The laboratory was established in 1970 to study production and protection problems of fruit and tree nut crops. It sits on a secured 1,200 acre research farm. The research staff is comprised of two interdisciplinary research teams, the "Prunus Research Team" and the "Pecan Research Team." Represented disciplines are plant breeding, tree physiology, horticulture, plant pathology, entomology, and nematology. Research problems addressed by the laboratory are national and international in scope and are focused on providing producers of Prunus and tree-nut crops with knowledge, strategies, and cultivars that enable sustainable husbandry. Research programs support the USDA-ARS national programs in Crop and Commodity Pest Biology, Control, and Quarantine, Integrated Crop Production and Protection Systems, Plant Diseases, and Methyl Bromide Alternatives. The Location is tasked with the responsibility for supplying knowledge, technology, strategies, and genetic materials to extension specialists, to other scientists, and to industry groups. Specific recommendations and extension related resources are available from extension specialists within each state.
The Location's research seeks to enhance the production, value, and safety of pecan, peach, nectarine, and plum crops; to enhance economic competitiveness of farm operations engaged in the production of these crops; and to ensure the successful contribution of these crops to the American economy.
Specific research is directed at developing:
Improved scion and rootstock cultivars for peach, nectarines, and plums
Husbandry strategies that minimize alternate bearing of pecan
Control strategies for production limiting arthropod, microbial, and nematode pests peach, pecan, and plum.
A primary problem affecting U.S. pecan [Carya illinoinensis (K. Koch) Wangenh.] growers, brokers, retailers, and consumers is alternate bearing, often referred to as biennial bearing. Pecan trees naturally exhibit extreme biennial fluctuations in individual tree production and in nut quality characteristics. This fluctuation also occurs at the orchard, regional, and national level. Nearly all pecan cultivars exhibit this tendency. The instability of supply and quality causes major problems in the development of domestic and foreign markets and an attendant instability of revenue. The severity of biennial bearing is influenced by a multitude of biotic and abiotic factors that interact to influence the amount of stress experienced by trees and orchards. Research efforts focus on developing knowledge and strategies that minimize these stresses and their impact on trees to allow growers to maintain proper equilibrium between crop load and canopy photoassimilate production.
PRODUCTION LIMITING DISEASES
Pecan scab [Cladosporium caryigenum (Ell. Et Lang) Gottwald] is considered the most serious disease threat to pecan [Carya illinoinensis (K. Koch) Wangenh.)] production in the humid southeastern United States. Pecan scab control requires about nine applications of fungicide during the season beginning at bud break (early April) and continuing through mid August. The discovery by our laboratory of two new pathogens, a yet unnamed species of Phomopsis and Phytophthora cactorum (Lebert & Cohn) Schroeter, and the "rediscovery" of a third organism, Glomerella cingulata (Ston.) Spuald. & Schrenk, all of which are associated with late season fruit decline, have introduced new concerns for disease control. Recent discoveries indicating that the persistence of pecan fungicides was less than previously assumed and the curative properties were not effective under commercial conditions, have complicated the task of developing effective disease control. Thus, research efforts focus on the introduction and evaluation of new sprayer technology for fungicide application, developing knowledge of the pathogens and critical periods of susceptibility of the host, orchard management decisions to reduce tree stress, and disease control based on predicted criteria.
Pecan [Carya illinoiensis (K. Koch) Wangenh.] production throughout the U.S. is adversely affected by certain insect and mite pests. In the southeastern U.S., the pecan weevil [Curculio caryae (Coleoptera: Curculionidae)] is the predominant pecan pest and yearly losses are substantial. Due to a scarcity of practical biological options for managing the pecan weevil, chemical options are relied upon. Chemical control of the pecan weevil and other serious nut-feeding pests leads to the destruction of natural enemies in the orchard and can result in outbreaks of foliar pests. Foliar pests, such as aphids and mites, contribute to decreased nut production across all pecan producing regions by inducing foliage to senesce early or by decreasing rates of photoassimilation. Research efforts focus on integrated pest management strategies which reduce broad-spectrum pesticide inputs while maintaining profitability to the grower. Biological control agents, cultural practices, and target-specific insecticides will be used in a comprehensive approach to pest management in pecan.