The perils of winegrowing

By Jamie Goode | 14th March 2024

I’d imagine most of us - even freelancers like me - have a good idea of what we are going to earn each year. If you are salaried, then you’ll know exactly how much is coming into your account each month. If you are a farmer, then you don’t have this luxury, especially if you are dealing with a vulnerable, fickle crop like wine grapes.

When most of us talk about vintage we are thinking about wine quality. For the grape farmer, it’s their income. And until the grapes are harvested then their income for the year is sitting out in a field. Right up to the point of harvest, this income is not assured.

Spare a thought for the wine growers in the Okanagan Valley of Canada, a major wine region where this vintage no grapes will be harvested. This winter there was a week so cold, with temperatures lower than minus 20 degrees centigrade for a prolonged period, that the buds on the vines that will produce this year’s grape crop were killed. Worse than this, it was so cold that many of the grape vines themselves will have been damaged to the point that whole vineyards will need replanting. In areas used to these sorts of freezes, often the vines are hilled over or covered with geotextiles, but to do this the vineyard needs to be pruned before winter and set up in such a way that the remaining growth is low enough that it can be covered. The Okanagan rarely experiences such cold, and so the vineyards all got hammered.

Cold is a familiar hazard to winegrowers, but it’s most often found in the form of frosts. Once the vines start budding in April (in the northern hemisphere; October in the southern) the new growth is vulnerable to frosty nights, and in areas prone to these low spring temperatures, protective measures are often in place such as frost fans, paraffin candles, water sprayers and even protective fabrics. These are expensive, and not perfect, and every year there’s news of a frost so bad that winegrowers have lost most of the crop for the year. The double whammy for winegrowers thus affected is that they’ve lost their income, but they still need to farm the vineyards for the season, and that costs money.

Fortunately, spring frosts are rarely encountered in South African vineyards. But as with every wine country, the vines are susceptible to diseases and pests. The most commonly encountered problem is a disease called powdery mildew. This came across from the USA in the 1850s. There, the local grapevines have lived with powdery mildew and have some resistance. Vitis vinifera, the Eurasian vine which is the species that has all the varieties we know and love, has no resistance, and so must be sprayed. Elemental sulfur is the commonly used remedy, although there are more modern, targeted chemicals that can be sprayed. This fungal disease is everywhere and is responsible for many of the tractor trips through the vineyard.

Another common disease that came from the USA is downy mildew, which is common in wine regions where there is some humidity or growing season rainfall. It’s a huge problem in many areas, but less so in many South African regions which are quite dry. The solution is another set of sprays, either modern systemic fungicides or copper-containing remedies for those farming organically. Copper isn’t ideal because it is toxic to soil life. And when grapes are ripe and ready for harvest, another fungal problem is bunch rot caused by Botrytis.

Diseases can result in reduced crops and less money for growers. So can bad weather around flowering, such as low temperatures or rain. This is a worrying time for the winegrower.

Weather is critical for grape growing. In South Africa, probably the biggest risks are from heat and drought. From 2015 to 2019 the Cape winelands suffered from a prolonged drought that lowered yields dramatically and even killed some vineyards. There’s not much that can be done about this. Fortunately, rainfall patterns have been more consistent since. And heatwaves are another issue, and can damage the grapes on the vine, or more worryingly result in bush fires. Even when bush fires don’t burn vineyards, the smoke can result in any grapes on the vine being tainted. ‘Smoke taint’ has become a major issue in warm regions like South Africa, Australia and California. Once grapes are affected by smoke, there is little than can be done in the winery to correct this problem.

One vineyard issue that has impacted South African vineyards, but which is actually a global problem, is grapevine viruses. These are spread by an insect called a mealybug and can also be spread by soil nematodes in some cases. Once one vine is virused, the mealybugs, which are sap suckers, spread the virus to neighbours. Very soon, the whole vineyard is affected. The vines don’t die, but their leaves lose their ability to photosynthesize towards the end of the growing season, and the grapes then struggle to ripen properly. Lots of work has gone into replanting vineyards with virus-free vines, and then controlling the mealybugs so they don’t bring virus into clean vineyards. South African wine quality across the board has improved because of this work.

There are many jobs that wine growers have to do to protect their crop and ensure good quality grapes. These include weed control, dealing with insect pests, spraying against fungal diseases, making sure the vines have good nutrition, managing the canopy of the vines so that the grapes ripen properly and don’t have too much or too little shade, and then harvesting at the right time. In the past, what’s known as ‘conventional’ viticulture used lots of chemicals and inputs to do this job. These days, there is a lot more emphasis on true sustainability, avoiding as many inputs as possible, bringing biodiversity back to the vineyard and building soil life. This is a welcome change in direction, but it costs money. Grape growers need to be paid enough that they can farm the right way, and as a result, we need to break our addiction to very cheap wine. This financial and human capital story is a part of sustainability.

So next time you open a bottle of wine, think about the farmers who grew the grapes and the uncertainty they live with from year to year.