Assessing repellency,movement, and mortality of three species of stored product insects after exposure to deltamethrin-incorporated long-lasting polyethylene netting

Long-lasting insecticide-treated netting (LLIN) has begun to be used in agricultural product protection. We investigated the effect of a deltamethrin-incorporated LLIN on three stored product insects, red flour beetle, Tribolium castaneum (Herbst), lesser grain borer, Rhyzopertha dominica (F.), and rice weevil, Sitophilus oryzae (L.). Long-distance repellency was assessed in a wind tunnel for adults of each species, but no repellency was observed. Insect movement and behavior was assessed by observing the movement of adult beetles on treated and untreated netting during a 5 min period for distance traveled, velocity, mobility, and time on each netting type. Among all netting combinations, T. castaneum spent the most time highly mobile, higher velocity, and traveled a greater distance. Sitophilus oryzae and R. dominica spent significantly more time immobile and lower velocity. Efficacy of LLIN was tested by exposing adults for 60 min, removing, and holding with or without food, and monitoring for mortality up to 7 d. All S. oryzae and R. dominica were either affected or dead at all post-exposure times. The number of affected and dead adult T. castaneum combined 7 d after exposure was 42% and 95%, with or without food, respectively, and 52% of affected adults were able to recover when food was present. Overall, LLIN had no repellency or negative effect on insect movement, which increases the probability of lethal exposures of adults from walking on the netting. LLIN can be adopted in existing integrated pest management (IPM) programs for food processing facilities to prevent stored product insect infestations.

     

Preliminary determination of limiting nutrients for standard plate count organisms in Chicago intake water

Previous studies on the factors associated with increased bacterial populations in water intakes and finished potable waters have been inconclusive. In the present study, a multi-factorial design was developed to determine the nutrients which could increase standard plate count densities in the Lake Michigan intake water for the City of Chicago. Carbon, Fe, nitrate, ammonia, and phosphate were considered as possible limiting nutrients. On the basis of this study, P emerged as the primary limiting nutrient with respect to both yield of microorganisms, and growth rate.     

Attention reduction and suppressed direct-current potentials in the human brain

Distraction suppresses direct-current potentials (contingent negative variation) recorded from the human scalp. This reduction is accompanied by retarded reaction time. Contingent negative variation and reaction time appear to reflect a common process, attention.