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202006 Fresh Quarterly Issue 9 14 Putting It In Pictures
Issue NineJune 2020

Putting it in pictures

Creating a complete image database of pome-fruit diseases and disorders. By Grethe Bestbier.

A picture tells a thousand words, and a compilation of pome-fruit disorder images does even more. In fact, according to Dr Ian Crouch, post-harvest physiologist at ExperiCo, such a collection of high-quality photographs might be the solution to all the confusion that exists around the various pome-fruit disorders and diseases. With his interest in photography and more than thirty years of industry experience, Crouch is attempting to create a complete visual database of pome-fruit defects to be used as reference and technical assistance tool. However, he needs the support and collaboration of industry for this project’s full potential to be realised.

Lost in translation

A large variety of fruit disorders and diseases exists across South Africa’s deciduous fruit industry. According to Crouch, this extensive list of defects has been the cause of much confusion over the years. Many disorders are not fully understood, and errors can arise when trying to describe symptoms or characteristics of a defect.

“When it came to identifying pome-fruit disorders, we often found that someone would be talking about something completely different to somebody else, just because there is no definitive guide available,” says Crouch.

While there is certainly an abundance of images and descriptions available online, South Africa has its own unique growing conditions and cultivars, and therefore images and information specific to our circumstances is very important.

“Anyone can search for a disorder on the internet and get thousands of pictures. The problem is, they may not be local to our cultivars and our situations. That is why I believe we need a database of good quality pictures, and that is what I’m trying to create.”

Clearing out the confusion

According to Crouch, his vision is to provide the industry with a comprehensive database so that all industry players can speak a common language across fruit kinds and disorders. The database will be regularly updated and eventually incorporated into either an electronic source or printed material such as guides or reference books.

Image quality is crucial. Crouch has a lifelong interest and experience in photography and takes the photos himself.

“Nothing annoys me more than a picture that is out of focus or too far away to show the disorder. I believe that it’s important to provide a good quality photograph that clearly illustrates the specific characteristics of the defect,” says Crouch.

Just as important is the information that accompanies the photographs. For that purpose, Crouch designed a form to capture the case history of fruit samples. Information such as climate, preharvest factors, and post-harvest handling and storage conditions, temperatures and fruit stages are critical for the correct diagnosis of disorders and diseases.

“The project is not only about taking pictures,” says Crouch. “It’s trying to understand the disorders better.”

A project for industry, by industry

A complete database of images will not only help researchers and research institutions, but also assist the fruit industry practically. Producers, field hands, pack houses – anyone dealing with pome fruit – will benefit.

Truly a project for the industry, it also needs the industry’s input. While Crouch has been building up a library of pome-fruit images over the past twenty years, the project needs industry input to develop its full potential.

“When this trial was initially put out there, the idea was for pack houses to contribute,” explains Crouch. “As people in the industry see a fruit with a disorder, the idea was to let us know.”

If possible, the research team at ExperiCo would then collect the sample, or the pack house could send it to ExperiCo, with full history, for image capture and inclusion in the database. However, the response has been slow. Crouch would like to thank all those who have contributed fruit samples and encourages all role players to continue to look out for any photo-worthy defects.

“At this stage I mainly rely on what we find in our laboratory and that is slowing down the process tremendously,” says Crouch. A list will shortly be distributed to highlight those disorders still missing from the database.

What are people saying about this research?

Richard Hurndall | Post-harvest technical specialist

It is not only the abundance of existing pome-fruit disorders that is causing confusion in the industry, but also the many new disorders that are surfacing, according to Hurndall. Therefore, it is about time we update our resources.

“The last photographic information of defects was published decades ago, so this database will be of immense value,” says Hurndall. “Such a database will also be useful for overseas receivers to identify defects and disorders correctly. The Europeans and Americans are currently collaborating to develop a defect database, but it is important to develop one for our local conditions.”

Image: Carbon dioxide damage in a Fuji apple.

Supplied by Ian Crouch | ExperiCo.

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