Elina Massó Villalón’s scientific contributions

Among the species of molluscs that most affect the Swiss chard culture is the snail Rumina decollata L., this species lacks ecological studies that facilitate its control. This study was carried out with the objective of evaluating the influence of temperature and relative humidity on the population density of R.decollata in the UBPC Organopónico Vivero Alamar. The population density was evaluated by the method of Andrews (1987) modified. The data were processed with the SPSS statistical package to determine the theoretical sampling distribution to which they had the best fit. A multiple regression analysis was developed with the use of the adjusted GAM (Generalized Additive Models) model, the regression trees were subjected to a cross validation and both were executed in the program R. The best fit was obtained with the quadratic regression. The regression tree showed that relative humidity is the factor with the greatest influence on the population density of R. decollata. Relative humidity above 73.52 % is optimal for increasing the population density of R. decollata in this production entity. The effect of temperature (between 23 and 35 °C) is positive and for each degree above 23 °C the population density of R. decollata increased in 13 individuals. The temperature favored the increase of the population density until 29oC, from this value it began to decrease. The interactions between the climatological variables show that the relative humidity values higher than 86.5 % C of temperature caused the highest population densities (17 snails/m and 25.35 oC). The worst conditions for the population densities of R. decollata were observed at temperatures above 34 °C with low levels of relative humidity (≤ 66 %).