Abstract
The life cycle of Monosteira buccata Horv. which attack some poplar species was studied in Iraq in 2009.The eggs was laid singly with the majority on the lower surface of the leaf in comparison with the upper one. The average number of eggs laid per female. incubation period. eggs viability (150.9.8.33.85%) respectively. The sex ratio of male to female was 1:1.M.buccata was observed to have five nymph instars. The newly hatched nymph is oval in shape and transparent white in color. In the case of the fifth instars. the mesotergum become prominent. forming solid pentagonal sclerotic extending backward to cover the third thorax and the first abdominal segments. Ecological study has shown that the area and percentage of damage started with the primary appearance of the poplar bag species adults at the beginning of may. The increasing of insects number caused an increase in the area and percentage of damage which reached their maximum means (10.39, 23.62, 6.99) cm and (30.19, 33.36, 26.72)% respectively for Populus nigra. P.deltoides and P.euphratica respectively. this happened when the insect number means reached the maximum (16.63, 19.84, 9.86) insect / leaves for the above mentioned poplar species. The statistical analysis showed that there is a significant correlation between the mean insect number and mean of area and percentage of damage in the 3 poplar species.
