INTERNATIONAL JOURNAL OF PEST MANAGEMENT

Assessment of the abrasion potential of pesticide-treated seeds using the Heubach test
Zwertvaegher IK, Foqué D, Devarrewaere W, Verboven P and Nuyttens D
During sowing of pesticide-treated seeds, pesticide-laden dust and abraded seed particles may be emitted to the environment, possibly leading to environmental contamination and posing health risks. In many countries there is currently no legislation concerning the acceptable amount of dust of treated seeds. This study aimed to gain insight in the abrasion potential of available pesticide-treated seeds and its associated factors. The abrasion potential of 45 seed samples of 7 different species ( sugar beet, oat, barley, wheat, spelt, pea, and maize) was determined using the Heubach test and amounts of dust were expressed as g 100 kg, g 100,000 seeds, and g ha. The abrasion potential fell generally within the boundaries of maximum permissible values adopted by different countries. Species, seed treatment company, number of active ingredient (AIs) and combination of AIs had significant effects on the abrasion potential, whereas little or no effect of agitation and conservation was found. However, species were situated differently with respect to each other depending on the unit in which the abrasion potential was expressed. A standard unit that takes into account the species' seed rate is suggested to give the fairest assessment of dust drift risk and would allow international comparison.
Evidence that rodent control strategies ought to be improved to enhance food security and reduce the risk of rodent-borne illnesses within subsistence farming villages in the plague-endemic West Nile region, Uganda
Eisen RJ, Enscore RE, Atiku LA, Zielinski-Gutierrez E, Mpanga JT, Kajik E, Andama V, Mungujakisa C, Tibo E, MacMillan K, Borchert JN and Gage KL
Rodents pose serious threats to human health and economics, particularly in developing countries where the animals play a dual role as pests: they are reservoirs of human pathogens, and they inflict damage levels to stored products sufficient to cause food shortages. To assess the magnitude of the damage caused by rodents to crops, their level of contact with humans, and to better understand current food storage and rodent control practices, we conducted a survey of 37 households from 17 subsistence farming villages within the West Nile region of Uganda. Our survey revealed that rodents cause both pre- and post-harvest damage to crops. Evidence of rodent access to stored foods was reported in conjunction with each of the reported storage practices. Approximately half of the respondents reported that at least one family member had been bitten by a rat within the previous three months. Approximately two-thirds of respondents practiced some form of rodent control in their homes. The abundance of rodents was similar within homes that practiced or did not practice rodent control. Together, our results show that current efforts are inadequate for effectively reducing rodent abundance in homes.
Quantification of GST and esterase activities in pyrethrin-resistant mosquitoes using pyrethroid-like fluorescent substrates
Kamita SG, Mulligan S, Cornel AJ and Hammock BD
Botanical pyrethrins and synthetic pyrethroids are highly potent and environmentally safe insecticides that are used to control a wide range of disease vector and pest arthropods. Unfortunately, resistance to these insecticides has been demonstrated in numerous medically important mosquito species. In this study adult sensu lato were captured in agricultural and urban locations in Fresno County, California, and subsequently exposed to a commercial formulation of pyrethrin insecticide by ultra low volume spraying. Following insecticide exposure, two pyrethroid-like, fluorescent substrates (-DCVC and -TFMCVC) and CDNB were used to measure esterase and glutathione -transferase (GST) activities in surviving mosquitoes. Elevated esterase activity (2.5-fold) was found in surviving urban mosquitoes at 12 h post pyrethrin exposure (in comparison to non-insecticide exposed control mosquitoes) when -TFMCVC was used as a substrate. Additionally, when CDNB was used as a substrate, 2.8-fold higher GST activity was found. A simple assay was established using our pyrethroid-like, fluorescent substrates that was able to detect low-level esterase activities in homogenates made from individual mosquitoes. The -TFMCVC-based assay suggested that esterase activity plays a role in pyrethrin resistance in urban mosquitoes in California.