الفهرس 
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Abstract
The Arab Republic of Egypt occupies a global advanced position in the production and export of fresh and frozen strawberries. Gray mold disease caused by Botrytis cinerea considered one of the most important diseases that affect strawberries, as the pathogen affects all parts of the plant, causing great economic losses that increase with increasing air humidity, especially with the observed climatic changes globally and locally. The experiments conducted to 1- Detection and assessment of resistance frequencies to fungicides SDHI fungicides and other fungicides belong to different groups 2- To discover the dual resistance between boscalid and pyraclostrobin 3- To determine the Half maximum effective concentration for the tested fungicides (EC50) 4- To find out the most appropriate fungicide which can be used in the control strategies against Botrytis cinerea 5- In the end, to figure out the protective and curative activity of the mixtures containing SDHI fungicides 1. Detection and assessment of resistance frequencies to fungicides SDHI fungicides :- 331 Botrytis cinerea isolates were collected over three years from 2019 to 2021 from different governorates (Beheira, Ismailia, Qalyubie, and Dakahlia) and tested to detect the resistance frequencies. 1.1. Assessment of resistance frequencies to boscalid :- 75 ppm concentration was used to distinguish between sensitive and resistant isolates. The results showed that 277 isolates (83.7%) were resistant to the fungicide. 1.2. Assessment of resistance frequencies to fluopyram :- 331 Botrytis cinerea isolates were tested for sensitivity to fluopyram and 10 ppm concentration was used to distinguish between sensitive and resistant isolates. The results showed that 317 isolates (95.77%) found to be resistant to the fungicide. 2. Detection and assessment of resistance frequencies to fungicides from different chemical groups :- 2.1. Assessment of resistance frequencies to pyraclostrobin : 331 Botrytis cinerea isolates were tested for sensitivity to pyraclostrobin and 10 ppm concentration was used to distinguish between sensitive and resistant isolates. The results showed that 277 isolates (83.7%) found to be resistant to the fungicide. 2.2. Assessment of resistance frequencies to fenhexamid :- 331 Botrytis cinerea isolates were tested for sensitivity to fenhexamid and 1 ppm concentration used to distinguish between sensitive and resistant isolates. The results showed that 59 isolates (17.82%) were resistant to the fungicide. 2.3. Assessment of resistance frequencies to fludioxonil :- 331 Botrytis cinerea isolates were tested for sensitivity to fludioxonil and 1 ppm concentration used to distinguish between sensitive and resistant isolates. The results showed that all isolates were sensitive to the fungicide. 3. Fungicide resistance frequencies in the different tested governorates :- 3.1. Resistance frequencies to the tested fungicides in Beheira governorate :- Over three years, 88 isolates from Beheira governorate collected to estimate the resistance to the different fungicides tested. The results showed that 92.05%, 86.36%, 100% and 17.05% of the isolates found to be resistant to boscalid, pyraclostrobin, fluopyram and fenhexamid, respectively. 3.2. Resistance frequencies to the tested fungicides in Ismailia governorate :- 94 isolates were collected during the study from Ismailia Governorate to estimate the resistance to the different tested fungicides. The results showed that 73.4%, 76.6%, 91.5% and 17.02% of the isolates were resistant to boscalid, pyraclostrobin, fluopyram and fenhexamid, respectively. 3.3. Resistance frequencies to the tested fungicides in Qalyubie governorate :- 94 isolates were collected from Qalyubie governorate to estimate the resistance to the different tested fungicides. The results showed that 86.2%, 89.66%, 95.4% and 19.54% of the isolates were resistant to boscalid, pyraclostrobin, fluopyram and fenhexamid, respectively. 3.4. Resistance frequencies to the tested fungicides in Dakahlia governorate :- 62 isolates were collected from Dakahlia Governorate to estimate their resistance to the different tested fungicides, and the results showed that 83.9%, 83.9%, 96.8% and 17.7% of the isolates were resistant to boscalid, pyraclostrobin, fluopyram and fenhexamid, respectively. 4. Resistance phenotypes of B. cinerea isolates :- 12 different phenotypes of resistance were discovered, as follows :- 6 isolates were sensitive to all fungicides. One isolate resistant to pyraclostrobin. 5 isolates resistant to boscalid only. 25 isolates resistant to fluopyram only. One isolate is resistant to both boscalid and pyraclostrobin. 4 isolates resistant to fenhexamid and fluopyram. 9 isolates resistant to boscalid and fluopyram. 15 isolates resistant to pyraclostrobin and fluopyram. One isolate resistant to boscalid, pyraclostrobin and fenhexamid. One isolate resistant to fluopyram, pyraclostrobin and fenhexamid. 2 isolates resistant to boscalid, fenhexamid and fluopyram. 210 isolates resistant to boscalid, pyraclostrobin and fluopyram. 51 isolates resistant to boscalid, pyraclostrobin, fenhexamid and fluopyram. No isolates resistant to fludioxonil. 