Earlier this month, we were lucky enough to have Frank Florus address growers at a tomato workshop. Over 40 people benefitted from Frank’s knowledge on a variety of topics covering growing during climate change, adapting to an energy crisis, viruses such as ToBRFV. This presentation was based on lessons learnt from North West Europe with some really useful learnings for New Zealand growers. 

 Frank was kept busy with a workshop and grower visits for Vegetables NZ as well. TomatoesNZ would like to thank a grant awarded by MPI as part of the NIWE fund which enabled Frank to travel here from Belgium. 

Frank Florus presenting at the workshop

Frank Florus is a consultant based in Belgium with extensive knowledge on growing greenhouse crops, especially tomatoes. TomatoesNZ brought Frank over funded by an MPI NIWE grant for growers to benefit from international experts.

During his short visit in early December, Frank addressed growers in 2 workshops – one hosted by Vegetables NZ focusing on capsicums, cucumbers and eggplant growers and another hosted by TNZ focusing on tomatoes.

Broadly speaking, the tomatoes workshop covered energy and adapting to climate change, the biosecurity issues of ToBRFV and PepMV and whitefly. All of these areas were to enable growers to learn from the experiences from North West Europe, where Frank does most of his consulting.

The presentation was almost 3 hours long and is available for viewing (link, password and rough index is all available here: https://www.tomatoesnz.co.nz/hot-topics/frank-florus-workshop/ ) but some of the key takeaways from the workshop were as follows:

Due to climate change affecting everything from radiation levels to extremes in air temperature and rainfall, having a plan for all eventualities is crucial.

Increases in fuel prices (both electricity and gas) were to some extent counteracted by the high price of tomatoes at market. One of the reasons for this was the lower than normal volumes of imported tomatoes from countries such as Spain and Italy which were negatively affected by ToBRFV. But as all growers know, prices are volatile and the situation for future years might not be so favourable.

LED lighting and screens are common place in NW European greenhouses. LED uses 30% less electricity than ordinary lighting but can increase yields especially when grey, rainy days are prevalent. The right type of screens can provide shade when radiation is high and insulate when temperatures are low.

When energy prices are high there is a tendency to focus on the temperature in the greenhouse. Reducing the temperature gauge in the GH will generally lead to a lower yield. Frank’s top tip was to instead focus on the humidity levels as this could help save fuel while improving yields, due to growing a stronger plant.

Choose a plant variety that can cope well at lower temperatures.

Install a pyrgeometre or radiation metre to monitor the amount of radiation escaping from the roof.

CO2, especially in the spring and autumn months when light levels might be lower, can help plants  and is thought to increase production by at least 5kg/m2. CO2 is thought to help with pollination, stronger trusses, better fruit sets and thicker fruit.

Don’t water more than 5 cycles per hour as it leads to lower oxygen levels in the growing slab. And only water until 2 hours after the peak position of the sun. So if the sun peaks at 1pm, don’t water after 3pm.

Hygiene is key for keeping viruses out. Everyone visiting your site, consultants, reps, mechanics all pose a risk and should attend only by appointment, wearing full PPE, only entering the greenhouse if necessary. All tools, crates, any reuseable packing are all susceptible and should be cleaned thoroughly. Employees work clothes shouldn’t leave the site but should be washed onsite and other clothes worn to travel between home and work. Personal mobile phones should be banned from greenhouses. Trolleys should be cleaned after every row.

ToBRFV is similar to PSTVd in terms of hygiene protocols but it can survive in the soil matter for years and is difficult to eliminate. ToBRFV doesn’t respond to heat treatment (PepMV is thought to be killed at 65 degrees). The only way of ridding it from a GH appears to be complete removal of all plant matter, thorough cleaning at least 5 times with 4 to 6 chlorine sprays and a further 1 to 2 Pherocon sprays. This is corrosive to the GH structure but imperative. Identifying ToBRFV on a plant is not easy as some symptoms are common in other diseases.; marbling on the fruit is similar to PepMV and brown spots are not so common.

As more ToBRFV resistant plant varieties are coming on to the market, growers should be aware that there are different levels of resistance – high levels of resistance will mean that even if exposed to the virus, the plant won’t get infected by it. Medium levels of resistance could mean that an exposed plant can become infected but never show any symptoms and spread the virus to the whole site.

TomatoesNZ would like to thank Frank for coming to New Zealand and sharing his knowledge. The next event with an international expert is set for breakfast with Marc Groenewegen on Thursday 28th March, exact time and location to be confirmed.

There is a link to the Zoom recording here and password y95M@xEC. The presentation can be found here.

The exact start times for each individual topic below, which are covered in the zoom recording: 

Introduction (and overview)  0 mins

Developments in North West Europe  - 14 minutes and 41 seconds

Climate change  - 15 minutes and 26 seconds

Energy crisis   -24 minutes and 36 seconds

Cultivation  - 33 minutes and 52 seconds

CO2   - 51 minutes and 37 seconds

Summer Climate  - 1 hour, 1 minute and 35 seconds

Summer Climate BER  - 1 hour, 18 minutes and 55 seconds

Viruses PepMV   - 1 hour, 27 minutes and 57 seconds

Viruses ToBRFV  - 1 hour, 39 minutes and 27 seconds

Virsues ToCV  - 2 hours, 21 minutes and 40 seconds

Whitefly  - 2 hours, 24 minutes 

Total recording time = 2 hours and 40 minutes