BROWN Marmorated Stink Bug (BMSB) and the Glassy Winged Sharpshooter might not be names familiar with wine lovers, but they could stop you enjoying your favourite drops in the future.
The fight to keep Australian and New Zealand vineyards safe from international pests and diseases has never been harder, possibly since Phylloxera terrorised the vinous world in the late 19th century. Biosecurity is an item on every annual report and SWOT analysis. “It’s a booming business, unfortunately,” comments Wine Australia’s Program Manager Craig Elliott and whilst 2020 has seen a lull in the fight against these invaders the threat level is still high. In fact, the New Zealand Winegrowers have published a Most Unwanted flyer listing the top 10 pest and diseases to stop at the borders.
BMSB is at the top of their list. Marmorated means ‘veined or streaked like marble’, which is a reference to its appearance. Originating from Asia, the insect damages fruit and opens wounds that can lead to fungal disease. Added to this, the bug emits a foul smell akin to rotten coriander or sweaty socks which, if caught up in the grape harvest, will taint the grape juice making it unusable. “BMSB has already been detected in freight consignments of imported machinery and vehicles as well as garden pots,” comments Craig. Sophie Badland is the Biosecurity and Emergency Response Manager for New Zealand Winegrowers, she explains that “BMSB overwintering in the northern hemisphere will often aggregate in outbuildings, warehouses, vehicles, large pieces of machinery, shipping containers etc, in places where they aren’t easily observed – small compartments, nooks and corners, wheel arches, cracks. Some of these vehicles, machinery, containers are then shipped overseas, bringing aggregations of BMSB with them.” Sophie reports that it is now widespread in the United States and spreading in Italy and France and most recently has been detected in Chile, near Santiago.
BMSB has been found on tourists clothing, their personal effects and packages from overseas. There is a real need for everyone in the community and visitors to our countries to be vigilant and be aware of what these hitchhikers look like. Maybe New Zealand’s excellent top ten ‘Unwanted Poster’ needs to be adapted and displayed at entry points? Australia has seen BMSB ‘incidents’ grow from below 10 per annum to over 50 per annum in the past ten years. Infested shipping containers are being stopped at or before the border and are often fumigated before reaching our shores.
The vine malady Pierce’s disease (caused by Xylella fastidiosa) is a bacterium that blocks the xylem, the tissues that transport water from the roots to the stems of the vine. It’s a fatal disease causing, not surprisingly, water stress. The vine dies within one to five years. The disease came to prominence in America in 1892. They are still fighting the disease in California and have a control programme to stop it spreading into Northern Californian wine regions. There is no treatment or sub species of vitis vinifera that is resistant to the disease, pinot and chardonnay succumb quicker than other varieties. The most threatening vector (a carrier insect) to spread Pierce’s disease, is the Glassy Winged Sharpshooter (GWSS) which is why the insect is on the most unwanted list. The insect has been getting geographically closer to New Zealand with it currently waiting in Tahiti and the Cook Islands for a ride west. But the disease could also be spread by a local insect that feeds off the xylem and in New Zealand they have identified the meadow spittle bug as a possible carrier as it is commonly found in vineyards. The strict quarantine regulations on plant material brought into Australia and New Zealand is the first line of defence against Pierce’s disease and is very effective. But it is the people that smuggle plant material in their luggage that is the most likely entry point – so please no plant cuttings hidden in your pyjamas! GWSS has not spread into Europe and, it is thought, that the cold winters kill off the insects sufficiently to stop outbreaks, but warmer countries such as Australia might not be as lucky. Xylella fastidiosa is not only found in vines, but over 500 hundred different plants, “many of these are asymptomatic,” notes Sophie.
Flavescence dorée (Candidatus Phytoplasma vitis) is one of the major vine problems in France, Spain and Italy. Phytoplasma is a bacterium, that is spread by grafting from infected plants, or carried by a vector. It causes the leaves to yellow and die and reduces yields dramatically as well as wine quality. Whilst the threat level is low, the consequences would be commercially devastating for both industries. One of the measures to counter the threat of Flavescence dorée is to use pesticides to cut down the vectors. However, if you are an organic/biodynamic farmer that would be against the rules and you could lose your accreditation. In 2015 French authorities took a Biodynamic Burgundian producer Thibault Liger-Belair to court for failing to spray his vines when ordered. The most common vector in France, Spain, and parts of Italy is the Scaphoideus titanus. In organic vineyards the pest is managed with Pyrethrins.
New Zealand has a biosecurity campaign running called ‘Ko Tãtou – this is us’ and a catch phrase, ‘Catch it, Snap it, Report it’ and have a hotline number 0800 80 99 66. Sophie makes an important point, “biosecurity is crucial for the sustainability of the New Zealand wine industry. Unfortunately, there is not a great diversity of plantings in the NZ wine industry and a few key varieties are relied upon quite heavily – an incursion of a new pest of disease could have serious consequences”.
Craig Elliott thinks that we rely too heavily on governments to protect us and feels biosecurity should be a normal part of business, just like WHS. The general public need to be aware of the threat and follow instructions of vineyard staff. “This might involve not entering production areas or to decontaminate shoes or vehicles before entering a property. If you have someone travelling around a number of vineyards day after day, they could easily transmit a pest like phylloxera on their shoes or clothing throughout a region and cause a major impact to wine production. We have a great reputation for producing quality wine with an emphasis on clean, green production. If we don’t stay on top of biosecurity, we place that at risk.”