Efficacy of variable timing of Pythium oligandrum applications on red clover grown under field conditions

Efficacy of Pythium oligandrum on improvement of lucerne yield, root development and disease score under field conditions

“…Among other root traits, only the fine root-mass score was improved under the intensive treatment at Site 2, Jevíčko. These results are in contrast to those for application of P. oligandrum to red clover, where the same treatments were found to support root branching and reduce the plant disease score in the second harvest year ( Pisarčik et al., 2020 ) or they resulted in increased total root dry mass and root potential index across years with drought stress, and with simultaneous improvement of plant disease score in the case of autumn treatment ( Pisarčik et al., 2021 ). The different responses of red clover and lucerne may be explained, at least partly, by differences in the aridity of the climate at the experimental sites.…”

“…Positive effects on forage yield have been reported in two independent experiments with red clover under treatments with intensive application of P. oligandrum but this improved yield was associated more with plant growth stimulation than from a direct protection against Fusarium ( 2021 ; Pisarčik et al., 2020 ). In lucerne, spring application of P. oligandrum was found to provide zero effect on yield and it even increased the proportion of infected plants in the last year of the field experiment ( Pisarčik et al., 2019 ).…”

“…The Fusarium and Verticilium generally represent the main root pathogens of lucerne ( Miller-Garvin and Viands, 1994 ) and were also identified as the key genera of lucerne root pathogens in central Europe ( Hakl et al., 2017 ). Efficacy of P. oligandrum (strain M1) against Fusarium ( F. avenaceum , F. oxysporum , F. culmorum , and F. solani ) in red clover stands has been presented ( 2021 ; Pisarčik et al., 2020 )…”

“…Optimization of the number of applications and dates of application is needed to ensure economic practice in crop protection ( Pisarčik et al., 2021 ). This is especially difficult for perennial forage crops that are utilized over multiple-year growing seasons covering the seeding year and two or three subsequent harvest years.…”

“…The results with a single spring application of P. oligandrum in lucerne have not provided positive yield response at the one location investigated so far ( Pisarčik et al., 2019 ). For red clover some benefits under an intensive or autumn application regime, in contrast to spring application, have been reported in terms of improved red clover yield and/or root traits ( Pisarčik et al., 2021 ). These previous outcomes for red clover highlights potential of P. oligandrum for forage legumes and gives further encouragement to extend the biological control research with treatments including variable timing of applications to lucerne.…”