Potential of a biofertilizer for biocontrol of Peregrinus maidis Ashmead (Hemiptera: Delphacidae), the insect vector of maize mosaic nucleorhabdovirus

Peregrinus maidis poses a significant threat to corn crops leading to considerable yield losses. To enhance corn yield, a combination of biofertilizer and synthetic fertilizer has proven effective. Beneficial microbes in biofertilizers play a vital role in plant defense against pathogens and insects, particularly through the expression of antimicrobial peptides (AMPs) like defensin and lugensin. In this study, authors focused on assessing how bio- and synthetic fertilizers impact insect response and AMP expression both in corn and insects. During insect infestation, defensin was found to be expressed in corn, with higher expression levels observed during the late nymphal and adult stages of the insects. Its expression among treatments does not differ quantitatively at time when the insect colonizing it is at the early nymphal stages. However, its expression increased when the insects are already at the late nymphal and adult stages. The number of insects colonizing the plant treated with a combination of synthetic and biofertilizers has lower numbers of insects compared to plants treated separately. Reduced number of insects colonizing the plants was also observed compared to separate treatments. Interestingly, the corn treated with biofertilizer plus urea had the highest number of oviposited eggs. However, no significant difference in ovipositional preference was observed among the treatments. After 21 days, late nymphal instars showed the highest development and survivorship into adulthood in plants treated with synthetic fertilizer, followed by biofertilizer, and the lowest in plants without fertilizers. It is worth noting that although female macropters prefer biofertilizer-treated plants for oviposition, it doesn't necessarily lead to more viable eggs. This research poses novel results as it explores the potential benefits of utilizing biofertilizers as a biocontrol method to manage the insect vector that transmits a viral phytopathogen affecting corn.