Managing infected material
Infected material poses ongoing risk of further spread as bacterial populations can rise quickly if left unmanaged. This can result in disease spread within and between orchards.
Experience has shown rapid, aggressive cutting is the best way to avoid the spread of Psa to other parts of the orchard.
Symptoms like shoot dieback, cane dieback, cankers and red/orange and white exudate, indicate Psa has moved into the vine's vascular system. If left untreated, these secondary symptoms will continue to progress and in highly-susceptible vines may lead to plant death. Additionally, leaving infected vines untreated increases the risk of infection spread to the rest of the orchard.
For orchards with Psa strains identified as resistant and/or tolerant to Psa protectant sprays, infection removal is particularly important to reduce the risk of spread of these new strains to other orchards.
Where symptoms are severe or repeated infection is occurring, consideration should be given to removing individual vines and/or susceptible varieties.
KVH encourages growers to remove and dispose of infected plant material as quickly as possible.
All kiwifruit plant material needs to be disposed of on-site and must not be transported from the property unless KVH has given approval. Contact KVH by email or phone 0800 665 825.
How to destroy kiwifruit stumps in an orchard
Removing the entire stump, for example with a bobcat, is the most effective way of preventing future regrowth. All woody roots must be removed. Stumps should be mulched or stacked in a suitable location (e.g. into a pit) and burnt. If burning, ensure all rural fire and district council requirements are met. Never dump stumps into a gully or forest area as they may regrow, resulting in further wild kiwifruit infestations.
Alternatively, glyphosate herbicide can be applied to the top and sides of a cut stump. A suitable herbicide mixture for use in an orchard is glyphosate mixed 1 to 1 with Kiwi Cover surfactant. This mixture should be applied to the top and sides of the freshly cut stump. A suitable applicator is a knapsack or 10 litre sprayer. The mixture must be applied under low pressure with no drift beyond the stump. Repeat applications may be necessary.