author(s)
R Velusamy

abstract
The lesser mealworm (Alphitobius diaperinus), also known as darkling beetle, is responsible for huge economic losses in poultry production. This insect has fully adapted to poultry houses and commonly found in high density in poultry litter. It is a potential transmitter of bacteria, viruses, fungi, protozoa and particularly tapeworms. Most strategies used to control this pest are based on the application of chemical insecticides. However, the widespread and inappropriate application of the chemical insecticides against these darkling beetles produced the risk of developing resistance to almost all the compounds introduced in the market. To overcome this problem, a study was conducted to evaluate the effect of essential oils (eucalyptus and lemon grass) at different concentrations against larvae and adult darkling beetles. The essential oils were mixed with acetone at three different concentrations viz., 5, 10 and 20%. Twenty adult beetles / larvae were placed into the glass vials and their mouth covered with muslin cloth. The filter papers impregnated with different concentrations of essential oils were placed into a bottle. The glass vials with beetles were hung at the geometrical centre of glass bottles, which were then closed with air-tight lids. Mortality/viability of insects was recorded after every 30 min., 24hrs and 48 hrs. The results of the current study showed that none of the beetles died even at the higher concentration of both the essential oils. The present study suggests that eucalyptus and lemon grass essential oils are not effective against the larvae and adult darkling beetles dwelling in poultry litter.