EVALUATING REPRODUCTIVE ABILITY OF THE RICE WEEVIL (PICIA MESOPOTAMICA) AT DIFFERENT TEMPERATURES ON RICE

Abstract

Rice (Oryza sativa L.) is one of the most important grain crops in Iraq. This crop is plagued by several significant pests, including the rice weevil aquatic (Picia mesopotamica) which is a serious pest in rice fields. This study was conducted out to learn more about the biological and environmental factors that influence how this insect survives and poses a threat to rice crops in the field. The results of reproductive ability revealed that temperature seems to have a significant impact on females' life cycles and survival rates during the first reproduction. Female egg productivity rates were found to be regulated by temperature, with the lowest rate occurring later in the female's life cycle. Moreover, the average age at the first reproduction of the female was 21 and 10 days at temperature 30°C and the highest rate of 30 and 19 days at temperature 20°C respectively and the highest average number of eggs 294.20 eggs/female at the temperature was 30°C. Further, the lowest average age of the female at first reproduction was 10 days at 30°C and the highest was 19 days at 20°C. The results also indicated the apparent effect of the tested temperatures on the net compensation rates of the insect females with the lowest being 8.793 females/generation at 35°C with the highest112.68 females/generation at30°C and the lowest average generation length 57.68 days at temperature. The population grew at an exponential rate of 0.035 females per day at 30°C, while the population grew at the slowest pace of 0.008 females per day at 35°C. Despite of the effect of temperature on other biological aspects of rice weevils requires more research. We found that temperature has a clear effect on the rice weevils reproductive activities on rice plants, and this research could be crucial in developing a successful pest management method.