الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 198 |  |  |
| | | from | 198 | | |
Abstract
Cucumber (Cucumis sativus L.) is one of the most important economically crops, which belongs to family cucurbitaceae. The economic importance of this crop appears in both local consumption and exportation purposes. Cucumber is grown either in the open field or under protected houses. The cultivated area of cucumber in 2003 growing season reached about 11881 feddan in open field which yielded 88575 ton fruits, in addition to 13267 greenhouses, yielded about 44771 ton fruits.
Cucumber powdery mildew caused by Sphaerotheca fuliginea (Schlectend: Fr.) Pollacci. This disease can cause damage to all plant parts including leaves, stems and fruits especially under protected house conditions and causing considerable reduction of quantity and quality of cucumber yields. Disease control is generally achieved by the use of fungicide.
Thus, the present work was conducted to founding alternative non-chemical methods to fungicides and reducing fungicides use to control of cucumber powdery mildew disease under protected houses.
The obtained results from present studies can be summarized as follows:-
1. Survey of cucumber diseases in protected houses revealed that, powdery mildew disease was important disease of cucumber grown in protected houses that observed in both surveyed locations. Wilt occupied the second order in its importance; meanwhile, virus infection recorded the third order.
2. Conidial germination was significantly reduced by all plant extracts. The high reduction was induced by garlic extract at concentration 20%
(88.13%) and clove extract at concentration 10% (84.74%) less than control.
3.All plant oils significantly reduced conidial germination. The high reduction was induced by clove oil at concentration 10% (89.83%), nigella oil at concentration 8% (74.57%) and olive oil at concentration 8% (72.87%) less than control.
4.Phosphate salt (K2HPO4) was significantly reduced conidial germination. The high reduction was induced by phosphate salt at concentration 100 mM/L (64.40%) less than control.
5.Conidial germination was significantly reduced by Bacillus filtrate, Trichoderma filtrate, propolis extract and their combination. The high reduction was induced by propolis extract + Bacillus filtrate + Trichoderma filtrate (88.30%), Bacillus filtrate + Trichoderma filtrate (85.52%) and propolis extract + Trichoderma filtrate (83.98%) less than control.
6.Induction of cucumber resistance to powdery mildew by plant extracts proved that all tested plant extracts significantly reduced the percentage of powdery mildew incidence and severity. The high reduction was induced by garlic extract 20% (85.73%) and clove extract 10% & withania extract 50% (57.20%).
7.Induction of cucumber resistance to powdery mildew by plant oils revealed that all tested plant oils significantly reduced the percentage of powdery mildew incidence and severity. Olive oil at concentration 8% completely prevented powdery mildew incidence. The high reduction was induced by olive oil 4%, rocket oil 8%, nigella oil 8% and clove oil 10% (85.73%).
129 Summary
8.Induction of cucumber resistance to powdery mildew by phosphate salt (K2HPO4) exhibited that phosphate salt (K2HPO4) significantly reduced the percentage of powdery mildew incidence and severity. The high reduction was induced by Topas-100 at concentration 50 cm3/100L (71.47%) and phosphate salt (K2HPO4) at concentration 100 mM/L (57.20%).
9.Induction of cucumber resistance to powdery mildew by biological agent filtrate, propolis extract and their combination revealed that all tested treatments significantly reduced the percentage of powdery mildew incidence and severity. Propolis extract + Bacillus filtrate + Trichoderma filtrate completely prevented powdery mildew incidence. The high reduction was induced by Trichoderma filtrate, propolis extract + Trichoderma filtrate, propolis extract + Bacillus filtrate and Trichoderma filtrate + Bacillus filtrate (85.73%).
10.Spraying with plant extracts on incidence and severity of powdery mildew disease in cucumber cv. Primo (during spring and autumn 2003) were studied. The result showed that all tested plant extracts at both seasons significantly reduced the percentage of powdery mildew incidence and severity. Garlic extract at 20% was the most effective treatment at both seasons (2.76%) followed by clove extract at 10% (3.67%), garlic extract at 10% (4%) and withania extract at 50% (4.67%) compared with control (15.67%). Generally increasing concentration of the plant extract tested significantly increased the reduction in powdery mildew incidence and severity.
11.Spraying of plant oils on incidence and severity of powdery mildew disease in cucumber cv. Primo (during spring and autumn 2003) was studied. Results revealed that all tested plant oils at both seasons significantly reduced the percentage of powdery mildew incidence and
Summary 130
severity. Clove oil at 10%, and olive oil at 8% were the most effective treatments at both seasons by (2.67%) followed by nigella oil at 8% (4%) and rocket oil at 8% by (4.34%) compared with control (15.67%).
