Limon uçkurutan hastalığının (Phoma tracheiphila Kanc. et Ghik.) yıl içinde infeksiyon süreci ile yaprak ve sürgünlerdeki saprofit mikofloranın saptanması

Abstract

44 SUMMARY The incidence of Mai Secco disease, Fhoma tracheiphila Kane, et Ghik. population developments of saprophytic mycoflora on lemon leaves and twigs, and effect of chemical applications on these were studied between September 1985 and August 1986. The study were conducted in the Horticultural Research and Training Center, Alata and in Çukurova University, Agricultural Faculty Research Station Field. To determine the infection period of the disease, Ku'tdiken lemon seedlings, local variety, grafted on sour orange rootstock or sour orange seedlings were exposed to natural infection in the lemon orchard contaminated with P. tarcheiphila in the Horticultural Research and Training Center Field, and change at monthly intervals. At the end of the one-month period, the seedlings were taken out of the field and replaced into the other field which was Mai Secco free at Çukurova University, Agricultural Faculty Sesarch Substation, Yumurtalık. It was observed for symptom development and number of infectious plants were counted by September 1986. Results showed that the contamination rate was 15 % in September, and the percent of the diseased plants reached to 100 by November. The percentage decreased to 40 by December, and increased again to 80 in January. Then a decrease started again and continued to go down Until April. There was no infection because of high temperature in May, June, July and august. The growth condition of the pathogen, relative humidity, temperature, precipitations -and rainy days were all responsible for infection. To determine the population growth of the saprophytic mycoflora, Ku'tdiken lemon trees were used in trials in Çukurova University, Agricultural Faculty, Plant Protection Department Resarch Field. The trees were seperated into three different groups. These groups were; 1) The trees which received no chemical application, 2) The trees treated with chemicals, 3) The trees treated only with Benomyl.The microorganisms were isolated from the leaf and twig of a surface of 100 cm2 taken from each lemon trees. The experiment was45 set up with randomial complete block design, and the results showed statistical differences between months for Cladosporiua spp., yeast and total saprophytic fungi. The saprophytic mycoflora population reached to the highest level, 99400 propagules/cnP in October. Then it decreased to 10070 propagules/cm2 and 11460 propagules/cir2 in August and September, respectively. The population of microorganisms isolated from the twig surface was higher than those isolated from leaves. It was observed that Cladosporium showed the highest density, the 50 % of all others. Besides, the percentage of the yeast was 42 and 30 % from twigs and leaves, Respectively. Benomyl and other chemicals caused 18 - 30 % reduction, respectively. 21 fungi were isolated in this study. It is possible that the determination of mycoflora population can be used as a step in the biological control of Mai Secco in Turkey. Biological control can be introduced by choosing antagonistic activity against P. tracheiphila among the fungi obtained as a result of isolations. Taking this study, which the population change of saprophytic mycoflora and infection period of Mai Secco has ben determined into consideration an appropriate integrated pest management could possibly be conducted.

44 SUMMARY The incidence of Mai Secco disease, Fhoma tracheiphila Kane, et Ghik. population developments of saprophytic mycoflora on lemon leaves and twigs, and effect of chemical applications on these were studied between September 1985 and August 1986. The study were conducted in the Horticultural Research and Training Center, Alata and in Çukurova University, Agricultural Faculty Research Station Field. To determine the infection period of the disease, Ku'tdiken lemon seedlings, local variety, grafted on sour orange rootstock or sour orange seedlings were exposed to natural infection in the lemon orchard contaminated with P. tarcheiphila in the Horticultural Research and Training Center Field, and change at monthly intervals. At the end of the one-month period, the seedlings were taken out of the field and replaced into the other field which was Mai Secco free at Çukurova University, Agricultural Faculty Sesarch Substation, Yumurtalık. It was observed for symptom development and number of infectious plants were counted by September 1986. Results showed that the contamination rate was 15 % in September, and the percent of the diseased plants reached to 100 by November. The percentage decreased to 40 by December, and increased again to 80 in January. Then a decrease started again and continued to go down Until April. There was no infection because of high temperature in May, June, July and august. The growth condition of the pathogen, relative humidity, temperature, precipitations -and rainy days were all responsible for infection. To determine the population growth of the saprophytic mycoflora, Ku'tdiken lemon trees were used in trials in Çukurova University, Agricultural Faculty, Plant Protection Department Resarch Field. The trees were seperated into three different groups. These groups were; 1) The trees which received no chemical application, 2) The trees treated with chemicals, 3) The trees treated only with Benomyl.The microorganisms were isolated from the leaf and twig of a surface of 100 cm2 taken from each lemon trees. The experiment was45 set up with randomial complete block design, and the results showed statistical differences between months for Cladosporiua spp., yeast and total saprophytic fungi. The saprophytic mycoflora population reached to the highest level, 99400 propagules/cnP in October. Then it decreased to 10070 propagules/cm2 and 11460 propagules/cir2 in August and September, respectively. The population of microorganisms isolated from the twig surface was higher than those isolated from leaves. It was observed that Cladosporium showed the highest density, the 50 % of all others. Besides, the percentage of the yeast was 42 and 30 % from twigs and leaves, Respectively. Benomyl and other chemicals caused 18 - 30 % reduction, respectively. 21 fungi were isolated in this study. It is possible that the determination of mycoflora population can be used as a step in the biological control of Mai Secco in Turkey. Biological control can be introduced by choosing antagonistic activity against P. tracheiphila among the fungi obtained as a result of isolations. Taking this study, which the population change of saprophytic mycoflora and infection period of Mai Secco has ben determined into consideration an appropriate integrated pest management could possibly be conducted.