الفهرس 
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Abstract
This work aimed to search for effective and safe methods to control an important soil borne diseases on cotton plants caused by Fusarium spp., Rhizoctonia solani and Macrophomina phaseolina.
The study addressed the impact of some of the control means of non-conventional and which serve as alternatives safe to pesticides and can be divided into means of combating different include biological control using bacteria (Bacillus Subtilis) and fungus (Trichoderma harzianum), commercial vitality compounds such as (Bio- Zead, Bio-ark and Plant guard), antioxidants as (salicylic acid, acetic acid and citric acid), microelements (iron chelate, zinc chelate and manganese chelate), resistance sever using different varieties such as (Giza 92,90,88, 87,86,85) in addition to use of different plant density (25, 40, 45 and 50 cm) compared drug control using chemical pesticides (Rizolex T-50, Mon cut 25%). the steps of this study, and the obtained results are summarized as following:-
1- Samples were collected from Kafr El-Sheikh, Sede-Salem, Desouk, Fowa and Qillein in Kafr El-Sheikh Governorate.
2- Isolation of the pathogens were performed from different samples of diseased plants. Seventy one fungal isolates resulted from cotton plants. These isolates were identified as Rhizoctonia solani, Fusarium spp., Macrophomina Phaseolina and Scloratium rolfsii.
3- The most frequent pathogen was Rhizoctonia solani (39.43%) followed by Fusarium spp. (29.57%) and then by Macrophomina Phaseolina and Sclerotium rolfsii (23.94 and 7.04%) respectively.
4- Pathogenicity test and varietal resistance of cotton cultivars under greenhouse conditions showed the varietal reaction of cotton under the artificial soil infestation conditions. Cotton cv. Giza 86 had the highest percent of pre-emergence damping off (54.64) while Giza 87 gave the lowest one (19.5%). All cultivars produced post-emergence damping off percentage ranged from 7.1-14.9%. Giza 87 cultivar was the most resistant-where it resulted the highest plant survival (73.4%) whereas Giza 86 was the lowest one (30.5%) and the most infected by R. solani.
5- Varity Giza 86 achieved the highest percentage in pre, post-emergence damping off 52.6, 18.9 and least percentage survival plants (29.5%), also it gave the most infected plants with Fusarium spp. and M. phaseolina.
6- Under the natural infection the tested cultivars had the same reaction. Giza 87 cultivar was the least infection (pre- and post-emergence) damping off and the highest resistant (86.7% survival plants). While, the cv. Giza 86 achieved the highest infection by R. solani and Fusarium spp. and least survival plants (46.7 %).
7- The effect of different treatments of cotton seeds germination in vitro were tested. Germination were higher significantly for most seed treatments, but the differences were not significant in any of T. harizanum, Bio-zead and citric acid compared with non-treated seeds (70; 80 and 80%, respectively and 70% for control). Root length, the radical growth was affected significantly by seed treatments. Shoot length, showed that there’s not significant differences between the most treatments and control treatment. Seedling dry weight was higher significantly for Bio-zed and citric acid (0.0627 and 0.0540g, respectively), while it was lower significantly for Bio-ark 0.0291g compared with non-treated seedlings (0.0320 g).
8- Evaluation of different treatments on pre-, post- emergence damping-off and survival percentage, root rot, dry weight under greenhouse conditions were studied. Statistically significant (P ≤0.05) increase occurred for seedling emergence. Pre- emergence damping off decreased significantly for B. subtilis, salsylic acid and citric acid seeds treatments (0.00%) compared with non-treated seeds (30.0%), but the differences were not significant in post-emergence percent compared with control treatment. The most of treatments saved by 50-100% of surviving plants. The canker severity for the most treatments was not significant except Bioark, Rizolex, Moncat and iron chelate which had the less significant reaction. Root rot severity decreased significantly by seed treatments except some treatments which were not significant decreased from control (Biozead, Salsylic acid, Acetic acid, Citric acid and manganese chelate). T. harzianum, Rizolex-T 50%, B. subtilis, Acetic acid and zinc chelate treatments increased the seedling dry weight significantly from control.
9- The different seed treatments in field experiments led to disparity in the percentage of the survival plants, the first treatment (B. subtilis) concluded recorded a significant increase in that ratio. It can be that plant density (25 cm) the check treatment, it observe that all treatments except citric acid led to significant increase in survival plants percentage. Most of the treatments did not show a significant increase in the disease severity except B. subtilis, T. harzianum, Plant Guard, Bio ark and Salsylic acid, which led to reduce disease severity significantly compared to control treatment.
