OVERTON — El Nino, aided and abetted by La Nina, will mean fewer peach trees producing a crop and perhaps even limb loss and tree death in some orchards.
Last month, horticulturists were worried that a late freeze would damage the peach crop in East and Central Texas. It now appears the freeze did little harm, but the damage was already done by last summer’s drought, which has been blamed on El Nino, and the unseasonably warm winter, attributed to El Nino’s sister, La Nina.
“It’s the worst combination of weather conditions for peaches that I’ve seen in my 25 years as a horticulturist in Texas,” said Marty Baker of the Texas Agricultural Extension Service in Overton.
Last year’s drought hurt peach trees as it did many other tree species in Texas. But the trouble for Texas peach orchards really began with the abnormally hot and dry weather of late August and September, which stunted new bud growth. As a result, Baker said, a large proportion of peach buds did not reach full maturity in many orchards.
“This may lead to a tremendous drop of fruit in late April and May,” Baker said.
Peach orchards were dealt a second blow by the extremely warm winter. Both January and February had record high temperatures both at night and during the day. Peach trees need a certain number of hours of temperatures in the range of 42 to 45 degrees, called “chilling hours.” The tree goes through hormonal changes that lead it to come out of dormancy and start producing complete flowers and leaves. Different peach tree varieties need different amounts of chilling hours.
Most peach trees planted from Tyler to Nacogdoches are matched to the 800 to 850 chilling hours usually received. Farther south, producers typically plant peaches matched to the 700 to 750 chilling hours received.
Not only were many days and nights last winter warmer than 42 to 45 degrees, some had “negative” chilling hours. That is, conditions were so unseasonably warm that they are considered to have subtracted from the chilling hours already received. As a result, most peach-growing areas are short about 200 chilling hours needed to produce a good crop, Baker said.
Not only do peach trees need chilling hours to produce full-sized fruit, some varieties also need a minimal number of chilling hours to produce leaves. In the field, these varieties may produce very few leaves, as few as one every two feet along a branch. Horticulturists call this syndrome “naked branches.”
Trees with naked branches are subject to sun scald, limb loss and even death. As the tree comes out of dormancy, its few leaves won’t protect it from the sun, and the thin bark will blister and scald. Without leaves to support photosynthesis, the tree will soon exhaust its stored nutrients. Limbs will drop, and many older trees — possibly even some younger trees — will die.
Exactly how severe and widespread these conditions won’t be clear until mid- to late-April, Baker said.
“We’re concerned about what’s going to happen in the next two or three weeks. If peach trees bearing heavy fruit loads do not put on leaves or put on leaves too late, we could see a lot of tree death.”
All is not lost, however. Orchard owners typically plant 5 percent to 10 percent of their trees with low-chilling hour varieties, such as Texstar, Flordaking, Junegold and Juneprince. Most years, the peaches of these low-chilling hour varieties are lost to early freezes. These varieties should produce a good peach crop this year.
To suggest strategies for producers in the interim puts horticulturists in a tough situation.
“Horticulturists and orchard owners are playing out a guessing game since these conditions have never happened before.” Baker said. He suggested peach tree owners consider the following:
— Thin all fruit off the tree. This will put fewer demands on an already stressed tree and perhaps save its life. If they leave the fruit, peach tree owners are gambling what will be a minimal crop against the life of their trees.
— DO NOT fertilize. Because the tree may not have enough leaves to support a vigorous photosynthesis, it will not take up the fertilizer and the nitrogen will likely burn the roots.
— Whitewash the tree’s lower limbs and trunk with latex paint, diluted one part paint to three parts water. The whitewash will help prevent sun scald while leaves develop. It also helps discourage peach tree borers.
— Maintain peach tree borer control if fruit is absent and leaves begin to fill the canopy.
— Prune off all dead limbs. It is not necessary to use pruning paints, but it is a good idea to whitewash the limb stubs, Baker noted.
Baker also noted that apple trees, which also need chilling hours, are beginning to show the same symptoms.
On a more positive note, the same weather conditions that threaten peach trees, are producing excellent plum, fig, blueberry, blackberry and strawberry crops this year.
Strawberry harvests, which are already in season, are up 60 to 100 percent, with some fields producing as much as 20,000 pounds per acre. Warm winter weather resulted in larger plants and a bigger bloom set.
A late freeze lightly thinned the blueberry crop just enough, producing not just bigger per-acre yields but bigger, better quality berries, Baker said. He also expects other berry crops, such as blackberries, to be excellent this year.