Survey of Summer Tomato Pests in Khartoum State, with Special Reference to Biology and Natural Control of Tuta absoluta

Abstract

A survey was carried out for tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera:Gelechiidae) on summer tomato (GS variety) in open field of four agricultural schemes of about 40 fedans in Khartoum State. The aim of survey was to evaluate the infestation of this pest on summer tomato. The results showed that no infestation scored by Tuta absoluta in summer tomato in all the period of experiment, although other pests were found such as:leaf miner ,leaf curl,boll worm and mealy bug . This may be due to the unsuitable Environmental conditions to the pest during July, August and September.The recommendation to cultivate the summer tomato (GS) on these months safley. Also there was two laboratory experiments were conducted in the Department of Plant Protection,Collage of Agricultural Studies, Sudan University of Science and Technology (SUST).The first study was to examine the lethal effect of seeds ethanolic extract of Jatropha curcas L,against the larvae of Tuta absoluta. Four concentrations were used in this experiment 5%, 10%, 15% and 20% .The result showed that all the tested concentrations caused higher mortality percentage than the control. The lowest concentration 5% gave 68% mortality after 72 hrs of exposure. The highest concentration 20% scored 100% mortality not less than the mortality precentage of the standard insecticides after 72 hrs of exposure.The recommendation can be to use this extract as a control agent for Tuta absoluta. The second laboratory study was to investigate the preference of larvae of Tomato leaf miner on leaves and fruits of five vegetable plants .The results showed that there was significant difference in preferences of larvae after five days of appearance of the the larvae. .The larvae only preferred the XI leaves of tomato 86.7% and potato 20% while their preference in fruits was zero.After ten days also there was significant difference in preferences of the larvae.The larvae was preferred the leaves of potato 20%, tomato 13%, eggplant 10% and pepper 6.6%.On fruits the larvae only preferred tomato 33.3% and potato 3.3%.The recommendation can be avoiding cultivating other solanacae beside tomato.