Authors: Serap TOKER, Mehmet BİÇİCİ
Abstract: Fruits of mandarin, orange, grapefruit and lemon, which received no fungicide treatment before harvest and at packing, stored at ambient temperature for 2 months, and kept at cold storage conditions for two and four months. During storage 16.8, 25.1 and 65.4 % crop losses were observed, respectively, due to development of total postharvest diseases. Citrus trees were sprayed with benomyl, fosetyl-Al, and CuSO4.5H2O+ZnSO4.6H2O+hydrated lime to control postharvest diseases 1-1.5 month before harvest time. Also, dipping of fosetyl-Al, benomyl, sodium o-phenylphenate, 2.4-D isopropyl-ester in water, and spraying of benomyl and imazalil in a water-wax were used to control for postharvest diseases of citrus fruits during packing processes. Some lemon fruits were stored in wrapped biphenyl emitted papers. Combination of preharvest fungicide treatments with treatments during packing, assumed to be the most effective control measure against postharvest diseases, resulted 2.4 % crop losses in 2 months ambient conditions, and 9.8-20.9 % in 2-4 months cold storage conditions. When compared with non treated control groups, the savings were 14.4 % in 2 months ambient conditions, and 15.3-44.5 % in 2-4 months cold storage conditions. The effect of combined treatments (some fungicide treatments in 1-1.5 month before harvest, and during packing period) on control of postharvest diseases was 89.9 aünd 60.1-72.1 % in ambient and cold storage conditions, respectively. Mandarin, orange, grapefruit and lemon fruits which were only treated during 1-1.5 month before the harvest were stored for 2 months in ambient conditions and for 4 months in cold storage rooms. In this case, total postharvest diseases were controlled at a rate of 57.5 and 40.0 %, respectively. However, in the case of fruits treated with fungicides alone in packinghouse, showed controlling levels of 68.8 and 55.1 %. The incidence of total postharvest diseases in the lemon fruits which were treated with the combined fungicide treatments and wrapped into biphenyl emitted papers stored 2 months in ambient and 2-4 months cold storage conditions were 2.5 and 0, 7.5 % and resulting disease control were 18.8 and 15.0, 33.8 %, respectively. In this study, then main postharvest diseases observed were Alternaria citri Ellis et Pierce stem end rot, Penicillium italicum Wehmer and Penicillium digitatum Sacc. blue and green molds, Colletotrichum gloeosporioides ( Penz.) Sacc. antrachnose, and Geotrichum candidum Link. ex Pers. sour rot on rotted mandarin, orange, grapefruit, and lemon fruits which were treated with the combined fungicide treatments. In combined fungicide treatments, A. citri stem end rot, P. italicum and P. digitatum blue and green molds, and antrachnose caused by C. gloeosporioides had resulted disease incidence of 3.0-12.5 %, 0.3-7.7 %, and 2.0-2.2 % on mandarin, orange, grapefruit and lemon fruits in ambient and cold storage conditions, respectively. The incidence of A. citri stem end rot, P. italicum and P. digitatum blue and green mold, and C. gloeosporioides antrachnose were determined to be 1.3-1.3 %, 0-0 % and 1.3-0 % on the lemon fruits which received combined fungicide treatments and wrapped into biphenyl emitted papers for 2 months ambient temperature storage and 4 months cold storage regimes. This treatment was determined to be the most effective control measures for lemon fruits against postharvest diseases.