Encapsulation of fungi may lead to new generation of biological insecticides

Researchers develop technology that uses insect-parasitizing fungi for pest control.

By Diego Freire  |  Agência FAPESP – Researchers at Brazil’s Federal University of São Carlos (UFSCar) and the São Paulo Biological Institute, subsidiary to the São Paulo State Agribusiness Technology Agency (APTA), are developing a new generation of biological insecticides for pest control with FAPESP’s support.

The technology involves encapsulation of the conidia of entomopathogenic fungi, which parasitize insects and can kill or incapacitate them but are not harmful to human health. The fungi adhere to the insect’s body by means of microscopic spores. Under the right temperature and humidity conditions, the spores germinate, penetrate the body, grow as hyphae, and colonize the interior of the organism.

The encapsulation process proposed by the researchers uses a biopolymer. Biopolymers are polymers produced by living organisms and include proteins, polysaccharides and nucleic acids. The idea is to protect and store conidia under stable conditions to guarantee lasting action against various insects that damage crops.

“The formulation ensures the product can be stored without refrigeration for up to 12 months and has been shown to be pathogenic to several pests, such as borers and sugarcane weevils,” said Inajá Marchizeli Wenzel Rodrigues, principal investigator for the project “Studies to identify low-cost biopolymers compatible with microorganisms for use in encapsulated formulations of entomopathogens and compatibility of adjuvants for use in formulations,” supported by FAPESP’s Innovative Research in Small Business (PIPE) program.

Encapsulation functions as a barrier to protect conidia against external factors such as ultraviolet radiation, temperature, competing microorganisms and oxidation, among others. The researchers wanted to produce a novel bioinsecticide as an alternative to agrochemicals and found that no formulated entomopathogens were available on the market.

According to the National Public Health Surveillance Agency (ANVISA), in 2010, Latin America accounted for 22% of global agrochemical consumption, with Brazil accounting for 19% of this share. Studies performed between the second half of 2010 and the first half of 2011 show that Brazil produced 96,000 metric tons of agrochemicals.

According to the researchers, the bioinsecticides that are available commercially are not formulated and use fungi in a raw state, without polymer encapsulation. The new technology is more commercially viable, just as powerful and easier to control.

Another feature that distinguishes this innovation from conventional bioinsecticides is its stability when stored for over a year at ambient temperature, facilitating production, stockpiling, distribution and use and enabling farmers to spray crops at any time, weather permitting.

In sum, the technology offers an efficient system for the application of entomopathogenic fungi, with protection of conidia from abiotic and biotic stresses. It is pathogenic only to the targeted insects and can be stored without power consumption.

The next step in commercialization involves studies of the most appropriate techniques for field application as well as further analysis of applicable crops and pests. Agribusiness interest and investment are expected, especially from the biological and synthetic insecticide industries.

The other researchers besides Inajá Marchizeli Wenzel Rodrigues are Moacir Rossi Forim, João Batista Fernandes and Maria Fátima das Graças Fernandes da Silva from UFSCar’s Center for Exact Science & Technology (CCET) and Antonio Batista Filho from the Biological Institute.