Even though growers are just completing this year’s harvest, it’s never too early to start thinking about winter sanitation.
Winter is the time to remove and destroy mummy nuts that harbor navel orangeworm (NOW) larvae, which can hatch in the spring and wreak havoc in the orchard. By removing the nuts, growers are eliminating both a shelter and food source for these overwintering pests. This practice falls in line with the strategic and effective Integrated Pest Management (IPM) program for NOW, one that includes different tactics depending on the time of the year.
“Winter sanitation is the core of IPM programs,” said David Haviland, a UCCE farm advisor in Kern County who specialist in entomology and pest management.
Here are some quick tips growers should keep in mind when preparing to remove mummy nuts from their orchards, a.k.a. “mummy shake”:
- Mummy nuts become most obvious after trees have shed their leaves, and growers should look to knock all the mummies off the trees no later than Jan. 15.
- A good time for winter sanitation is when dew has formed or after it’s rained because mummy nuts will have absorbed some moisture, making them heavier and more likely to fall. In addition, a wet orchard floor helps to increase NOW mortality rates.
- Growers can remove mummy nuts by bringing the shaker through their orchards or hiring crews to knock mummies to the ground using long poles.
- To note: Both hard- and soft-shell varieties can harbor overwintering NOW, so growers must be sure to remove mummies in both types.
- Growers should aim to have fewer than two mummers per tree before bud swell (around Feb. 1). However, growers in the San Joaquin Valley should aim for less than one mummy per tree.
- Once on the ground, mummy nuts should be swept into windrows and destroyed, either with a flail mower or by disking them into the soil, by March. 15.
Removing mummy nuts and reducing NOW levels using environmentally friendly techniques is key to helping the California almond industry achieve its Almond Orchard 2025 Goals, one of which is to increase adoption of environmentally friendly pest management tools by 25% by 2025.
Josette Lewis, the Almond Board’s director of Agricultural Affairs, said growers must realize that in the end the cost of efficient winter sanitation pays for itself.
“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,” Lewis said. “In other words, without good winter sanitation, yield loss occurs due to rejection of mummy nuts from the previous year and heavily NOW-damaged nuts from the current season.”
To help remind growers to break the link between mummy nuts and NOW, the Almond Board of California created a parody song that’s sure to be an “orchard smash.” It’s “The Mummy Shake” — and if you and your family dance and sing along, you’ll be in the running to receive tickets to a luncheon at The Almond Conference 2019 in Sacramento in addition to either tickets to Disneyland or a $500 Amazon gift card! Visit Almonds.com/NOW to learn more.