الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
Cucurbits considered one of the most important and widely distributed vegetable crops in Egypt and all over the world. The cultivated area has been increased to face the increasing demand of cucurbits, which they are mostly tropical or subtropical plants .
Family Cucurbitaceae belongs approximately about 90 Genera, but three are grown in Egypt in open fields or under protected cultivation, i.e. Cucumis spp. (cucumber, melon and snake cucumber), Cucurbita spp. (squash & pumpkin) and Citrullus spp. (watermelon). They are grown throughout the year round in many locations in Egypt, either in open fields and / or protected cultivations.
Fruit rot diseases are economically very important which attack Cucurbit plants during flowering and fruit growth stages causing destructive effect on plants and fruits which responsible for the losses in fruit yield due to diseases infection.
Result obtained from this investigation could be summarized as follows:
1. Typical symptoms on fruits of Cucurbits infected with various fungal genera namely, Botrytis cinerea, Macrophomina phaseolina, Sclerotinia sclerotiorum, Fusarium solani, Fusarium subglutinass , Fusarium moniliforme and Fusarium oxysporum those responsible for cucurbits fruit rots during marketing and storage were noticed.
2. All tested isolates were pathogenic to cucurbits fresh fruits under laboratory-controlled conditions. The different isolates varied in their virulence with clear and significant differences. The
wounded fruits were infected with higher levels of infection in comparison with unwounded fruits.
3. The wounded fruit cucumber treatments were varied between all tested isolates. The highest disease severity was recorded by Macrophomina phaseolina, followed by Sclerotinia sclerotiorum, while the lowest infection severity was noticed on wounded cucumber fruits that inoculated by Fusarium oxysporum.
4. Cucumber fruits that inoculated un- wounding on fruit surfaces, the most aggressive isolates were Macrophomina phaseolina, Sclerotinia sclerotiorum isolate 3, while the lowest infection severity was noticed on wounded cucumber fruits that inoculated by Fusarium oxysporum.
5. All tested fungi were pathogenic to Cucumber and Squash fruits on plants under greenhouse conditions and varied in their aggressiveness.
6. Macrophomina phaseolina was the most aggressive fungi on infecting cucmber and squash fruits on plants under laboratory conditions, followed by Sclerotinia sclerotiorum. The least aggressive fungus was Fusarium oxysporum.
7. Additionally, Macrophomina phaseolina had the highest pathogenicity among all tested fungi. In particular, comparing different fungus types revealed that disease index was significantly different between the following pairs; Macrophomina phaseolina/ Fusarium subglutinass ; Botrytis cinerea,Fusarium oxysporum; Botrytis cinerea,Fusarium solani; Sclerotinia sclerotiorum, Fusarium solani.
8. All tested fruits of cucumber cultivars were reacted as highly susceptible to infection that incited by all tested pathogenic fungal
isolates; wounding of fruits surfaces raised the disease index in comparison with unwounded.
9. Six cultivars of cucumber, i.e., New star, Star ,Bietalpha, Heikal, Samar and Sinai 1 were used in pathogenicity tests under controlled conditions in laboratory. Bietalpha cultivar was the most susceptible one followed by Samar cultivar while Heikal cultivar revealed as the least susceptible cultivar.
10. Compared to Sclerotinia sclerotiorum all fungus types had significantly higher disease index except Botrytis cinerea. Additionally, disease pathogenicity were lower in unwounded fruits compared to wounded fruit. Also, compared to the cultivar-Sinai, Bietalph and Samar had significantly higher disease index, but Delta star and Samar had lower disease index. Unwounded fruit had lower disease index than wounded fruit.
11. Macrophomina phaseolina infection led to register the highest rate of weight loss, followed by Botrytis cinerea, while the lowest rate of weight loss was recorded by Fusarium solani .
12. Soaking the wounded fruits of cucumber wounded in plant extracts led to a reduction in the severity of the occurrence of fungal infection, which led sprayed fruits option Garlic extract and Marjoram of 10% concentration to give the highest rates in reducing the severity of injury. Fusarium momiliforme caused less severe injury followed by Fusarium solani while the highest severity of the injury was Macrophomina phaseolina at the same concentration.
13. Soaking fruit in each of garlic and marjoram extract at the concentration of 10% led to severe injury was obtaind, followed by ginger extract, while the highest severity of injury when soaking extract garlic in the same concentration
14. Soaking fruit in garlic extract at a concentration of 10%. prevented the fungal infection with the exception of Sclerotinia sclerotiorum as well as extract spray carnations to prevent fungal infection except Macrophomina phaseolina as well as soaking extract Marjoram has prevented infection fungal true except of Sclerotinia sclerotiorum and Macrophomina phaseolina.
15. Soaking in the natural Chitosan concentration of 2.5% of the fruits of others wounded option Disease Index fungal infection giving different.
16. Soaking in the natural Chitosan concentration of a 2.5% led to completely prevent infection with all of Fusarium momiliforme , Fusarium oxysporum , Fusarium solani and Sclerotinia sclerotiorum.
17. Fusarium oxysporum agive less Disease Index on the fruits of cucumber wounded soaked in natural Chitosan.
18. Soaking in the chemical Chitosan at a concentration of 2% and 2.5% whether the fruits of cucumber wounded or un- wounded halted all fungus infection completely true except Macrophomina phaseolina.
19. Fusarium subglutinans gives less Disease Index with different concentrations of the chemical Chitosan.
20. Biological control agents greatly affected fungal isolates growth in dual cultures. Significant differences between linear growth of the different isolates. Trichoderma spp greatly affected linear growth of the pathogens isolates.
21. The highest percentages of growth reduction were recorded by Trichoderma harzianum (iso.4)
22. Biological control agent minimized the disease symptoms compared to the infested control treatments under laboratory conditions.
23. The maximum fungal growth was observed for Macrophomina phaseolina fungi regardless of the type or concentration of fungicide, such that fungal growth declined with the increase in fungicide concentration. Specifically, the highest fungal growth were observed in Macrophomina phaseolina treated with Tecto 50 ppm (68.89mm), Macrophomina phaseolina treated with Ridomil 100ppm (40mm), M. phaseolina treated with Ridomil or Teledor 150ppm (33.33mm), M. phaseolina treated with Ridomil or Tecto 200ppm (17.78mm), M. phaseolina treated with Teledor 250 ppm (11.11mm), M. phaseolina treated with Teledor 300ppm (8.89mm)