By mid-November Greg Daviet, like many other pecan growers in New Mexico’s Mesilla Valley, was waiting for the first hard freeze of fall to bring down the leaves on his trees so he could begin this year’s harvest. Normally, that’s around the third of fourth week of November.
Daviet is operations manager for his family’s Dixie Ranch, near Las Cruces, which dates back more than a century. It includes 250 acres of pecan trees, predominately Western Schley along with Barton and Bradley varieties.
As expected this spring, based on a late-May nut count, his 2013 crop looks to be about average in size for an off-year like this one. Daviet estimates production will average about 1,400 pounds per acre.
This year, as usual, the majority of shucks in his orchards had begun opening in early October, signaling that the nuts had finished developing. Once the first shuck in his orchards opens it may take as long as six weeks before the last one does so. However, most of the crop finishes within a two- to three-week period, he notes.
A heavy monsoon storm system in early September provided at least a temporary break in the region’s continuing drought in the form of about 2.5 to 6 inches of rain that fell throughout the valley. Rainfall on his farm totaled a little over 3 inches.
“That storm put a little water in the reservoirs,” Daviet says. “But the only real relief from the drought would be a good snowpack in the mountains of northern New Mexico and southern Colorado, the source of our surface water for irrigation.”
Still, the September rains helped flush some of the salts out of his soils. Over the past several years, he’s had to supplement very limited supplies of surface water with well water with its higher salt content. That has added to salinity levels in his soils.
He also attributes some of that buildup of soil salts to his irrigation practices. Over the past several years, he’s followed the practice, common among the higher-producing pecan growers in his area, of applying less water per irrigation but irrigating more frequently.
“For whatever the reason, I wasn’t successful in replicating their results,” Daviet says. “Field sensors and salt damage showed that the tails of the fields weren’t getting enough water.”
So, early this summer, he switched from irrigating his orchards an average of every eight days, based on soil types, during the peak irrigation season to an average of every 12 days.
“We’re putting on the same total amount of water in a given period. We’re applying more each time but less frequently,” he explains. “This makes for a flatter wetting curve and it seems to be working.”
This year Daviet has been challenged by some unusual pressure from two of his major insect pests. One was the pecan nut casebearer. Larvae, tunneling into nutlets shortly after pollination, often destroy all nutlets in a cluster.
Daviet, who limits use of insecticides as much as possible, commonly can go two or three years without spraying for any insects. However, in May he had to spray his trees to protect them from a much higher-than-normal threat from the pecan nut casebearer.
Normally, populations of the insect peak and then subside several times through the season. “This year they showed up again around the first of July,” Daviet says. “They kept coming in a low trickle through the rest of the season. The numbers never got high enough at any one time to justify the cost of spraying them. However, that continuing, low population ended up causing more damage than we’ve seen from this insect pest in the past 10 years or so.”
The yellow aphid also surprised Daviet by not showing up until late September, rather than late August, when it normally appears.
“The orchards were very clean until around Sept. 25 when we started seeing a few of the aphids,” he says. “In the first week of October, their population blew up, covering the trees with aphids. We’ve never had an aphid problem so late in the season.”
Daviet chose not to spray them. However, a number of farmers experienced high enough pressure to warrant an insecticide treatment despite the late-season timing, he adds.
Normally, Daviet sprays for yellow aphids only in conjunction with any insecticide application he may be making at the time to control the pecan nut casebearer.
He prefers, instead, to rely on lady bugs to keep yellow aphid numbers below damaging levels. During the peak aphid season from the end of May until early July he distributes them weekly at the rate of 1 to 2 gallons every 20 acres.
“We don’t get the same level of control with the lady bugs as we do with chemicals,” Daviet says. “But, between them and the other beneficial insects, our biocontrol program is effective enough that, usually, we don’t have to spray later in the season to control the aphids.”
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