Natural Formulation Based on Diatomaceous Earth and Botanicals against Stored Product Insects

Diatomaceous earth (DE) has long been known as a potential protectant for stored cereals against various stored product insects. Despite favorable effect for the environment and human health, DE has some negative side effects on the treated commodity. In order to minimize negative response and to improve its efficacy, this paper represents a study of developed natural formulation based on DE SilicoSec^® enhanced with botanicals (essential oil lavender, corn oil, and bay leaves dust) and silica gel. The activity of formulation (labeled as N Form) was tested against Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium castaneum (Herbst) in seed wheat and barley under controlled conditions. As a reference comparative value, DE SilicoSec^® was used. N Form showed higher efficacy than DE, especially in barley at the lowest concentration, inducing higher mortality of all three insect species. The highest average progeny inhibition was recorded in R. dominica population both in seed wheat and barley with 94.9% and 96.3% of inhibition, respectively, followed with S. oryzae and T. castaneum inhibition of 90.6% and 86.1%, respectively, in wheat and 94.9% and 89.7%, respectively, in barley. Results indicate that the developed natural formulation N Form enhanced the activity of DE SilicoSec^® using lower amount of DE dust and that it could be successfully implemented for storage of cereals as alternatives to chemical pesticides for stored product insect control.