The post-harvest vine disease risk assessment service is developing in leaps and bounds

The number of hectares of table grape vineyards monitored by ExperiCo Agri-Research Solutions in Limpopo province, before the start of the harvest and in the packing station, quintupled to reach around 1,000 ha over two years, helping farmers farmers to minimize risk and possible quality claims.

The disease risk management system (DRMS) developed by Dr Johan Fourie at ExperiCo is based on the monitoring of vineyards and packing stations, with the aim of quantifying the level of risk before transport and marketing. Production and quality parameters, as well as signs of deterioration and degradation, are carefully controlled. Injuries from insects, birds and mechanical damage serve as gateways for pathogenic infections.

Dr Johan Fourie inspecting grapes (photos provided by ExperiCo)

The DRMS ​​program was extended last season to the North Cape, covering around 200 ha of vineyards. Western Cape table grape growers would also benefit from their risk control system and advice, says Dr Pieter Louw, post-harvest pathologist at ExperiCo.

“Botrytis spores are always present in the environment and easily enter through wounds,” he explains. “There are many rotting pathogens out there, but Botrytis poses the greatest threat to table grapes – they like the same things we love about grapes, like sugars, and will cause rot if conditions are right. . “

The specific stage of development of a grape contributes to a large extent to postharvest rot and quality risk. The closer the harvest, the higher the sugars in the grape berry, hence the risk of berries cracking in rains and humid conditions, increasing the risk of Botrytis infections. “It is a challenge for grape growers in all table grape producing countries to harvest the grapes when it rains,” he says.

“We are halfway through the season in Limpopo and the North Cape. We have seen rainfall in these two areas. The vineyards are generally doing well, with minor concerns. Most growers do a great job of keeping disease risk to a minimum. . “

Anné Matthee from ExperiCo

Now producers can have a risk report in hand
A new feature that ExperiCo is offering this year is a real-time risk report generated using an app, in which the data entry in the vineyard and the packing station is transformed into a one-page report. . The report generated within 24 hours of assessment allows growers to see, at a glance, where the problem areas are and where corrective actions are needed to reduce post-harvest quality risks.

Dr Louw notes that a number of risk mitigation actions can be taken, depending on the problem identified. If there are problems in the vines, it is advisable to clean the bunches by sanitation in the vineyard, followed by the application of suitable and acceptable fungicides or biofungicides, as well as selective harvests to avoid introducing infected grapes. in the packing station.

Packing procedures
According to Dr. Fourie, cleaning and disinfecting work surfaces on a scheduled schedule with an approved chemical that will not leave any residue should be advocated.

“In the packing station, we examine, among other things, the cooling systems, damage and rotting of berries, whether the perforations of the bags are open or not, the use of MAM (moisture absorbing materials) and SO₂ sheets.”

Data from vineyards and packing stations could potentially be combined with a GIS system, so growers can visualize it in the future on a dashboard, integrating weather data and records from previous seasons to show which blocks have been problematic in the past, and the potential reasons for it.

“From this data, you can draw conclusions about a whole range of aspects such as rootstocks, microclimates and quality risks. This is something we would like to offer in the future.

At this point ExperiCo is focusing on table grapes due to their years of experience in table grapes, thanks to Dr Fourie who was instrumental in the development of this program and the sulfur dioxide laminated leaves. widely used in the table grape industry.

“Our vision is to expand the risk management system in the future to incorporate blueberries, stone fruits and stone fruits, offering growers a potential advantage of having a firm and traceable grip on the management of post-harvest rot. “

For more information:
Dr Johan Fourie
ExperiCo
Phone: +27 21 887 1134
Email: [email protected]
Dr Pieter Louw
Phone: +27 21 887 1134
Email: [email protected]
www.experico.co.za