AS  Vol.3 No.7 , November 2012
Use of carnauba based carrier for copper sprays reduces infection by Xanthomonas citri subsp. citri and Diaporthe citri in Florida commercial grapefruit groves
Abstract: Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a bacterial disease of citrus and results in peel blemishes rendering fresh fruit unsalable. Xcc is most active in warm, wet Florida summers where tissues are infected during periods of active growth. Melanose, caused by Diaporthe citri, is common in citrus producing countries, but, like canker, is only important for fresh market fruit. To control canker and melanose, Florida growers spray trees with copper formulations (Cu), but these sprays are removed by strong rains and intense radiation of Florida summers. A study was undertaken in FL commercial grapefruit groves in 2009 and 2010 to assess the efficiency of a spray combining copper with a specially formulated, hydrating wax (WashGard?) (WG). Using a 21-day spray schedule for the season, fruit were sprayed with WG + Cu, Cu and Control (no spray). Fruit from trees sprayed with WG + Cu had approximately 10 and17% more canker free fruit in 2009 and 2010 respectively compared to trees sprayed with copper alone. Compared to control trees the canker free fruit incidence was increased by ≈10% in 2009 and 57% in 2010. For melanose there was 40% more disease free fruit (treated) over fruit from trees with no treatment in 2009 and approximately 20% more in 2010. Controlling infection with this spray significantly reduces citrus canker and melanose, increasing the percentage of marketable fruit.
Cite this paper: Narciso, J. , Widmer, W. , Ference, C. , Ritenour, M. and Diaz, R. (2012) Use of carnauba based carrier for copper sprays reduces infection by Xanthomonas citri subsp. citri and Diaporthe citri in Florida commercial grapefruit groves. Agricultural Sciences, 3, 962-970. doi: 10.4236/as.2012.37117.

[1]   Brunings, A.M. and Gabriel, D.W. (2003) Xanthomonas citri: Breaking the surface. Molecular Plant Pathology, 4, 141-157. doi:10.1046/j.1364-3703.2003.00163.x

[2]   Das, A.K. (2003) Citrus canker: A review. Journal of Applied Horticulture, 5, 52-60.

[3]   McGuire, R.G. (1988) Evaluation of bactericidal chemicals for control of Xanthomonas on citrus. Plant Disease, 72, 1016-1020. doi:10.1094/PD-72-1016

[4]   Schubert, T.S., Rizvi , S.A., Sun X., Gottwald, T.R., Graham, J.H. and Dixon, W.N. (2001) Meeting the challenge of eradicating citrus canker in Florida, again. Plant Disease, 85, 340-356. doi:10.1094/PDIS.2001.85.4.340

[5]   Agostini, A., Bushong, P.M., Bhatia, A. and Timmer, L.W. (2003) Influence of environmental factors on severity of citrus scab and melanose. Plant Disease, 87, 1102-1106. doi:10.1094/PDIS.2003.87.9.1102

[6]   Timmer, L.W., Garnsey, S.M. and Graham, J.H. (2000) Compendium of citrus diseases. 2nd Edition, APS Press, St. Paul.

[7]   Timmer, L.W. and Kucharek, T.A. (2009) Melanose. EDIS # pp150, University of Florida, IFAS Extension, Fort Pierce.

[8]   Mondal, S.N., Agostini, J.P., Zhang, L. and Timmer, L.W. (2004) Factors affecting pycnidium production of Diaporthe citri on detaches citrus twigs. Plant Disease, 88, 379-382. doi:10.1094/PDIS.2004.88.4.379

[9]   Ziv, O. and Frederiksen, R.A. (1983) Control of foliar diseases with epidermal coating materials. Plant Disease, 67, 212-214. doi:10.1094/PD-67-212

[10]   Walters, D.R. (2006) Disguising the leaf surface: The use of leaf coatings for plant disease control. European Journal of Plant Pathology, 114, 255-260. doi:10.1007/s10658-005-5463-7

[11]   Kudsk, P., Mathiassen, S.K. and Kirknel, E. ( 1991) Influence of formulations and adjuvants on the rainfastness of maneb and mancozeb on pea and potato. Pesticide Science, 33, 57-71. doi:10.1002/ps.2780330107

[12]   Rich, S. (1954) Dynamics of deposition and tenacity of fungicides. Phytopathology, 44, 203-213.

