ACCESSION NO: 0195509 SUBFILE: CRIS
PROJ NO: LAB93624 AGENCY: CSREES LA.B
PROJ TYPE: MCINTIRE-STENNIS PROJ STATUS: NEW
START: 31 JAN 2003 TERM: 31 JAN 2007 FY: 2004
INVESTIGATOR: Jones, J. P.
PERFORMING INSTITUTION:
PLANT PATHOLOGY & CROP PHYSIOLOGY
LOUISIANA STATE UNIVERSITY
BATON ROUGE, LOUISIANA 70893
The Occurrence and Development of Loblobby Pine Decline
NON-TECHNICAL SUMMARY: Loblolly pine decline strikes trees which are 40+ years old and causes serious losses in these older regenerated stands. The purpose of this project is to refine and confirm our understanding of the conditions necessary for development of loblolly decline and develop management practices which minimize or prevent the occurrence of this disease.
OBJECTIVES: The overall objective for this project is to confirm that we know the conditions which lead to the development of loblolly decline and are able to predict its occurrence. This will enable the development of management recommendations designed to minimize its occurrence, which is the ultimate goal. Some of the intermediate goal-oriented tasks are: 1. To use spatial data to develop a method to determine whether and how much loblolly decline is present and to predict where and when it will occur. 2. To compare symptoms of Loblolly decline and Leptographium spp. levels as predicted by spatial data with observed symptoms and Leptographium levels on selected sites. 3. To determine the occurrence and role of Phytophthora cinnamomi on understory woody bushes and hardwood trees.
APPROACH: Geographical data will be obtained from the U.S. Forest Service GIS Web page (www.r8web.com/GIS) and topographic data from the DEM in the GeoCommunity GIS Data Depot database (http://data.geocomm.com/). The topographical features most predictive of loblolly pine decline in Alabama were slope, aspect and surface convexity of aspect. Loblolly pine stands in the Kisatchie National Forest that have values for these features similar to both the decline and healthy stands in Alabama will be identified. At each selected site, one central plot and three sub-plots identical to it will be established; sub-plots will be marked off 120m away from the central plot at bearings of 120, 240, and 360 degrees. We will monitor the sites for development of decline symptoms and sample one sub-plot every year for three years to check for the presence/absence of Leptographium species in soil and/or roots. Roots of three dominant/co-dominant trees from each plot will be sampled according to Otrosina's modified two root technique, except we will take increment hammer samples to minimize damage to the root system. We will also test for presence of Phytophthora cinnamomi in soil and roots of both loblolly and woody understory species. Soil samples within 6 inches of sampled roots will be taken with a soil probe. Live crown ratio, crown light exposure, crown position, crown density, crown dieback and foliage transparency values will be determined for all loblolly pines with diameter breast height (dbh, 137 cm above ground) 12.7 cm or more to describe relative tree health. We will also determine tree species composition (pines and hardwoods) of each site, dbh., age, growth increment (5 and 10 yr), and basal area (10 factor) for the loblolly pines and total trees present. These measurements will provide a measure of site conditions, stand density and influence of external stresses. There will be 16 sites selected, eight with DEM characteristics in agreement with the symptomatic sites previously studied in Alabama, and eight which have the characteristics of non-symptomatic sites. Half of the sites selected will be composed of loblolly 40+ years old and half of trees <30 years old. All data obtained will be incorporated into the DEM for the Kisatchie to test the predictive value of the selected parameters. Loblolly root pieces will be placed on CSMA (malt extract agar, containing 800 mg/l of cycloheximide and 200 mg/l of streptomycin sulfate) a medium selective for Leptographium spp. One ml. aliquots of a soil suspension made of 10 gms. soil and 40 mls. of water will also be spotted onto CSMA plates for soil isolations. Subcultures of any Leptographium will be established from each root piece and root sample for identification to species. Phytophthora cinnamomi will be isolated using a standard baiting technique combined with a selective medium. The basic technique consists of submerging the sample to be tested, either root piece or soil, in 300 mls. of water, and floating 2 cm disks of camellia leaves on the water surface; after 24 to 48 hours the disks are placed on a selective medium for culturing of P. cinnamomi.
PROGRESS: 2004/01 TO 2004/12
Leptographium species, particularly L. serpens and L. procerum are involved in southern pine decline. L. procerum was recovered from soil in close proximity to roots of declining trees but no other Leptographium appear to have a soil phase. Preliminary studies in Arkansas of dying and dead outplanted shortleaf seedlings revealed that 100% of the roots and the soil around them were infected with L. procerum. L. serpens has been associated with wilting longleaf in Georgia, Alabama and Louisiana. It has also been isolated from expanding shortleaf disease centers, resembling the disease centers of red pine decline. We are therefore actively investigating the possibility that, under some circumstances, Leptographium species may be significant pathogens by themselves. The southern pine decline hazard map developed in this lab is >90% accurate in Alabama and Georgia and is undergoing evaluation and refinement for use in Louisiana, Mississippi, Arkansas and Texas. The decline risk map model also has been applied to historical data of southern pine beetle (SPB) outbreaks and >85% of SPB spots initially appear in predicted high hazard (for decline) sites. This methodology offers a new approach to SPB hazard mapping for the landscape level, using geographical information systems. This possibility is being investigated.
IMPACT: 2004/01 TO 2004/12
The risk mapping technique developed in this lab has been adopted by Forest Health Protection arm of the Forest Service, and by the U.S. Army at Ft. Benning, Ga., as a major management tool. This technology will have a major impact on the practice of forestry in the southeastern United States.
PUBLICATIONS: 2004/01 TO 2004/12
1. Eckhardt, L.G., Jones, J.P., and Klepzig, K.D. 2004. Pathogenicity of Leptographium species associated with loblolly pine decline. Plant Dis. 88:1174-1178.
2. Eckhardt, L.G., Goyer, R.A., Klepzig, K.D., and Jones, J.P. 2004. Interactions of Hylastes species (Coleoptera:Scolytidae) with Leptographium species associated with loblolly pine decline. J. Econ. Entomol. 97:468-474.
PROJECT CONTACT:
Name: Jones, J. P.
Phone: 225-578-1383
Fax: 225-578-1415
E-mail: jpjones@agcenter.lsu.edu