Bell pepper (Capsicum annuum) is a widely grown vegetable crop that is nutritious and flavorful and economically important for growers worldwide. A significant limiting factor in the postharvest storage and long-distance transport of peppers is gray mold caused by Botrytis cinerea. The pathogen is widespread in nature, highly aggressive, and able to cause disease at cool refrigerated temperatures during transport and storage. Fungicides have been relied on in the past to reduce bell pepper rots in storage; however, concern over residues on the fruit and environmental degradation have heightened the importance of natural and generally recognized as safe (GRAS) solutions that effectively limit disease. Essential oils, plant extracts, inorganic chemicals, biocontrols, defense activators, hot water treatments, and modified storage conditions have been tested to reduce losses from gray mold. Despite significant amounts of research on natural methods of control of B. cinerea postharvest, research specific to gray mold in peppers is limited. The objective of this review is to summarize the research conducted with environmentally friendly alternatives to chemical fungicides to control this important pathogen of peppers postharvest. To ensure a steady supply of healthy and nutritious produce, more research is needed on the development, use, and application of non-hazardous Botrytis control methods. Until an effective solution is found, using a combined approach including environmental controls, sanitation, and GRAS products remain paramount to limit Botrytis fruit rot of peppers postharvest.

Sweet pepper (Capsicum annuum L.) is an important vegetable crop grown in Israel for local and export markets. Bell pepper ‘Dinamo’ and sweet bite pepper exhibiting fruit spotting were observed in ...

Chrysanthemum (Chrysanthemum × morifolium) plants exhibiting stem and foliage blight were observed in a commercial nursery in eastern Oklahoma in June 2019. Disease symptoms were observed on ~10% o...

Pathogen management commonly includes environmental regulation and sanitization. There are limited numbers of effective registered bactericides. In 3 years of greenhouse trials, Postiva^TM, a premix of pydiflumetofen (6.9%) and difenoconazole (11.5%), was tested for activity against xanthomonas leafspot of geranium, zinnia, ficus and bacterial wilt of geranium caused by Ralstonia solanacearum. Postiva^TM applied at 0.73–1.5 L/ha significantly reduced disease incidence and/or severity on each crop tested. Postiva^TM applications were similar (p = 0.05) to commercially available standards on geranium, zinnia and ficus. Postiva^TM (0.73 L/ha) reduced incidence and severity of bacterial wilt similar to that observed with applications of Cease^® (9.35 L/ha). Postiva^TM may be beneficial in an integrated disease management program to control bacterial diseases. Postiva^TM is highly promising as a rotation option to reduce the buildup of bacterial populations resistant to copper compounds and antibiotics that are frequently used in the industry.

The oomycete Phytophthora capsici is a destructive pathogen infecting more than 50 plant species and is one of the most serious threats to cucurbit production. Phytophthora blight caused by Phytophthora capsici can affect all plant growth stages, and fungicides and cultural controls are used to limit losses. Dissecting pathogen virulence and fungicide resistance can provide insights into pathogenic mechanisms and inform effective management practices to control P. capsici. In this study, we assessed virulence, mefenoxam sensitivity, and genetic diversity of nine P. capsici populations collected from Cucurbitaceae, Solanaceae, and Fabaceae host families in Michigan from 2002 to 2016. We developed 992 simple sequence repeats (SSRs) in the P. capsici genome and identified 60 SSRs located within or close to RXLR-class (Arginine-any amino acid-Leucine-Arginine) effectors and 29 SSRs within or close to effector CRN (CRinkling and Necrosis) family protein, which represent 62 RXLR and 34 putative CRNs. Population structure analysis shows that mefenoxam resistance was not associated with the year of collection, host type, or location, but there were significant differences in virulence among the populations. Using the general linear model and mixed linear model-based association analyses with all effector-related SSR markers, we identified four SSR markers significantly associated with at least one of the virulence-related parameters. Of these, one (Pce_SC18) was in a predicted CRN effector and had high identity with the putative PhCRN37 effector in the pathogen Plasmopara halstedii, which can be further verified for virulence identification in P. capsici.

Sweet basil (Ocimum basilicum) is an important spice herb grown in Israel for local markets and export. The crop is used as a fresh culinary herb or spice, and the essential oils are used in cosmetics and food flavorings. Due to increased demand, the production area of basil has increased in Israel. Postharvest losses due to fungal disease are a major economic concern for growers. In the summer of 2019, a leaf spot was observed in postharvest shipments of sweet basil destined for Europe; in late winter of 2022, leaf spots were observed on greenhouse-grown sweet basil. Fungal isolates from infected leaves were characterized by morphology in culture as Alternaria spp. PCR amplification of the Alternaria major allergen Alt a1, ITS, and gdp gene regions of the recovered isolates confirmed the presence of A. alternata, a common pathogen of numerous herbs and spice plants. In vitro growth tests demonstrated that 25°C was the optimum temperature for growth of the isolates. The isolates were tested for pathogenicity and found to infect a commonly grown cultivar of basil, cultivar Eli (previously cultivar Perrie). Foliar symptoms in pathogenicity tests were identical to those observed in commercial shipments and in the field, which completed Koch’s postulates. Control of the nascent disease by applying fungicides to the plants may be necessary to reduce postharvest losses.