A Researcher’s Diary: winter monitoring on the woodland strawberry project

Through a series of articles we will talk about the monitoring process on the woodland strawberry project and its resilience against natural enemies such as aphids, psyllids, caterpillars, leafhoppers and white flies, as well as drought, written in a diary format. Are you interested in learning about the ability of strawberries to defend themselves and their biological efficiency? Pay attention, then! We are about to start with the researcher’s diary.

As introduced in the blog post of 18 November 2019, ‘Sierra de Guadarrama’ Research Center is collaborating with Ghent University, Swedish University of Agricultural Sciences, University of Turku, and King Juan Carlos University in a project investigating how natural enemy communities and drought affect defense and performance of woodland strawberry along a European latitudinal gradient. This gradient consists of 5 common gardens, of which the southernmost is located at the Research Center.

I first visited the Research Center at the end of September, together with Johan Stenberg and Anne Muola. Johan had brought runners from the 16 woodland strawberry genotypes that we had planted in the four other common gardens. The main goal of this first visit was to cut the little plants from their runners and plant them in pots with substrate and ample moisture in order to let them develop roots and establish correctly. With the great help of the National Park staff, we also put up a vole-proof fence around the common garden area and started construction of the rainout shelters. It was quite hot for the time of year and our main worry was the survival of the little plantlets, so we planted several per pot to be on the safe side and installed a sprinkler system..

The woodland strawberry common garden at the Research Center. Author: Martijn L. Vandegehuchte

On my second visit in early November, alone this time, I was to finish the construction of the shelters, thin the pots to one plant per pot and place them in their correct position in the common garden. I arrived and was relieved to find that most plants had survived and grown, so after thinning we had a full set as planned. I also performed the first assessment of plant size, runner production, leaf damage from herbivores, insect herbivores present on the plant, and disease incidence. This first “time zero” measurement is necessary to provide a baseline to compare with after the plants have been exposed to the drought treatment. Apart from some heavy rain- and hailstorms, which made working outside quite a challenge, all went according to plan. I also found the time to explore a bit of the wonderful national park and surroundings, even though mostly in the rain.

During the first week of December, I visited for the third time. It had snowed, and the landscape was beautiful. The weather was mostly sunny this time, but rather cold. The purpose was to perform the “time one” measurements of the same variables as the previous time, but now after the plants had been in the common garden for several weeks. The first morning I wanted to start inspecting and measuring the leaves, this turned out to be impossible as it was about -5ºC and the leaves were frozen stuck. Only after the sun had thawed them out, I could start. Given the temperatures, I was not expecting many live insects on the plants anymore, but to my surprise I found several aphid colonies, even with newborn nymphs, a few caterpillars and a leafhopper. These insects are clearly tougher than one could imagine. This time, I finished my stay with an ascent of the Peñalara, covered in snow, returning over Risco de los Pájaros and Risco de Claveles, and along the Laguna los Pájaros, through a truly magnificent winter landscape.

We will be back in the spring to assess winter survival of the plants and then in the summer to keep measuring herbivory, disease, and performance, but also to quantify flowering and fruit set.