Fipronil enhanced natural occurrence of Fusarium solani (Hypocreales: Nectriaceae) on building infesting termite Heterotermes indicola Wasmann (Blattodea: Rhinotermitidae)

The Southeast Asian subterranean termite, Heterotermes indicola Wasmann (Blattodea; Rhinotermitidae), is recognized as a building infesting lower termite species in urban environment. The extensive use of chemical termiticides against aerial mud tubes and underground nests of H. indicola beneath the buildings could not suppress its infestation; however, it enhanced the environmental contamination and insecticide resistance. In the present study, we tried to control termites using naturally occurring entomopathogenic fungi Fusarium solani (Mart.) Sacc., along with sublethal concentrations of termiticide fipronil in no-choice feeding pathogenecity bioassay for 20?days. Termite mortality after 20?days of continuous exposure to highest fungal treatment 1?×?10⁹?conidia/mL was 10% exclusively, whereas 100% mortality was calculated just after 16?days of concurrently exposure to 5?ppm of fipronil and highest rate of fungus 1?×?10⁹?conidia/mL. These results indicated that insecticidal stress declined the immune response of termites and reduced the repellency of termites against fungal conidia by breaching the primary defense mechanism (allogrooming). This co-application of F. solani at suitable sublethal concentrations of fipronil showed the promising potential against termites that may reduce the selection pressure of pesticides and resistance risk by targeted pests, but further investigations are necessary for developing field trials.     

Annual TSP and Trace Metal Distribution in the Urban Atmosphere of Islamabad in Comparison with Mega-Cities of the World

The objective of this work was to assess the current concentrations of total suspended particles (TSP) and trace metals in the urban atmosphere of Islamabad, Pakistan, where local industries, transportation, and urbanization are adversely affecting air quality. Air sampling was done using a high-volume sampler and the metals were estimated in TSP by Flame Atomic Absorption Spectrophotometry. An annual mean TSP of 151.9 μ g/m³ was determined for the period May 2003–April 2004, which exceeded the World Health Organization's (WHO's) primary and secondary standards of air quality. The TSP metal concentrations were compared with those reported in literature for other regions of the world and with air quality standards laid down by regulatory agencies. The levels of Na, Fe, Zn, Pb, Mn, Cr, Co, and Cd for the present study were higher than most of the levels reported for other typical industrial and urban areas of the world. The airborne Ni concentrations were higher than the WHO and the U.S. Environmental Protection Agency's standards. Cluster and Principal Component Analyses of the data were used to identify the sources of the metals and establish their mutual correlations in the local atmosphere.