Fungi are a group of organisms that are very diverse with secure ties to the field of agriculture. A number fungi lead to annihilating crops diseases as others are crops themselves such as mushrooms. Some groups of fungi are utilized successfully for crops protection from various pests. The most important fungi are the ones that are utilized as biological control agent (Jackson, Schisler, Slininger, Boyette, & Silman, 1996).
There are several advantages related to the use of fungi for biological control. Fungi have the ability to actively infect and cause death to the weed or insect host. Spores of fungi are able to germinate as well as penetrate a healthy insect or weed and without the need to a compromise the defense of the host. Due to this benefit that fungi possess as well as the large number of pathogenic fungi of weeds, a list of agents of biological control under evaluation for weed control named 22 fungi and no bacteria (Jackson, Schisler, Slininger, Boyette, & Silman, 1996).
Fungi have propagule stability. Sclerotial propagules or spores of fungi are usually more stable as compared to cells of bacteria. Stability and tolerance to desiccation as a dry preparation are a total condition for commercial application. The accessibility of many pathogenic fungi for insects and weeds control is another benefit to the commercial utilization of these organisms as biological control agents. Fungi possess the possibility to create pan epidemic in the population of the host. This is mainly factual in control strategies of insects (Jackson, 1997).
A number of commercial products of fungi are developed as spores that are easily adjusted to existing technology of application, for example, spray rigs. Fungi have comparatively wide host range and, therefore, there can be an achievement of control of a number of pests using one product.
High spores concentrations are frequently required in order to get sufficient pests control in a crop, and this can reduce the effectiveness of cost of fungal products. Fungi have a long kill time. The wide host range of fungi may at times be a trouble, particularly when beneficial insects are there in a crop. Non-target death in beneficial insects’ populations may have negative impacts on the achievement of the overall program of biological control. Environmental aspects may as well have a crucial role in the fungal success. High relative humidity conditions in the crop canopy are frequently essential for effectiveness of the control. Extended exposure to sunlight may also render spores inactive, thus lowering their persistence in the crop. Due to these environmental restrictions, natural fungal outbreaks have a tendency to be sporadic and very uneven in the environment, and this may restrict their efficiency in pests control (Jim McNeil, 2011).
Metarhizium anisopliae is an entomopathogenic fungus that is recognized for infecting more than 200 species of insect pest, including termites (Cloyd, 1999). Currently, it is utilized as an insecticide to biologically control a number of pests like thrips, termites, among others. It is also under investigation for use as biocontrol agent against of malaria-transmitting mosquitoes (McNeil, 2005). M. anisopliae has no apparent ability to infect animals or humans and is thus regarded as a safe insecticide. The spores, which are microscopic, are characteristically sprayed on the areas of the crop that are affected.
In 2007, Indian Institute of Chemical Technology scientists found out a more competent way of production of biodiesel that utilizes lipase, an enzyme secreted in significant amounts by Metarhizium anisopliae. Contrary to other reactions that utilize enzymes that need heat to activate them, the lipase reaction takes place at room temperature.
When Metarhizium anisopliae spores get into contact with the susceptible insects’ cuticle, they sprout and directly grow through the cuticle to the host’s inner body. Metarhizium anisopliae proliferates all over the body of the insect and drains the insect of nutrients, ultimately killing it.
Hoppers and Bugs foliar spray ought to be sprayed on the plant that is growing using spray equipment of either hand, ground or aerial. For vine weevils and root grubs soil application, Metarhizium anisopliae may be sprinkled all over the root – zone and integrated into the soil either through watering of plants or mechanically. It can as well be integrated into the soil via systems of drip irrigation following filtering with suitable filters.
Verticillium lecanii is also an entomopathogenic fungus whose mycelium produces bassianolide, a cyclodepsipeptide toxin, and other toxins that are insecticidal like dipicolinic acid that infect whiteflies, aphids, scale insects, rust fungi and cause death to the host. Verticillium lecanii is a crucial insects’ pathogen, isolate from aphids, whiteflies and coccids (Liu, Xie, Xue, Zhang, & Zhang, 2011).
When Verticillium lecanii spores get into contact with the susceptible insects’ cuticle, they sprout and directly grow through the cuticle to the host’s inner body. This fungus proliferates all over the body of the insect and drains the insect of nutrients, ultimately killing it in about 48 to 72 hours.
The product of this fungus ought to be sprayed on plants’ foliage by use of hand, ground, or aerial spray equipment. It is important to give a good coverage on the undersurfaces of the leaves.
Cloyd, R. A. (1999). The Entomopathogenic Fungus Metarhizium anisopliae. Midwest Biological Control News, 6(7).
Jackson, M. A. (1997). Optimizing nutritional conditions for the liquid culture production of effective fungal biological control agents. Journal of Industrial Microbiology & Biotechnology, 19, 180-187.
Jackson, M. A., Schisler, D. A., Slininger, P. J., Boyette, C. D., & Silman, R. W. (1996). Fermentationstrategies for improving the fitness of a bioherbicide. Weed Technol, 10, 645-650.
Jim McNeil, P. (2011, July 19). Fungi for the biological control of insect pests. Retrieved April 19, 2013, from http://www.extension.org/pages/18928/fungi-for-the-biological-control-of-insect-pests
Liu, W., Xie, Y., Xue, J., Zhang, Y., & Zhang, X. (2011). Ultrastrucural and cytochemical Characterization of brown soft scale Coccus hesperidum (Hemiptera:Coccidae) infected by the Lecanicillium lecanii (Ascomycota:Hypoceales). Micron, 42, 71-79.
McNeil, D. G. (2005, June 10). Fungus Fatal to Mosquito May Aid Global War on Malaria". 104:. The New York Times, pp. 135–151. Retrieved April 19, 2013, from http://query.nytimes.com/gst/fullpage.html?res=9A07E0D71038F933A25755C0A9639C8B63