Over 57,000 acres of pecans [Carya illinoinensis (Wangenh.) K. Koch] are planted in the Western Region, which includes far west Texas and southern areas of New Mexico, Arizona, and California. Western Schley' is the main cultivar planted, with Wichita' trees used as pollenizers. All orchards are flood-irrigated and almost no diseases are present. The pecan aphid complex is the predominant insect problem; however, pecan nut case bearer and hickory shuckworm may be a problem in future years. Orchard crowding is becoming a problem, and growers are thinning orchards and transplanting trees to new sites.
The Western Pecan growing region extends from West Texas to California, it has been the most constant and dependable pecan production area in the US of America. All orchards are irrigated with water wells with the exception of the Mesilla Valley, located North and South of Las Cruces, NM (Dona Ana County) and El Paso Valley in Texas, located south of the Mesilla Valley. California and Arizona pecan orchards have less potential problems with late freezes than New Mexico and West Texas; early freezes (late October) could also be problem. Usually the first freeze occur Mid to late November. Pecan growers start harvesting after early freezes knock leaves off the trees.
Pecan orchards in the Western Region spread over 57,780 acres in far west Texas, southern New Mexico, southern Arizona, and southern California (Herrera, et al., 1990). The combined production of all these areas in 1992 amounted to 60 million pounds (Table 1). Production increased in 1993 but price per pound was lower. The reverse was true in 1994. "Western Schley"is the predominant cultivar grown in the Wester Region and "Wichita", which is planted mainly as a pollenizer, is second. Some orchards in Arizona and California have Wichita as the main cultivar and use Western Schley as the pollenizer. Some of the old orchards in Arizona and New Mexico have the Ideal (Bradley) cultivar as a pollenizer. No natives are grown int Western Region.Table 1. Acreage and pecan production in the Western pecan growing region of the United States, 1992
| State | (Million Lbs) | (US$ Million) | ||
| Arizona | ||||
| California | ||||
| New Mexico | ||||
| Texas(Far W.) | ||||
| Total |
z - Estimated
Source: National Agricultural Statistics Service, USDA (December
Crop Report 1993)
Flood irrigation is used in most areas either where water is supplied from reservoirs or water wells. Furrow irrigation (water wells) and high pressure irrigation (mainly trickle or micro spraying) also are used. Usually, most orchards are changed to flood or furrow irrigation once they reach full production (12-14 years). However, more and more growers are retaining high-pressure irrigation systems after orchards reach full production.
The most common plant spacing in the western region is 30 ft. X 30 ft. Tree crowding eventually occurs, and some growers thin out trees to prevent shading which results in low quality nuts and a decrease in production (Herrera, 1987; Wheeler, 1983). Growers usually wait too long to remove trees; therefore pecan production usually increases with good tree removal practices. Tree removal should be done when sunlight in the orchard floor does not reach 30-40 % in the middle of the day (Malstrom, et al. 1982). It is expected that in the future all orchards will be thinned to 60 ft. X 60 ft. spacing.
Research is underway at New Mexico State University to find out the best Pruning and fertilising practices needed for transplanted pecan orchards. However, more research is needed to answer grower's questions related to orchard management for mature transplanted pecan trees. Fertilisation practices are centered around nitrogen and zinc nutrition. In established orchards, 4-5 zinc sprays are applied early in the season when leaves are expanding. Every year, 150-200 units of nitrogen are incorporated into the soil, some growers apply more than 200 units of nitrogen; usually nitrogen rates are split into two or three applications, sometimes more if the fertiliser is distributed with irrigation water.
Pecan trees in the Western Region do not suffer from most of the disease problems encountered in the Eastern Region. Until recently, problems have included only the aphid complex, black margined Monellia caryella (Fitch); yellow pecan aphid, Monelliopsis pecanis (Bisell); and the black pecan aphid Melanocallis caryaefoliae (Davis). Insecticides used to control aphids are highly successful, but aphid resistance develops with continual use. Currently, thanks to extension programs nationwide, pesticide application timing has been optimised and fixed-schedule applications have been avoided for the prevention of resistance buildup (Estes, 1987). The number of growers successfully using beneficial insects (lacewing flies, lady beetles) to control aphids has increased every year.
The pecan nut casebearer (PNC) Acrobasis nuxvorella (Nuenzing) was spotted first in El Paso, TX, in 1988 (Glogoza et al., 1989). Hickory shuckworm (HSW), Cydia caryana (Fitch), was found first in west Texas in 1990 (Glogoza and Davis, 1991). Both were reported for the first time in the lower Mesilla Valley in New Mexico in 1992 (Davis and Lucero, 1993). The PNC was found for the first time in a commercial orchard in 1994, and an insecticide had to be sprayed. Pecan growers will have to change their pest control programs when these insects become established in the Western Region. However, some growers would like to cease spraying insecticides altogether.
New Mexico State University's entomologists are researching this subject to find beneficial organisms that attack these pests; they are working with a beneficial insect from other pecan-growing areas of the country and are hoping these insects will adapt well in New Mexico (Ellington and Carrillo, 1992).
The earliest date growers can start pecan harvesting in the Western Region is usually around the second half of November. Most growers in the area wait for the first hard freeze to bring pecan moisture down and to cause shucks to open. Usually 'Western Schley' pecans yield 55-60% kernel and have about 63-74 nuts per pound. 'Wichita' pecans yield from 56-62% kernel and have 50-62 nuts per pound; sometimes they are larger (Herrera, 1994).
