Monitoring of housefly [Musca domestica] population abundance in Alexandria governorate and assessment of its susceptibility towards some commonly used insecticides

This study was conducted to monitor the housefly "Musca domestica" population abundance in different districts of Alexandria Governorate throughout one year from January to December 2002. Also, it determined the susceptibility of housefly against different currently used insecticides by Ministry of Health and Population [namely malathion and azamethiphos against adults and chlorpyriphos against larvae]. In addition, it evaluated the effect of a botanical compound; neem oil against both adults and larvae as an alternative insecticide. The data demonstrated that the highest housefly abundance was observed in El-Amreya and West Districts with mean grid count of 75.0 +/- 40.8 and 72.9 +/- 46.3, respectively. The lowest housefly abundance was observed in Borg El-Arab and East Districts with mean grid count of 37.7 +/- 19.7 and 39.5 +/- 28.1, respectively. The order of housefly population abundance in different districts of Alexandria Governorate was as follows: El-Amreya > West > El-Montaza > Middle > El-Gomrok> East> Borg El-Arab. Also, the abundance of housefly was greatly affected by temperature fluctuation where there were two peaks observed in Spring and Autumn while there were two depressions in Summer and Winter. There was a negative significant correlation between housefly abundance and both shadow and wind. As regards the susceptibility of housefly towards tested insecticides, the LD[50] of malathion against adult insect using topical application for laboratory strain was 0.0199 mg/fly while in case of field strain, it was 0.0363 mg/fly [1.824 times more than that of laboratory strain]. As regards azamethiphos using diet treatment, the LC50 for laboratory strain was 0.0281% while it was 0.0312% for field strain [1.11 times more than that of laboratory strain]. The EC50 of chloropyriphos using diet treatment against first instar larvae of field strain of housefly was 3.50 ppm. The most prominent toxic effect of neem oil emulsion was noticed in larval stage where EC[50] for laboratory strain was 1982.9 ppm, while it was 2045.3 ppm for field strain. Neem oil had no toxic effect on adult housefly by either topical application or diet treatment. In conclusion, the study reports no resistance of housefly against the tested compounds

Biochemical effects of some insecticides on lysosomal enzymes in brain tissue

The effect of dimethoate, permethrin and AC 222-705, on the activity of brain beta-glucuronidase, acid ribonuclease and alpha- naphthyl acetate esterases of male mice was investigated. The data indicated that, these insecticides induce disturbances in the activities of the tested lysosomal enzymes, which constitute important indices for carcinogenicity

Assessment of the interaction between chemical and biological control of biomphalaria alexandrina: the intermediate host of schistosomiasis mansoni

The acute molluscicidal activity of bayluscide is 80-100 times more than that of lannate, against both the target snail, B. alexandrina, and the biocontrol snail, L. carinatus, which showed about twice sensitivity to the tested compounds. Prolonged exposure for 7 weeks to sublethal concentration of lannate or bayluscide [1/10 LC50] in the presence of the biocontrol agent changed water pH, although, the changes were still in the survival range of the target snail. However, pesticide treatments and biocontrol agent had an adding action on increasing the death rate of the target snail which was more susceptible to lannate than to bayluscide. The tested concentration of Lannate associated with the biocontrol agent, positively influenced the egg laying capacity of the target snail, while Bayluscide treatment decreased this capacity. Nevertheless, conditioned water with L. carinatus snails for 6 weeks decreased the egg laying capacity of B. alexandrina snails, although the capacity was significantly increased when the conditioning was combined with Lannate residue as well. Hatchability was significantly declined when the eggs were laid in treated-conditioned water and left to hatch either in the same kind of water or in dechlorinated tap water