MECHANICAL HARVEST OF BLACK CURRANTS AND THEIR SENSITIVITY TO DAMAGE

During three consecutive years 2 trials on mechanical black current harvest were performed.
One, placed at Dabrowice included 4 cultivars: Ben Nevis, Ben Lomond, Ojebyn and Titania.
The second one, performed at Dabrowice included cvs: Ojebyn, Roodknop and Titania.
Harvesters were driven with different speed.
Fruit were shaken with different vibration frequency assuring 90 % accuracy of berry picking.

At Lyszkowice fruiting and terminal shoots were evaluated separately.

At Dabrowice Titania’s shoots were the most severely injured: little less Ben Nevis bushes.
The smallest damages were observed on Ojebyn and Ben Lomond cvs.
This regularity was repeated in all three years of the experiment.

At Lyszkowice Titania. cv showed the highest % of damaged current growth shoots.
But, when fruiting shoots are taken into consideration it was Roodknop which was the most injured.

It is expected that mechanical harvest of currant is efficace, brings high accuracy and does not harm bushes.
The quantity of these disadvantages is due to three basical parameters of harvester: driving speed, amplitude and vibration frequency of shaking fingers.
Character of currant species and variety, together with maintaining system play also an important role.
The degree of damages is assessed with bulk of shaken leaves and number of damaged shoots.

In 1990–1992 in the Experiment Station at Dabrowice the degree of shoot damage in the course of mechanical fruit harvest was estimated.
Fruits of Ben Nevis, Ben Lomond, Ojebyn and Titania cvs were picked with currant harvester KPS-4b coupled with two pairs of shakers.
At the same time at Lyszkowice fruits from Ojebyn, Roodknop and Titania black currants were harvested with KPS-4a furnished with a pair of shakers.

Number of damaged shoots was rated on a scale I to II, where:

1. – shoots with bark rubbings up to 2 cm long

2. – shoots with bark rubbings above 2 cm long

3. – broken shoots

Characteristics of tested cultivars and % shoots damaged in I and II degrees are shown in tables.

There was no III degree damage.
At Lyszkowice fruiting shoots and current growth were counted separately as well as damage rates.

In 1990 at Dabrowice harvester was driven at the speed 1.2 km/h with shaking fingers vibration frequency 18.3 Hz.
The data are presented in Table 1. In 1991 driving

VI International Symposium on Rubus and Ribes

Z. Salamon

https://doi.org/10.17660/ActaHortic.1993.352.14