Help! My Grape vine is under attack!

The past few 5 weeks, I have answered almost 450 emails! And most of them were about training the grape vine, pruning the grape vine, what varieties to use and many more. But let me tell you of some the real attack you must be looking out for!

How can you, the home grape grower, put a suit of armor on your grape vine? Just like any other living thing, your grape vine needs protection from outside attacks and you will have to ensure that they are ready. Obliging actions can save your vine from these attacks, which can ruin your grape harvest in a matter of days.

You dare not ignore these five enemies, because the grape vine is their main target and oh boy, are they well trained sharpshooters.

1. Frost / cold damage:

For you to understand the dangers of frost and cold damage, you need to know that you probably will not loose your whole crop, but you will endure losses. The reason I say this, is that there are three growing points inside a grape vine’s node (primary-, secondary- and tertiary buds). The primary node is the normally the grape carrier and shoots first when the growing season starts. If frost damage or kill this shoot, the secondary and tertiary buds will sprout. They also can produce grapes, but normally not as much and not as high quality as the grapes produced by the primary bud.

Without digging to deep into the development of frost and factors that cause the air temperature to drop below frosting point, a rule of thumb is, that if it is a wind free, clear sky, and dry evening and the temperature drops below 2.2°C (36°F), there is a chance of cold damage to the vine. The lower the dew point, the higher the risk

There are a few things a home grape grower can do to lower the risk of cold damage.

Sprinkle irrigation can be turned of when the temperature decrease below freezing point 0°C (32°F), the temperature of the water will rise to freezing point and freeze or ice. The freezing process will generate some heat that will raise the temperature of the atmosphere (heat of fusion).
Choose a late variety to plant where frost is a problem, this will ensure that bud break is later, lowering the risk of damage.

Choose the warmest, sunniest spot in your garden, to plant your grape vine.

Prune as late as possible (near bud break), and cane prune at first and later on, after the dangers of frost is gone prune your short bearers where you want them. Refer to the “Complete Grape Growers Guide” how to cane and short prune.

Sandy soils are more hazardous, because they store less water and therefore some sort of ground cover will lower the risk of frost damage.

2. Birds and Animals:

You have probably know that birds and other animals love your grapes. Allowing them to have a feast in your vineyard, will result in total crop loss. You as a gardener, loves nature, and killing these animals will not do any good.

What you need to do is to prevent them from getting to your vine. Easier said than done, but there are a few things you can do.

Cover the bunches with netting will prevent birds from reaching your grapes.
There are safe, commercial sprays you can spray on your plants, that will prevent animals from eating them.

Buy these products online at Garden Alive, or you can enquire at your local nursery about these items.

3. Rain:

Rain during, or close to harvesting your grapes will have a serious effect on the quality of your grapes. Certain varieties are more susceptible to rain damage than others. Varieties like Flame Seedless and Thompson Seedless are very susceptible to rain damage and should be avoided if summer rain often occur. Refer to the page where you downloaded “The Complete Grape Growers Guide” for a list of varieties you can plant that is not so susceptible to rain damage.

There’s not much you can do to stop rain, is there? But you can dust your vine with a copper sulphar dust to prevent the spread of fungus and to try out the cracks on berries, caused by the rain. Remove cracked berries by hand if you have the time, this will ensure that botrytis will not spread to nearby healthy berries – this is a rime consuming job, but well worth a try.

4. Phylloxera:

The cancer of the grape vine! Never underestimate the danger of this disease. If you plant a Vitis Vinifera variety, DO NOT use cuttings.

Phylloxera is a pest of commercial grapevines worldwide, originally native to eastern North America. These tiny, pale yellow sap-sucking insects, related to aphids, attack the roots of grape vines. The insects and secondary fungal infections can girdle roots, gradually cutting off the flow of nutrients and water to the vine and eventually kill the vine.

In the early 1800, Phylloxera destroyed almost the whole wine industry of Europe and more than 60% of the vines were killed!

Be on the lookout for symptoms of Phylloxera as this desease can kill your vine in no time at all.

5. Too dense vines

Ok, so you might say this is no attack on the vine! Fair enough, but a too dense vine will make your vine a sitting duck. A too tense vine is more susceptible to diseases like downy mildew, powdery mildew, botrytis (grey rot) and many other diseases.

Controlling the growth of your vine is sometime not that easy as a vigorous variety like Sultana on a fertile soil, will grow like mad without any fertilizer. The use of a less vigorous rootstock will help prevent the vine from growing to strong.

Always remember that a dense vine looks lovely, until the first rain!

Preventing these attack is better than trying to cure them and it will save you lots of time, money and frustration. The Complete Grape Growers Guide, helps you to put a suite of armor on your vine.

Have a grape (great) day.

Danie
“The Grape Guy”

PS: Remember that the X-Mas special on “The Complete Grape Growers Guide” ends soon! Don’t miss out on this one!