IN YOUR ORCHARD
TIME TO CONSIDER
By the time this article is published growers will be finishing up this year’s harvest. It is also the time of year where you will look at delivery statements. You might be wondering what caused your rejects . Every year it feels like the almond industry faces a new pest. Navel orangeworm (NOW), leaffooted bugs, stink bugs, ants, carpophilus beetle…the list goes on. In this article I will address the damage these insects cause and what the actual damage looks like so you can see the difference amongst this ever-growing list of pests.
Let’s start with the longstanding number one pest on a grower’s hit list: navel orangeworm ( NOW ). NOW is still the largest driver for rejects in the almond industry. Growers focus on year-long programs to try to reduce and control this pest. This includes winter sanitation, mating disruption and treatments with insecticides. What does the damage from this pest look like ? Only the NOW larva feed on the kernel. They remove the skin of the nut and eat the meat. You will usually find large frass and webbing that is left from the larva feeding. The larva itself is a pinkish/cream color with a dark
color with a brownish head and two brownish projections at the end of the abdomen. The damage on the kernel is different compared to NOW. While carpophilus does feed on the kernel, it causes little to no damage to the skin of the nut. The frass has a fine, powdery consistency that’s white in color and
Pinhole damage caused by NOW. Photo credit: Mel Machado
Carpophilus damage. Photo credit: Mel Machado
can be intermixed with nut meat meal left behind from feeding. Control of this pest is still uncertain, but research is currently under way. The first battle was learning that this pest exists, so if we want to win the war, we need to learn how to control it! Rounding out the big three, or maybe four now, is damage caused by leaffooted bugs and stink bugs . The leaffooted bug is easy to identify since it has a small appendage on its hind leg that looks like a leaf. Stink bugs can be a little more difficult since we have multiple species in the orchard. The two that cause damage are the green stink bug which is a native species to California; they look just like they sound. The second, possibly more worrisome stink bug, is the invasive brown marmorated stink bug also known as BMSB. The damage caused by each of these pests is very similar. Each feed on the nut using piercing/sucking mouthparts, much like a mosquito. The feeding causes a clear gumming to extrude from the nut. This damage will either cause the nut to abort or leave the reject known as “brown spot.” Monitoring for this pest is still the best tactic to prevent damage. Lastly, I wanted to talk about two pests that are usually a second thought. Ants can cause severe damage, but much of it is not seen on your grower statements. Ants feed on the meat of the nut but will leave the skin of the almond intact. I like to say they leave the crust of the bread. These
Large NOW larvae. Photo credit: Mel Machado
brown head. However, the biggest indicator is the crescent shaped mark right behind the worm’s head. Now that harvest is coming to an end, the first attempts to control this pest lie in winter sanitation by removing overwintering habitat for this pest. As more studies are conducted on this pest, new techniques develop to control it. I will share those with you once available.
The carpophilus beetle has garnered ample attention this year, and for good reason. Both the adult and the larva feed on the nut, and a control strategy for this pest has yet to be established. The adults are small, only about 2-3 millimeters long. The larva is a creamy white
Evidence of carpophilus feeding. Photo credit: Mel Machado
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ALMOND FACTS
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