12.Study of spraying phosphate salt (K2HPO4) on incidence and severity of powdery mildew disease in cucumber cv. Primo (during spring and autumn 2003) was studied. The results showed that in two experiments phosphate salt (K2HPO4) at both seasons significantly reduced the percentage of powdery mildew incidence and severity. Phosphate salt (K2HPO4) at concentration 100 mM/L was the most effective treatment at both seasons followed by (3%) Phosphate salt (K2HPO4) at concentration 75 mM/L (4%).
13.Spraying some biological agents, propolis extract and their combination on incidence and severity of powdery mildew disease in cucumber cv. Primo (during spring and autumn 2003) was studied. The results revealed that, all tested treatments significantly reduced the percentage of powdery mildew incidence and severity. Propolis extract + Bacillus filtrate + Trichoderma filtrate were the most effective treatments at both seasons by (1.67%) followed by propolis extract + Trichoderma filtrate & Trichoderma filtrate + Bacillus filtrate and Bacillus filtrate & Trichoderma filtrate (2%).
14.Evaluation of spraying with plant extracts on controlling powdery mildew disease in cucumber cv. Delta star showed that, all tested plant extracts significantly reduced the percentage of powdery mildew incidence and severity. The high reduction in disease severity was induced by garlic extract (45.27%) followed by clove extract (39.60%) and withania extract (26.43%). Also, all tested plant extracts significantly increased the number fruits/plant and weight fruits/plant. The highest increase in number of fruits/plant and weight fruits/plant
131 Summary
was induced by garlic extract (31.26 and 35.84%) followed by clove extract (52.02 and 28.01%) and withania extract (18.75 and 21.38%) compared with control.
15.Spraying with plant oils on controlling powdery mildew disease in cucumber cv. Delta star revealed that, all tested plant oils significantly reduced the percentage of powdery mildew incidence and severity. The high reduction in disease severity was induced by olive oil (67.91%) followed by clove oil (64.18%), nigella oil (60.38%) and rocket oil (47.20%). Also, all tested plant oils significantly increased the number fruits/plant and weight fruits/plant. The highest increase in number fruits/plant and weight fruits/plant was induced by clove oil (37.50 and 37.65%) followed by olive oil (26.79 and 28.30%) , nigella oil (21.43 and 24.40%) and rocket oil (13.39 and 15.96%) compared with control.
16.Spraying cucumber plants cv. Delta star with phosphate salt (K2HPO4) to control powdery mildew disease showed that, Phosphate salt 100 mM/L as well as Topas-100 significantly reduced the percentage of powdery mildew incidence and severity. Phosphate salt and Topas-100 reduced disease severity by 35.88 and 37.55% compared with control. Also, phosphate salt and Topas-100 increased the number fruits/plant and weight fruits/plant (14.31and 16.18%) and (13.39 and 13.55%) compared with control.
17.Spraying cucumber plants cv. Delta star with biological control agent to control powdery mildew disease showed that all tested treatments significantly reduced the percentage of powdery mildew incidence and severity. The high reduction in disease severity was induced by propolis extract + Trichoderma filtrate + Bacillus filtrate (69.84%) followed by Trichoderma filtrate + Bacillus filtrate (60.38%), propolis extract + Trichoderma filtrate & propolis extract + Bacillus filtrate
Summary 132
(58.52%) and Bacillus filtrate (54.73%). Also, increased number and weight of fruits/plant. The highest increase in number and weight fruits/plant was induced by propolis extract + Trichoderma filtrate + Bacillus filtrate (43.83 and 44.00%) followed by propolis extract + Trichoderma filtrate (38.41and 40.06%) and Trichoderma filtrate + Bacillus filtrate (37.50 and 39.17%) compared with control.
18.Treatment of powdery mildew spore suspension with UV for 30 minutes or temperature 90°C for 10 minutes or adding chloroform 1.0 ml/L spore suspension inhibited the spore germination completely. While treatment of powdery mildew spores with UV for 20 minutes or temperature 70°C for 10 minutes or adding chloroform 0.5 ml/L spore suspension reduced the percentage of conidia germination from 40.33% in control to 12.76, 13.33 and 14.67% respectively.
19.Treatment of powdery mildew spores by using UV, temperature and chloroform revealed that increasing time of exposure to UV, temperature or increasing amount of chloroform led to increase efficacy of the treatment. The most effective treatments which complete inhibited all spores of powdery mildew and no disease was developed had been recorded when spores were subjected to one of the following treatments: UV for 30 minutes, 90°C for 10 minutes and 1 ml chloroform /L.
20.Spraying cucumber cv. Delta star with powdery mildew with non-germinated spore by UV, temperature, chloroform to induce resistance led to reduce powdery mildew disease severity by 69.84, 62.25 and 54.73% less than control in addition increased the number and weight of fruits/plant. The highest increase in number and weight fruits/plant was induced by UV (25.02 and 25.00°/0) and temperature (18.75 and 19.88%) compared with control.
