Normally, pecan trees in the southern part of Eddy County in New Mexico’s Pecos Valley break dormancy around March 20 — but not this year. The buds didn’t begin breaking until the end of the month, with most trees waiting until the first part of April.
Woods Houghton, New Mexico State University agricultural Extension agent for the county, based in Carlsbad, attributes the late start to frigid weather Feb. 2, when temperatures nosedived to 10 degrees below zero. In fact, temperatures stayed below the killing frost level of 28 degrees for more than 87 hours, he says.
“Based on the records I searched, that hasn’t happened before.” Still, he doubts it will affect yields or harvest dates this year.
This reflects the unusual physiology of a pecan tree, which has three layers of buds, stacked one above another. It’s a survival mechanism — if the first bud dies, the next one will develop, Houghton explains. The deep freeze probably killed the topmost bud.
“I haven’t seen any damage to the second bud, the one that normally would have developed next year. It should start flowering about two weeks later than the first one would have. Once photosynthesis starts, a new third bud will form. Depending on heat units, the trees will probably catch up to the delayed start in June or July and by harvest you won’t notice any difference.”
The late bud break in the Carlsbad area is in contrast to the situation about 140 miles farther north in the county, where bud break in pecan trees began mid-March, as normal.
Even though those orchards are about 1,200 feet higher than in the south of Eddy County, the early February cold air that moved into the state from the north drained down to the lower altitudes. This probably led to colder conditions in Houghton’s area than in the higher elevations in the northern part of the county.
There could be an upside to the severe February cold spell for local pecan growers — it might mean less pressure from the pecan nut casebearer, the major insect threat.
First generation casebearer eggs are deposited on pecan nutlets soon after pollination, and shortly thereafter the larvae tunnel into the nutlets, often destroying all of the nutlets in a cluster.
“Normally, the first generation comes out the last week of May or first week of June,” Houghton says. “If nut development is delayed, maybe the nutlets will then be too small for the insects to lay eggs on them. That could really help reduce the population and make it easier to control the remaining two generations this season.”
Fertilizing after bud break
He expects growers to begin fertilizing trees two weeks after bud break. Typically they make a foliar application of nitrogen and zinc, either in the form of liquid urea zinc or a mixture of liquid ammonium sulfate and zinc. The zinc is needed to deal with high calcium carbonate levels in soils, which tie up the nutrient, preventing uptake by the tree roots.
Depending on leaf tissue analysis the previous year, Houghton typically recommends growers make a total of four applications every two weeks following bud break. Usual rates for each application include 2 to 3 pounds of zinc sulfate per 100 gallons of water and 1.5 quarts of liquid urea (32 percent N) per 100 gallons of water, or 1.5 quarts of NZn per 100 gallons of water.
“The goal is to provide 150 to 200 pounds of actual N per acre each year and to incorporate 150 to175 pounds of actual phosphorus in the form of P2O5 into the soil annually,” he says.
He says there are about 20 or so growers in the county who produce pecans for a living — far fewer than number of people in town who grow pecan trees in their yards. In fact, he estimates that the county’s town residents produce two pounds of pecans for every pound grown on commercial orchards.
The town growers sell their nuts to accumulators, who grade and ship them to shellers. This practice dates back to a county agricultural agent some 50 to 60 years ago, who promoted the production and sale of yard-grown pecans as a way for residents to pay their water bills. The practice spilled over to parts of neighboring Chaves County to the north, Houghton says.
Whether they produced pecans in their yards or in large orchards, New Mexico growers enjoyed record high prices for their 2010 crop. “Based on the state’s production and market prices, those nuts were worth about a nickel a piece,” he says.