Development of a crop management method to control the spread of Potato Virus Y (PVY)
(2017)
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- Abstract
- Potato virus Y (PVY) is a pathogenic plant virus transmitted in a non-persistent manner by aphids, and PVY is currently the most important virus challenge faced by seed potato (Solanum tuberosum L.) production systems worldwide. Several PVY control strategies are available, the most popular of which are the spraying of insecticides and use of mineral oils. However, insecticides have little impact on PVY spread, while the efficacy of mineral oil is highly variable from one year to the next. Therefore, there is a need to find more efficient control methods. The objective of this thesis is to provide a better understanding of the epidemiology of PVY and propose more adapted control strategies to seed potato growers. The main findings are as follows: First, two surveys of PVY isolates genetic diversity in Switzerland revealed an increase in the prevalence of PVYN-Wi strain, while the prevalence of PVYNTN strain has decreased over the same period. Two hypotheses behind this change in population dynamics are discussed: (i) important differences in the resistance of cultivars to these two PVY strains and (ii) a faster translocation of PVYN-Wi in comparison to PVYNTN. Second, this thesis sheds new light on mature plant resistance to PVY. An important part of this resistance mechanism is associated with the physiology of the potato plant, as the mother tuber degenerates and physically prevents the virus from translocating from one stem to another. This result further emphasises the need to protect younger plants when the vascular bridge through the mother tuber is still functional. Third, the thesis suggests intercropping with oat (Avena sativa L.) and hairy vetch (Vicia villosa Roth) as new efficient PVY control methods. The non-host plants act as virus traps/aphid’s stylets cleansing; whereby aphids progressively lose their PVY inoculum as they repeatedly probe the plant(s). However, the neighbouring plants compete for nutrients with the potato plant, leading to significant yield losses. Further research is necessary before these control methods can be widely implemented by seed potato growers. Finally, this thesis confirmed that mineral oil is the most efficient means of controlling PVY spread in the field compared to insecticides and plant elicitors. However, because the efficacy of mineral oil treatment on interfering with virus transmission is less significant in the early stages of plant development, this approach needs to be complemented by other control methods such as straw mulching. The results suggest that the synergies between these two methods are significant, paving the way for other combinations of treatments with complementary modes of action. Taken together, these findings contribute to a better efficacy of PVY control methods and a reduction of their negative impacts on the environment. This in turn helps achieve a more sustainable seed potato production.
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Citations
Dupuis, B. (2017). Development of a crop management method to control the spread of Potato Virus Y (PVY). https://hdl.handle.net/2078.5/176105