IMPROVING THE PROTECTIVE FUNGICIDAL ACTIVITY O F NICKEL SULFATE AGAINST LEAF RUST OF WHEAT AND CROWN RUST OF

A marked improvement in the retention of protective activity of 400 nickel sulfate hexahydsate against leaf rust of wheat and crown rust of o ats was noted when the non-ionic surfactant Triton X-114 at 0.1% o r the anionic surfactants castor oil at 0.1% o r a constituent of G-3300 at 0.25% were included in the solution. at 0.25% and the petroleum oil Imperial Oil 862- B at 0. (the latter for leaf rust only) were also effective, one -half of s imulated rain. addition'of the non-ionic surfactants Triton X-100 at and T riton B- 1956 at 0. the anionic surfactant dodecylbenzene sodium sulfonate a t 0.25% o r the surfactant Hyamine 3500 at 0.03%. The polybutene Indopol L-10 This activity persisted after the application of Less improvement was shown with the; rust (Puccinia recondita Rob. e x Desm.) on Thatcher, Marquis and Red Bobs wheat in the field. The success of the nickel salts in field use seemed attributable to their ability to eradicate the rust infections present in the leaf and not to any protective action of the nickel. This was somewhat surprising since nickel compounds had been shown to be effective as protective fungicides against leaf rust in the greenhouse (5) at concentrations one-fourth of those required f or eradicative action. shown (6) that the protective action of the nickel was rather easily removed with simulated rain. of nickel as a fungicide but no systematic study had been made of the relative effectiveness of spray additives in improving the protective fungicidal activity of the nickel ion. ments designed to compare the effectiveness of various compounds, mainly surface ,active agents, in enhancing the protective action of inorganic nickel compounds both with and without simulated rain.