California is the newest pecan production area in the Western Region. It has a more varied climate than the other states in the region, and may possibly be able to grow profitably varieties which the other western states are unable to grow. Currently California grows about 3,500 acres of pecans, mainly in the southern San Joaquin Valley, encompassing Tulare, Kings, Fresno, Kern, Madera, and Merced counties. Some orchards also are also located in the far northern counties of Butte and Colusa. Tree age varies from one to fifteen years; most pecan acreage is around ten years old. Annual production from this developing acreage is currently listed around 2-3 million pounds (Herrera et al., 1990).
There are about 17,000 acres of pecan trees in Arizona mainly in Cochise, Pima, Pinal, Maricopa, Mohave, La Paz and Yuma counties. Most orchards are over 20 years old. Arizona and California pecan orchards are harvested earlier than other areas in the western region. New Mexico and far west Texas are considered to have similar soils and climate. A high water table exists in some acreage located in the lower El Paso Valley. The same cultivars are grown, and similar orchard problems exist. The 1992 pecan orchard survey conducted in New Mexico by the New Mexico Department of Agriculture revealed a total of 25,280 acres in the state, up 4,464 acres (22.5%) from the previous survey conducted in 1985. Out of this new acreage, 1,485 acres were transplanted trees. All 25,280 acres of pecans planted in New Mexico are grown in the southern area--70% of which are located in Doa Ana County; the rest occur in the adjacent counties of Luna, Sierra, Otero, Lea, Eddy, and Chaves. Do¤a Ana and Chaves counties had the most acreage of transplanted trees.
Far west Texas, defined as the area south of Midland-Odessa and west of a line from Big Springs to Del Rio, has approximately 12,000 acres, with 50% of that located in El Paso County. The remainder occur in Pecos and Culberson counties and the Permian Basin area. The combined annual production from far west Texas and southern New Mexico is about 42 million pounds (Herrera et al., 1990).
Five of the top 10 pecan-producing counties in the United States are located in the western region. In fact, the top three counties in the country are situated in this region. Do¤a Ana, NM, is first followed by El Paso, TX and Pima, AZ. Pinal county in Arizona is ranked eighth followed by Pecos, TX. (U.S. Department of Commerce, 1992). There are four shelling plants in the Western Region: Visalia, CA; Sahuarita, AZ; Las Cruces, NM; and El Paso, TX. Another plant in Juarez, Mexico, State of Chihuahua, services pecan growers from northern Mexico.
The Western Pecan Growers Association Annual Conference includes an educational program, a trade and equipment show, a pecan nut competition, and the Food Fantasy, where young and adult cooks compete for prizes with food or dessert items from recipes which include pecans. The conference is held every year during the first weekend in March. A 5-day Pecan Orchard Management Shortcourse is offered the first week in June (every other year, in even years) at New Mexico State University at Las Cruces.
In spite of having received good pecan prices during the 1989-1992 period and in 1994, it appears that pecan acreage in the Western Region will not increase significantly in the near future. Few orchards have been planted in New Mexico and Arizona in the last five years. In fact, a reduction of 3,000 acres of pecans took place in the last three years in Arizona, mainly due to high water costs. Salinity and poor nut quality due to hot weather also contributed to the reduction. Most new plantings have taken place in far west Texas (Midland and Pecos counties), and in California. Any significant pecan planting that may occur in the future will probably take place in California.
The increased acreage in the Western Region has resulted mainly from removing trees from crowded orchards. Most of the newly planted acreage is in Mexico, especially in the state of Chihuahua, which has a climate like southern New Mexico and west Texas.
The western pecan growing region has a potential to produce over 100 million pounds of pecans within the next 10 years. No significant new plantings are foreseen within the same period. Northern Mexico, with the same type of climate, could also produce 100 million pounds in the next 10 years. Significant acreage of new plantings have occurred during the last 5 years in Mexico. Water availability may become a problem for these areas; water use for agricultural purposes is ranked in importance behind population and industry needs. However, a more pressing need for western pecan growers is to receive the best prices for their production. Marketing and promotional efforts for pecans should be a high priority for western region pecan growers.
Davis, J. H., and V. S. Lucero. 1993. Update on the status of pecan nut casebearer and hickory shuckworm in El Paso
County, Texas and Dona Ana County, New Mexico. 1992. Western Pecan Conference Proceedings 27:6-16.
Ellington, J. J. and T. Carrillo. 1992. Biological control of pecan insectsin the Mesilla Valley, NM. Western Pecan Conference Proceedings 26:10
Estes, P. M. 1987. Pecan aphid biology and its relation to pest management and resistance development. Proc. Southeastern Pecan Grower Association 80-133-135.
Glogoza, P., J. White and S. Helmers. 1989. Pecan nut casebearer. Western Pecan Conference Proceedings 3:97-104.
Glogoza, P., and J. H. Davis. 1991. The discovery of hickory shuckworm, Cydia Caryana, in El Paso County. Western Pecan Conference Proceedings 25:2-6.
Herrera, E. A., S. Helmers, G. S. Sibbett and M. Kilby. 1990. Pecan growing areas in the western region: current situation and future outlook. Pecan Husbandry: Challenges and Opportunities. 1st National Pecan Workshop
Proceedings USDA-ARS Publication 96 pp 159-162.
Herrera, E. 1987. New Mexico grower meets with success in tree transplanting. Pecan South 21(3):27-29.
Herrera, E. 1994. Pecan varieties for New Mexico. New Mexico State University, Cooperative Extension Service Guide H-639.
Malstrom, H.C. and R. D. Riley. 1982. Continuous hedge pruning affect light penetration and nut production of western pecan trees. The Pecan Quarterly 16(3):4-15.
United States Department of Commerce. 1992. Census of Agriculture.
Wheeler, C. 1983. Tree removal in mature orchards. Western Pecan Conference Proceedings, 17:116-118.