Summary
133
21. Evaluation of the effect of the best resistance inducers i.e. garlic extract at 20%, clove extract at 10%, clove oil at 10%, olive oil at 8%, propolis extract + Trichoderma filtrate, Trichoderma filtrate + Bacillus filtrate, propolis extract + Trichoderma filtrate + Bacillus filtrate, K2HPO4 at 100 mM. and Topas-100 at 50 m1/100L in addition to untreated control on peroxidase (PO), polyphenol-oxidase (PPO), chitinase activity and lignin content was showed following points.
1.Peroxidase (PO) activity:
All treatments significantly increased PO activity compared with control in all times. The highest value of peroxidase enzymes obtained after five days from inoculation with powdery mildew spores, while the highest increased in peroxidase activity compared with control was induced by propolis extract + Trichoderma filtrate (231.48%) before inoculation with powdery mildew spores.
2.Polyphenol-oxidase (PPO) activity:
All treatments significantly increased PPO activity compared with control in all times. The highest value of (PPO) enzymes obtained after five days from inoculation with powdery mildew spores while the highest increase in (PPO) activity compared with control was induced by propolis extract + Trichoderma filtrate (397.12%) after one day from inoculation with powdery mildew spores.
3.Chitinase activity:
All treatments significantly increased chitinase activity compared with control in all times. The highest value of chitinase enzymes obtained after five days from inoculation with powdery mildew spores. While the highest increased in chitinase activity compared with control was induced by propolis extract + Trichoderma filtrate was induced by propolis extract +
Summary 134
Trichoderma filtrate (692.50%) after one day from inoculation with powdery mildew spores.
4. Lignin content:
All treatments significantly increased lignin content. The most effective treatment were garlic extract, propolis extract +Trichoderma filtrate, phosphate salt (K2HPO4), propolis extract + Trichoderma filtrate + Bacillus filtrate and clove extract which they increased total lignin by 92.11, 82.90, 71.58, 56.84 and 52.36% respectively over control.
22. Study effect of foliar spraying with plant extracts, plant oils, phosphate salt and the fungicide Topas-100 on sugar content in cucumber plants revealed that, the reducing sugars were significantly decreased by all treatments except Topas-100. The highest decrease was induced by clove oil & nigella oil (54.11%) followed by olive oil, withania extract, clove extract, rocket oil, garlic extract and phosphate salt (K21-1PO4) decreased the reducing sugars by 41.10, 37.68, 29.47, 26.32, 19.79 and 1.68%, respectively less than the control, while Topas-100 increased it by 63.79% over control.
All treatments increased the non-reducing sugars except olive oil and withania extract decreased it. The highest increase was induced by garlic extract, clove extract, Topas- I 00, rocket oil, nigella oil, phosphate salt (K2HPO4) and clove oil increased it by 280.85, 232.00, 100.00, 97.87, 82.98, 65.96 and 17.02% compared with control, while olive oil and withania extract decreased it by 34.04% less than the control. On the other hand, Topas-100, withania extract, garlic extract, and phosphate salt (K2HPO4) increased the total sugars by 68.2, 37.36, 7.28 and 4.41% over control, while clove oil, nigella oil, olive oil, rocket oil and clove extract decreased it by 47.70, 41.76, 40.42, 15.13 and 5.94% less than control.
135 Summary
23.Spraying of cucumber plants with plant extracts, plant oils, phosphate salt and Topas-100 showed that, all tested treatments increased the free phenols. The highest increase in the free phenols was induced by Topas-100 (326.88%) followed by K2HPO4 (289.96%) and clove oil (205.73%) over control.
As for all tested treatments the highest increase in the total phenols was induced by Topas-100 (97.33%) followed by K2HPO4 66.27%) and clove oil (56.80%). Meanwhile all treatments decreased the conjugated phenols except Topas-100, garlic extract and clove oil. In this respect, withania extract, nigella oil, clove extract, rocket oil, phosphate salt(K2HPO4) and olive oil induced high decrease by 45.49, 31.00, 27.32, 18.17, 10.88 and 7.29% less than control treatment. While, Topas-100, garlic extract and clove oil increased it by 18.17, 7.29 and 5.44% over control.
24.Spraying of cucumber plants with plant extracts, plant oils, phosphate salt and Topas-100 revealed that, all treatments significantly decreased the total amino acid content. Olive oil, clove extract, garlic extract and withania extract were induced the highest decrease by 94.55, 85.19, 78.70 and 77.92%.
25.Study the effect of some biological control agents’ filtrate and propolis extract compared with fungicide on sugar content of cucumber plants proved that all treatments decreased the reducing sugars except Topas-100 compared with control. The highest decrease was induced by propolis extract + Bacillus filtrate, propolis extract + Bacillus filtrate + Trichoderma filtrate and Bacillus filtrate 54.84% while, Topas- 100 increased it by 63.79%.
As for the non-reducing sugars, Trichoderma filtrate, Topas-100, Bacillus filtrate and Bacillus filtrate + Trichoderma filtrate increased the