Here’s a look at how stone fruit growers can “stop drop,” protect quality, and gain critical harvest flexibility in accelerated seasons.

California stone fruit growers are facing an increasingly common challenge: compressed and accelerated harvest windows driven by weather variability. In 2026, many regions across the state are experiencing harvest timelines running two to three weeks ahead of normal. While early maturity may seem beneficial on the surface, it creates significant logistical and economic pressure—particularly when labor availability cannot keep pace with rapid fruit ripening.

One of the most serious risks in these accelerated conditions is premature fruit drop. As fruit reaches maturity, the natural plant hormone ethylene triggers ripening and eventual abscission. Once fruit falls to the orchard floor, it is no longer marketable due to contamination and food safety concerns. For growers, that means direct losses in both yield and revenue.

ReTain® Plant Growth Regulator for California provides a critical tool for managing this challenge for stone fruit (excluding cherries). By temporarily inhibiting the production of ethylene, ReTain slows the ripening process and helps keep fruit on the tree. This ‘stop drop’ effect allows growers to extend their harvest window, better align picking schedules with available labor, and preserve fruit quality.

“In fast-moving seasons like this, stopping premature fruit drop is critical.” — Todd Burkdoll, Valent U.S.A.

“ReTain gives California stone fruit growers the ability to temporarily pause the clock on ethylene production so they can maintain fruit integrity until crews can get into the orchard. That flexibility can make a significant difference in overall packout and profitability,” said Todd Burkdoll, Valent U.S.A. Regional Manager, Field Market Development West.

Why Ethylene Management Matters

Ethylene plays a central role in fruit ripening and drop. When environmental conditions accelerate crop development—as seen in warm spring and early summer periods—ethylene production increases earlier than expected. Without intervention, fruit can quickly move past optimal harvest timing.

By temporarily suppressing ethylene synthesis, ReTain helps growers maintain control over the harvest timeline. This mirrors its well-established role in apple production, where it is widely used to manage harvest timing and reduce pre-harvest drop.

Additionally, accelerated growing conditions can shorten the overall fruit development period, which may result in smaller fruit size at harvest. By slowing ethylene production and delaying maturity, ReTain helps extend the effective fruit growth window. This additional time on the tree allows fruit to continue sizing for more marketable fruit.

“You’re essentially buying time with ReTain—time to harvest at the right moment, with the right crew. Plus, more time for the fruit to increase in size.” — Todd Burkdoll

Best Practices for ReTain Use for California Stone Fruit

1. Optimal Timing: Apply ReTain 7 to 14 days before anticipated harvest, prior to significant ethylene production.
2. Target Mature Fruit: Focus on blocks approaching harvest where delays are expected due to labor or logistics.
3. Coverage: Ensure uniform spray coverage and follow label guidance for spray volume and adjuvants.
4. Harvest Integration: Prioritize high-risk blocks and align applications with harvest scheduling needs.
5. Environmental Conditions: Apply under favorable conditions and avoid extreme heat that may limit uptake.

A Strategic Tool for Modern Harvest Management

In today’s dynamic growing environment, tools that provide flexibility and control are more valuable than ever. ReTain enables California stone fruit growers to respond proactively to early-harvest pressure, helping protect and enhance both yield and fruit quality.

As weather variability continues to challenge traditional harvest timelines, proven technologies like ReTain can help growers keep fruit on the tree longer—supporting optimal sizing & quality, harvest operations, and ultimately delivering the best fruit to consumers.

To learn more, contact your PCA, Valent representative, or visit Valent.com/ReTainCA.

Always read and follow label instructions.