Entomopathogenic fungus
Pathogenicity for insects is widely distributed in the kingdom of fungi and occur in six fungal phyla (Ascomycota, Oomycetes, Basidiomycota, Chytridiomycota, Zygomycota, and Microsporidia).
[1] Entomopathogenic fungi all typically disperse through the environment through the use of microscopic spores (usually asexual or Conidia) that commonly use hydrophobins and adhesins to attach to and recognize the host cuticle.
Some fungi keep the insect cadavers attached to foliage using rhizoids to ensure that they remain in the same environment where it is more likely to encounter suitable new hosts.
[8] Eight phyla contain Entomopathogenic fungi: Ascomycota, Basidiomycota, Chytridiomycota, Microsporidia, Oomycetes, Entomophthoromycota, Blastocladiomycota and, Kickxellomycotina.
[1] Most entomopathogenic fungi in the Phylum Ascomycota infect and proliferate in the insect body in a parasitic phase before eventually killing the host.
Upon the death of the host, these fungi have the ability to grow saprophytically in and on the insect cadaver and produce and release spores.
The most characteristic group of insect pathogens in the Phylum Ascomycota is the order Hypocreales which include genera such as Ophiocordyceps, Cordyceps, and Hypocrella.
[12] Upon the death of the host, the O. unilateralis produces a stalk-like structure erupting from the head of the dead ant from which spores are released to the peripheral environment.
[12] The phylum Basidiomycota are commonly known as "superior fungi" due to their production of well-developed septate hyphae and fruiting bodies.
[1] Microsporidia are obligately unicellular spore forming organisms and are strictly intracellular parasites,[15] and are generally host-specific[1] and extremely dependent on their host.
[15] Almost all stages of their lifecycle can only take place inside the host cells due to their characteristics lack of mitochondria and inability to perform oxidative phosphorylation.
[14] However, their production of biflagellate zoospores during asexual reproduction and their cell wall structure sets them apart from most fungi.
[14][1] The widespread taxonomic distribution of entomopathogenic fungi—with representatives including unicellular fungal parasites (e.g. Microsporidia) to more derived groups such as Ascomycota and Basidiomycota—indicates multiple evolutionary origins of pathogenicity for insects.
For example, three families in the order Hypocreales (Clavicipitaceae, Cordycipitaceae and, Ophiocordycipitaceae) appear to have independently developed this nutritional habit.
[20][5] In classical biological control, there are two demonstrated examples of potential use of entomopathogenic fungi against exotic insect species affecting agriculture.
The oldest example is the use of Entomophthora maimaiga against the Spongy moth (Lymantria dispar) in the United States during early 1900s.
Despite the accidental nature of introduction, several subsequent research has found that E. maimaiga is effectively keeping the spongy moth populations at control preventing outbreaks in North-east USA.
[21][4] Similarly, various strains of entomopathogenic fungi have shown efficient substrate removal of a diverse range of anthropogenic pollutants including Triazine, Synthetic estrogens, n-alkanes etc.
For example, the ectoparasite Cephalonomia tarsalis is susceptible to B. bassiana but it cannot detect the presence of free conidia of this fungus or infected hosts.
