Last winter we, the research station for vegetable production in Sint-Katelijne-Waver, investigated the ideal UV-C dose to efficiently combat Bremia lactucae in lettuce, without damaging the crop. A fully automated horizontal UV-robot applied the UV-C light during the night. The speed at which the robot drove determined the applied dose of UV-C light. The plants were inoculated by spraying a spore suspension over the crop.
In a first experiment we found that a dose of 175 J/m2 caused phytotoxicity. In a second experiment we applied a dose of 0, 50, 100 and 150 J/m2. In this experiment we found an increasing efficacy to combat Bremia lactucae with an increasing UV-C dose. We could however not get completely rid of the fungi. This could be because the inoculation caused a too high pressure of Bremia lactucae.
In following research we will investigate the effect of UV-C light on other fungi and on crop protection agents. We do not want UV-C to interfere with standard crop protection.
We will also test the effect of UV-C on Bremia lactucae with a natural infection.