Adana ve Mersin Nar Bahçelerinde Hasat Öncesi Meyve Çürüklük Patojenleri ve Farklı Zamanlardaki İnokulasyonların Hastalık Oluşumuna Etkisinin Araştırılması

Abstract

Pre-harvest fruit rot is an important problem and causes serious crop losses in pomegranate orchards. The study aimed to determine the prevalence of pre-harvest fruit rot in pomegranate orchards in Adana and Mersin provinces, to detect fungal pathogens associated with fruit rot, and to reveal the effect of inoculations performed at different times on disease incidence. Totally 39 orchards were surveyed in 2018 and symptomatic fruit samples were collected. Fungal pathogens were isolated by standard mycological procedures and identified by classical and molecular techniques. Pathogens were inoculated at two different periods (flowering-fruit set and fruit growth stages) in field conditions, fruitlet drop and calyx rot incidence were recorded respectively. According to results, the prevalence of fruit rot in Adana and Mersin was found to be 70.6% and 22.7% respectively. The average disease incidence in these provinces was calculated as 5.0% and 1.1% in the same order. The isolates including Alternaria spp., Aspergillus niger, Aureobasidium pullulans, Botrytis cinerea, Colletotrichum sp., Diaporthe ambigua, Nigrospora oryzae, Penicillium spp. and Talaromyces spp. were obtained from the symptomatic fruits. Some of these fungi caused fruitlet falling off 87.5-100% when inoculated at the fruit set time; however, the dropping rates were 60-70% in the control just treated with tap water. These results indicated that all inoculated species were pathogenic on flowers and fruitlets and they caused falling off these parts. On the other hand, when the fruits reached half size, only Coniella granati and Diaporthe ambigua inoculations caused calyx rot on the fruit, whereas other species could not it. While Diaporthe ambigua has not been reported to be associated with pomegranate fruit rots, this study revealed that it was an aggressive species on fruits.