Effects of chronic root herbivory by the rice water weevil on nutrient concentrations in rice plants

Root herbivory is extremely damaging to plants, often leading to considerable yield losses, particularly in crops. Belowground herbivory can alter plant performance. For instance, feeding by insects on roots can affect the synthesis of phytohormones, production of chemical defense metabolites, water and nutrient absorption, and carbohydrate storage. Plants have developed multiple strategies to mitigate the impact of herbivores by expressing traits that reduce the amount of injury caused by herbivores (resistance traits) or by expressing traits that reduce the yield or fitness losses resulting from injury by herbivores (tolerance traits). This study was conducted to investigate the effects of chronic feeding by rice water weevil on rice plant growth, nutrient uptake, and production of plant hormones in a hybrid and an inbred rice cultivar. Results from this study demonstrated that chronic root herbivory by rice water weevil negatively affected plant nutrient uptake of macro and micronutrients essential for growth and development. The reductions in nutrient uptake in weevil-infested plants may be the primary cause for subsequent reductions in plant growth and yields. The hybrid cultivar in this study, as previously reported, was more tolerant to weevil infestations than the inbred cultivar. This may be due to higher root and shoot biomass accumulation and yield potential in the hybrid compared to the inbred cultivars.