Abundance of major pests of rose and gerbera in relation to temperature and relative humidity under protected condition

Abstract

Abundance of major pests of rose and gerbera was studied in relation to temperature and relative humidity under protected conditions at Navsari Agricultural University, Gujarat. Thrips Frankliniella schultzei population varied from 0.44 to 42.70 per plant (10.63 ± 11.68) indicating highest (42.70/plant) and lowest (0.44 thrips/plant) populations during 42 and 18 SMWs, respectively whereas no thrips were noticed during 4-8 and 19-26 SMWs. Correlation between thrips population and weather factors was non-significant indicating negative relationship with temperature (maximum, minimum and average)(‘r’ = - 0.2519, -0.1541, -0.2189) and relative humidity (r’ = -0.0633). On the other hand, no population of bud borer, Helicoverpa armigera larvae was observed on rose during the course of investigation. Mite population on rose varied from 1.89 to 11.89 per plant on 2 cm2 leaf area (6.32 + 2.58) indicating its peak (11.89) at 31 SMW and lowest population (1.89) at 51 SMW. Correlation of mite population with weather factors was positive with relative humidity (r’ = 0.3886) and negative with temperature (maximum, minimum and average temperature) (r’ = -0.2409, -0.1795, -0.2255). Likewise, thrips, F.schulizei population on gerbera varied from 0.04 to 46.54 per plant (11.79 + 13.26) indicating highest density (46.54) during 42 SMW and lowest (0.04) during 18 SMW. Correlation between thrips and weather factors indicated negative relationship with temperature (maximum, minimum and average)(‘r’= -0.1735, -0.1301 and -0.1618) and relative humidity (r’= -0.4423). Lastly, mite population on gerbera peaked at 31 SMW (12.83 /plant on 2 cm2 leaf area) while, it remained lowest (2.70) at 51 SMW indicating positive correlation (r’ = 0.4448) with relative humidity and negative correlation with temperature (maximum, minimum and average) (’r’= -0.2091, -0.1945 and -0.2146).