Insect Microbiology Insect Pathology Prof. Abdelwahab A. Ibrahim Entomology Department, Faculty of Science, Benha University

Prof. Abdelwahab A. Ibrahim Insect Microbiology FUNGI Fungi are eukaryotes , with a well-defined nucleus and organelles, characterized by chitinized cells. The cells are formed into filaments or hyphae together forming a mycelium Entomopathogenic fungi are found in several subdivisions. The relation between insects and fungi: Many fungi associated with insects are not pathogenic. Facultative fungi grow inside or outside Dead insects. Certain fungi may spend parts of its life temporarily on the cuticle of insects without killing them. Fugal spores germinate on the host cuticle and penetrate using enzymes and mechanical pressure. suitable temperature and humidity are needed for fungal growth. Inside the haemocoel the fungus multiplies rapidly by budding or hyphal fission. Fungi may kill insects by asphyxiation or starvation, or by toxins released in the Healthy larva (yeast phase). The cadaver desiccates as the hyphae use host nutrients and water to develop. Hyphae break through the cuticle after death. Spores may be liberated passively or actively to continue the infection cycle. Conidia ofE. grylli Metarhizium Beauveria Spores

Prof. Abdelwahab A. Ibrahim Insect Microbiology FUNGI Examples of pathogenic fungi Class: Phycomycetes Order: Entomophthorales Entomophthorales have one family (Entomophthorales) E.g. Entomophthora musca (infect houseflies), Entomophthora grylli (infect locusts and Lepidoptera), Entomophthora funosa (infect mealybugs), Entomophthora aphids (infect Aphids). Most fungi of this genus cannot be cultured in artificial media and must be cultured in complex media. Some produce mycelium but do not form spores. Genus Coelomoyces contains a group of aquatic fungi and so infect aquatic insects as mosquitoes. Infected larvae became white yellow or orange in color.

Prof. Abdelwahab A. Ibrahim Insect Microbiology FUNGI Examples of pathogenic fungi Class: Ascomycetes Fungi belong to genus Cordyceps are mostly colored and are widely distributed in many insect orders as Diptera, Hemiptera, Lepidoptera, Hymenoptera and Coleoptera. Cordyceps militoris is the best-known and most frequently collected insect-killing Cordyceps. The victim for Cordyceps militaris is a pupa or larvae (usually of a butterfly or moth). Its mycelium colonizes the living insect and mummifies it, keeping it alive just long enough to generate the biomass it needs to produce the mushroom--a "spore factory" that allows the Cordyceps to reproduce. With Cordyceps militaris the bug is buried in the ground or in well decayed wood, which means the mushroom collector usually sees only a little orange club with a finely pimply surface.

Prof. Abdelwahab A. Ibrahim Insect Microbiology ENTOMOPATHOGENIC FUNGI ON H. ARMIGERA Metarhizium anisopliae Nomuraea rileyi Beauveria bassiana

Prof. Abdelwahab A. Ibrahim Insect Microbiology Thanks