The new Devrinol formulation, Devrinol DF-XT, is still a fifty percent dry flowable formulation, but includes UV (ultraviolet light) protection, so the product is no longer broken down on the soil surface by sunlight. Devrinol 50DF has been labeled and recommended for use a variety of vegetable and fruit crops for decades. Due to the product’s sensitivity to sunlight, recommendations have generally been PPI (preplant incorporated), or preemergence under plastic mulch, when followed by overhead irrigation within 24 hours, or for application in late fall when days are short and the sun is lower on the horizon, such as in established matted row strawberries.
Like most preemergence herbicides, rainfall or overhead irrigation is still needed before weed germinate for activation, but none of the Devrinol will lost waiting for water, improving the utility of the herbicide. The UV protected Devrinol DF-XT performs no differently under black plastic mulch where the herbicide is protected from sunlight, but will perform more reliably between rows of plastic mulch where Devrinol use has been avoided. Mechanical incorporation is difficult to accomplish between rows of plastic mulch due to the risk of tearing the mulch, and since the crop is usually trickle irrigated under the plastic, overhead irrigation may not be available and is certainly extra work and an extra expense.
Improved crop safety is frequently observed when Devrinol is applied preemergence to direct seeded crops, such as labeled cole crops, compared to PPI applications. Mechanical preplant incorporation places the herbicide under the germinating seed, and has resulted in a narrower margin of crop safety. The reduced margin of crop safety is more likely to be observed in coarse textured (sandy) soils low in organic matter, and is less apparent in fine textured (heavy) soils and in soils with high organic matter content. The use of Devrinol as a preemergence herbicide is more practical use with the addition of UV light protection, and the improved crop safety observed when Devrinol is used preemergence can expand use in direct seeded crops.
