Hello!
My name is Dirk Ulrich with UMC, and this is my second year working with Hilltop as their agronomist to answer any questions Hilltop growers have about almond production.
Now that the 2024 almond season is almost over and stockpiled almonds are nearly processed, we’re finding that this year could be as high as last year for NOW (Navel Orangeworm) damage. Early in the season, NOW trap counts and damage in outside row early splitters started off lower than the previous year. But after multiple heat waves, with over 50 to 60 days above 100 degrees from early July through early October, the risk for major damage increased. In several blocks with later harvest dates, I saw above 25% NOW damage. On the other hand, I also saw blocks with less than 1% damage across all varieties.
Common Factors in High NOW Damage (5% to 25%)
Blocks with NOW damage of 5% to 25% had some common patterns. Some growers tried to achieve good sanitation but ran out of time due to rain or bloom time, while others chose not to do any sanitation at all. Growers with the resources, along with lighter soils that allowed shakers to get in when nuts were soggy wet in December and January, managed effective mummy shaking, getting all the nuts on the ground, blowing strips, and destroying them. These growers saw less than 1% NOW damage.
Even if sanitation is adequate on 80% of a block, significant damage is still possible. Another factor is whether your neighbors do effective sanitation. If a neighbor doesn't clean up his mummies and shakes his Nonpareils before you do, the moths emerging from his mummies will look for places to lay eggs and will fly over to your splitting Nonpareils. Building a good relationship with your neighbors and coordinating sanitation efforts can help reduce this issue.
What is Good Sanitation?
A simple definition of good sanitation is fewer than ½ nut per tree (or fewer than 50 nuts per acre), with all nuts on the ground destroyed.
Here’s what that looks like:
1. **Shake Mummies nuts at the Right Time**:
Shaking mummies is more effective when there’s some moisture, making them heavy enough to fall with a light shake. Shaking on dry winter days often only removes half the mummies. In dry weather try scheduling shakes for nights when dew is present to make the nuts soggy.
2. **Shake Different Varieties in Order**:
If the weather is dry, start with Nonpareils, which usually shake better. When it gets wetter, you can then shake the harder-to-shake varieties.
3. **Using Hand Labor**:
When wet ground prevents shakers from accessing certain areas, consider hand labor in late January or early February to get the remaining nuts down. Though the cost may run over $200 per acre, this step can help avoid losses that could reach up to $1,000 per acre from worm damage.
**Destroying Fallen Nuts**
Once nuts are on the ground, they need to be destroyed by March 15th. Most years, adult moths don’t emerge from mummies until after this date. In colder, wetter springs, emergence may be delayed until early April. The goal is to break open the nuts so the worms or moths can’t survive inside. Standard destruction is with a mower, but make sure to fully crack and break the nuts. Other methods, like covering nuts with compost or manure, can also be effective due to the nut rotting and decomposing killing the worms and moths. Modifying your mower with heavier blades or making two passes may help achieve full destruction.
Reducing Dependence on Sprays and Mating Disruption
Heavy NOW damage over the past two years shows that sprays or mating disruption alone can’t protect blocks with poor sanitation. Without thorough sanitation—meaning fewer than 50 nuts per acre and complete destruction of nuts on the ground—you’re taking a big risk and could face NOW damage above 25%, which may cost you over $1,000 per acre.
Please don’t hesitate to call if you have any questions or if you’d like to set up a meeting.
Thank you
Dirk Ulrich
209-531-6662
Dirkulrich55@gmail.com