Maximizing Biopesticides Benefits

 

Food security and efficient agricultural production are two of the most important global challenges of our age. Insect pests are one of the greatest problems in agricultural systems. They are responsible for about 36%-42% of the losses in some staple crop systems. The main strategy for reducing crop damages attempts controlling pests by addressing the obstacles and coping with food production and food security challenges.

 

Entomopathogenic fungi are widely used as biopesticides in biological pest control. The fungi possess a unique mode of action along with environmental- friendly properties. However, the difficulties in achieving competitive levels of field efficacy, and the high cost of biopesticides in general, have prevented them from making a significant global dent. The development of advanced formulations for biopesticides that can meet the demands for high pest control efficiency under different environmental conditions is of paramount importance. These formulations must exhibit high performances under different environmental conditions. How can research efforts help improve efficiency and achieved high performance? First, they must find ways to maximize the distribution of entomopathogenic fungi on the plant canopy. Then, they must ensure the prevention of spray drift from the leaves in order to increase persistence and protect against UV.

A BARD-funded research project combines the expertise of researchers from different disciplines. Dr. Mechrez is a material science expert, Dr. Ment is a plant protection expert in microbial control and Dr. Shapiro-Ilan specializes in invertebrate pathology and biological control of damaging crop pests. The research team aims to develop a new formulation for fungal biopesticides based on single-cell encapsulation in oil in water Pickering emulsion. They hope to develop a highly stable silica-based paraffin-in-water Pickering emulsions with proper droplet size and composition for single-cell encapsulation of the fungal conidia. They hope to protect against UV by chemical modification of the nanoparticles. The model fungal biopesticide, Metarhizium brunneum strain Mb7 in this research, will be incorporated in the studied Pickering emulsions for achieving single cell encapsulation of the conidia in the oil droplets.

The emulsion composition will be optimized to meet demands of highly efficient pest control activity by exhibiting high conidia distribution on the plant canopy, low conidia spray-drift from surfaces and increased persistence and UV protection functionality. The studied Pickering emulsion/conidia formulations is characterized in accordance with these three demands in vitro. Once the formulation will meet the required demands, the research teams will proceed to study the formulation in two diverse pest-plant systems: 1. S. littoralis larvae in cotton plants and 2. the pecan weevil, Curculio caryae, larvae and adults in pecan. Each system represents a different niche for application. This will allow the research teams to examine the functionality of the formulation in two diverse ecosystems. 

Together, the researchers will be able to test the feasibility of using Pickering emulsion with single conidia encapsulation as a novel strategy for biopesticide formulation against two destructive pests. This will be accomplished by exhibiting different niches, each of which is relevant to the agricultural practices of a specific country. All three investigators will be involved in tuning the resulting Pickering emulsion conidia system to meet three demands: increased dispersion, minimized drift and UV protection. Tuning will be achieved using the data obtained from testing the in-vitro functionality of the formulation in light of these three demands.