کارایی مزرعه‌ای قارچ‌کش پروپیکونازول + دیفنکونازول در کنترل بیماری‌های‌ لکه برگی قارچی شایع گندم در مقایسه با دیگر قارچ‌کش‌های توصیه شده

Fungal incited diseases are responsible for about 15-20% wheat yield losses annually worldwide. The management of these diseases is primarily achieved through the application of the chemical fungicides. In present study, a field experiment was conducted at Safiabad Agricultural Research, Education and Natural Resources Center in Dezful to assess the effect of propiconazole + difenoconazole (Harbor®) fungicide on control of fungal pathogens causing leaf spot on wheat caused by Puccinia striiformis f. sp. tritici, P. triticina and Zymoseptoria tritici in two commercial cultivars of Verinak and Chamran in two separate research farms compared with other conventional foliar fungicides. Experiments were designed as completely randomized blocks with nine treatments including propiconazole + difenoconazole at three doses of 0.3, 0.4 and 0.5 L ha-1, propiconazole + cyproconazole (0.4 L ha-1), spiroxamine + tebuconazole + triadimenol (0.6 L ha-1), azoxystrobin + cyproconazole (0.75 L ha-1), propiconazole (1 L ha-1), tebuconazole (1 L ha-1) and a treatment sprayed only with distilled sterile water as untreated control. The measuring control effectiveness of foliar fungicides was performed under natural inoculums of stripe and leaf rusts. On the contrary, the conidial suspension of Z. tritici strain Dezful was adjusted at concentration of 1 × 106 spores mL-1 and evenly sprayed on experimental plots. Collected data were analyzed using SAS® software. In the first farm, where the Chamran cultivar was sown, all fungicides were significantly able to reduce the disease severity of septoria blotch and leaf rust diseases compared with untreated control except the lower doses of the propiconazole + difenoconazole (0.3 and 0.4 L ha-1). No significant difference was detected between fungicides in reduction of stripe rust, although chamran cultivar showed the lower incidence and severity of the stripe rust. A significant increase in thousand-seed weight and yield per hectare of the Chamran cultivar was detected in plots treated with the fungicides. The highest yield was seen in plots treated with the tebuconazole and propiconazole + difenoconazole (0.5 L ha-1) with an increase yield of 44% and 23%, respectively compared with untreated control. In the second farm, where the Verinak cultivar was sown, all foliar fungicides applied including propiconazole + difenoconazole (0.5 L ha-1) could significantly reduce the severity of the septoria leaf blotch and stripe rust diseases compared with untreated control. on wheat.