RESUMEN
A large scale field trial under natural conditions was conducted to observe biological effects of methoprene on mosquito immature and mature stages. In addition non-target invertebrates [N. T. Os] in the treated breeding places were also checked for any adverse effect. One dose of Altosid briquet formulation one briquete per 100 sq. ft. and two dosages 250 ml/hect. and 300 ml/hect. of liquid SR-10 methoprene were tested. Negligible% [less than 1%] adult mosquitoes emerging from pupae were observed during the first week after treatment with briquets or 300 ml/hect. On 18
h day of observation after treatment only 50% adults emerged from breeding places treated with 300 ml/hect. and same% from treated with briquets but on the 21
t day after treatment. Morphological abnormalities were noticed among the surviving adults, emerging between 6-15 days after treatment. Significant sex proportion distortion was also noticed among the apparent normal adults emerging between 3-12 days after treatment. Both the formulations of methoprene were found to be very safe in handling and for N. T. Os