بررسی نقش قارچ‌ها و استفاده از قارچ کش در سیاه‌شدگی، ریزش محصول و لکه‌برگی در باغات پسته استان کرمان

Pistachio (Pistacia vera) is one of the most important orchard products in Iran. and the main non-oil export of the country. Several problems are observed in pistachio trees such as blackening and abscission of fruit and leaf spot. Despite of the role of fungal agents in causing these symptoms is not known, fungicide compounds are used, which causes environmental hazards and economic costs. In order to evaluate the effect of Captan fungicide on fungal agents including Alternaria alternata and A. arborescens that may be involved in causing symptoms in fruits and leaves, a research was carried out in 2021 in one of the gardens of Kerman city. This experiment was conducted in complete randomized block with 3 treatments (1- Captan fungicide, 2- water, 3- control) and 3 replications (each replication includes 5 trees). The selected trees were Akbari variety and 35 years old; distance rows were 6 meters and between trees was 1 meter. Garden management and as well as trees selected in age, health, trunk diameter, height, and crown were uniform. The degree of blackening and fruit abscission was evaluated before treatments at the beginning of April 2021, and data were collected at 45-day intervals during three stages after treatments. Also, after harvesting all the fruits of each treatment fruit weight was measured on 17 Sep. 2021. randomly was selected 100 pistachio fruits with the hull and their weight was measured with a 0.01 grams scale accuracy. At each stage of sampling, blackening fruits and leaves were collected and investigated in laboratory. The samples disinfection and were cultured on potato dextrose agar PDA (Merck) medium and incubated for 15 days. the growth and pathogenicity of isolated fungi such as Ulocladium sp., Fusarium sp. were evaluated. Based on the results, no pathogenic fungus was involved in the symptoms caused in the fruit and leaves, and no significant difference was between the blackening and fruit abscission treatments, leaf spots and the weight of the fruits. Therefore, fungi no causal agent of symptoms, and the use of fungicides was ineffective in preventing damage.