Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh

Abstract

This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.

Mining Tamarix ramosissima roots for endophytic growth promoting fungi to improve wheat root growth

“…Specifically, endophytes capable of producing auxin exhibit a red/pink color change upon addition of Salkowski’s reagent, attributed to the interaction between auxin and iron resulting in complex compound formation. Previous studies have documented the auxin-producing abilities of Aspergillus 26 , Talaromyces 27 , Fusarium 28 , and Alternaria 29 species. This study represents the first documentation of A. bicephalus’s capacity to produce auxin.…”

“…27 , Fusarium 28 , and Alternaria29 species. This study represents the rst documentation of A. bicephalus's capacity to produce auxin.…”

Antifungal potential of two synthetic vanadium (IV) oxalate compounds to control blue mold of oranges and apples under storage conditions

“…This method shows the effect of the solubility of the compounds in a PDA medium. The diameter of fungus growth on PDA (in mm) with and without the compounds (control) was measured as described by (Nira et al, 2022).…”

First Record of Alternaria pogostemonis: A Novel Species Causing Leaf Spots in Pogostemon cablin

“…Wijayawardene et al [ 14 ] reported that Alternaria contains 366 accepted and recognizable species. Alternaria black spot, blight disease, and seed-borne pathogens are major pathogens distributed worldwide on cruciferous crops and other economically relevant plants that cause considerable yield losses [ 15 , 16 , 17 ].…”