Population Changes of Tuta absoluta (Mey.) (Lepidoptera, Gelichiidae): A New Introduced Tomato Crop Pest at Biskra in Algeria

The aim of this work was to investigate the population infestation of Tuta absoluta on tomato crop Lycopersicum esculentum Mill. under greenhouse conditions in two sites at Biskra (South- east of Algeria). A high numbers of different stages of T. absoluta were collected in April with 908 and 827 adults, 191 and 237 eggs, 234 and 295 larvae and finally 50 and 45 pupae, however, very low numbers were recorded in November with 5 and 0 adults, 8 and 0 eggs, 27 and 0 larvae and 0 pupae at Bouchagroune and Sidi Okba, respectively. The study showed that the total leafminer numbers were more significant at Bouchagroune than at Sidi Okba. This were probably due to the significant greenhouse numbers in this part of the locality. For Sidi Okba, it might be that greenhouses isolation and regular pesticide applications were responsible for the low numbers. The leafminer population progress is increasing during tomato phenologic cycle due mainly to the rise in greenhouse temperature. No natural enemies of T. absoluta was found following to crop pesticide applications.