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Out with the Old...

December 18, 2019

By John Wood, Certis Biologicals Regional Manager, CA South Central Valley

Here’s to hoping that Santa and his reindeer deliver you some brand new pruning shears for Christmas, because we all know that right after the Big Man leaves and the tree is hauled to the curb or to the attic, you’ve just got to get out to your orchard and start pruning your nut trees.

I’ve seen a lot of great information about pruning and some updated trial research hit my inbox lately, so I thought I’d share those great resources and some other pruning tips to help you get you thinking ahead for that task.

The first thing to consider regarding how you’re going to prune depends on how mature your trees are.  If you need a refresher, our friends at UC-Davis have this great page with pruning guides for each stage of your almond tree’s life. I personally like the step-by-step videos for each level.

I’ve talked a lot about the need for scouting and taking a good, hard look at your orchard and trees during dormancy. While you prune, it’s a great time to do just that. During pruning, you can pretty easily identify dead limbs that may have been caused by shothole borer or Pacific flatheaded borer. Be sure to remove those immediately and burn them away from your orchard to prevent spread.

Just because it’s cold out doesn’t mean that all pests have gone away. When leaves are gone from trees, it’s less likely, but you might still see some of those critters hanging around and causing damage. I really like the page dedicated to dormant scouting on the UC-IPM site. With up-close pictures of the pests, it leaves you little guesswork about what you are seeing.

I was delighted to see some new pruning research from the University of California published in a recent issue of AgFax. Let’s be frank: pruning is necessary for a healthy orchard, but it leaves fresh wounds - which can open your trees up to the spread of canker and other problems. You have to be very careful to avoid this.

With the rainy growing season we had this year, I saw canker problems on the rise. We all benefit from making sure that these don’t further spread during the dormant periods. 

Research included in this article said that “results from sampling over 140 almond orchards found 21 different fungal pathogens associated with these canker diseases.” That’s a significant number which causes some concern. The article also found that the wounds were most susceptible to fungal disease immediately after pruning.

Probably the best way to keep infection at bay is to watch the weather. Rain events are ripe environments for canker diseases to grow. If rain is on the forecast for your area, don’t prune immediately before. That will help to keep your trees under the protective bark coating and less likely to be infected.

Additionally, be prepared to do an immediate application of a pruning wound protection product after your pruning is complete. The UC researchers include some recommendations in their article and I agree that those are great choices.

If you are using Kocide® copper during this dormant season, bear in mind that it can be tank-mixed or rotated with many of these products. Our products tend to play nice with others, so don’t worry if your pruning and wound protection coincide with a Kocide® application. Your PCA can advise about specific products.

If you want to wish me a happy holiday or share your Christmas wish list, don’t forget that you can drop me a line at

I hope everyone has a blessed holiday season!  I’ll see you back in 2020.

This series is part of a partnership with Tree Nut Farm Press. You can read the original here.

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