Monday, September 26, 2016

It’s No Time to Squirrel Away Those Mummy Nuts in Trees

Sounding like a broken record – or faulty CD – field scout Jenna Mayfield continues to repeat her message over and over to almond growers.

This time, though, Jenna makes another case after continuing to spot harvested orchards with trees littered with leftover nuts hanging on the trees: Watch out for pesky squirrels and other rodents in the future.

Squirrels can be troublesome for growers.      (UC IPM photo)
“In years past, we had so many squirrels in orchards. They will come before June,” Jenna says. Leaving nuts on the trees can become an invitation to these crop-damaging critters to bunk down in the orchards during their winter hibernation. 

In the Central Valley, ground squirrels breed from February through April and average seven to eight per litter, according to UC IPM. Normally, they will eat grasses and plants after waking up from their hibernation. Almonds become the squirrel’s food du jour after the nuts start to dry in the summer.

So here’s the catch. The squirrels may stick around and raise their family in the orchard if there are nuts from the previous season still in the trees.
Here is evidence of ground squirrel damage in an almond tree.

Ground squirrels “can damage young shrubs, vines, and trees by gnawing bark, girdling trunks (the process of completely removing a strip of bark from a tree's outer circumference), eating twigs and leaves, and burrowing around roots,” UC IPM says. Moreover, they “will gnaw on plastic sprinkler heads and irrigation lines.”

Of course, we can’t forget to mention once more that mummy nuts also become home to overwintering navel orangeworm.

“There are still trees with lots of nuts. It’s important to get your post-harvest work done. Don’t put it off,”  Jenna said. If growers don’t have a hand pole crew available, Jenna suggests going out with a leaf blower knock off the remaining nuts. 

Stink bugs are showing up in almonds.         (UC IPM photo)
Meanwhile, Jenna reports spotting stink bugs in the orchards. “That’s kind of odd.”  Normally, stink bugs are a threat from May through July. They will pierce through a hull into a kernel, causing the nut to become wrinkled or misshaped. 

 Black spots will show up on hardened kernels.  Jenna will continue to monitor this development.
In the fields, field scout Carlos Silva says many alfalfa growers are poised to extend the season into the early fall. Those who wrapped up another cutting this month, are now irrigating their fields. “They’re still planning to go into October.”

 In cotton, growers are mapping out their defoliation schedule.  Whitefly and aphids remain a threat to create sticky cotton.  “Growers will have to monitor for these pests right up to defoliation,” Carlos says.

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