By-product of biofuel production could be used for insect pest control

As part of a multimillion-dollar project funded by the U.S. Department of Energy’s Office of Bioenergy Technologies, researchers from the USDA-ARS Center for Cereals and Animal Health Research (CGAHR), from the National Renewable Energy Laboratory (NREL) and Michigan State University investigated whether byproducts of cellulosic biofuel production could be used to manage a range of important insects in agricultural products and stored.

Their findings, published this month in the Journal of Economic Entomology, show that some of these by-products show promise as insecticides targeting stored product pests.

The “co-products” of biofuel production are ill-suited to fuel streams, but they could increase the profitability and sustainability of biofuel production by being applied for other purposes rather than being wasted.

Rob Morrison, Ph.D., one of the researchers wrote for Entomology Today: “One of the main processes in the production of biofuels is pyrolysis, in which biomass is deconstructed by high heat in the absence of oxygen. Our research team examined co-products heated to specific temperature ranges, also called “fractions”, from this pyrolysis process and found that they successfully mimic insect growth regulators when applied to a range of stored product insects, including the red flour beetle (Tribolium castaneum) and the confused tribolium (Tribolium confusum).

“Even at low concentrations, the oils have been found to cause deformities in normal development, such as incomplete metamorphosis or partial hardening of the pupa. Ultimately, many exposed larvae never mature into adults. At higher concentrations, there was 100% suppression of the population of red flour beetle larvae and confused flour beetle larvae, in contrast, adults were relatively unaffected. price of intermediate pyrolysis oil was very reasonable at less than $1 per kilogram (kg) to produce, while final pyrolysis oil cost between $1.41 and $1.70 per kg. 0.9% of the cost of commercially available insect growth regulators for stored product insects.

“Finally, a life cycle assessment of greenhouse gas (GHG) emissions was also carried out, and the team found that the use of pyrolysis oil could reduce GHG emissions associated with the insecticide production supply chain by 25-61% compared to that of a fossil fuel-based insecticide or pyrethroid.

“So pyrolysis oil is incredibly inexpensive to produce, highly effective against insect larvae and longer lasting than conventional alternatives. We are encouraged that the adoption of these bio-oils as pest control tools in agriculture will help improve the sustainability of using biofuels to provide at least some of society’s energy, while contributing to global food security.