Birds, Bugs and Bats!
Fiona and I recently attended a seminar on vineyard biodiversity, presented by NSW DPI and Dr Mary Rettalack, an agricultural scientist and third generation viticulturalist, based in SA. The seminar was held in Orange, and we can attest that Orange can equal Canberra in its ability to put on a really freezing day for visitors!
Mary categorises agricultural landscapes as “simple” if they have less than 6% native vegetation and “more complex” if they have around 23% native vegetation, with 30% required to stop species loss. In addition to this overall benefit to sustainability, native vegetation plays host to a whole range of creatures, great and small, that are happy to help
themselves to many vineyard pests.
The idea is not new, but more research has enabled more targeted efforts. A good friend of ours, Geoff Carter, has spent much of his life in vineyards and wineries, and planted his own vineyard Cartobe Wines, near Boorowa, in 1978. He selected black wattle as part of his windbreak to attract lady birds who prey on scale and mites.
We are blessed at Yarrh to be surrounded by native vegetation, with well over 30% of our property forest, and as much again in native pastures. However, there is more we could do, planting specific species that provide year round food and shelter to the birds, bugs, spiders and bats(!) that provide ecological “services” to our agricultural endeavours.
Beneficial birds - many of the little, non-flocking native birds out there (including fantails and thornbills) are insectivores, and love to feed on things we don’t like – light brown apple moth (LBAM) and vine caterpillars for example. LBAM larvae create conditions for botrytis to take hold, and vine caterpillars can strip vines clean.
Beneficial bugs and spiders - lacewings, shield bugs, predatory wasps and ladybirds are four of many beneficials bugs that prey on scale, caterpillars, mealybugs and other vineyard pests. Some of these you can buy to populate your vineyard, but of course encouraging natural populations is more sustainable.
Beneficial bats - small bats (not fruit bats!) and micro-bats (smallest weigh around 2g – how cute is that!) can eat their weight in moths, more if they are lactating! There’s an app now (of course) that you can use to record the sounds these bats emit and have this analysed by an expert, useful for monitoring populations.
The first rule is to not kill or discourage any natural populations you already have. This season we had a significant population of lacewings and had little trouble with LBAM. We already stick to soft fungicides and have been gradually reducing the amount of sulphur we use (known to be detrimental to some beneficials).
The second rule is to create or augment habitats that provide food and shelter for these beneficials. Doing this in the areas immediately surrounding the vineyard, or within the vineyard, helps with the varying ranges of these beneficials. The vines themselves are good providers of shelter and food, but not all year round, and not if you do have to battle an outbreak of, say, downy mildew, when they may need alternative shelter.
This is an area where we plan to do more work, in and around the vineyard. We have already identified some local species of grasses and shrubs that can
provide shelter and alternative sources of food (nectars, pollens, saps, prey). Some examples include the blackthorn bush (pictured), and local species of wallaby grass. We’ll trial planting wallaby grass in the undervine area, where it also has the potential to be an easy to manage “living mulch” for the vines without creating too much competition for resources (nutrition, water) during the growing season.
Exciting stuff, watch this space! I’ll finish with a quote:
“When we kill off the natural enemies of a pest, we inherit their work.”
Dr Carl Huffaker, University of California, Berkley.