Metal Micronutrient and Silicon Concentration Effects on Growth and Susceptibility to Pythium Root Rot for Hydroponic Lettuce (Lactuca sativa)

The objectives were to evaluate the effects of increasing metal micronutrient concentrations and silicon (Si) on plant growth susceptibility Pythium root rot with hydroponically grown lettuce (Lactuca sativa). In first experiment, was in hydroponic solutions micronutrients iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) supplied at either 0, 2.5, 5, or 10 mg∙L−1. A standard commercial solution also included as a control, 2 Fe, 1 Mn, 0.5 Cu, Zn second Si 7, 14, 28, 56 Hydroponic treatment for both experiments dosed myriotylum (Pythium treatment) 1.80 × 104 oospores per L deionized water non-Pythium control. Data collected leaf SPAD chlorophyll content, shoot height width, total fresh mass, disease severity. Increasing Cu concentration decreased severity but reduced yield. other tended reduce had no significant influence disease. Supplementing effect slightly mg∙L−1 Si. Results this study suggest that management nutrition is not an effective strategy and, best, risky controlling lettuce. Growers would likely benefit from maintaining within ranges (in mg∙L−1) 5.5 0.1 2.0 0.6 Zn, 0 28 many crops. has potential negatively quality certain species, testing necessary phytotoxicity risks prior implementing practice. Overall, successful mitigation pathogens production requires combination proper sanitation, best cultural practices, appropriate system design, implementation design multi-barrier approach.