5.Determination of half maximum effective concentration (EC50) of B. cinerea isolates to different fungicides :- 5.1.Determination of half maximum effective concentration (EC50) of B. cinerea sensitive and resistant isolates to boscalid :- 17 sensitive isolates were tested at concentrations (0 - 0.1 - 1 - 2 - 4 - 8) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.0067 to 1.14 µg/ml with an average of 0.29 µg/ml. 17 resistant isolates were tested at concentrations (0 - 10 - 25 - 50 - 75 - 100) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 2.1 to 16.2 μg/ml with an average of 7.3 μg/ml. 5.2. Determination of half maximum effective concentration (EC50) of B. cinerea sensitive and resistant isolates to fluopyram :- 10 sensitive isolates were tested at concentrations (0 - 0.01 - 0.05 - 0.1 - 0.5 - 1) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.01 to 0.094 µg/ml with an average of 0.047 µg/ml. 21 resistant isolates were tested at concentrations (0 - 1 - 5 - 10 - 25 - 50) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.14 to 14.4 μg/ml with an average of 2.15 μg/ml. 5.3. Determination of half maximum effective concentration (EC50) of B. cinerea sensitive and resistant isolates to pyraclostrobin :- 15 sensitive isolates were tested at concentrations (0 - 0.01 - 0.05 - 0.1 - 0.5 - 1) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.04 to 0.66 µg/ml with an average of 0.1 µg/ml. 20 resistant isolates were tested at concentrations (0 - 5 - 10 - 15 - 25 - 50) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.4 to 13.1 μg/ml with an average of 5.1 μg/ml. 5.4. Determination of half maximum effective concentration (EC50) of B. cinerea sensitive and resistant isolates to fenhexamid :- 21 sensitive isolates were tested at concentrations (0 - 0.001 - 0.005 - 0.01 - 0.05 - 0.1) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.003 to 0.06 µg/ml with an average of 0.02 µg/ml. 11 resistant isolates were tested at concentrations (0 - 0.1 - 0.5 - 1 - 5 - 10) and the results showed that the value of the mycelial growth inhibition for 50% of fungus ranged from 0.23 to 12.03 µg/ml with an average of 4.64 µg/ml. 5.5. Determination of half maximum effective concentration (EC50) of B. cinerea sensitive isolates to fludioxonil :- 18 sensitive isolates were tested at concentrations (0 - 0.001 - 0.01 - 0.05 - 0.1 - 0.5 - 1) and the results showed that the value of the mycelial growth inhibition concentration for 50% of fungus ranged from 0.001 to 0.008 µg/ml with an average of 0.004 µg/ml. 6. Measurement of fungal mycelial growth in vitro and in vivo and sclerotia production Mycelial growth rates in vitro assessment conducted to find out the ability of the resistant and sensitive isolates to different fungicides (five resistant isolates and one sensitive isolate) to grow on PDA media. The results revealed that after 72 hours, it was clear that all boscalid resistant isolates mycelial growth rates significantly reduced compared with the sensitive isolate when grown in PDA media in the absence of some fungicides tested such as boscalid, fluopyram and pyraclostrobin. Mycelial growth in vivo results revealed that most of boscalid, fluopyram and pyraclostrobin resistant isolates pathogenicity decreased significantly compared with the sensitive isolate. Sclerotia production decreased in some cases such as boscalid and fenhexamid resistant isolates comparing with the sensitive isolates while, there were obvious variation between pyraclostrobin, and fluopyram resistant isolates in the ability in sclerotia production. 7.The protective and curative efficacy of some fungicides and their combinations :- 7.1. Assessment the protective and curative efficacy of Bellies fungicide (a combination of boscalid and pyraclostrobin) against resistant and sensitive isolates infecting strawberry leaves :- The efficiency of the fungicide estimated using three resistant isolates and one sensitive to boscalid and pyraclostrobin. The efficiency estimated by measuring the growth of the mycelium and calculating the ability of the fungicide in the inhibition of the mycelial growth. The results revealed that the fungicide mixture showed high ability to inhibit mycelium growth for resistant isolates (136, MB 52, BN 298) and the sensitive isolate H4(34) when tested as protective as follows (82.17, 83.28, 77.02, 100%) respectively. In addition, when the mixtures tested as curative treatment there were reduction in the efficiency as follows (57.33, 63.74, 41.1, 82.68%) respectively. 7.2. The protective and curative efficacy of Abash fungicide (boscalid) against resistant and sensitive isolates infecting strawberry leaves :- The efficiency of the fungicide estimated using three boscalid resistant and one sensitive isolates. The efficiency estimated by measuring the growth of the mycelium and calculating the ability of the fungicide in the inhibition of the mycelial growth. The results revealed that the fungicide showed good ability to inhibit mycelium for resistant (136, MB 52, BN 301) and sensitive isolate (BN 310) When tested as protective treatment as follows (89.23, 86.25, 78.49, 100%) respectively. In addition, when the fungicide tested as curative treatment it showed moderate efficiency to control the infections as follows (68.71, 58.53, 51.93, 78.05%) respectively. 7.3. The protective and curative efficacy of Drax fungicide (pyraclostrobin) against resistant and sensitive isolates infecting strawberry leaves :- The efficiency of the fungicide estimated using three pyraclostrobin resistant isolates and one sensitive isolate. The efficiency estimated by measuring the growth of the mycelium and calculating the ability of the fungicide in the inhibition of the mycelial growth. The results revealed that the fungicide showed high ability to inhibit mycelium for resistant isolates (131, S 217, BN 298) and the sensitive isolate H4(34) When tested as protective treatment as follows (74.81, 100, 100, 100%) respectively. In addition, when the fungicide tested as curative treatment it gives also high efficiency as follows (64.52, 100, 96.58, 100) respectively. 7.4 Testing the protective and curative efficacy of Luna tranquility fungicide (a combination of fluopyram and Pyrimethanil) against resistant and sensitive isolates infecting strawberry leaves :- The efficiency of the fungicide estimated using three resistant and one sensitive isolates to fluopyram by measuring the growth of the mycelium and the efficiency of the fungicide in inhibition the mycelial growth. The results showed that the rates of fungicide inhibition of mycelium for resistant isolates (S 144, BN 296, MB 111) and the sensitive isolate S 233 When tested protective as follows (100, 100, 100, 100%) respectively. In addition, when tested curative as follows (83.43, 68.96, 41.93, 83.45%) respectively.