Friday, August 5, 2011

Cutting Off the Water to Prepare for Harvest

Editor’s note: We are featuring a guest blog by UC IPM entomologist Walt Bentley, whose specialty includes managing pests in almonds.

Navel orangeworm egg deposition has dropped as of Wednesday, Aug. 3. I expect that to continue for at least another week.

This drop signals the end of second-generation egg laying by NOW moths. This second generation NOW eggs usually result in very minimal infestation. I have seldom seen over 2 percent infestation resulting from worms hatched from these eggs. Additionally, these hatched worms or larvae are the ones that our hullsplit spray targets.

In talking with the almond farmers in the project, the timing of that spray for Nonpareils was excellent. What we must now focus on is the harvest before the third generation eggs are laid. The third generation is the one that can result in substantial damage and, if you have your Nonpareils on the ground before these eggs are laid, you will avoid NOW infestation.

I recognize many of you have a number of acres to harvest. Some of you don’t have harvest equipment and must rely on others to come in and shake the almonds. If you have Nonpareils, try to arrange for harvest as soon as you can. This means timely cut off of water. Remember the impact that late irrigation has on the development of hullrot. Those with higher density plantings are particularly susceptible.

So focus on getting the water off and preparing for Nonpareil harvest. If there are orchards that have had more problems than others in the past, schedule them first for harvest.

Finally, make sure you take some samples from the nuts that are on the ground. You can collect 500 to 1,000 from each orchard, throw them in the freezer and crack them out when you have time later. This will give you an idea of what infestation or disease issues are present in your orchard. Good luck on this year’s harvest.
Walt Bentley is a long-time entomologist with the University of California Statewide Integrated Pest Management program at the Kearney Ag Center in Parlier.


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