Shoot Dieback of Planted Sand Pine Caused by Fusarium moniliforme var. subglutinans G. M. BLAKESLEE, Assistant Professor of Forest Pathology, School of Forest Resources and Conservation and Department of Plant Pathology, and S. W. OAK, Biologist, and S. H. KRATKA, Assistant in Forest Pathology, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, Gainesville 32611 subglutinans, as did cultures derived ABSTRACT BLAKESLEE, G. M., S. W. OAK, and S. H. KRATKA. 1980. Shoot dieback of planted sand pine from conidia transferred from sporo- caused by Fusarium moniliforme var. subglutinans. Plant Disease 64:703-704. dochia. The fungus isolates were morphologically the same (8) as those Fusarium moniliforme var. subglutinans was identified as the cause of shoot dieback in plantation- regularly obtained from slash pine grown Ocala and Choctawhatchee varieties of Pinus clausa in Florida. Isolates cultured from sand cankers as well as from sporodochia of F. pine were pathogenic to seedlings of both slash and sand pine. Sand pine seedlings were also moniliforme var. subglutinans from a susceptible to isolates of F. moniliforme var. subglutinans obtained from pitch cankers on slash variety of hosts and locations. (C. S. pine. Moses [personal communication] has recently isolated F. moniliforme var. subglutinans from a naturally occurring Pitch canker disease, caused by tested (3) by inoculating actively growing stem canker on a young Ocala sand pine Fusarium moniliforme Sheld. var. shoots of 2-yr-old potted slash pine and planted in a research area in Alachua subglutinans Wollenw. and Reink., is 18-mo-old potted Choctawhatchee sand County.) widespread in southern pine plantations pine seedlings. At least three replicate All isolates of F. moniliforme var. and seed orchards in the southeastern seedlings were inoculated for each subglutinanstested caused shoot dieback United States (2,6,9). Damage has been isolate-host combination. Additional on inoculated slash and sand pine most severe in slash pine (Pinus elliottii sand pine seedlings (three per isolate) seedlings. All inoculated seedlings Engelm. var. elliottii) plantations in the were inoculated with isolates of F. developed advanced pitch canker pine flatwoods regions of Florida, where moniliforme var. subglutinans obtained symptoms typical of those reported in the fungus causes branch cankers from a branch canker on a slash pine previous inoculation tests (3,5). All resulting in shoot dieback, reduced (Volusia County), a sporodochium on a water-inoculated controls were asympto- growth rates, stem deformity, and slash pine (Liberty County), and an adult matic. The cross-pathogenicity of the mortality (4,9,10). Although the known deodar weevil (Pissodes nemorensis, slash and sand pine isolates on both hosts host range for F. moniliforme var. Volusia County). Seedlings inoculated follows the pattern of nonspecificity subglutinans is rather broad (1,2,5,7) and with sterile water served as controls for among various pine hosts described by includes most of the economically each inoculation series. All seedlings were Dwinell (5). important southern pines, neither the incubated in a greenhouse for 8 wk under Because of its currently limited Ocala nor the Choctawhatchee varieties favorable conditions for plant growth. distribution and low incidence on sand of sand pine (Pinus clausa (Chapm.) pine, pitch canker does not appear to Vasey var. clausa Ward. and var. RESULTS AND DISCUSSION pose an immediate threat to this species. immuginata Ward., respectively) have Field conditions and disease symptoms. However, the known destructive potential been recognized as natural hosts. The affected Ocala and Choctawhatchee of this disease (4,6,9,10), the demon- We report the isolation of F. monili- sand pines were growing on deep, strated cross-pathogenicity of slash and forme var. subglutinans from cankers on excessively drained, sandy soils typical of sand pine isolates, and the increasing sand pine, describe the symptomatology the native sandhill habitat of the species. interest in sand pine management suggest of the naturally occurring infections, and The Ocala sand pine plantation was that pitch canker could become a pest establish proof of pathogenicity. adjacent to a planting of young slash management problem for this species in pines heavily infected with pitch canker. the future. MATERIALS AND METHODS No potential inoculum source for the In December 1978, we observed shoot Choctawhatchee sand pines was evident LITERATURE CITED dieback on numerous trees in a 6- to 8-yr- nearby. 1. ARTMAN, J. E. 1973. Eastern white pine-A old plantation new host for Fusarium lateritium f. pini. Plant of Ocala sand pine in Although the cankers were resinous Dis. Rep. 57:182-184. western Calhoun County, Florida. and the xylem tissues beneath the cankers 2. BERRY, C. R., and G. H. HEPTING. 1969. Similar symptoms were observed in were resin soaked, the resin flow from the Pitch canker of southern pines. USDA For. December 1979 on several planted 5-yr- cankers on the sand pine shoots was Scrv., For. Pest Leafl. No. 35. old Choctawhatchee sand pines in Taylor 3. BLAKESLEE, G. M., S. H. KRATKA, R. A. much less copious than the resinosis SCHMIDT, and C. S. MOSES. 1978. County. In both instances, conspicuous, associated with pitch cankers on slash Sporodochia of the pitch canker fungus girdling cankers subtended symptomatic pine. The symptoms were similar to pitch (Fusarium moniliforme var. subglutinans) as shoots, samples of which were collected canker infections on shoots of loblolly found in diseased slash pine in Florida. Plant Dis. for diagnostic evaluation and isolation. Rep. 62:656-657. pine (5,6). Small salmon-pink sporo- 4. BLAKESLEE, G. M., and S. W. OAK. 1979. The pathogenicity of several isolates dochia were detected in bark crevices Significant mortality associated with pitch obtained from the diseased trees was above the cankered areas on some of the canker infection of slash pine in Florida. Plant Dis. Rep. 63:1023-1025. Choctawhatchee shoots. Cankered 5. DWINELL, L. D. 1978. Susceptibility of shoots southern pines to infection by Fusarium Florida Agricultural ranged from 1 to 7 cm in diameter; Experiment Stations Journal moniliforme var. subglutinans. Series 2324. both terminal and lateral shoots were Plant Dis. Rep. infected. 62:108-111. 6. DWINELL, L. D., P. L. RYAN, and E. G. Isolations and pathogenicity. Isolations KUHLMAN. 1977. Pitch canker of loblolly pine 0191-2917/80/07070302/$03.00/0 from cankers on numerous trees in seed orchards. Pages 130-137 in: Proc. 14th ©1 980 American Phytopathological Society consistently yielded F. moniliforme var. South. For. Tree lmprov. Conf., Gainesville, FL. Plant Disease/July 1980 703 .