Abstract:
This study was carried on the infested areas by the tomato leaf miner (Tuta absoluta) and its main host plants in Khartoum State during 2012-2013, for estimation of damage percentage ,to know the life cycle of the insect and to know the effects of extracts Neem, jatropha on the eggs , of Neem, jatropha and Hargal on the larvae of T. absoluta .
The results of the study indicated that there were three areas highly infested, five areas moderately infested and three areas of low infestation in Khartoum State. Also, the results of the study showed that, the total percentages of damage on tomato crop in Four Months in Abu Halima were 40 , 50, 70 and 80% damage in fruits only, 52%, 87.5%, on leaves, 72% on unripe fruits and 45% on stem, and there were no preferred parts for the insects, which feed on all plant parts.
The results of the study showed that, the adult of the tomato leaf miner mate after a short period of emergence, that ranges from 4to7 days. The number of eggs was 61-64 eggs per female, , with a mean of 55.5 eggs .The stages of egg, larva and pupa were completed within 9±1.0, 31.2±2.6, and 6.1±1.5 days, respectively, at the temperature range of (19-21)ºc .The percentage of insect life span from egg to adult was 64.7±1.7%, and the mean mortality rate in egg was 21.3±1.6%. At the temperature range of (30-34)º c, the stages of egg, larva and pupa were completed within 4±1.0, 13±2 .1 and 6±2 days, respectively .
The results of the study showed that, the percentages of egg mortality by plant seed extracts from Neem and Jatropha, sprayed after 24 hrs. by the concentrations, 1000، 500، 250، 125 و 62.5 mg/L , had slight effects on eggs, with mortality ranging between 22 – 26%. With the larvae, percentages of mortality, at concentrations of 6000 و 8000, 4000, 2000 mg/L, of Argel, Neem and jatropha extracts were, 33-48.5 ,33-46.5 و23- 46.5, respectively, in the first day, while 100% mortalities were obtained in 4th day.
