PCA Conference in Adelaide

Protected Cropping Australia (PCA) organise a biennial conference in a different growing region of Australia each time. In 2023 the conference was in Brisbane, within distance of the many greenhouse and protected crop growers that operate along the East coast. This year the conference was in Adelaide, I hadn’t realised how many covered crop growers there were in the North Adelaide Plains, mostly growing under plastic and with tomatoes and capsicums dominating but strawberries becoming increasingly popular as well. One estimate had the number of growers in the area at around 1,850! Sadly, there weren’t many local growers who attended this conference, so they missed the opportunity to learn from domestic and international suppliers and of course from chatting to those involved in various aspects of the industry!

I think it’s fair to say that in general, Australian covered crop growers appear to face the same issues as those of NZ:

1. The cost of energy
2. The cost of labour
3. Biosecurity threats

These all see bottom lines diminishing and, added to this, is the ever declining consumption of vegetables in Australia – a trend that is mirrored here (thought to have decreased by 45% in recent years).

Interestingly, while the conference 2 years ago had a strong focus on vertical farming being the way forward, the huge cost of energy has changed that narrative and vertical farms are thought only to have a place where space is restricted. Instead, medium to high-tech GHs are now thought to offer the best balance between input costs (too high in vertical farms) and variable quality of produce (outdoor crops, due to climate). In terms of tech, there wasn’t too much on offer, but there were discussions about the likelihood of robotic harvesters (that age-old discussion!) and how AI might help growers in the future. The consensus seemed to be that robots have a place in the GH, but even with a median wage in Australia of $42.50/hour, they are too expensive and still not precise enough. On the other hand, AI plays a role in helping growers manage larger GHs but for limited tasks, accounting for only 10% of the current workload. So not a game changer yet.

IPM and banker plants

There was a presentation with some interesting ideas on using banker plants as part of an IPM. A banker plant is one that is planted in the GH specifically for beneficial insects (BCAs) to use as a ‘home base’. If there is a food source, they will live quite happily in the right environment on the banker plant waiting for when the pests appear. The problem that the TNZ/ALT trial observed is how to then encourage the BCAs into the tomato plants to eat the pests. That trial had some success with breaking off banker plant leaves and spreading these amongst hot spots. An idea from the conference was to have banker plants in pots so that the whole plant can be moved to where the pests are seen. Some suggestions for where to position banker plants are: near doors, in cold spots, at the end of rows, in the gutters. There was even the novel idea of in hanging baskets near vents to try to stop the pests from coming inside. I imagine there would be some health and safety requirements that need to be checked if you plant to try this out.

What to use as a banker plant will depend on the BCA being used. It’s a good idea to talk to your BCA supplier for suggestions but some tips from the conference were: using spare tomato plants; a plant that flowers consistently; having several seedlings of banker plant in one pot to increase the concentration. Also, only sourcing banker plants from a trusted supplier and then monitoring them for pests is key – you don’t want to introduce extra issues into your GH.

Some other advice for a successful IPM are:

• Be honest with your supplier about how many pests are present so that they can send the right number of BCAs.
• Consider what chemicals were used at the end of the previous crop cycle – are residues still present in the GH that might kill the BCA? Are residues present in the substrate if this is being recycled?
• BCAs can be harmed by environmental chemical use so knowing what your neighbour is spraying and thinking about when you spray weeds near the GH are both important.

Outside of the conference, we were able to visit the brand new demonstration GH at Apex Greenhouses in Virginia. This was built in conjunction with a number of organisations as a research and extension space and is seen as a grower hub for the region. The 2 compartments currently have ToBRFV resistant tomatoes (5 rows, each a different variety) and strawberries, on guttering that allows for maximum density while not compromising light hitting the plants. Apex themselves are trialling some different ideas – the GH isn’t vented in the tomato section. Unlike in NZ, South Australia doesn’t have an issue with humidity so instead they have introduced a wet wall, to add moisture to the environment. It’s always exciting to see a brand new greenhouse and it’ll be great to hear results of current and future trials.

Finally, for obvious reasons, ToBRFV was a hot topic both in workshops at the conference and in chatting to growers and industry. North Adelaide was where the first cases of ToBRFV were detected 12 months prior to the conference and it would be fair to say that there have been many learnings in that time. Some that were shared with us are: That NZ is lucky to have representation of tomato growers with the ability to claim compensation if growers are directed to destroy crops. In Australia, tomato growers can choose to be members of PCA but there is no legislated commodity levy and no seat at the table when unwanted viruses make an appearance.

That said, the advice for NZ was that the Australian experience has shown that it is almost impossible to successfully eradicate ToBRFV and it would therefore be better to agree to a long term management plan and have this confirmed ahead of time.

The eradication plan that was agreed following the SA detections, didn’t allow the movement of fruit from quarantined properties and even now, 12 months on neither the large grower nor the nursery are in full production. The lesson shared was that any plan must be sympathetic to the grower and ensure they are able to continue trading. The way growers in Europe deal with this disease was quoted often – high levels of hygiene and growing resistant varieties. SA growers hope that the management plan being confirmed since an eradication plan was abandoned in late May, allows growers to follow a similar vein of self-management.

Thank you to the following people and organisations:

Folco Faber at Apex Greenhouses for showing us around the demonstration site.

The PCA committee for organising this event and for giving the TNZ delegates the opportunity to attend.
James Bertram, Rijk Zwaan and AusVeg SA for introducing us to growers either at and after the conference.

Thank you to all the growers who willing talked to us.

And finally thank you to the TNZ board for enabling this fact finding trip.