268 Percival and Haynes: The Influence of Calcium Sprays to Reduce Fungicide play an influential role in conferring protection. Wojcik (2001) concluded the anion was important in influencing plant cal- cium uptake and translocation, which in turn conferred greater protection against brown rot of cherry. A role of the anion itself has sometimes been directly implicated in pathogen resistance. Calcium nitrate as a means of reducing pathogen severity has been criticized as the nitrogen in this material can stimu- late additional shoot growth and potentially increase disease severity (Wojcik 2001). Such a response was not recorded in this investigation, as calcium nitrate application reduced leaf and fruit scab severity in both the 2006 and 2007 trials. Chlo- ride is widely used as a means of sterilizing long-term, stored food products, against bacterial and fungal infection. Due to the toxic nature of the chloride ion against mammalian tis- sue the use of chloride alone as a plant protection product has limited applicability (Fixen 1993). Calcium chloride is also a caustic salt that can corrode sprayer parts (Fixen 1993). Boron has been shown to be an important compound in in- fluencing disease reduction caused by several root and fo- liar pathogens such as tan spot disease of wheat [Drechslera tritici-repentis (Died.) Shoem.], club root of cabbages (Plasmodiophora brassicae Woronin), and Eutypa die- back of grapevines (Eutypa lata) (Dixon and Webster 1988; Rolshausen and Gubler 2005; Kostas and Dordas 2006). In field trials, calcium sulfate application was found to have had an effect on soil moisture tension by affecting the soil matrix potential, making the soil environment less conducive to Phytophthora infection and survival. Applications of cal- cium sulfate have also been shown to reduce disease severity of Phytophthora infestans (potato blight), and Erwinia amylo- vora (black leg of potato), the bacterium also responsible for fire blight of fruit trees and potato scab (McGuire and Kel- man 1984; McGuire and Kelman 1986; Bain et al. 1996; Ols- son 1998). The influence of protein based amino acids as plant protection compounds has received little attention due to the expense nature of the product; however, the nonprotein amino acid DL-3-amino-n-butanoic acid was found to provide >95% protection against P. infestans when sprayed onto tomato plants (Cohen 1994). Likewise low molecular weight proteins (elicitins) have been shown to possess systemic acquired resistance induc- ing activity against a range of plant pathogens (Percival 2001). As the calcium products used in this investigation are clas- sified as fertilizers then they are not, at least in the UK, subject to the stringent legislative restrictions that relate to the use and application of synthetic fungicides. This also means calcium products can be used in management programs against foliar pathogens of urban trees for which no fungicides are registered. This would be of fundamental importance in the UK where an- thracnose of willow [Marssonina salicicola (Bres.) Magnus] and London Plane [Apiognomonia veneta (Sacc. et Speg. Hohnel], leaf spot of cherry [Blumeriella jaapii (Rehm) v. Arx.] and blos- som wilt of cherry [Monilinia laxa (Aderh. and Ruhland) Honey], are increasing in severity on an annual basis, resulting in deaths of heavily infected trees. Likewise, calcium products cost in gen- eral 40%–60% less than conventional fungicides. Viewed in this context, the development of calcium-based products may provide a useful addition to existing methods of plant pathogen control. In conclusion, current management strategies for foliar pathogens throughout the United Kingdom and Europe are heavily dependent upon repeat fungicide applications. In order ©2009 International Society of Arboriculture to improve the effectiveness and sustainability of current strate- gies, a new holistic approach has been studied. These research findings confirm that foliar calcium applications offer a use- ful, practical supplement to existing scab fungicide programs that can be easily implemented with existing spray technolo- gies and may have applicability for the control of other foliar pathogens of ornamental and urban trees. However, the abil- ity of calcium alone to reduce scab must not be overstated, and should not be used as a replacement for conventional fungicides. Acknowledgments. The author is grateful for funding in part from the TREE Fund (Hyland Johns Grant). LITERATURE CITED Akbudak N., H. Tezcan, B. Akbudak, and V. Seniz. 2006. Effect of harpin protein on plant growth parameters, leaf chlorophyll, leaf colour and percentage rotten fruit of pepper plants inoculated with Botrytis ci- nerea. Scientia Horticulturae 109(2):107–112. Bain, R.A., P. Millard, and M.C.M. Perombelon. 1996. The resistance of potato plants to Erwinia carotovora subsp.atroseptica in relation to their calcium and magnesium content. Potato Research 39(1):185– 193. Berbezy, P., L. Legendre, and A. Maujean. 1996. Purification and charac- terisation of alpha-amylase from vine shoot inter-nodes. Plant Physi- ology and Biochemistry 34(3):353–361. Berrie, A.M., and X.M. Xu. 2003. Managing apple scab (Venturia in- aequalis) and powdery mildew (Podosphaera leucotricha) using Adem (TM). International Journal of Pest Management 9:243–249. Biggs, A.R., M.M. El-Kholi, S. El-Neshawy, and R. Nickerson. 1997. Ef- fects of calcium salts on growth, polygalacturonase activity, and infec- tion of peach fruit by Monilinia fructicola. Plant Disease 81:399–403. Børve, J., L. Sekse, A. Stensvand, and J. Ystaas. 1998. Cuticular fractures as infection sites of Botrytis cinerea in sweet cherry fruits. Acta Hor- ticulturae 468:737–739. Børve, J., L. Sekse, and A. Stensvand. 2000. Cuticular fractures promote postharvest fruit rot in sweet cherries, Plant Disease 84:1180–1184. Butt D.J., A.A.J. Swait, and J.D. Robinson. 1990. Evaluation of fungicides against apple powdery mildew and scab. Tests of Agrochemicals and Cultivars 11. Annals of Applied Biology (supplement) 116:34–35. Chardonnet, C.O., C.E. Sams, and W.S. Conway. 1999. Calcium effect on the mycelial cell walls of Botrytis cinerea. Phytochemistry 52:967–973. Chardonnet, C.O., C.E. Sams, R.N. Trigiano, and W.S. Conway. 2000. Variability of three isolates of Botrytis cinerea affects the inhibitory effects of calcium on this fungus. Phytopathology 90:769–774. Christiansen, E., P. Karokene, A.A. Berryman, V.R. Franceschi, T. Krekling, F. Lieutier, A. Lonneborg, and H. Solheim. 1999. Mechani- cal injury and fungal infection induce acquired resistance in Norway spruce. Tree Physiology 19:399–403. Cline, R.A., and G. Tehrani. 1973. Effects of boron and calcium sprays and of mulch on cracking of Italian prune. Canadian Journal of Plant Science 53:827–831. Cohen, Y. 1994. Local and systemic control of Phytophthora infestans in tomato plants by DL-3-amino-n-butanoic acids. Phytopathology 84(1):55–59.
September 2009
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
