Fungal biodiversity on maize kernels in an insecticide evaluation trial

Abstract

The European corn borer (ECB) Ostrinia nubilalis and Fusarium ear rot Fusarium spp. pose a continuous threat to maize production worldwide. There are several reports indicating that ECB damage to maize ears promotes Fusarium ear rot infection. The aim of this study was to monitor the influence of different insecticide treatments (a.i. chlorantraniliprole, indoxacarb, and chlorantraniliprole+lambda-cyhalothrin) on the ECB and fungal diversity on maize kernels in the field in a four-year trial (2013-2016). A total of 16 different fungal genera were isolated from maize kernels, and Fusarium species were confirmed to be the dominant pathogens, present in all treatments, throughout the four years of experiments. The incidence of Aspergillus spp. and Penicillium spp. was established to be low. Apart from Fusarium species, the most frequent genera were: Aspergillus spp., Mortierella spp., Mucor spp., Penicillium spp., Acremonium spp. and Rhizopus spp. Treatments with chlorantraniliprole and chlorantraniliprole+lambda-cyhalothrin showed higher efficacy, though not statistically significant, compared to indoxacarb, in reducing the number of ECB larvae and damage they cause. However, no direct effect on the number of isolated fungal genera has been observed in any of the three insecticide treatments.