Monday, January 30, 2017

Wind, Rain and Fungus Alert for Valley Almond Growers

It’s been wet – enough to give the Valley farm land a nice soaking.

It’s been windy – enough to topple weakened, but once productive trees.

Storm clouds give way to a rainbow over an almond orchard.
Even so, we pretty much survived the gusty winds that reached up to 33 mph and the more than 1.6 inches of rain that battered the Fresno region a week ago.

“We had such crazy rain and crazy wind,” says almond field scout Jenna Mayfield. “We haven’t seen such weather in years.”

So far, more than 6 inches of rain has fallen this month – nearly double the amount a year ago. Of course, we all remember how a meager .2 inches fell in January 2015 and a quarter inch during the first month of 2014.

Yes, after five years of drought, everyone has welcomed the rain. And despite the inclement weather, Jenna points out almond orchards survived fairly well – with only some trees along the margins that were already weakened by years of dry weather being uprooted by the winds.

Almond tree toppled by the wind.
The rains also bring worries. Almond growers are starting to think about fungicide treatment to protect their trees against diseases. 

“Fungus can be spread by the wind,” Jenna said. Because of this year’s weather, “we may have problems that we haven’t experienced before with fungus.”

University of California farm advisors point out that almond orchards always have fungi present that can cause diseases. The amount depends on the previous year’s disease level and the current weather conditions.

It’s important to be proactive, especially this stormy winter. A good disease control program hinges on a combination of choosing the appropriate fungicides and good timing and coverage. Proper identification of the disease in the orchard will dictate the selection of materials.

Here is the impact of armillaria root rot on an almond tree.
Remember, not all fungicides are equally effective on diseases. Growers should use more than one variety of fungicide to broaden the effectiveness.  Jenna says growers should consult UC’s fungicide efficacy table to help with fungicide selection.

Jenna also points out the return of a wet weather pattern this winter should make it an interesting year on the tree disease and pest front.

 It could be the winds and rains will impact the overwintering pests and keep those numbers down this upcoming season. It also could be this year’s winter storms could trigger disease problems.

“Growers will have to be really vigilant and monitor their orchards closely this year,” Jenna says.  In farming, it is safe to say that every year brings a new surprise.

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