fruitweb model Pear psylla

Attention: this model is still in beta phase

This model describes the population development of the first two generations of the Pear psylla (Cacopsylla pyri). The model is based on the calculation of temperature sums. The development threshold is 3.5°C for all stages. The model was developed in Switzerland and is now used in the SOPRA information system

The pest development is displayed on two levels

  1. The upper part shows how many individuals (all figures in %) are currently in the corresponding development stage. The green areas represent the living adults (dark green = overwintering generation, light green = 1st summer generation). The laid eggs (yellow/brown) and the larvae (light blue/dark blue) are then shown as a line.
  2. In the lower part, the developmental progress of the individual stages (from 0 to 100%) is shown. Here, only the entry into the respective stage is taken into account. It is therefore possible to see at what time, for example, 50% of the eggs were laid or when 100% of the larvae developed into adults of the 1st summer generation.

Since at the moment only temperature sums are used for the calculation, the model can only give a rough overview of the actual pest development. We see potential for improvement especially in the consideration of the specific oviposition conditions. Here we will further develop the model in the future.


L. Schaub, B. Graf & A. Butturini (2005 ) Phenological model of pear psylla Cacopsylla pyri, The Netherlands Entomological SocietyEntomologia Experimentalis et Applicata117:105 – 111