Ultraviolet rays against Botrytis cinerea

12 Sep 2024
1078

Physical, chemical, enzymatic or microbiological changes can be the cause of the quality decline that occasionally occurs in sweet cherries between harvest and consumption. In addition to the economic losses resulting from quality changes, the potential presence of toxins or pathogens represents a risk for the consumer. Several plant species in the temperate zone are infected by Botrytis cinerea, a haploid, filamentous heterothallic fungus.

This fungus starts the infection directly in the field. It is in fact endowed with sclerotids, special biological structures that allow it to be preserved during the most unfavourable periods, until favourable atmospheric conditions are created for the formation of spores (called conidia). During rainy events, these spores disperse and deposit on various parts of the plant.

Initially, they are visible at flower level, located at the base of the receptacle in a resting state. However, they become visible during the post-harvest period, when the fruit ripens. Ultimately, cherries are completely destroyed when they develop rapidly under favourable conditions. 

The economic losses associated with the disease induced by grey mould are considerable. To try to reduce the contamination rate, various treatments with ultraviolet (UV) rays are being experimented with. Researchers at the Tashkent State Technical University (Uzbekistan) evaluated the effectiveness of different combinations of distance and duration of ultraviolet (UV-C) treatment in comparison to untreated cherries.

Ten cherries per treatment were placed in a polypropylene container and kept at room temperature for five days. In the untreated cherries, it was observed that filamentous fungi developed on the fruit surface after three days and completely enveloped the fruit after five days. The safety of the cherries in the outdoor environment was further increased by two days due to the infection that started to develop on the fifth day after UV-C treatment.

To assess the impact of UV-C on cherries, the term ‘fungal infection’ was defined as the number of infected cherries divided by the number of total cherries. Interventions at a distance of 25 cm and 35 cm were the most effective, as the lowest infection values of 37% and 40%, respectively, were obtained.

This is due to the fact that sweet cherries have a lower incidence of filamentous fungi visible to the naked eye. Consequently, it can be concluded that the most appropriate distances to position the fruit in relation to the UV lamps for irradiation are 25 cm and 35 cm, respectively, and that the most appropriate treatment exposure time to achieve the desired effect is 6 minutes.

The reason is that UV-C radiation damages the DNA of microorganisms, causing mutations that hinder cell replication and ultimately lead to microbial mortality. Immediately harvested fruits are resistant to fungal infections but become more susceptible to infection during the ripening process and after harvesting.

This is because Botrytis cinerea can remain latent at the base of the receptacle, causing the fruit to rot only when it reaches maturity. The results of this study are reliable and make it possible to identify the optimal processing method for preserving sweet cherries. This will increase the availability of the fruit for an extended period and ensure that the product is of adequate quality and price for the end consumer.

Source: D E Saparov et al 2023 IOP Conf. Ser.: Earth Environ. Sci. 1231 012033. 10.1088/1755-1315/1231/1/012033.
Image: Paicent

Melissa Venturi
University of Bologna (IT)


Cherry Times - All rights reserved

What to read next

A natural cherry orchard in the Himalayas: a veteran's ethical choice

Specialties

29 May 2025

On a shaded hillside in Narkanda, a veteran and his wife grow chemical-free cherries. Their journey, born from personal loss, became a beacon of hope and resilience. A touching story of natural farming that nourishes the body, honors the earth, and inspires hearts everywhere.

Poland Hit by Frost: Cherry Production Down 30% in 2025/26

Markets

09 Jul 2025

Poland’s cherry output is forecast at just 115,000 tons in 2025/26, marking a 30% drop due to severe spring frosts. Early varieties were worst hit, with some orchards losing up to 90%. Imports rise sharply while domestic inventories vanish, tightening the EU market.

In evidenza

Argentina's 2025/26 cherry season at risk as Capci tones down export outlook

Markets

28 Oct 2025

Argentina’s 2025/26 cherry season begins with mixed signals. Capci warns of early fruit drop affecting export volumes. Despite good fruit quality, unstable weather and production issues may impact international shipments, pushing forecasts toward stability or slight decline.

Micropropagation protocol for Gisela 17 tested in a commercial nursery in India

Rootstocks

28 Oct 2025

A new micropropagation protocol for Gisela 17 rootstock was developed in Aurangabad, India. The study achieved excellent results in asepsis, rooting and shoot proliferation, paving the way for healthy cherry stock production and modern nursery propagation techniques.

Tag Popolari