Identification and Laboratory Fungicides Screening of the Pathogenic Fungus of Stem Spot of Pitaya (Hylocereus spp.) Stems

Abstract

In this study, the pathogenic fungus of stem spot disease of pitaya (Hylocereus spp.) stems was identified by isolation and purification, pathogenicity test, morphological characteristics, and analysis of rDNA-ITS sequences. The results turned out that the rDNA-ITS sequences of the H1 strain showed 100% of identity with Botryosphaeria dothidea, indicating that the pathogenic fungus of stem spot disease of pitaya stems was Botryosphaeria dothidea. Meanwhile, the H1 strain was then used as a reference strain to screen some commercial fungicides. The bioassay test results indicated that prochloraz had an obvious inhibitory effect on Botryosphaeria dothidea with the EC50 value of 0.0798 μg/mL. Our study could provide a theoretical basis for the effective control method of stem spot disease of pitaya.

Advances in the Understanding of Postharvest Physiological Changes and the Storage and Preservation of Pitaya

“…Furthermore, pitaya is vulnerable to mechanical damage during transportation, which can lead to infection by pathogenic microorganisms. This may cause anthracnose, brown rot, stem rot, or black rot and aggravate the softening and rotting of the fruit [40][41][42][43][44]. As a result, the edible and economic value of pitaya is reduced, which can impact consumer purchasing behavior.…”

“…The imidazole fungicide imidacloprid has also been used, inhibiting plasma membrane ergosterol synthesis and inducing fungal cell death [113]. Imipramine inhibited the growth of Staphylococcus aureus in pitaya fruit [42]. Additionally, imipramine and hot water treatment prolonged the shelf life of mango to 20 days and inhibited the development of stem-end rot and anthracnose in the absence of disease symptoms [114].…”

Curvularia lingshanensis sp. nov., a New Pathogen Causing stem and leaf rot on Curcuma kwangsiensis and Its Sensitivity to Five Fungicides

“…Mycelial disks (5 mm diameter) from the edge of the colonies were transferred onto the center of PDA plates and incubated in an incubator at 28°C. After 5 days, colony diameter was measured using a ruler and inhibition rate I (%) was calculated by the following formula, where C (cm) and T (cm) represent the fungi diameters of the control and treated PDA plates, respectively (Vincent 1947;Hui et al 2022). Meanwhile, the EC50 (concentration for 50% of maximal effect) values of mancozeb, difenoconazole, tri oxystrobin•tebuconazole, triadimefon and thiophanate-methyl against CK21.1 were calculated using the Graph Pad Prism software.…”