Abstract:A survey was carried out in 2011 to study the epidemiology of tomato yellow leaf curl virus (TYLCV) in tomato growing sites of the Tobas and the Jenin districts. The survey studied the population of the virus-inoculative whiteflies and the possible virus reservoirs throughout the year. The maximum TYLCV-inoculative whitefly population was recorded in Tobas, compared with the Jenin district in the different growing seasons of tomato. In the Tobas district, the inoculative whiteflies started to appear in March and reached the maximum value of 7% in July and August. In the Jenin district, the maximum inoculative whitefly population of 6% was recorded in August. Such whiteflies started to appear in May, which is two months after their appearance in the Tobas district. Furthermore, populations of inoculative whiteflies occurred when farmers started their tomato growing seasons. The appearance of inoculative whiteflies coincided with availability of the virus natural reservoirs which harbor the virus and support the vector during the crop-free period. Infected cheese weed mallows (up to 12%) and tobacco plants (up to 7%) were the virus sources for whiteflies throughout the year in the Tobas and the Jenin districts respectively. Infected volunteer tomatoes (up to 93%) play a secondary role in the virus epidemiology as they disappear during winter (crop-free period) in both districts.

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Studying the retention of nucleic acid of the Palestinian isolate of the tomato yellow leaf curl virus in the whitefly vector, Bemisia tabaci, by using the polymerase chain reaction (PCR) showed, on one hand, that the viral DNA was retained for at least 24 days after the 48-hours of acquisition access on TYLCV-infected tomato plants. On the other hand, enzyme-linked immunosorbent assays (ELISA) revealed that the virus's antigen persisted for only eleven days, which is much shorter than the retention of the virus’s genome. This feature proved that there is a close relationship between the capsid’s retention in the whitefly vector and the virus’s transmissibility which remained for eleven days. In addition, In Vitro studies proved that the non-vector insects including whitefly, Trialiorodes vaporariorum, and aphids, Myzus persicae, Aphis gossypii and Macrosiphum pisi can also acquire both the viral DNA and the capsid, when given 48-hour acquisition access on infected tomato. Furthermore, studying the viruliferous B. tabaci collected from tomato fields in Al-Far'a region revealed high association of both the viral DNA and the capsid compared with those collected from eggplants near tomato fields which showed low association. This research also proved that the above mentioned non-vector insects pointed out above have the ability to acquire the virus under field conditions with various rates. Therefore, the maximum acquisition of the viral DNA recorded in T. vaporariorum collected from Al-Far'a region was found to be 50%.

An experiment was carried out in 2008 to study the incidence of Erysiphe cichoracearum, the causal agent of powdery mildew on squash and cucumber in different growing seasons of the Tobas and Jenin districts. The incidence was studied in both open fields and plastic houses. Also, the research studied the genetic variability between the fungal isolates using RAPD. The maximum fungal incidence was recorded on squash, compared with cucumber in all growing seasons. The maximum disease incidence of 70% was recorded on squash during both spring and summer growing seasons in Tobas district. Autumn was considered the second most serious growing season of both crops as the fungal incidence ranged from 4 to 53% and 3 to 42% on squash and cucumber, respectively. In late winter growing season, the fungal incidence was much lower on both crops planted in Tobas district compared with the other growing seasons (4 to 20% on squash and 2 to 18% on cucumber) . In addition, studying the genetic variability between the fungal isolates showed that these isolates were genetically different between Tobas and Jenin districts. Furthermore, polymorphism was in squash and cucumber from obtained isolates the between observed Tobas district while no polymorphism was recorded in Jenin district. اجريت دراسة لمعرفة مدى انتشارمرض البياض الدقيقي على نباتي الكوسا والخيار في محافظتي طوباس وجنين خالل موسم 2008. كذلك تم في هذا البحث ايضا دراسة االختالف الجيني بين العزالت الفطرية في منطقتي الدراسة باستخدام RAPD. وبشكل عام كانت االصابة بهذا المرض عالية على الكوسا مقارنة بالخيار في المنطقتين وفي جميع المواسم الزراعية، كذلك كان انتشار المرض االعلى خالل موسمي الزراعة الربيعية والصيفية مقارنة بمواسم الزراعة االخرى، حيث سجلت اعلى اصابة في هذين الموسمين على محصول الكوسا في محافظة طوباس، اذ وصلت ّ70%. احتل موسم الزراعة الخريفية المرتبة الثانية من حيث مدى انتشار المرض فيها حيث تراوحت االصابة من 53-4% ومن 42-3% على محصولي الكوسا والخيار على التوالي. اما بالنسبة للزراعة الشتوية فقد كانت اكثر امنا لدى المزارع، كون االصابة فيها كانت قليلة مقارنة بالمواسم االخرى، اذ تراوحت االصابة من 20-4% على الكوسا ومن 18-2% على الخيار. ومن ناحية اخرى بينت الدراسة ان العزالت الفطرية تختلف وراثيا بين محافظتي طوباس وجنين. كذلك تبين ايضا وجود اختالفات وراثية للعزالت الفطرية التي عزلت من محصولي الكوسا والخيار في محافظة طوباس في حين اثبتت الدراسة عدم وجود هذه االختالفات بين العزالت من كال المحصولين في محافظة جنين.

The main objective of this project is to develop sustainable method of innovative agriculture practices that relies on reducing the liquid and solid waste generated from olive mill and limestone slurry by-product from factories in Palestine. The second aim is to use these waste by-products in a proper ratio mixture and their feasibility in the agricultural use for optimal and best conditions. The overall output is the implementation of applied research on wheat crop and solanaceous vegetables including tomato and pepper which proved their tolerance to grow well in such natural medium. It was observed that the best mixing ratio of the two parameter of limestone slurry and OMW was at 90:10 respectively. Crop growth, plant length and leaf area were measured. The best ratio of lime to OMW in wheat and pepper was 90:10, while tomato 80:20. It appears that the best result including plant height and leaf surface area were obtained at 90:10 mixing ratio of limestone and OMW as medium of limestone, pomace and OMW was suitable for cultivating the different types of studied crops. In general, the best results of plant growth were achieved when the percentage of limestone was high in the medium. The research has shown that it is possible to prepare an alternative media for plant growth from three major environmental by-products that were considered pollutants. In general, as the percentage of limestone increased in the medium, the plants grow proportionally. Selection of project site was within the AAUP Biology department and arboretum