Carot, J.M., García-Marí, F., Labuschagne, T.I., Peña, J.E., Román, A., & Ibáñez, V. 2003 Methods of estimating degree-days of scales in citrus.. Bulletin OILB/SROP (Sect. Reg. Ouest Palearctique) 26(6): 103-106.

Notes: [Conference proceedings: 'Integrated control in citrus fruit crops'. Proceedings of the IOBC/WPRS Working Group, held in Valencia, Spain, 6-8 November, 2002 Published by International Organization for Biological and Integrated Control of Noxious Animals and Plants (OIBC/OILB), West Palaearctic Regional Section (WPRS/SROP), Dijon, France, Garcia-Marí, F. (Ed.)] One of the most important factors to achieve a good control of citrus armoured scales is the timing of pesticide application, which is related to the percentage of immature stages in the population. The average daily temperature and sampling data from seven citrus orchards in València, Spain were analysed to develop a predictive equation, with accumulated degree-days, for the first maximum of immatures of the citrus red scale Aonidiella aurantii. The descriptive analysis showed a sigmoidal trend in the graphic result. By correlating accumulated degree-days with accumulated percentage of immatures (expressed as probability units or "probits"), a linear model was obtained, with the possibility of comparing significant differences between orchards.