Issue link: https://www.e-digitaleditions.com/i/1170186
8 A L M O N D O R C H A R D 2 0 2 5 G O A L S PEST MANAGEMENT Nut Industries Convene at Navel Orangeworm Summit Navel orangeworm (NOW) has a well- deserved reputation for being the most damaging pest to almonds. In fact, it's a threat so serious that this summer the Almond Board of California (ABC) convened what amounted to a war council to ramp up efforts around NOW control and to encourage nut industry members to be vigilant in their management. Held at the Modesto Junior College Ag Pavilion on June 18, the ABC-hosted Navel Orangeworm Summit brought together more than 150 growers and processors in almonds, pistachios and walnuts, as well as pest control advisors, University of California Cooperative Extension (UCCE) specialists and other leaders from the almond, walnut and pistachio industries. "As 2017 taught us, we have to remain vigilant with NOW," said Josette Lewis, ABC's director of Agricultural Affairs. "The summit elevated the collaboration across the nut industries to address a pest of common concern. Joint action is required to reduce the overall pest population." Expert speakers reiterated the seriousness of the problem — increased costs, rejected shipments and even lost markets — while laying out an "all of the above" strategy to beat back the NOW threat. That strategy included reinforcing tried-and-true techniques while also trying some relatively new ideas. Sanitation, sanitation, sanitation Adult NOW moths lay their eggs three to four times a year and their most devastating attack comes after hullsplit, when they lay eggs directly on maturing almonds. Hatching worms burrow into the nuts, damaging and exposing kernels to another serious threat: the fungi Aspergillus flavus and Aspergillus parasiticus, both of which produce aflatoxin. Even tiny amounts of aflatoxin, as little as 10 parts per billion, exceed food safety standards in many countries, leading to rejected shipments of almonds. Cultural practices, such as early harvest and winter sanitation, remain by far the most important methods for controlling the overall population of NOW and infestations and damage within the orchard. Harvesting as early as possible, that is, as soon as good removal can be achieved – when 100% of nuts are at hullsplit at the 6- to 8-foot level of tree canopy – is important to minimizing kernel infections. 1 This practice is also important as it removes nuts from the orchard floor as soon as practicality allows, which therein prevents eggs from being laid in the harvested nuts. Perhaps the most important cultural practice growers have at their disposal, though, is that of winter sanitation: returning to the orchard post-harvest (before bud swell) to re-shake or hand pole the trees to remove unharvested "mummy" nuts, which provide perfect sanctuary for overwintering NOW. Once shaken off the tree, mummies should be raked or blown to the center of rows and destroyed by disking or flailing by March 1. The importance of controlling mummies cannot be overstated. Summit speaker Lane Parker, who grows almonds in Stanislaus and Merced counties, described the three most important tools for controlling NOW as "sanitation, sanitation and sanitation." Last year, in an effort to increase awareness about the importance of winter sanitation, ABC launched a viral video, "The Mummy Shake," paired with a contest where industry members could submit their own "mummy shake" videos for a chance to win a grand-prize trip to Disneyland. ABC will repeat the contest this year, so stay tuned for further details from the Almond Board. 1 https://www2.ipm.ucanr.edu/agriculture/almond/navel-orangeworm/ Navel orangeworm creates wounds favoring the growth of the fungus Aspergillus flavus, thus leading to aflatoxin contamination. Continue on page 9