Appearance of microfungi in maize stalks due to injuries caused by the European corn borer ( Ostrinia nubilalis Hbn.)

Abstract

A better understanding of the relationships between insects and microfungi could help to identify the unknown factors reducing yields in maize. As the first step in current research, the aim was to isolate the microfungal species that can be found in the larval cavity of the European corn borer ( Ostrinia nubilalis Hbn. Lepidoptera. Pyraustidae ) (ECB), one of the most important insect pests of maize. In this way, the scale of potential phytopathogens spread by intermediate hosts could be reduced.Fifty stalk sections damaged by ECB larvae were collected in autumn and fifty in spring on a 20-hectare plot in Ráksi (Somogy county). These were placed in wet chambers and incubated at room temperature under natural light. Identification was done from a pure culture inoculated into potato dextrose agar. Twenty-one species from 14 fungus genera were identified, the majority of which were mitosporic fungi. Species belonging to the Fusarium, Acremoniella and Cladosporium genera were predominant. Most of the species were saprotrophic, though some phytopathogenic species ( Gibberella, Colletotrichum, Nigrospora and Fusarium ) were also identified. The number of genera and the incidence of fungi were much higher in spring samples than in autumn ones, except for Fusarium , where incidence was lower in spring. It was found that failing to harvest the maize significantly enhanced the spread of several fungus species, especially phytopathogenic species, the following year, thereby serving as a source of infection.