Using black soldier fly larvae to break down organic waste is not a new technique, but it is new to the vineyards of Schutz Barossa.
Fifth-generation grape grower Tammy Schutz is always looking for new opportunities to use waste from within the wine industry and redirect it into improving her vineyards.
While reading about the efficiency of black soldier fly larvae as bio converters, Tammy became interested in the possibility of applying this “natural technology” to wine industry waste such as grape skins and seeds, commonly referred to as marc.
This led her to a farm with a difference – Mobius Farms. Based in the Barossa Valley, Mobius Farms farm millions of black soldier fly larvae to recover the nutrients from organic “waste” streams, and return it back into the food system as insect protein or fertiliser.
Co-Owner Jeannine Malcom describes the larvae as “nature’s super composter.”
The larvae eat the organic waste, rapidly converting it into protein and fats within their bodies and into frass (insect poop).
The larvae have value as feed ingredient for pet, poultry and aquaculture feed. The frass is what is of interest to growers like Tammy who see its benefits as a fertiliser and soil improver.
With two grants, one from Barossa Australia (a peak wine and tourism industry body in South Australia) and one from Penfolds Evermore (a community and sustainability platform for Penfolds wine), Mobius Farms began trials for grape marc insect bioconversion with Schutz Barossa as an industry partner. In Autumn 2024, Schutz Barossa applied insect frass to a vineyard block in Stonewell, Barossa Valley, South Australia.
The frass was applied at varying application rates of one tonne to the hectare, 0.75, 0.5 and 0.25 tonnes, to determine which concentrations yielded the best results.
Tammy says they applied a commercial fertiliser to an adjacent section to act as a control for the trial.
She hopes that the frass will have a positive effect on the plant and soil health by adding essential nutrients like nitrogen and phosphorous, as well as beneficial soil microbes.
Black soldier fly frass also contains chitin which is a compound that forms the exoskeletons of insects (and shellfish). Research has shown that this can also have beneficial outcomes for plant and soil health by improving soil structure and disease resistance.
“If we can build up the soil microbiology, hopefully we will end up with a more resilient vine that can remain strong through adverse weather conditions,” Tammy says. “This year we experienced drought conditions, which ultimately makes for a very challenging season.”
During the 2025 vintage, Mobius Farms collected grape marc from Treasury Wines (Penfolds’ Wines parent company) to feed to their larvae. Red and white grape marc will be processed and the frass analysed separately to determine if different grape varietals produce different frass nutrient profiles.
“Different grape marc varieties might produce higher potassium levels in the frass, something that may be of a concern for some grape growers,” Tammy says.
“This research project will help determine whether we have to blend the frass with something else to get a balanced fertiliser, or whether it will be better suited to a crop other than wine grapes.”
Black soldier fly larvae bioconversion is rapidly gaining interest worldwide. Reported to be up to 10 times faster than composting and vermicomposting, the larvae are able to process a broad range of organic materials and can be farmed intensively.
“One kilogram of larvae will eat about four or five kilos of organic waste in just 10 days. You don’t need a big farm or paddock to do this. If you wanted to, you can start something like this in your shed,” says Jeannine.
Like any new trial and technology, scaling up the infrastructure can be challenging.
“Working out how to scale up the technology without breaking the budget has been a test,” says Jeannine.
“The larvae require specific environmental conditions to optimise their bioconversion and breeding performance. What they eat affects the nutrient profile of the larvae, and the frass. We value support like these grant programs to enable us to continue learning and contributing to building a circular economy around waste.”
Almost one year on from the frass application, and a very dry season in the Barossa, Tammy says it is too early to measure the full impact of frass in the vineyards.
“It is expected to take several years to collate adequate and accurate results,” she says.
“We plan to reapply the frass this autumn to the same block and will continue to monitor the trial over the coming years, but the results so far are promising.”
