The concept of population of carrot flies is described for french carrot-growing regions, in order to advise growers and agronomists on pest control methods.
The concepts of forecasting of population levels as applied to P. rosae is explained in terms of biotic and abiotic factors.
After rewieving previous methodology, the authors describe recent advances achieved in forecasting, such as the dates authors at which the insect will be present and the size of the population.
The study of biotic factors involves collection of pupae from the preceding generation and observation of their emergence, to define the time preceeding insects become active in the crop, as well active the proportion of the population for any given sowing date.
By subjecting the pupae thermal shock, such information can obtained faster.
The use of statistical tools, combined with automatic measurement of climatic data enables calculation of the amount of temperature necessary for the development of each generation.
This can then be compared with the population estimate made using a trap.
The P. rosae trap was the focus of extensive work in an effort to make it effective, easy to use and not to expensive.
Sowing and harvesting dates as well as aspects of insect biology are taken into account as the basis for creating decision models for crop protection.
Significant process is expected to result from the study of topographical paramiters (landscape, hedges, etc.) and their effect on population distribution.
This will lead to identification of endangered zones and enhance the reliability of decision models.