The effect of surfactants and some herbicides on teliospore viability in Puccinia thlaspeos (Schub.)

Puccinia thlaspeos is being studied as a potential biocontrol agent for Isatis tinctoria. The goal of the work reported here was to gather information pertinent to the integrated use of herbicides and P. thlaspeos. The effect of three herbicides currently used to control I. tinctoria on viability of teliospores from inoculum was studied along with common surfactants. Neither chlorsulfuron nor metsulfuron-methyl had a significant impact on teliospore germination when used alone but the 2,4-D formulation used in these studies decreased teliospore viability. The surfactants Sylgard and IFA-S90 reduced spore germination while Regulaid had little effect. However, when rust-infected plants were sprayed with different combinations of herbicides and surfactants, the viability of teliospores produced on those plants was not decreased.