Dry Weather Might Mean Mites

Transitioning into spring after a dry winter has growers trying to predict how yield-robbing mite populations will react once almond trees come out of dormancy.

Patrick Dosier, Western region market development manager for MANA Crop Protection in Palo Alto, CA, says current conditions signal that an early and heavy mite threat could be headed our way. “Knowing in advance what combination of miticide tools will be used and at what intervals will improve a grower’s approach to season-long control and maintain their bottom line,” he says. “Decisions to delay in addressing a mite problem is a calculated risk that I would advise against this season.”

Dennis Dunbar, an entomologist with R3 Ag Consulting in Clovis, CA, agrees with Dosier that growers who take a wait-and-see approach to treatment may find themselves in a hole that is too costly to dig out of by harvest. “A lot of growers don’t like to spray until they see mites at a certain threshold and then re-apply if they don’t get the control they want,” says Dunbar. “But, if mites get an aggressive head start before control measures can be applied, growers could find themselves fighting a losing battle.”

Rapid Reproduction

Dunbar says the problem with a reactionary approach is that mite populations can explode fast under the right conditions. “A small concern early-on can turn into a big problem very quickly due to mites’ short generation time,” he says.

Theoretically one adult female mite can produce up to 120 offspring during a single reproductive cycle. When optimal temperatures range between 93°F and 95°F, life cycle development from egg to adult can occur within five to seven days. In as little as 15 days, 60 adult female mites have the potential to produce 26 million mites by way of re-population in just three to four generations. Left untreated, mite populations can surge from one generation to the next, resulting in non-stop feeding that often causes devastating crop losses.

High-impact integrated mite management strategies are evolving from industry insights that integrate older tools with newer tools in order to achieve modern-day success.

Under a systematic platform, MANA Crop Protection advises growers to rely on an early-season application of Apollo SC (clofentezine) ovicide/miticide followed by a mid- to late-season spray of Abba (abamectin) Ultra miticide/insecticide.

Using both of these proven tools in a planned, comprehensive program, Dosier says growers can expect results by way of improved residual control, less risk of resistance, more abundant beneficial insect populations, and increased return on investment.

One-Two Punch

Apollo can be applied as early as March to prevent initial early-season surges of mite populations. Its mode of action targets eggs. Adult females exposed to sprays or foliar deposits lay non-viable eggs, which interrupts the mite life cycle. “In years when mites have come charging into almond canopies, there was little time to react,” says Dosier. “It makes sense to use an ovicide to break the mite life-cycle early, when mites first appear and are most susceptible.”

Dunbar agrees. By hitting the issue early with an ovicide, he believes costs can often be held down by delaying or even eliminating later season adulticide sprays, because populations are greatly reduced from the onset.

Some mites that are present at the time of application will be left behind after an ovicide application. But the growth rate of the developing mite population will be slowed due to the activity on eggs and young immatures, resulting in decreased potential for economic damage. The existence of living mites fills a needed role as a food source for predatory mites and insects. “Because Apollo is extremely soft on beneficials, it helps growers build an even greater defense through the work of abundant predatory mites and insects,” Dosier adds.

Powerful IPM

MANA Crop Protection’s newest offering has a higher concentration of abamectin which provides the same long-lasting control with reduced amounts of formulated product per acre and a reduced impact on air quality. “Abamectin is a great tool that growers can rely on for in-season mite control,” says Dunbar, who has worked with the compound since its early development in California.

Both Dosier and Dunbar believe the economics for a proactive, early season ovicide followed by a later-season abamectin application are especially favorable for this coming season. “An ovicide tool offers a completely different mode of action and process in addressing mite management. It’s a preventative method which allows you to take initiative and lay down needed security against yield loss,” says Dosier. “Using Apollo systematically with Abba Ultra guarantees a positive return on investment delivered by way of a simplified strategy, higher yields, improved performance, less package waste, easier handling, and clean-air compliance.

“With all signs pointing toward heavy mite pressure, an early start will gain and maintain control this spring, which will be critical for a strong finish next fall,” Dosier concludes.