Combination of Trichoderma koningii with Fluorescent Pseudomonads for Control of Take-all on Wheat

Abstract

Trichoderma koningii significantly reduced the severity of take-all of wheat caused by Gaeumannomyces graminis var. tritici in growth-chamber experiments and slightly enhanced the growth of wheat in the absence of G. graminis var. tritici. In field trials, T. koningii applied to the seed furrow increased the yield of spring wheat by 65% at Mt. Vernon, WA, and reduced crown root infection by G. graminis var. tritici on winter wheat by 40% at Pullman, WA. T. koningii was generally more suppressive of take-all than Pseudomonas fluorescens Q29z-80 or a mixture of P. fluorescens and P. putida strains at both sites. In field trials, the combination of T koningii and Q29z-80 increased yield compared to Q29z-80 alone but was not different from T. koningii alone. In growth-chamber experiments, combinations of T. koningii and any of six bacterial treatments provided substantially better disease control than the bacterial treatments applied alone. Combinations of T. koningii and certain bacterial treatments (e.g., P. chlororaphis 30-84, P. fluorescens Q2-87, and a four strain mixture) provided greater suppression of take-all than T. koningii alone. All combinations of T. koningii and fluorescent pseudomonads were compatible.