Heat treatments for killing Pseudomonas syringae pv. actinidiae on contaminated kiwifruit pollen
The bacterial pathogen, Pseudomonas syringae pv. actinidiae strain V (Psa-V), has caused a devastating epidemic of the gold cultivar of kiwifruit, Actinidia chinensis 'Hort 16A', in New Zealand. Psa-V is causing a global pandemic of kiwifruit and is also present in Italy, Greece, Portugal, France, Japan and Chile. Kiwifruit have male and female flowers on sexually differentiated vines. Application of pollen by artificial means has been shown to improve pollination compared with pollination by bees. The result is higher yields and larger fruit. Pollen from the Bay of Plenty in New Zealand is often contaminated with Psa-V. In order to reduce the introduction of new inoculum by pollen to orchards that are not yet infected, a programme was initiated to identify protocols that kill Psa-V but retain pollen viability. A combination of heat and desiccation in anoxic conditions was shown to reduce the population of Psa-V on artificially contaminated pollen by 7.9 log-fold, whilst retaining pollen viability. Results so far show that the kiwifruit pollen was naturally contaminated with 104-105 CFU g-1, and therefore the treatment should kill all Psa-V on this pollen.
Everett, K.R., Vergara, M.J. and Pushparajah, I.P.S. (2016). Heat treatments for killing Pseudomonas syringae pv. actinidiae on contaminated kiwifruit pollen. Acta Hortic. 1144, 385-390
Actinidia deliciosa, A. eriantha, thermal reduction, biosecurity, kiwifruit canker, incursion, cultural control