![]() | Only 14 pages are availabe for public view |
Abstract Strawberry (Fragaria ananassa Duch) belongs to the family of Rosaceae. In the last few years, it was considered as an important vegetable crop in Egypt. It has been considered one of the most important export crops in Egypt in 2014. Egypt ranked 4th globally in exporting strawberry in terms of quantity and quality. Fresh strawberry are grown in three main governorates of Egypt: Beheira, Qalioubia and Ismailia. In 2016, the area of planted strawberry reached 9985 hectares, according to FAO statistics in 2016. Strawberry attacked by many diseases that cause great economic losses, many of which may destroy the entire crop. Some diseases that affects on the crown and causes rot such as fungal disease caused by fungus Macrophomina phaseolina. It is one of the most important diseases affecting the strawberry crop and causes economic losses for strawberries in Egypt. M. phaseolina is a common fungus in the soil that attacks strawberry plants either in the nursery or in the production land and causes the rotary mold disease, which in turn leads to the collapse of the plants and their death, even if the plants do not collapse and die, productivity decreases. This study was carried out at the Plant Pathology laboratory at the Modern Agriculture Company PICO in the Badr Center in Beheira governorate and the plant diseases laboratory at the Faculty of Agriculture in Shebin El Koum Monofia University under the conditions of the greenhouse in the Modern Agriculture Company PICO in Badr governorate of the governorate of Beheira during the period from 2016 to 2018. The work plan was designed to study the following points: 1- Survey of the disease in different locations in Beheira Governorate. 2- Isolation, purification and Identification of the causal organism. 3- Pathogenicity test of the isolated fungal isolates. 4- Biological control of charcoal rot on strawberry plants. 5- Chemical control of charcoal rot on strawberry plants. Pathogenicity tests were conducted using all isolates of the fungus causing the pure disease at the same time to using determine the strongest isolates of the isolated fungal pathogen, as well as to know the most sensitive strawberry cvs. to charcoal rot disease. A number of laboratory studies were conducted on the isolates to differentiate between them. Also, an evaluation test was conducted on the commercial strawberry cultivars cultivated in Egypt using the strongest isolates of the fungus causing the disease to determine the sensitivity of the varieties to infection. Methods of control to this disease have been followed under this study belonging reduce environmental pollution and reduce the use of pesticides. It attempts to control the disease using biocontrol agent that have been isolated from the environment surrounding the infected plants. These experiments were carried out under the conditions of the greenhouse. Attempts were also made to control the disease using some recomented pesticides the Egypt and compare them with biological control. The obtained results can be summarized as follows: 1-The disease was screened 69 of the most strawberry growing areas, namely the Beheira governorate (Badr Center and Kom Hamada center) the disease was found in 37 of these areas according to the morphological disease and the distribution of the disease in the crown area. 2-Seven isolates of M. phaseolina were selected from infected plant samples showing symptoms of the disease obtained from seven different regions. 3-Eight isolates of the Trichoderma spp. were isolated from soil samples and from the rhizosphere of strawberry plants isolated from the same sampling areas. The isolates were three isolates of T. viride, three isolates of T. hamatum, on isolate of T. harzianum and one isolate of T. koningii. 4-Pathogenicity tests of seven isolates of M .phaseolina was determined using Festival of c.v strawberry, which is the most sensitive commercial categories. The tested isolates showed varying capacities to infect the plants. 5-Pathogenicity tests reveal of that there were significant differences between the isolates used in the infection in terms of its ability to cause the disease. The strongest isolates was No. (3), which isolated from the area of Abdelmajid Morsy at Badr location from (Festival) cv. This isolate was selected to complete the study (Varietal sensitivity, chemical control, and biological control). 6-In the tests of the susceptibility of four commercial varieties i.e., (Festival, Winter Star, Fortuna, 029) which the most grown in Beheira governorate, 029 cv. showed the lowest degree of susceptibility to the disease, while Festival was the most susceptible cv. under greenhouse conditions. 7-When testing the effect of fungicides under the conditions of the greenhouse in the control of charcoal rot on strawberries, Rhizolex-T and Sendo were more effective, where the proportion of survival plants treated with Rhizolex-T 80%, and Sendo 60%, while the pesticide Ridomil Gold Plus was the least effective one, since where the proportion of survival plants were 10%. 8-When testing the effect of fungicides in inhibiting the growth of the fungus M. phaseolina under laboratory conditions and in petri dishes, the pesticides showed a decrease in the growth of M. phaseolina in varying degrees at the highest concentration of 200 ppm. The highest percentage of inhibition of pathogen growth was obtained by the pesticide Rhizolex -T gave a 96.67% inhibition followed by Sendo, which gave 95.56% inhibition. Ridomil Gold Plus was the least pesticide, giving an inhibition ratio of 43.06%. 9-Under laboratory conditions and in petri dishes, biocontrol agent showed a positive effect against four isolates of M. phaseolina, reduced the growth of pathogenic fungal isolates. The highest inhibitory rate was obtained in the growth of pathogen isolates (1) by T. hamatum (1), while T. harzianum was the least inhibitory rate against this isolate from the pathogen. In Isolate, (3) of the pathogen also T. hamatum (1) gave the highest inhibitory factor while T. harzianum was the least inhibitory rate against this isolate of the pathogen. In isolate, 6 of the pathogen T. hamatum (3) was the highest inhibitory factor while T. harzianum was the least inhibitory rate against this isolate of the pathogen. Isolation of the pathogen (7) was holily inhibited by T. viride (1) while T. harzianum gave the least inhibition rate against this isolate from the pathogen. 10- Results of biological control under greenhouse conditions, showed that biocontrol agent gave positive results against four isolates of the fungus M. phaseolina, T. hamatum (1,2) showed the highest percentage of survival plants against isolation (1) from the pathogen. T. harzianum showed the lowest percentage of survival plants. When isolate (3) from the pathogen was used T. hamatum (1) and T. koningii isolates showed the highest survival plants, whereas T. harzianum isolates recorded the lowest percentage of survival plants. T. hamatum (1) and T. koningii (1) recorded the highest percentage of survival plants against isolate No 6 of M. phaseolina, while T. harzianum had the lowest percentage in this respect. T. hamatum(2) was used as abioagent to word isolation .7 of the latest of pathogen the highest percentage survival plants, while the T. harzianum had the lowest percentage of survival plants. |