How We Grow

2019 July/Aug How We Grow

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16 RESEARCH UPDATE ABC Makes Record Investment in NOW Research Navel orangeworm (NOW) is a year-long pest that brings growers grief and gives handlers heartburn, to the tune of higher aflatoxin levels, lower returns and product rejections at the port. For over 20 years, the Almond Board of California (ABC) has funded NOW research and made strides in identifying practices growers have at their disposal to implement NOW control, including mating disruption, winter sanitation, the use of egg and pheromone traps, and target spraying. As a result, over the last 15 years, growers have seen reduced pest damage and insect damage rejections at the handler. However, an uptick in rejections in 2017 and concerns about resistance to current NOW management products served as a reminder that the industry cannot be complacent in finding new ways to manage the pest. What's more, NOW problems persist in some almond-growing regions due to weather changes and shifts in almond varieties. These multiple factors led the Almond Board to take a big step to explore a viable option for NOW control. This spring, ABC announced it will fund a record $1 million on promising new research: a NOW Sterile Insect Technique (SIT) project. "Since 1973, we've funded $3.3 million in navel orangeworm research — that's nearly half a century of scientific findings focused on one pest and its impacts," said Richard Waycott, president and CEO, ABC. "Putting $1 million of growers' dollars toward navel orangeworm research demonstrates our seriousness in combating this pest. We want to explore all available options to find effective controls for NOW." NOW, meet SIT Navel orangeworm is a major pest in almonds and pistachios and a secondary pest in walnuts and several other fruit and nut crops grown in California's Central Valley. Larvae bore into the almonds and damage the nut, which can lead to fungal Aspergillus flavus infections that are a significant concern for almonds and other nut crops, due to the residue of aflatoxin. SIT looks to eradicate this issue at the source. This technique was first developed in the 1930s to disrupt the reproductive process of moth insects. In the case of almonds, researchers use radiation to sterilize male insects and then release them into the orchard in large numbers to mate with native females when the first generation of mating occurs. While the physical aspect of mating still takes place, the female is not fertilized, resulting in an unproductive process where the females do not produce viable eggs, and, in time, overall populations decline. Josette Lewis, director of Agricultural Affairs at ABC, noted that SIT also fits into the almond industry's Almond Orchard 2025 Goal of increasing the adoption of environmentally friendly pest management tools by 25% by 2025. "The Almond Board has spent decades researching NOW to better understand how growers can combat this pest and better protect their crop, and through that research we've had great findings," Lewis said. "Still, there's more work to be done and the Almond Board looks forward to partnering with researchers, the almond industry and the broader ag community in exploring this sterile insect opportunity for NOW control." Key partnerships required for success While the future of SIT research in almonds is promising, to reduce the NOW population in almonds alone would only bring short-term success — controlling NOW requires solutions that work beyond almonds. Even if NOW damage is reduced on an annual basis in almonds, the pest will still be flying to other crops, such as pistachios and walnuts, and replenishing its population there. Because mummy nuts left in the orchard provide a home for overwintering NOW, growers must practice winter sanitation, removing mummies from their trees and destroying the nuts once they hit the ground.

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