Leaf Removal

Question 1

Three main types of leaf removal

Answer 1

• Traditional Leaf removal
• “early” leaf removal
• Apical to the bunch, “late” leaf removal

Question 2

When is traditional leaf removal?

Answer 2

Removal of the basal leaves from fruitset to veraison

Question 3

Is removing the basal leaves significant for photosynthesis?

Answer 3

No

Question 4

When is the best time for mechanical leaf removal? Why?

Answer 4

During the lag phase of berry growth, mid july
Because when the berries are soft they are much more sensitive and there is a risk of damage

Question 5

Four reasons why leaf removal can be a good idea?

Answer 5

1. Improve bunch microclimate
2. Increase light
3. Increase ventilation
4. Decrease rot

Question 6

Defoliation is very important for when the overall density of the canopy is too much. How many leaf layers should we ideally have?

Answer 6

When we have 2-3 leaf layers we are ok, but more than that we need to remove leaves. This issue can be because of a lack of shoot thinning or bad pruning.

Question 7

Do we affect photosynthesis when we perform leaf removal on a very dense canopy?

Answer 7

Not necessarily, it depends on the amount that we do, optimal is around 6m2 per row

Question 8

What are the four most common crop adjustments?

Answer 8

• Winter pruning
• Shoot Thinning
• Cluster thinning
• Flower or berry thinning (chemical, mechanical)

Question 9

With a very dense canopy, via leaf removal, we can improve _______, ______, ________, _______ and reduce _______.

Answer 9

1. Color
2. Flavor
3. Sugar
4. Quality
5. Acidity

Question 10

There are 4 factors related to the cluster, contributing for quality, on each of those early leaf removal is able to impact:

Answer 10

1. Compactness
2. Berry size and relative skin growth
3. Competition
4. Berry composition

Question 11

Discuss what is going on and why it is happening?

Answer 11

If we want to increase fruit set, we need to trim the shoots before flowering.

Removing the shoot tip also removes the strongest competitive sink for the cluster

Question 12

What is this picture showing and why do we do it?

Answer 12

This is the idea leaf removal in which we remove 6-8 leaves just before flowering.

It is ideal because we are inducing a carbon stress, a source limitation having the primary objective of decreasing fruit set

Question 13

Overall conclusions when looking at defoliated vines versus control (7)

Answer 13

Defoliated Control
- Yield/vine Lower Higher
- Cluster Lower Higher
weight
- Berries/ Lower Higher
cluster
- Cluster Lower Higher
compactness
- Botrytis Lower Higher
- Brix Higher Lower
- Anthocyanins Higher Lower

Question 14

As a general effect of early leaf removal we see an ______.

Answer 14

Increase in quality

Question 15

Two types of machines that can be used?

Answer 15

1. Leaf pluckers
2. Air blowers

Question 16

Which one is the early season leaf removal?

Answer 16

The vineyard on the right was subjected to early leaf removal because there was a resumption of growth with laterals

Question 17

When we say early leaf removal what do we mean?

Answer 17

Early means something done before flowering or before it has started.

Question 18

two alternatives to leaf removal:

Answer 18

1. Shading (very difficult)
2. Anti-transpirant spray (much more feasible)

Question 19

5 advantages of using Anti-transpirant sprays

Answer 19

1. Fast and no chance of cluster damage
2. High Flexibility
3. We have extensive knowledge about it
4. Source is limited, yet microclimate is unaltered
5. Accepted by growers