Figure 4 courtesy of UC Davis IPM
before you see one. But be prepared; they sound like a Chinook helicopter buzzing by. Since these pests are hard to find in the field the best way to identify a potential problem is probably also the most depressing. You must look for the damage . The damage is identified by dropped or aborted nuts— especially in March and April—or nuts with exuding gumming ( Figure 4 ). These insects will continue to feed after the nut has hardened, which will result in the reject known as brown spot ( Figure 5 ). The damage caused by both insects can be severe. You may lose production from aborting nuts, have high reject levels because of brown spot, or even both. Controlling the pests becomes the number one priority. The problem is, as growers, you have lost some of the best tools against these pests. Chlorpyrifos used to be a successful product when battling these bugs, but with new restrictions it has become a relic of the past. This leaves growers with pyrethroids, which can cause secondary pest issues like mites when used multiple times. The hardest part about controlling these pests is the spray material needs to make contact with them. They are notorious for walking on their “toes” and not having much contact with foliage. They also feed from deep inside the nut, so they have little chance of ingesting material. In my opinion, the best way to achieve control starts well before an application. It starts
Figure 5 courtesy of Mel Machado
with finding and removing areas or hosts where these pests can overwinter. Leaffooted bug will overwinter in fruit trees (pomegranates), evergreens, and wood piles. Stink bugs can over winter in the orchard, but that is why scouting becomes vital as we enter the season. Once a bug or damage is found there is no waiting period before an application should be made. The longer you wait, the longer they will have to feed. Lastly, choose the correct product and make sure to have a good application. Your PCA can help you will all the things I have listed. There may be a few of you readers who have not dealt with these pests and are wondering why I am talking about them so much. Here is why: According to our reject data, since 2014, brown spot has increased dramatically and is now the number two cause of rejects, only behind navel orangeworm. In some cases, the damage has been so severe that reject levels have gone over 30% deeming those deliveries as oil stock. These are pests that you need to be aware of, scout for, and control. The carpophilus beetle is the newest pest almond growers are facing. Much is still being learned about this pest, so control strategies are still developing. The critical timing for a chemical
application for this pest will be at hull split. Timely and early harvest also shows promise because vulnerable nuts are exposed for a shorter time. In our reject data, there was a relatively small amount of damage caused by carpophilus, but that does not mean it will not continue to spread or increase. Researchers are still working on strategies for this pest but one thing they all agree on is the need for quality winter sanitation to prevent the overwintering of this pest. We will continue to monitor carpophilus and will update growers if issues arise. To repeat what I said at the start of this article, insects originated 480 million years ago. That means we will likely be dealing with them for another 480 million years or more. The best thing you can do as growers is to be diligent in scouting for these pests, targeting them at the right time, and using the best control method to prevent them from damaging your crop.
Trent Voss, Lead Regional Manager, Blue Diamond Member Relations
45
MARCH–APRIL 2025
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