Project

Matrix population models for aphid vectors of potato virus Y

The quality of seed potatoes is measured in part by the degree of infection by viruses, such as PVY, which are transmitted from plant to plant by aphids. In the Netherlands, there is an extensive certification system for seed potatoes to ensure quality and health of the tubers. However, over the last 20 years, there has been a gradual increase in the number of years with a high percentage (>15%) of devaluated batches of seed potatoes. Multiple causes can be pointed out, including climate change, changes in the genetics of the virus and the aphids, and in the availability of (chemical) control options.

The quality of seed potatoes is measured in part by the degree of infection by viruses, such as PVY, which are transmitted from plant to plant by aphids. In the Netherlands, there is an extensive certification system for seed potatoes to ensure quality and health of the tubers. However, over the last 20 years, there has been a gradual increase in the number of years with a high percentage (>15%) of devaluated batches of seed potatoes. Multiple causes can be pointed out, including climate change, changes in the genetics of the virus and the aphids, and in the availability of (chemical) control options.

Interestingly, climate change, and in particular decreasing numbers of frost days and increasing minimum temperatures in winter, can influence the probability of survival of overwintering parthenogenetic populations of aphids. Most aphid species have a life cycle, with sexual forms in autumn which lay eggs that survive the winter on the winter host. Under mild winter conditions parthenogenetic aphids can survive as well and do so on the summer host(s). Overwintering parthenogenetic aphids tend to have a faster population build-up in spring and do not have to migrate to find the summer host. This can have significant consequences for virus transmission in seed potatoes and other crops that serve as summer hosts of the aphids.

Here, the consequences of climate change on aphid population build-up will be investigated. A literature review will be conducted to retrieve (temperature-dependent) demographic rates for one or more aphids species. Next, a matrix model will be constructed and parametrized. The models will be used to study a) the effect of survival probabilities of overwintering aphids, and b) the population dynamical consequences of a higher proportion of overwintering parthenogenetic aphids.

The study is part of a larger ongoing study in which the goal is to a) provide tools to the seed potato sector (growers, advisers, NAK) to better assess the risk of PVY infections and 2) analyze the production chain and develop strategies to better tackle the virus (vector).

Used skills

  • Exploring literature
  • Writing
  • Analysing data with survival analysis, building a dynamic state variable model

Requirements

Courses Statistics I and II, basic entomology, matrix algebra, population models

Credits

Between 24 and 39 credits