Susceptibility of french and african marigold germplasm to Tetranychus urticae koch (acari: Tetranychidae) in agroclimatic conditions of Haryana, India

Population dynamics of Tetranychus urticae Koch were recorded weekly on germplasm materials of marigold and effect of season on mite population was recorded. More number of mites/leaf were found during summer season as compared to winter and rainy season. French marigold (Tagetes patula) was found more susceptible to mite infestation as compared to African marigold (Tagetes erecta). Significant difference in mite population was recorded on three different leaf stages of plant i.e. tender, grown up and older leaves. A significant positive correlation of mite population was observed with maximum temperature (r=0.469), sunshine hours(r=0.490) and evaporation (r=0.567). However, negative significant correlation of morning relative humidity (r= -0.824), evening relative humidity(r= -0.798) and minimum temperature (r= -0.674) was recorded with Tetranychus urticae population.