Technical Yearbook 2023

Buckwheat plants blooming mid-season and providing nectar to beneficial insects.

established under the vines. This was an exciting finding because those natives were established as small plants that took time to grow yet they were still delivering benefit in year one. By the end of the first season several, especially Dampiera and Myoporum, were aggressively covering more ground and out-competing the adjacent weeds but still retained their prostrate growth habit. This meant that they did not climb into the vine foliage and, at an average of less than 20 cm high, were considerably shorter than the weedy plants in the control plots in the trials which comprised the original groundcover. Those grassy and broadleaved weeds were typically around 50 cm high so much more likely to impede air flow through the vines and around bunches. We Key facts • Several native and non-native plant species have been identified as agronomically well suited for use as vineyard cover crops both mid-row and under vine; • Several species (including perennials) established and achieved significant levels of ground-coverage and competed well with weeds; • Several species exhibited a prostrate growth habit in vineyard settings to the extent that they were shorter than the weedy vegetation they replaced and thus can be assumed to improve air flow, so reducing frost risk and fungal disease severity; • Fruit bunch attack by light brown apple moth was greatly reduced by some cover crop treatments such as alyssum; • Both incidence and severity of botrytis bunch rot was reduced by some cover crop treatments, including alyssum, which suggests that reductions in the severity of light brown apple moth attack can have a knock-on effect in reducing the botrytis fungus infection within bunches.

Light brown apple moth: one of the key vineyard pests and for which cover crop can provide protection by attracting beneficial insects such as nectar-feeding Trichogramma wasps.

help inform which plants might be used as vineyard cover crops, as well as for selecting species suitable for ‘insectary plantings’ beside vineyards, and even help understand which native woody plants might be valuable in shelterbelts and the wider landscape. Vineyard trials So much for boffins playing with bugs in the lab; what actually happens in the field? Vineyard trials were conducted in 2021-22 in the Orange district to assess ease of establishment of various cover crop species and measure the benefits of each. An important finding from this season long trialling was that some of the plants that were shown to be useful to Trichogramma wasps in the laboratory led to reduced levels of field damage to bunches by light brown apple moth. In the case of alyssum established as under vine plots, for example, the numbers of damaged fruit bunches were reduced by two thirds at both the organically managed site (See Saw Wine’s Balmoral Vineyard) and a conventionally-managed site (Angullong Vineyard). Moreover, the alyssum cover crop led to lower numbers of fruit bunches affected by botrytis and, for those affected bunches, the severity of rot was reduced. Similar effects, though slightly less pronounced, were apparent when a mix of low-growing, perennial native plant species was

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TECHNICAL YEARBOOK 2023