بررسی تاثیر برخی قارچکش‌های شیمیایی در کنترل بیماری‌های لکه برگی نخل (Phoenix dactylifera) در استان‌ کرمان

The date palm (Phoenix dactylifera) belongs to the Arecaceae family. Date palm leaf spot disease causes damage by reducing the green area of infected trees. Symptoms of the disease on the leaves are mainly in the form of yellow to brown rectangular spots, but round, oval or irregular shapes may be seen on the leaf axis. Previous research has shown that Alternaria sp., Cladosporium sp., Colletotrichum sp., and Nigrospora sp. have a role in the occurrence of leaf spot disease and drying of the leaves of date trees in the southern region of Kerman province. This research aims to investigate the effect of several fungicides and potassium sorbate chemical salt along with control against fungi that cause diseases Date palm leaf spot. it was carried out in both laboratory and garden conditions in the southern region of Kerman province. The effectiveness of fungicides calculated using the percentage of inhibition of radial growth rate, and in garden conditions using the parameters of the number of spots in the leaflets and the severity of the disease in the third and sixth leaf rings. The results of the comparison of the average inhibitory effect of different fungicides on the radial growth of the above-mentioned fungi showed that among the investigated treatments, after six days, the fungicides Dithan M 45, (Mancoezbe 40%+ chlorothalonil 20% + simoxanil 5%, WP 65%), (Iprodion+ Carbendazim WP 52.5, and Bordeux mixture respectively had an inhibitory percentage of 100, 95.4, 89.5 and 86.4% were the best treatments. Potassium sorbate salt and captan fungicides with inhibition percentages of 76 and 73.2%, respectively, located in the next groups. Chlorothalonil WP 75%, Cuprocyt C WP 43.95%), salicylic acid and cuprooxychloride with the effectiveness of 53.9, 49.2, 48.8 and 44.9% respectively, ranked in the last group. In garden conditions, in the third leaf ring, the number of spots per leaf in the control treatment increased from 2.7 to 9.5 and the level of infection (disease severity) increased from 5.8% to 95%. The average control efficiency of three times of evaluation showed that Orthocide, (Mancoezbe + chlorothalonil + simoxanil), Dithan M 45, (Iprodion+ Carbendazim) and Chlorothalonil fungicides with control efficiency of 93.7, 89.7, 88.7, 85.5 and 84.1% of the treatments, respectively were recognized as superior and can be used for chemical control of palm leaf spot disease. The evaluation of the severity of the disease in the sixth ring of leaves showed that it is not economically important. Therefore, if there is a need for chemical control of date leaf spot, only foliar spraying of the first to fifth leaf rings is necessary, and there is no need to spray the sixth ring or later.