How We Grow

2019 Nov/Dec How We Grow

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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 Continue on page 9 Winter Sanitation – It Pays for Itself David Haviland has been a University of California farm advisor for 15 years. In that time, he's seen some major advances in the fight against Navel Orangeworm (NOW), the single-largest insect threat to the almond industry and a source of aflatoxin in mature nuts. From his base in Kern County, Haviland has led research efforts initiated and funded by the Almond Board of California (ABC) to reduce NOW infestation. He also has collaborated with other farm advisors and USDA and UC researchers to educate growers about their options when it comes to protecting their orchards and the significant investment they've made in their crop. Growers know that winter is the time to remove and destroy mummy nuts that harbor NOW larvae. This practice, known as winter sanitation, is all part of a strategic and effective Integrated Pest Management (IPM) program, one that includes different tactics depending on the time of the year. "Winter sanitation is the core of IPM programs, and winter is the time for growers to take a big-picture look at their IPM efforts and evaluate what, if anything, they can improve on in the upcoming crop year. It's an opportunity to reset the clock," Haviland said. What growers may not know, however, is that winter sanitation can ultimately pay for itself. All growers seek to control costs and achieve a sustainable return on investment. And while there are manpower and machinery costs associated with winter sanitation, there are also costs and consequences to improperly managing NOW, including decreased yields, insect-damaged nuts and lost premiums. Putting pencil to paper quickly reveals the overwhelming benefits of winter sanitation. "Winter sanitation pays for itself," said Mel Machado, director of Member Relations at Blue Diamond Growers. "When a grower thinks about the cost of winter sanitation, it is important to recognize that the return on investment comes from both a higher yield after shelling and a higher price premium at the handler," Machado said. In other words, growers should remember that reject losses hit them in two ways: first in reduced value per pound and second in lost weight or yield. At the Almond Board's Navel Orangeworm Summit this past June, Machado shared that the actual loss a grower experiences is really double what they see on the grade sheet that they receive from their handler. "The harvesting and hulling/shelling process removes at least as much as is reported on the grade sheet. Anything above 2.0% is excessive, and financial losses can add up very quickly above that level," Machado said. This means growers should make the investment necessary to ensure reject levels remain at or below 2.0% in order to provide an excellent return. Haviland agrees that winter sanitation — coupled with newer, more environmentally friendly techniques to control NOW during the growing season — will continue to be an important component of IPM. "In an ideal world, winter sanitation would be cheap, easy and 100% effective. Applications would kill every bad thing in an orchard," he said. "That's not reality. IPM can be expensive. Every grower wants to do more but wishes it would cost less. The key is to find a balance." Haviland advises growers to closely survey their orchards after harvest is complete and the trees have shed their leaves because at that time mummy nuts will be most obvious. The almond industry's goal is to have no more than two mummies per tree before bud swell, which is around Feb. 1. In the San Joaquin Valley, however, growers are recommended to aim for less than one mummy per tree. "When conditions on the ground allow, you need to send a shaking or poling crew into the orchard to remove the mummies," Haviland said, reminding growers who re-shake to be careful as trees that are badly scratched can be susceptible to disease. Wet and foggy conditions help the nuts come off the trees more easily, so an optimal time for winter sanitation is when dew has formed or after it's rained. At that "Winter sanitation pays for itself. When a grower thinks about the cost of winter sanitation, it is important to recognize that the return on investment comes from both a higher yield after shelling and a higher price premium at the handler." – Mel Machado While mummy shaking does require additional labor, it is a vital practice that prevents NOW from wreaking havoc in your orchard.

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