10- Effect of different treatments on growth seedling stages of cotton plants, clear that all tested 17 treatments showed significantly, effects compared to control.
a) Plant height resulted the highest values (29.30 and 28.68 cm) at plant density 50 cm and Rizolex-1, respectively, while the lowest value were 22.07 and 22.83 in salicylic acid treatments at both seasons.
b) Fresh and dry weights, all treatments showed significantly increment in fresh and dry weights. The fresh weight of cotton plants were elevated worth at plant density 50 cm, iron element and T. harzianum treatment, at both seasons and the lowest worth in manganese chelate treatment. Dry weight of cotton plants were highest values (10.60) at plant density treatment 50 cm and the lowest value was (3.42) in acetic acid at season 2014. The highest value in dry weight (8.83) was achieved with T. harzianum treatment and the lowest value (2.98) with manganese chelate treatment at 2015.
c) Leaf area, through two seasons 2014 and 2015, the results indicated that the leaf area of cotton plants gave the highest value (53.52 and 54.26) at plant density treatment 50 cm at seasons 2014 and 2015, respectively, while, the lowest values (30.97 and 31.18 cm2) in plant density 25cm (as a control) treatment at 2014 and 2015, respectively.
d) Chlorophyll ”a”, the effect of treatment on plant pigments concentration it found that chlorophyll ”a” of cotton plants gave the highest values (1.925 and 1.95) at iron chelate as a microelement treatment at both seasons, respectively. While acetic acid and plant density (25 cm) treatments gave the lowest values (0.960 and 1.048) at seasons 2014 and 2015 Chlorophyll b, appeared to be higher value (0.680 and 0.69) at iron chelate at both seasons, respectively, while, the lowest values (0.34 and 0.34) in plant density treatment 25 cm at season 2014 and 2015 respectively.
11- Growth parameters of Fruiting stage at the two seasons 2014 and 2015. All treatments gave the highest significancy in the characters study, The results showed that:
a) The plant height appeared to be higher value (217 and 208.66 cm) at microelements treatments zinc chelate through two seasons, while the lowest values (179.66 and 181.66 cm) in biological control B. subtilis at season 2014 and 2015.
b) Plant fresh weight of cotton plants gave the value (658.15) at plant density 50 cm treatment and the lowest value (378.77) in chemical control Rizolex-T treatment at the two season 2014 and 2015, respectively.
c) Dry weight of cotton plants showed higher values (139.02) and (146.25) at plant density treatment 50 cm at both seasons 2014 and 2015, respectively. On the other hand, the results appeared the lowest values, (62.2 and 66.54) in bio commercial production, plant guard and microelement zinc chelate treatment at season 2014 and 2015.
d) The highest values of leaf area of cotton plants were obtained in microelement iron chelate and plant density treatment 50 cm, through two seasons. While, the lowest values (208.73 and 281.82) in chemical control Rizolex-T treatment at 2014.
e) Chlorophyll ”a” concentration of cotton plants were highest value at biological control T. harzianum and microelements iron chelate at two seasons and the lowest value (0.651) in microelements zinc chelate and plant density 25 cm at both seasons. Chlorophyll “b” concentration of cotton plants gave the highest value at biological control treatments T. harzianum, chemical inducers salicylic acid, microelements iron and zinc chelate treatments in seasons 2014 and 2015. While, the lowest values (0.204 and 0.199) chemical control Rizolex-T treatment at the two seasons 2014 and 2015, respectively.
12- Anatomical studies, showed that there were significant differences between the large treatments compared to untreated plants. Diameter of xylem vessels, have shown a significant increase have been achieved in xylem vessels diameter at treatment with iron chelate treatment. Xylem thickness, the highest value in xylem thickness were achieved under treatment with manganese chelate, T. harzianum and Bio-zead. While, the lowest values in xylem thickness were achieved when the treated with salicylic acid and Rhizolex-T. Phloem thickness gave the highest value in the treatments with manganese chelate, citric acid and T. harzianum. On the other side, the lowest values in phloem thickness were achieved under treatment with plant density 25 and 40 cm. The highest increasing in cortex thickness were achieved at plants treated with B. subtillus, T. harzianum and Bio-zead, respectively in comparison with the other treatments. While, the lowest value in cortex thickness was achieved with plant density 25 cm.
13- Yield and its components characters.
a) Boll weight, show that there were no-significant differences in boll weight as a result of the use of various treatments, where, they found a boll weight under treatment with control plants density 25 cm in comparison with other treatments at season 2014 and 2015 respectively.
b) The number of fruiting branches per plant had significant differences number of fruiting branches per plant under treatment conditions. The highest values in number of fruiting branches were achieved under treatment Bio-zead and T. harzianum at two seasons.
c) Earliness index, the results cleared that there are significant difference between treatments for earliness index in the two years. Also, the results exhibited that plant density at 50 cm gave low value for earliness index (39.44%). On the other hand, some treatments were more earliness compared to control (Bacillus, Trichoderma, Bio-zed, Rhizolex-t, plant density 40 cm and zinc chelate through two seasons.
d) Lint index, illustrated the significant differences in lint index under all different treatments. The highest increasing in lint index were achieved at plants treated with iron chelate, plant density 50 cm, plant density 45 cm and T. harzianum (8.48, 7.94, 7.45 and 7.27%) respectively, in season 2014, while, there were no-significant differences in lint index under all different treatments in season 2015.
e) Seed index and lint percentage, showed that there were no-significant differences between different treatments.
f) Seed cotton yield, the results cleared that most treatments surpassed compared to control (Plant density 25 cm) which ranged from 8.95 through season 2014, while, Plant density 45 cm and citric acid achieved 17.47, 17.33 respectively, in season 2014. Also, the best treatments which gave high yield were Bio-ark and manganese chelate.