Biology of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under different temperature and relative humidity

Abstract

Tomato leaf miner, Tuta absoluta (Meyrick) is a pest of Solanaceae crops, particularly tomato (Lycopersicon esculentum (Miller)) and potato (Solanum tuberosum Linnaeus) in the world. There are different records on the biology of T. absoluta in the world mainly due to variations in temperature and relative humidity. In Ethiopia, night temperature is very low and day temperature is very high. Due to this reason, it is expected that the biology of T. absoluta is somehow different from what was so far recorded elsewhere. Hence, the biology of T. absoluta was studied at different temperatures and relative humidities under laboratory and glasshouse conditions for two consecutive seasons. In the experiment, developmental stage, adult longevity, fecundity and ovipositon period were recorded. T. absoluta female laid about 60.56% of her egg on the upper side surface of tomato leaf, while the lowest (0.85%) was laid on tomato stem. The highest number of eggs of 233.75±14.42 was laid at 20.5±2°C and 55±5% R.H., whereas the lowest number of eggs (177.5±9.26) was laid at 32.0±2°C and 40±5% R.H. Considering the life cycle and longevity of adult T. absoluta, the results revealed that at 20.5±2°C (55±5% R.H.), no significant (P > 0.05) difference was observed between laboratory and glasshouse conditions in the case of complete life cycle. The life expectancy of adult was high at low temperature and low at high temperature. As temperature increased (20.5°C and above), developmental time of the moth appeared to decrease.   Key words: Biology, life span, fecundity, Tuta absoluta, temperature, relative humidity.