ANTIBIOTIC P-9 IN THE CONTROL OF CEREAL RUSTS
Recurrent outbreaks of stem rust, Puccinia graminis Pers. f. sp. tritici Erikss. & Henn., following the widespread use of previously rust-resistant wheat varieties have emphasized the need of alternative means of rust control. A new antibiotic, P-9, available as yet only in impure form, has several properties that suggest its potential usefulness in the control of cereal rusts. It has systemic and eradicative action, is non-phytotoxic to the host crop at concentrations of a higher order than required for the control of cereal rusts, is probably non-zootoxic, and is highly water-soluble.In greenhouse tests P-9 arrested infection completely in leaf rust, P. recondita Rob. ex Desm., and in stem rust and it was apparently translocated more readily distally than proximally. In field plot tests in 1959 and 1960 it reduced rust infection and increased yield substantially.