Studies on some pests of tomatoes and their biological control in the Southern valley of Egypt

The present study focused on a survey of the important pests of tomato plants at Nasser Lake region Aswan Governorate, and their biological control using certain natural enemies. Results showed that the mean rate of infestation with S. exigua was 4.1 % while infestation rates with the other pests were comparatively very small; (E. discipenus and liriomyza SPP. 0.9 %, T. urticae 0.75 %, Aphis spp 0.5% and B. tabaci (0.33 %. The mean rate of infestation With H armigera larvae was 9.6%.Usmg pheromone traps, the mean number of moths /trap was 9.8 at 2006/2007 season compared to 2007/2008 season. Statistical analyses showed a negative correlation between the rate of infestation H. armigera and temperature and a positive correlation with humidity. The percentage of reduction in H. armigera infestation due to releases of T evanescens during 2006/2007 season was 41.4 %. While in 2007/2008 evaluation of releases of different ages of T evanescens and T evanescens + Chrysoperla carnea (as a predator) were made, The combined release of the predator and the parasitoid gave the highest percentage of reduction 63.7 % in the pests larval population, compared to reduction percentages of 59.8 and 50.9 %, at the treatments with the parasitoid alone respectively. The effect of certain weather factors on the pupae of T evanescens under field conditions was investigated. Pupal period was prolonged at low temperatures. The shortest pupal period was 4 days when the parasitoid was released as 7 days old pupae, at a temperature of 24.9 ºC and 32.6% R.H.. The longest pupal period was 13 days at 15.3 .C and 33.2% R.H. when the parasitoid was released as 4 days old pupae. The shorter pupal period was 7 days at 25.1 .C and 33.2% R.H.. The longest period was l7 days at 13.9ºC and 28.4% R.H.. The rate of parasitism of T evanescens was 89.9±0.3, 86.5±1.3 on H armigera and S. cerealella, respectively. Sex ratio (M: F) was; 1: 3.9 and 1: 3 in H. armigera and S. cerealella, respectively. The efficacy of C. carnea larval consumption when fed on the eggs of H armigera was investigated. The total duration of the larval stage was 8.3 and 9.2days for the larvae reared on H armigera eggs and aphids, respectively. The percentages of larval mortality were relatively higher in case of rearing the predators larvae on A. craccivora. Durations of the pupal stage of C. carnea were 8.2±0.66 and 8.4±0.68 days in the case of rearing on C. Carnea and aphides, respectively. Rates of adult emergence of C. carnea from the pupae were 92.7 and 93.5 %, respectively, and sex ratio was 1: 0.93 and 1: 0.9, respectively. The mean longevities of C. carnea males 35.7±0.7 and 41.5±0.88 days, respectively. Female longevities were 40:1:0.7 and 36.2+-1.8 days, respectively. The mean number of eggs/ female of C. carnea was 912±1.28 and 778.6±1.62 eggs/ female, on 25±2ºC and 60±5 % R.H., respectively