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Tree nut updates from across the valleys

Spring weather increases growers’ confidence in bees’ work.

Logan Hawkes 1, Contributing Writer

April 17, 2019

6 Min Read
Grower with hand-held device in orchard
Alex Bergwerff, manager of Manteca, Calif.-based Winters Farming Co., checks conditions in the farm’s almond orchard near Oakdale, Calif., last spring.Tim Hearden

Winters in California can range from mild to cold - then can get even colder some years, like this one.

The rains fell hard over most of the winter months across the middle California Valleys, snow being more common in northern regions of the Sacramento Valley late in the season, enough to powder the earth on numerous occasions and accompanied by unexpected chilly temperatures.

With spring weather finally settling in, however, many growers are feeling more confident that the bees may have managed to do a better job pollinating than as first feared and growers are holding out hope it could still be a successful year for tree nuts.

Scouring across the two Valleys for updates and waltzing through University of California Cooperative Extension (UCCE) and industry blogs and vlogs the last week or so provides a glimmer into what’s happening now as April stretches into Easter Week with May a few days away.

Emily J. Symmes, Sacramento Valley Area IPM Advisor, UCCE and Statewide Integrated Pest Management Program, reminds us in her latest Walnut BLOG that “the foundations of integrated pest management are rooted in economics,” and relying on the right plan can save you money and heartache in challenging times.

Now is the time for trap monitoring and collection of data that will provide insights into orchard history.  It is also the time for in-season trap and damage counts that will be key in understanding evolving pest pressures and the optimum timing for conventional pesticide applications and mating disruption efforts.

Also of concern following cold, wet early seasons are canker diseases in almonds. At a recent Kern County Almond Day meeting in Bakersfield, diagnosis and management of almond canker diseases were the topic of a session led by Florent Trouillas, Cooperative Extension Specialist at University of California (UC)- Davis, who voiced concern that the rain and cold of winter this year could give rise to canker-related problems.

Overview available

An overview of canker in almonds is available online and includes photos of canker damaged almond trees for those unfamiliar what to look for as the season progresses. Early detection and treatment can improve chances of saving infected trees, but diligence and action are required at first signs of a developing problem.

Western Farm Press also offers up some good advice about canker in almonds and worth your while if you suspect your orchard may be in danger of canker problems.

The other elephant in the room this time of year is, of course, weed management and with all the ground moisture dropped across the Central Valley last month, this could be a busy year for weed control.

You’ll find a world of useful information about good weed management in this UC Division of Agriculture and Natural Resources (UC ANR) Integrated Weed Management guide regardless which nut populates your orchard. Just like integrated pest management, staying on top of the problem is your best defense, and having the right plan in place for when things start going downhill is your best chance to of getting safely to the other side of weedsville.

As you would expect, there are many things to be concerned about now that spring has arrived. A few of the problems might include Anthracnose, which may be a problem if rainy weather persists though April and temperatures are warm, especially in orchards with a history of the disease. Anthracnose infects nuts and causes marginal leaf necrosis and branch dieback. Be sure to alternate fungicides to avoid resistance development. More treatment options are available here.

Another pest management concern is Shot Hole. This fungus survives on infected twigs and as spores in healthy buds. Spores are moved by water to new sites; prolonged periods of wetness, either due to rain or sprinkler irrigation, are required for the disease to develop. Shot hole can cause losses in yield, defoliation, and weakened trees. Here’s more information on the topic.

It may be early in the year but reports of some problems associated with gophers are already circulating. Heavy rains may have helped to reduce gopher numbers according to UC ANR, but it also is giving rise to new, succulent vegetation as the gopher mating season rushes in this month and next. Here’s more on the subject from UC ANR’s Dani Lightle to get you started.

What about those Golden State snowpacks?

There’s still a lot of joy and jubilation going on across California nut country over the white snow gift of winter past. And there’s room for celebration. The California Department of Water Resources conducted its monthly snow survey on April 2 in the Sierra Nevada mountains and has reported California’s snowpack has tripled from what the state experienced last year.

After some tough water years leading up to this year’s snow events, it’s a pleasant surprise in a time when it seems so many things can go wrong. According to an AgWest report, the state’s largest 12 reservoirs are nearly all at their historical average. Millerton, Perris, Castaic, and Pine Flat are the only four not at or above the average for this point in the season.  San Luis Reservoir is just below its overall capacity, but Shasta, Oroville, Melones, and Don Pedro are all above 80 percent of capacity and well above the historical average.

Those dirty rats?

If you live or work in a tree nut orchard in the San Joaquin Valley and think you have been invaded by giant rats, take heart, for your eyes may not be all that bad. Nutria, a big rat-like creature is a rodent and is now considered an invasive species because of the rapid proliferation and adaptability they have demonstrated.

The California Department of Fish and Wildlife has been working with several government partners to roundup and capture some of these critters. It’s been just over a year since an Incident Command System was launched to respond to the invasive pest. The good news is a lot of the animals have been captured. The bed news is they are reproducing in the wild faster than the trappers can pick them up. Learn more about the pesky rodents and how to report them – and don’t worry about getting your eyes checked.

Upcoming events

If you haven’t already, mark your calendar for Apr 30-May 2 to attend the 38th Annual Almond Alliance Convention in Napa. And if you happen to be in the neighborhood, catch the Blue Diamond MASTERS Apr. 25 on the Sacramento Blue Diamond Campus. 

For more news on tree nuts as reported by growers and farm advisors, subscribe to the Tree Nut Farm Press e-newsletter.

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