Effects of binary mixtures of diatomaceous earth dust and botanical insecticides in bed bug management

In the past two decades, infestations of the common bed bug, Cimex lectularius (Hemiptera: Cimicidae), have increased dramatically not only in North America, Europe, and Australia but all over the world. Bed bugs are now considered a pest of “significant public health importance” and an emerging public health problem across the United States by the US Centers for Disease Control and Prevention (CDC) and the US Environmental Protection Agency (EPA). The development of pyrethroid resistance in bed bugs and the withdrawal of several effective insecticides registered for bed bugs from the UK and US markets has further reduced the options for control. Therefore, there is a need to develop new techniques and products for controlling bed bug infestations. Since bed bugs are cryptic and spend most of their lives in concealed harborages including cracks or crevices, there is a need for insecticides with residual effects. Diatomaceous earth (DE) dusts are especially useful as crack and crevice treatments for bed bugs partly due to their residual effect and owing to their ability to be transferred horizontally by bed bugs. We will demonstrate the potential of using binary mixtures of DE dust and botanical insecticides in the management of bed bugs. Our results show that combination treatments are significantly more effective than either treatment alone in terms of enhanced toxicity, reduced killing time and the amount of DE dust used. Increased toxicity of mixtures has been correlated with greater damage to the cuticle and subsequent water loss in the insects.