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Maintain vigilance against Phytophthora in almonds

(Sponsored) The drought progressing throughout California is taking a toll on the fertile Central Valley, home to the world’s largest acreage of almond orchards. Yields from last season are down due to record heat and water allocations. 

Some growers are replacing older trees with new plantings that can more efficiently use water. If you are part of that group, be sure to have a plan in place to monitor for and manage Phytophthora. In addition, for established trees, extra caution is required, as this pathogen is thought to be present in most surface and ground water, which means it’s likely to be present in most orchard soils as well. If left unchecked, an orchard can quickly succumb to infection.


There are several areas you can focus on to manage the Phytophthora pathogen in your almond orchard:

  • Water management
  • Planting practices
  • Disease control

Phytophthora is a soilborne pathogen that causes root rot and crown rot diseases,” explained Tanner Lowrey, Area Business Manager for Atticus. “That makes water management the number one tool for keeping Phythophthora from wrecking havoc in your orchards.” 

If the crown is infected with crown rot, it can quickly move through the tree and cause death, especially in the spring as temperatures rise. If root rot develops, tree health will decline over time before the tree eventually dies. The keys to water management include:

  • Keep water from pooling around trees
  • Irrigate more frequently in smaller amounts
  • Improve drainage capacity in low-lying areas, in soils with poor water penetration, and in areas that flood frequently

Young trees are particularly susceptible because their root system and crown area are smaller than mature trees, and these diseases impede their ability to absorb nutrients and water. But you can give your new plantings a fighting chance when you follow a few simple guidelines:

  • Plant on berms to minimize prolonged water exposure to crowns and roots 
  • Manage irrigation rate and volume, as noted above
  • Select rootstocks that pair well with soil conditions and varietals

Actively monitoring your orchards for early signs of Phytophthora can help trigger fungicide treatments to keep infection in check. Symptoms often mimic drought stress and nutrient deficiency, so look for wilting leaves, slow vegetative growth, and limb decay. You can also collect soil samples from around roots, as well as root samples, to be tested. 

“You want to catch Phytophthora early because it can become a costly problem to fix with multiple fungicide applications and in cases of tree loss, replanting trees,” Lowrey stated. “ReCon™ Bold SL systemic fungicide with the active ingredient mefenoxam provides excellent protection against this pathogen, especially when treated early. With root to leaf protection, ReCon Bold SL improves both root and overall tree health.”

Maintaining vigilance against Phytophthora through strategic water management, planting practices, and fungicide treatments can help you stay one step ahead of this almond enemy. Using a branded-generic fungicide from Atticus, like ReCon Bold SL comparable to Ridomil Gold® SL, will help you be battle-ready against Phythophthora this season. 

As your pest-defense ally, Atticus works closely with its retail distribution partners to deliver value-driven, branded-generic products that meet agronomic and business needs so you get the most from your input requirements. Atticus puts its experience to work so you can focus on production and help meet the demands of the food supply now and in the future. Learn more at

© 2022 Atticus. Important: Always read and follow label instructions. Not all products are registered for use in every state. ReCon™ Bold SL is not manufactured, or distributed by Syngenta, seller of Ridomil Gold® SL. Ridomil Gold® is a registered trademark of a Syngenta Group Company. ReCon™ is a trademark of Atticus, LLC.

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