|Abstract in English:|
The emission of suckers is a characteristic of hazelnut (Corylus avellana L.). Their presence at the vegetative restarting can cause several problems both to plants and to crop management. Cultivated trees are trained either to a single trunk or to a multi-branched structure. Both trainings require many applications to eliminate basal shoots every year, with associated recurrent costs. With the single trunk, mechanization for sucker removal is much easier. Desuckering can be done on herbaceous or lignified suckers. Different methods can be used ranging from mechanical to physical and chemical ones. A thermal control management is a recently investigated procedure.
With the aim of ascertaining the effectiveness of thermal control techniques, desuckering tests with steam and flame were performed in a hazelnut orchard, with cv “Tonda Gentile Romana” and 5x5m plant spacing. With both techniques, a short blast of intense heat was carefully directed at the basal shoots keeping a short distance from the target. Both treatments cause scalding of plant tissues and in a few days exposed vegetation will wilt and die.
A small steam generator-applicator machine was used. Steam flows at approximately 300°C out of the boiler and can be directed through a handheld outlet pipe. Flaming was carried out with a tractor-drawn model, equipped with a handheld single-torch flamer and two LPG tanks placed in a housing with warm water. The two methods were compared for fuel consumption, resulting in 215 g/min of diesel fuel and 77 g/min of LPG. Two different parameters for heat contact-time were used: a 60 sec and a 30 sec half time exposure. The growth stage is a key factor in determining control effectiveness. As the results suggest, it is preferable that small suckers be treated, as they then die completely. No damage to plants was observed. Flaming is easy to use, requires low cost equipment and low fuel consumption. Steam applications need slow speed, large amount of water and fuel, and expensive equipment, but collective ownership of devices may be an option.