Formulations for the control of dutch elm disease

Solutions of methyl benzimidazol‐2‐ylcarbamate (carbendazim, formerly MBC) in dilute hydrochloric, orthophosphoric or hypophosphorous acid and in dilute hydrochloric acid containing methanol (“Lignasan”) and aqueous solutions of 2‐(thiazol‐4‐yl) benzimidazole (thiabendazole) hypophosphite, 8‐hydroxyquinoline (oxine)hydro‐chloride and dodecylguanidine acetate (dodine), were tested in the field for their efficacy in controlling Dutch elm disease caused by Ceratocystis ulmi. All gave some degree of control although some were phytotoxic, the benzimidazoles being the most active compounds tested. The anion and the concentration of acid present in the formulation may have some effect on retention of active material within the crown of the tree.