Tomato yellow leaf curl begomovirus (TYLCV) severely invaded tomato plantations in Egypt (Lower and Middle Egypt) in 1989. This study aimed to discover the relationship between TYLCV and other epidemic-associated factors in the Fayium area. The rate of TYLCV infection was inspected visually for three successive years (1994/1996) in the Fayium area. During the same period, whiteflies were collected for virus detection using bait-plant and DNA hybridization techniques. DAS-ELISA was used to detect mixed virus infections in tomato plants. TYLCV infection was prevalent (60-68%) and severe (2.1-3.0) in the Fayium fields. Cucumber mosaic cucumovirus (CMV) was found in some fields (5-28%) with moderate severity (1.0-20). Potato Y potyvirus (PVY) and potato leaf roll polerovhs (PLRV) were found in few fields (5-19% and 5% respectively) at very low seventy. There was a negative correlation between TYLCV Occurrence and distance from the source of infection, and a positive correlation (98%) between TYLCV intensity and percentage of viruliferous whiteflies in 1994 and 1995. There was no positive correlation between TYLCV and the total population of whiteflies caught during the same period. Five percent of viruliferous whiteflies, as proved by cDNA hybridization, led to 46% TYLCV infection. The same percentage of whiteflies, as shown by bioassay, led to 68% TYLCV infection. Monitoring of viruliferous whiteflies could be used for early prediction of TYLCV infection.

Four experiments were conducted at Embaba, Giza Governorate by planting beans four times during 2011, 2012 and 2013 to assess the annual variation in population of Melanagromyza phaseoli attacking bean plants Phaseolus vulgaris (L.) in relation to certain climatic factors, synchronization of plant age with insect counts, generation numbers, and injury on plants. Obtained results cleared that adults and larvae of this fly attack plants as soon as seedlings emergence in all growing seasons. In spring 2011, adult females reached highest counts 1.17, 1.17 and 1.1 individual/ sweep at 12 th April, 10 th May and 7 th June, respectively. Their larvae reached highest 2.2 and 15.33 larvae/leaf at 26 th April and 31 st May. The highest tunnels number during season was 26.87 tunnel/leaf. In summer 2011, larvae reached highest counts 1.4, 29 and 2.3 larvae/leaf at 5 th July, 23 rd August and 20 th September at temperature 27.17, 29.84 and 27.97°C and relative humidity 54.14, 54.57 and 57.71%, respectively. During summer 2012, both adults and larvae reached its highest three times, larvae were 1.9, 4.87 and 7.2 larvae/leaf. Tunnels number was 11.07/leaf in highest case. Leaf miner population was rather low during winter 2012/2013. Capabilities of insect to produce progeny and to injure plants were discussed. Insect produced three generations/ growing season. Temperature and relative humidity revealed their presence inside the optimum range for the insect activity. Plant age had positive relationship with larvae counts in spring and summer seasons. Management program must be directed against insect during period 39-74 day of plant age.