Rootworm and Mechanical Damage Effects on Root Morphology and Water Relations in Maize

Abstract

There is little information in the literature concerning the effect of corn rootworm larval feeding on the physiology of maize (Zea mays L.). This study was conducted to determine if root damage caused by western corn rootworms (Diabrotica virgifera virgifera LeConte) affects relative water content, leaf water potential, or stomatal conductance in leaves of the host plants. The effect of mechanical root‐cutting treatments was also evaluated. The experiment was conducted under controlled‐environment conditions in a greenhouse. Plants were damaged at the V9 stage of leaf development by prior infestation with 50 or 150 larvae per plant or by cutting 25 or 75% of the root system from the plant. Root systems and plant water relations were evaluated at this stage of development and again at tassel. Larval root damage was confined to the axes of the fourth and fifth nodes of roots. There were no differences in relative water content, leaf water potential, or stomatal conductance between infested plants or controls at V9; at tassel, however, leaf water potential was significantly higher and stomatal conductance was significantly less in infested plants (P < 0.05). Mechanical cutting of roots caused significant differences (P < 0.05) in relative water content and stomatal conductance at both sampling dates. These results indicate that mechanical root damage reduced the ability of root systems to provide adequate water to the shoots to a much greater extent than did corn‐rootworm damage.

Evaluating Management Factor Contributions to Reduce Corn Yield Gaps

“…Corn rootworm larvae (Diabrotica spp.) feed on corn roots, thereby limiting plant uptake of water and nutrients (Kahler et al, 1985;Riedell, 1990;Spike and Tollefson, 1991), increasing the incidence of corn lodging, and reducing CO 2 assimilation, biomass accumulation, and carbohydrate partitioning Frommelt, 1998a, 1998b;Riedell and Reese, 1999). European corn borer damage includes leaf feeding and tunneling of the stalk and ear shank (Rice, 2006), resulting in yield reductions from disruption of water and nutrient translocation to the ear, stalk rot, and pre-harvest losses due to stalk lodging and dropped ears (Steffey and Gray, 2002).…”

Danos Causados Pela Larva-Alfinete Em Milho Em Condições De Campo

“…A lesão decorrente do ataque larval ocorre, geralmente, do terceiro ao sexto nós de raízes adventí-cias, pois o desenvolvimento dessas raízes coincide com o tempo de eclosão dos ovos e das larvas em desenvolvimento (Riedell, 1990).…”

Dynamic Precision Phenotyping Reveals Mechanism of Crop Tolerance to Root Herbivory

“…Unfortunately, we know very little about the underlying mechanisms for crop tolerance. Over the years, one resounding message has been that the physiological processes affected by herbivory should be better characterized before breeding tools can be leveraged in a rational way to generate improved varieties that maintain high yields under herbivore pressure (Riedell, 1990). Rational decision making in the breeding selection process requires rigorous phenotyping; however, present phenotyping tools tell us little about the plasticity of root systems, especially when it comes to understanding mechanisms for crop tolerance to attack belowground.…”