avoid any potential injury. In highbush blueberries, a directed or shielded application with 3 pints per acre (not more than 6 pints per acre per year) may be made in the spring. In row middles, a directed application may be made in summer or fall after harvest. The PHI is 30 days.

In strawberries, Embed-Extra should be used only in established plantings. Applications using 2 to 3 pints per acre (limit to one application per season) may be made in early spring when strawberries are still dormant or immediately after the last picking as part of renovation. In cranberries, the label allows using 2.5 pints per acre (no more than 5 pints per acre per season) and requires directed, wiper or spot applications when weed tops are above crop.

The PHI for cranberries is 30 days. For use in pome, stone and nut orchard floors, Embed-Extra label recommendations are similar to Embed.

Amine formulations of 2,4-D such as Weedar 64 3.8L and Formula 40 3.7L are also labeled for use in tree fruits, tree nuts and strawberry. Please see the labels of each product for detailed specifications for use in each crop.

Did you find this article useful?