Apple growers shift to peaches
Casas Grandes growers say they’re feeling the effects of global warming.
Casas Grandes grower Dana Johnson explains his cousin Lester’s peach growing systems.
As the climate has gotten hotter, fruit growers in Chihuahua, Mexico, have been switching from apples to peaches. In the Casas Grandes area there are now 2,000 hectares (5,000 acres) of peaches and only 500 hectares (1,250 acres) of apples.
Grower José Luis “Pepe” Armendariz said that ten years ago there were more apples than peaches.
“The reason is, the climate has changed a lot,” he said. “We have fewer chilling hours, and that’s the main problem. We’re trying to grow peaches, especially California peaches that have a lower chilling requirement.”
Last winter, the region had only 500 chilling hours. A lack of chilling leads to a lack of bud break and areas of blind wood on the tree limbs, despite treatments with either Dormex (hydrogen cyanamide) or Revent (thidiazuron).
Armendariz said he’s been switching his apple plantings to Gala because it requires fewer chilling hours than other varieties. “We cannot grow any more Red Delicious,” he said. “It needs over 1,000 hours.”
Another reason for switching to Gala is to target the early market, when prices are higher. Area growers started out growing Royal and Imperial Gala, but are moving to more highly colored strains, such as Buckeye and Brookfield. The Mexican market likes a striped apple, he observed.
But the fruit has been small. Armendariz said he is trying to improve fruit size by growing smaller trees on Malling 9 rootstocks. He started out with sprinkler irrigation for the first two years, then switched to drip irrigation, but has undertree sprinklers for frost protection. “We’re trying to be more efficient with irrigation,” he explained. “Water here is getting scarce.”
Despite the scarcity of water, growers in the Casas Grandes area of Chihuahua report trouble with a root disease called Texas root rot (Phymatotrichopsis omnivora), a pathogen that is fairly common on fruit and nut trees in Mexico and the southwestern United States, but unknown in northern areas. The soil-borne fungus attacks plant roots, which are then unable to take up enough water to maintain the plant in warm weather.
Cornell horticulturist Dr. Terence Robinson said the problem in Armendariz’s orchard might actually be phytopthora, rather than Texas root rot. The Malling 9 rootstock can become infected in clay soils where irrigation is too frequent and water sits around the shank.
Armendariz recently went to Spain with a group of Mexican fruit growers to look at peach production and came back enthused about the growing concepts they saw, such as mechanical hedging to control the size of the tree.
Lester Johnson was one of the first in the Casas Grandes area to try growing peaches on a V system. With trees anywhere from three to six feet apart, he had great success with it, harvesting 40 bins per acre from the early variety Rich May. During a visit to Chihuahua, International Fruit Tree Association members met with his cousin Dana Johnson, who is taking care of the orchard while Lester is away on a three-year church mission.
Lester has multiple varieties, with the harvest season extending from mid-May to mid-October, to spread the risk. He has also been planting some early Michigan apricot varieties to get early cash flow.
“Lester has been very innovative,” Robinson commented.
Most winters, the low temperatures are between 15 and 30°F, but there are big swings between night and day temperatures. Daytime temperatures in winter can rise to the 50s and 60s. It snows once or twice each winter, though the snow never accumulates.
The trees bloom in late February or early March, and Lester begins thinning soon afterwards. He has scored the limbs in an effort to improve fruit size. “It’s been successful, but not enough to warrant the amount of work that goes into it,” Dana observed. “With early thinning, he can get good-size peaches.”
With the elevation a mile high, spring frost control is a serious concern. Lester uses undertree sprinklers for both irrigation and frost control, and can gain up to 6°F in temperature—close to the amount of heating that burners used to provide before the high price of fuel made them uneconomical. The groundwater used for frost control comes out at a temperature of between 65 and 70°F, which provides an immediate heating effect. The Johnsons keep a ground cover to optimize the surface area for ice formation during frost control.