Regenerative push prompts swing to biological inputs

Image: Bayer Territory Business Manager Ian Cook and Rob Kuzmicich take a closer look at capsicum development on the family’s Carnarvon property in WA.

Rob and Dan Kuzmicich grow capsicums over 6 hectares and eggplants over 2.5 ha in shadehouses, while capsicums are also grown over a further 5 ha of open land.

Capsicum and eggplant crops are planted in March and harvesting spans six to eight months, with the produce finishing on wholesale and retail market shelves primarily in WA.

The crops are fed via an automated Netafim irrigation system, with tensiometers and soil probes also guiding irrigation, nutrient and management decisions.

Production areas are not rotated and, hence, soils are topped-up with carbon and biological ameliorants to help maintain soil health and productivity.

The brothers also fumigate soils, however they are now looking at another shadehouse that will allow them to spell areas and grow cover crops during summer and winter to further build soil health.

“Soil health is everything and if you don’t look after it, you will run into problems,’’ Rob said.

“The regenerative approach has always been in the back of our minds – understanding how everything is connected in the plant biology process and the opportunity cost of all decisions.’’

When it comes to controlling fungal diseases like bacterial spot in their program, the brothers have primarily used copper sulphate previously, however with the regenerative push and focus on building soil microbiology, they have since turned to the biological fungicide, Serenade® Opti.

“The use of copper fungicides has been really prevalent to mitigate infection and some farmers are becoming concerned about copper toxicity in their soils,’’ Rob said.

“We are trying to maintain soil and plant health and to build the plants’ immune system.

“We use Serenade Opti for balanced applications on the foliage and we also use Serenade Prime to help root development. We use it at the beginning of the season with a bunch of other microbial products and if a crop is struggling through the season, it’s one of the products we will go to.’’

Serenade Prime and Serenade Opti, from Bayer, contain unique properties of the QST 713 strain of Bacillus amyloliquefaciens bacteria

In the case of Serenade Prime, after germination, these beneficial bacteria live on plant root surfaces and in the soil zone around the root system, called the rhizosphere, where they can ameliorate soil nutrients for the plants under suitable conditions. In annual or perennial crops, pre-emptively colonising young roots with Serenade Prime provides the opportunity to build the supply of plant-available nutrients ahead of critical periods of nutrient demand.

Serenade Opti is a formulated combination of spores and fungicidally active compounds produced during fermentation. It acts as a fungicide by preventing spore germination and germ tube elongation and penetration, and as a bactericide by direct contact activity. The product also has the ability to activate the plant’s natural disease resistance mechanisms.

In addition to its use in capsicums, Serenade Opti suppresses bacterial spot in tomatoes and chillies, and can be used under permit in eggplants, where it also targets early blight, botrytis grey mould and powdery mildew. It also controls botrytis in grapevines, as well as stem end rot and anthracnose in avocados, mangoes and other tropical fruit crops. It is compatible with many commonly used insecticides, fungicides and other treatments, plus Serenade Opti is registered as an organically certified input by ACO and OMRI, allowing its use in organic farming systems.

Rob said bacterial spot and other diseases like botrytis and mildews can have a significant impact on crop yields and quality.

“HIA Australia has indicated that the return on investment on a vegetable farm is a meagre 3.9 per cent, so there is not much margin to have a problem.’’

“You need to optimise yields and pack-out – and disease can alter premium pack-outs. Your costs of production also go up per unit and some production is not retrievable.’’ 

Rob said using Serenade Opti made complete sense with its mode of action and he liked the fact it was convenient to use and compatible with most inputs they used.

“It simplifies the complicated matrix we had before. We have enough to think about as farmers, so something that is easy to use and compatible is great.’’

In future, data from Department of Primary Industries and Regional Development (DPIRD) weather stations will help the brothers to further fine-tune their protection and remedial strategies against fungal and bacterial diseases.

Multiple applications of Serenade Opti are performed at a rate of 200 g per 100 L of water through the family’s airblast sprayer.

Rob said they also still used low-impact, selective fungicides with minimum withholding periods and copper sulphate still had its uses, but they did not want to become reliant on it to solve a problem.

“If we have a specific problem now, we may do a low-impact fungicide and then, if we are applying an IPM-friendly insecticide four to five days later, we might also include Serenade Opti to provide further disease protection.’’

“Serenade Opti has helped us develop a rotational spray program that allows a spread of (fungicide) Groups to be used.

“It has a zero withholding period and minimal impact on plants and while it has activity on certain pathogens, its impact on beneficial microbes is minimal.’’

This also suited their push to use IPM-friendly products, protecting beneficial species at their property including lacewings, ladybird beetles, hover flies, beneficial mites and parasitic wasps. When used as directed, Serenade Opti is soft on most beneficial species.

Rob said they would continue to focus on developing a spray program that had minimal affect on the plant habitat and which ensured plants could reach their full potential.

“It’s a small part of the overall program, but it plays a big part for plant health,’’ he said.

“The whole process is targeted at maximising output from every square metre of dirt and having high targets for premium pack-out fruit. And with the sum of all parts, it is improving.

“It’s been super frustrating at times and there will continue to be the challenges in farming, but we believe we are developing a more resilient and robust system. However, we are only at the beginning – by no means have we got it sorted.

“Ultimately, it’s about a greater focus on the environment and the health of farmers, and importantly their staff and through to consumers. It’s important to understand the stakeholders in the whole production system.

“We are in the game of producing healthy food, so we need to develop a healthy production system and biological products provide an opportunity for transition,’’ Rob said.