Vol. 123 (2010): Proceedings of the Florida State Horticultural Society
Citrus

Streptomycin and Copper Formulations for Control of Citrus Canker on Grapefruit

PDF
  • James H. Graham,
  • Megan M. Dewdney,
  • Monty E. Myers
Photos: Florida contains over half the wild orchid species found in the United States, at roughly 100 species. The endangered Ghost Orchid (Dendrophylax lindenii) makes its home in the area of southern Florida known as the Big Cypress Swamp (including the

Published 2010-12-01

Keywords

  • Xanthomonas citri subsp. citri,
  • copper residues,
  • phytotoxicity

Abstract

Control of citrus canker (caused by Xanthomonas citri subsp. citri) on grapefruit is required to reduce blemishes on fresh fruit. The objective was to evaluate formulations, rates, duration of residues for copper materials, combinations of copper materials and streptomycin, and application timing for effective canker control on young, fruiting grapefruit trees. Copper applications were made at 21-d intervals starting at spring flush in March until fruit were fully expanded in October. The period of fruit susceptibility to canker was established by applying sprays at 21-d intervals through the fruit growth period, with separate treatments ending spray application at each interval so that duration of protection varied and number of applications ranged from 3 to 11. The risk and predisposing factors for fruit phytotoxicity were also assessed. In addition, the residual activity of Kocide 3000 (copper hydroxide, Dupont) on fruit, as affected by the adjuvant polymer delivery system (PDS), was measured at 7, 14, and 21 d after application. Copper formulations containing copper hydroxide or basic copper sulfate (metallic rates of 0.67 to 1.12 kg/ha), varied from low to moderately effective for canker control depending on late-season, wind-blown rains. Copper pentahydrate, at a lower metallic copper rate/ha per application, provided equivalent control to other copper formulations. Streptomycin (FireWall, Agrosource, Inc.), alone or with a reduced rate of Kocide 3000, in July and early August gave equivalent control to Kocide 3000 alone. Copper phytotoxicity risk coincided with accelerated fruit growth after summer rains. Greater canker susceptibility of fruit in later season is likely because more prolonged opening of stomates in cooler weather may enhance bacterial entry, when coincident with more numerous windblown rain events. The only factor that led to significant reductions (P < 0.0001) in copper residue per fruit surface area over time was the Kocide 3000 concentration. PDS had no effect on the residue.
PDF

References

  1. Albrigo, L.G., L.W. Timmer, K. Townsend, and H.W. Beck. 1996. Copper fungicides—Residues for disease control and potential for spray phytotoxicity. Proc. Fla. State Hort. Soc. 110:67–70.
  2. Alva, A.K., J.H. Graham, and C.A. Anderson. 1995. Soil pH and copper effects on young ‘Hamlin’ orange trees. Soil Sci. Soc. Amer. J. 59:481–487.
  3. Anonymous. 2009. Citrus canker; movement of fruit from quarantined areas 7 CFR Part 301. Animal and Plant Health Inspection Service, Dept. of Agriculture. Federal Register 74(203):54431–54445, 22 Oct. 2009.
  4. Behlau, F., J. Belasque, Jr., A. Bergamin-Filho, J.H. Graham, R.P. Leite, Jr., and T.R. Gottwald. 2008. Copper sprays and windbreaks for control of citrus canker on young orange trees in southern Brazil. Crop Prot. 27:807–81.
  5. Behlau F., J. Belasque, Jr., J.H. Graham, and R.P. Leite, Jr. 2010. Effect of frequency of copper applications on control of citrus canker and the yield of young bearing sweet orange trees. Crop Prot. 29:300–305.
  6. Bock, C.H., J.H. Graham, T.R. Gottwald, A.Z. Cook, and P.E. Parker. 2010. Wind speed and wind-associated leaf injury affect severity of citrus canker on Swingle citrumelo. Eur. J. Plant Pathol. 128:21–38.
  7. Canteros, B.I., M. Rybak, A. Gochez, P. Velazquez, M. Rivadeneira, M. Mitidieri, S. Garran, and L. Zequeira. 2008. Occurrence of copper resistance in Xanthomonas axonopodis pv. citri in Argentina. Phytopathology 98:S30.
  8. Dewdney, M.M. and J.H. Graham. 2010. Citrus canker, p. 117–121. In: M.E. Rogers, M.M. Dewdney, and T.M. Spann (eds.). Citrus pest management guide, SP-43. IFAS, Univ. of Florida. PP-182.
  9. Gottwald, T.R. and M. Irey. 2007. Post-hurricane analysis of citrus canker II: Predictive model estimation of disease spread and area potentially impacted by various eradication protocols following catastrophic weather events. Plant Health Progress: doi:10.1094/PHP-2007-0405-01-RS.
  10. Graham, J.H., T.R. Gottwald, T.D. Riley, and M.A. Bruce. 1992. Susceptibility of citrus fruit to citrus bacterial spot and citrus canker. Phytopathology 82:452–457.
  11. Graham J.H., R.P. Leite, Jr., H.D. Yonce, and M. Myers. 2008. Streptomycin controls citrus canker on sweet orange in Brazil and reduces risk of copper burn on grapefruit in Florida. Proc. Fla. State Hort. Soc. 121:118–123.
  12. Graham, J., B. Castle, and T. Spann. 2008. Management recommendations for citrus canker and windbreaks. Citrus Ind. 89(4):16–18.
  13. Graham, J. and M. Dewdney. 2010. Management recommendations for citrus canker in 2010. Citrus Ind. 91(3):10–12.
  14. Graham, J.H., T.R. Gottwald, J. Cubero, and D.S. Achor. 2004. Xanthomonas axonopodis pv. citri: Factors affecting successful eradication of citrus canker. Mol. Plant Pathol. 5:1–15.
  15. Graham, J.H., T.R. Gottwald, and R.P. Leite. 2006. Prospects for control of citrus canker with novel chemical compounds. Proc. Fla. State Hort. Soc. 119:82–88.
  16. Leite, R.P., Jr. and S.K. Mohan. 1990. Integrated management of citrus bacterial canker disease caused by Xanthomonas campestris pv. citri in the State of Paraná, Brazil. Crop Prot. 9:3‑7.
  17. Ritenour, M. 2009. Fresh fruit issues: Proposed canker rule and MRLs. Citrus Ind. 90(9):18–19.
  18. Ritenour, M., J. Graham, and J. Narciso. 2008. Managing citrus canker for the fresh fruit industry. Citrus Ind. 89(10):20–22.
  19. Salas, H., J. Ramallo, and B. Stein. 2008. Observations on the effect of windbreak on canker incidence in a grapefruit orchard in Northwest Argentina. Proc. Intl. Soc. Citriculture, Wuhan, China. p. 237.
  20. Stein, B., J. Ramallo, L. Foguet, and J.H. Graham. 2007. Citrus leaf miner control and copper fungicide sprays for management of citrus canker on lemon in Tucumán, Argentina. Proc. Fla. State Hort. Soc. 120:127–131.