Over the years, numerous Fruitfed Supplies Technical Horticultural Representatives (THRs) and other personnel have returned from overseas study tours with fresh ideas to benefit local growers.

Recently a viticulture-focused group travelled to Margaret River in Western Australia with Corteva. The group comprised four THRs: Tim Mounsey, Canterbury; Spence Southey, Wairarapa; and Simon Hoban and Blair McLean, Blenheim. They were accompanied by Jon Peet, Technical Specialist – Viticulture; Richard Rutherford, Product Manager; John Van der Linden, Corteva NZ; and local Corteva Territory Manager Linda Viviers.

At Willespie Wines in Wilyabrup, Nathan Schultz, Viticulturist and Winemaker, talked with the group about their 25 ha of grapes which include some of the oldest vines in the region, planted in 1976. Nathan manages the vineyard according to organic principles, but it’s not certified organic which means he retains the flexibility to apply certain one-off, non-organic products if necessary. He uses a kelp product for vine health and applies chicken manure for nitrogen. Their early harvests allow the retention of vine canopy for up to six weeks post-harvest. They continue to protect the canopy against late-season disease and apply nutrition for post-harvest carbohydrate storage.

The group spent time looking at research and development trials around the district with Corteva’s South Australia Technical Special Chris Brown and Scott Paton, Research Agronomist with Nutrien Ag Solutions.

Jon Peet explains: “One of Scott’s specialities is his knowledge of mealybug lifecycles and methods of control. He is an expert at identifying the very early growth stages of mealybug for the most effective application timing for different active ingredients. Scott advises that very early season mealybug monitoring should target vine trunks and head, not the leaves and cordon. He also says that early identification of first and second instars is vital for control. Most people can identify only the third mealybug instar and adult females. My annual technical grower meetings in spring will include a discussion based on our learnings from this Western Australian study tour.”

On another of Scott’s trial sites, brown lacewings are released to offer biological control of mealybugs. The predator insects spread on the wind and follow the mealybug pheromones, as part of an integrated control approach.

At another site, they talked about powdery mildew control with Scott achieving very good control with the application of sulphur and two targeted fungicides. Scott highlighted the importance of understanding the impact of dilute vs. concentrated spraying on coverage and efficacy.

Established in 1973, Woodlands Wines is one of the first five wineries in the region. This family-owned winery focuses on Bordeaux-style blends and runs one vineyard organically and the other conventionally. There is an approximately $10,000 per hectare difference in production costs between the two, with the organic vineyard sprayed every seven days throughout the growing season. They use chicken manure as a post-harvest source of nitrogen along with inter-row cover cropping to support soil organic matter, which is 4.5 percent and high for most Australian soils. They rely on subsoil storage of winter rainfall and, at the time of the tour, hadn’t had any significant rain since 10 mm in September last year.

The group also visited a rural supplies business Cowaramup Agencies, which supplies mainly dairy and viticulture customers with a large focus on organics and a range of familiar products. They concluded their tour with a visit to the fertiliser and grain port at Kwinana run by Co-operative Bulk Handling (CBH Group). More than 3,500 farmers own the group that receives and exports around 90 percent of the Western Australian grain harvest. They also import fertiliser, trade grain and are involved with processing.