BIOLOGICAL AND ECOLOGICAL STUDY OF IRAQI BEETLE

Abstract

The life cycle of Adoretus irakanus Ohs. Which attack poplar species was studied in Iraq in 2007under laboratory conditions ( 30.5 C° and 25.5% ). The study showed that the mean length of incubation ,eggs viability and larval stages ( 7.51 day, 82% 342.8 days ) respectively ,It was appeared that the larval stages live inside the ground and feed on the decayed material and roots of different plants present in the soil . The mean period of pupa was 7.1 days. After the emerge of adult it laid the eggs in the soil singly and separate . The study also indicated that the mean number of eggs laid by a single female were 106.5 . The sex ratio of male to female was 1.1:1. The longevity of adults, males and females were 27. 35 , 30.75 days respectively. Also it was found that this species of insect has one generation per year. The hibernation appeared in the second larval instar. Ecological study has shown that the area and percentage of damage started with the primary appearance of the Iraqi beetle adults at the beginning of April.The increasing of insects number caused an increase in the area and percentage of damage which reached their maximum means 16.20,12.11,10.7cm2, 44.87,17.35,41.07% respectively for Populus nigra, P.deltoides and P.euphratica respectively this happened when the insects number means reached the maximum 2.81,2.31 and 2.0 insect/leaves for the above mentioned poplar species to mean temperature 27.42°C and R.H 34.5%.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 with r value (90.64,93.05 and 89.62) for damaged area, and for damage percentage (90.31,88.32 and 89.49), respectively.