Fruit rot of Strawberry pear (pitaya) caused by Bipolaris cactivora

Abstract

Strawberry pear (pitahaya, pitaya) [Hylocereus undatus (Haw.) Britt. and Rose] postharvest fruit rot was found at an agricultural products store in Itoman city, Okinawa Prefecture in 2006. The symptoms included depressed, water-soaked lesions with olive to black powdery spots coalescing into a soft rot. The causal fungus was identified as Bipolaris cactivora (Petrak) Alcorn. This is the first report of strawberry pear fruit rot caused by B. cactivora.Keywords Pitaya Á Fruit rot Á Bipolaris cactivora Á Water-soaked lesions Á Black powdery spot Strawberry pear [pitahaya, pitaya; Hylocereus undatus (Haw.) Britt. and Rose] is a perennial succulent plant in the family Cactaceae. In Okinawa Prefecture, strawberry pear has emerged in recent years as a cash crop with high commercial value. A fungal disease clearly different from anthracnose (Taba et al. 2006) was observed on strawberry pear fruits at an agricultural products store in Itoman city in November 2005. The purpose of this study was to identify the fungus causing this disease and to confirm its pathogenicity. SymptomsBrown spots were initially observed on fruit (Fig. 1a). Water-soaked to depressed water-soaked developed lesions. Olive to black powdery spots then formed in the center of expanding, coalescing lesions (Fig. 1b), ultimately resulting in a soft rot of the fruit. Isolation and identification of the pathogenLesions were cut into ca. 5 mm 3 pieces, immersed in 70% ethanol for 30 s and in 2% hypochlorous acid solution for 1.5 min., washed with sterile distilled water, and air-dried on a clean bench. Surface-sterilized lesion tissues were then placed on PDA (potato dextrose agar) plates and incubated at 25°C. Hyphal tips were aseptically transferred to fresh PDA. Five monoconidial isolates (PBW-1, PBW-2, PBW-3, PBR-1 and PBR-2) were obtained from the PDA cultures. Colonies on PDA consisted of a pale-olive to black aerial mycelium (Fig. 1c). Conidiophores were pale to light brown, caespitose, straight or flexuous, and often swollen at the apex and at the base (Fig. 1d), and were 72.6-238.4 · 4.1-9.7 [length (L) · width (W), average 181.9 · 7.8] lm. Cespitose conidiophores were also present on the diseased fruit (Fig. 1e). Conidia (porospores) with a basal hilum were straight, ellipsoidal, fusiform or obclavate, 2-4 septa, pale light brown to brown (Fig. 1f), and were 35.3-45.5 · 8.5-10.9 (ave. 42.8 · 9.7) lm. The mycelium was often narrow and sclerotized (Fig. 1d).

Terroir Is the Main Driver of the Epiphytic Bacterial and Fungal Communities of Mango Carposphere in Reunion Island

“…Fungal species and genera such as Alternaria, Bipolaris ( Taba et al, 2007 ), Stomiopeltis ( Ajitomi et al, 2017 ), Nigrospora ( Alam et al, 2017 , 2020 ), Passalora (i.e., Passalora fulva, syn. Cladosporium fulvum) ( Altin, 2016 ), Stagonospora, Ascochyta ( Milgroom and Peever, 2003 ), Diaporthe, Gibberella ( Guenther and Trail, 2005 ), Mycosphaerella, Zasmidium, Sterigmatomyces, Helicoma, Puccinia, Exobasidium, Lasiodiplodia, Exserohilum, Curvularia ( Oeurn et al, 2015 ; Hafiz et al, 2019 ), Phytophthora, Peniophora ( Taylor, 1969 ), and Neofusicoccum ( Hara et al, 2016 ) are commonly associated with plant disease and are most likely opportunists, which develop on stressed or dying fruit and leaf tissues ( Om et al, 1999 ; Galsurker et al, 2018 ).…”

Fruit brown rot caused by Neoscytalidium dimidiatum on Selenicereus monacanthus in the Philippines

“…Diseased fruits may be rejected during export due to the biosecurity rules of the importing countries. The common fungal pathogens that attack dragon fruits are Bipolaris cactivora (Taba et al 2007, Tarnowski et al 2010 and N. dimidiatum (Lan et al 2012, Ezra et al 2013, Yi et al 2015, but no fruit disease has yet been scientifically reported in the Philippines. Fruit diseases are better addressed when the cause of the disease is identified.…”

Ecology of pitaya stem rot caused by Gilbertella persicaria and its biological control by phyllosphere bacteria

“…Pitaya can be easily cultivated in the open air and remains relatively disease‐free. However, recently, successive disease outbreaks such as mosaic (Natsuaki & Shinkai, 2001), anthracnose (Taba et al, 2003), Rhizopus rot (Taba et al, 2006), fruit rot (Taba et al, 2007), and Gilbertella stem rot (Taba et al, 2011) have been reported. In particular, stem rot is a considerable problem, which not only causes softening and rotting of the stem nodules but also causes poor fruiting and postharvest damage.…”