Assessment of retention and persistence of copper fungicides on orange fruit and leaves using fluorometry and copper residue analyses
Gerhardus C. Schutte and Charl Kotze
Citrus Research InternationalJ. Gideon van Zyl and Paul H. Fourie
Department of Plant Pathology, Stellenbosch University
High volumes of copper hydroxide, cuprous oxide and copper oxychloride were sprayed under natural conditions onto mature orange trees to compare the etention on citrus leaves and fruit over a period of 56 days by means of copper residue analyses and a spray deposition assessment protocol using fluorometry, photomacrography and digital image analyses. Rainfall and increase in fruit size were also recorded to determine if it had an influence on weathering of copper residues.