Interaction between western corn rootworm (Coleoptera: Chrysomelidae) larvae and root-infecting Fusarium...

Area of Science:

• Agricultural Entomology
• Plant Pathology
• Mycology

Background:

• The western corn rootworm (Diabrotica virgifera virgifera) is a major maize pest.
• Fusarium verticillioides is a plant-pathogenic fungus that produces mycotoxins.
• Interactions between root herbivores and plant pathogens can impact crop health.

Purpose of the Study:

• To evaluate the effect of western corn rootworm larvae on Fusarium verticillioides root infection in maize.
• To investigate how the timing of pathogen and insect application influences root colonization and larval development.

Main Methods:

• Greenhouse experiment with controlled application of F. verticillioides and western corn rootworm.
• Real-time polymerase chain reaction (PCR) used to quantify F. verticillioides root colonization.
• Assessment of western corn rootworm larval development (instar ratio, head capsule width).

Main Results:

• Root feeding by western corn rootworm larvae increased F. verticillioides root colonization up to 50-fold with high inoculum density.
• Earlier application of F. verticillioides relative to insect egg addition enhanced colonization.
• F. verticillioides slightly suppressed larval development and reduced head capsule width.

Conclusions:

• Root herbivory by western corn rootworm can enhance F. verticillioides colonization of maize roots.
• The timing of pathogen and insect introduction is critical in determining the interaction outcome.
• F. verticillioides may negatively impact western corn rootworm larval development under specific conditions.