[13]   Van Zyl, S.A., Brink, J.C., Calitz, F.J. and Fourie, P.H. (2010) Effects of adjuvants on deposition efficiency of fenhexamid sprays applied to Chardonnay grapevine foliage. Crop Protection, 29, 843-852. doi:10.1016/j.cropro.2010.04.017

[14]   Suheri, H. and Latin, R. X. (1991) Retention of fungicides for control of Alternaria leaf blight of muskmelon under greenhouse conditions. Plant Disease, 75, 1013- 1015. doi:10.1094/PD-75-1013

[15]   Van Bruggan, A.H.C., Osmeloski, J.F. and Jacobson, J.S. (1986) Effects of simulated acidic rain on wash-off fungicides and control of late blight on potato leaves. Phytopathology, 76, 800-804. doi:10.1094/Phyto-76-800

[16]   Neely, D. (1970) Persistence of foliar protective fungicides. Phytopathology, 60, 1583-1586. doi:10.1094/Phyto-60-1583

[17]   Vincent, A., Armengol, J. and Garcia-Jimenez, J. (2007) Rain fastness and persistence of fungicides for control of Alternaria brown spot of citrus. Plant Disease, 91, 393-399. doi:10.1094/PDIS-91-4-0393

[18]   Mondal, S.N., Vincent, A., Reis, R.F. and Timmer, L.W. (2007) Efficacy of pre and post-inoculation application of fungicides to expanding young citrus leaves for control of melanose, scab and Alternaria brown spot. Plant Disease, 91, 1600-1606. doi:10.1094/PDIS-91-12-1600

[19]   Mondal, S.N., Vincent , A., Reis, R.F. and Timmer, L.W. (2007) Saprophytic colonization of citrus twigs by Diaporthe citrus and factors affecting pycnidial production and conidial survival. Plant Disease, 91, 387-392. doi:10.1094/PDIS-91-4-0387

[20]   Hess, D.F. and Falk, R.H. (1990) Herbicide deposition on leaf surfaces. Weed Science, 38, 280-288.

[21]   Walker, J.C. (1957) Plant pathology. McGraw-Hill, New York.

[22]   Horsfall, J.G. (1956) Principles of fungicidal action. McGraw Hill, New York.

[23]   Han, J. (1990) Use of antitranspirant epidermal coatings for plant protection in China. Plant Disease, 74, 263-266. doi:10.1094/PD-74-0263

[24]   Hintze, J.L. (2006) Number crunching statistical systems. Kayesville.

[25]   Rao, P.V. (1998) Statistical methods in the life sciences. Duxbury Press, Pacific Grove.

[26]   Duveiller, E. (1994) A pictorial series of disease assessment keys for bacterial leaf streak of cereals. Plant Disease, 78, 137-141. doi:10.1094/PD-78-0137

[27]   Pfender, W.F. and Eynard, J. (2009) Field assessment of a model for fungicide effects on intraplant spread of stem rust in perennial ryegrass seed crops. Phytopathology, 99, 696-703. doi:10.1094/PHYTO-99-6-0696

[28]   Jorgensen, L.N., Seeker , B.J.M. and Nielsen, G.C. (1996) Monitoring diseases of winter wheat in both a field and a National level in Denmark. Crop Protection, 15, 383-390. doi:10.1016/0261-2194(96)00009-9

[29]   Martin, J.T. and Juniper, B.E. (1970) The cuticles of plants. St. Martin’s Press, New York.

[30]   Juste, F., Sanchez, S., Ibanez, R., Val, L. and Garcia, C. (1990) Measurement of spray deposition and efficiency of pesticide application in citrus orchards. Journal of Agricultural Engineering Research, 46, 187-196. doi:10.1016/S0021-8634(05)80125-8