Zinc (Zn) and manganese (Mn) are needed at key times throughout the season by many crops, including tree fruit, nuts, and grapes. Annual crops such as peppers, beans, and tomatoes also benefit from Zn and Mn, which are essential plant nutrients that support photosynthesis, root and shoot growth, leaf development, and metabolism of nitrogen, among many other functions.

One of the key times when demand is high for Zn and Mn is early in the season, when leaves, shoots, and roots are growing quickly. This is also a time when mite and fungal populations are developing but have not yet reached damaging levels; perfect for a foliar product that delivers miticidal and fungicidal action along with Zn and Mn.

Agro-K’s Mite-Phite ZM™ is a 5% zinc and 2% manganese nutrient solution that is also EPA-approved as a miticide and fungicide. Richard Warner, Ph.D., National Research and Technical Service Coordinator for Agro-K, says he observed mite suppression activity during his work with these nutrients on almonds.

“We began collecting data once we noticed the Pacific mite (Tetranychus pacificus) populations decreasing at levels similar to a contact miticide after application of the solution,” Warner says. “Both in the lab and in the field, it has a significant effect — about 40% to 50% depending on the population. We don’t know the exact mechanism, but we have the data that show it is effective at suppressing mite populations in tree fruits, nuts, grapes, peppers, beans, and other crops affected by the Pacific mite, European red mite (Panonychus ulmi), and the two-spotted mite (T. urticae.)”

Phosphite nutrient formulations are especially effective at getting nutrients into the plant fast, and they are easily translocated into the plant’s roots. Plus, it’s well documented that you can get increased root growth with phosphites, Warner says, which allows increased uptake of nutrients already in the soil. In addition, phosphites have been shown to have fungicidal properties, especially against pathogens such as Phytophthora, Rhizoctonia, Pythium, and Bremia lactucae, downy mildew.

“We also have anthracnose on the Mite-Phite label, and we are continuing to look at other fungi where it can be effective” Warner says. “Plus, phosphites have been documented to trigger the systemic acquired resistance (SAR) mechanism of the plant, which helps in the long term.”

Many areas of the U.S. have received significant rain this spring, and Warner says that can lead to an increase in soil fungal diseases like Phytophthora. “If you’re already going to be spraying the nutrients like Zn and Mn they need, it would be beneficial to use Mite Phite, because it also has the fungicidal and miticidal activity.”

Mite-Phite can be tank-mixed with other fungicides and insecticides. When making a mite spray, Agro-K recommends that Mite-Phite be applied with a conventional miticide for maximum control. Mite-Phite has suppressive effects on mites not residual and therefore isn’t intended to be used as a stand-alone.