Population dynamics of Stethorus Pauperculus Weise (Coleoptera: Coccinellidae) Godhani H.S., Shukla Abhishek* AINP on Agricultural Acarology, Department of Agricultural Entomology, N.M. College of Agriculture, Navsari Agricultural University, Navsari-396450 *Email: abhishekshukla@nau.in
Part of Master's thesis submitted to the Navsari Agricultural University, Navsari Online published on 3 December, 2015. Abstract The population dynamics of Stethorus pauperculus Weise was studied on sorghum and baru grass under field conditions from 36th standard meteorological week (SMW) of 2012 to 35th standard meteorological week of 2013. These revealed that this mite predator has two population peaks i.e. first during 40th SMW (5th to 10th October 2012) with 4.20 predators per plant and the second during 17th SMW with 2.73 predators per plant (26th April to 2nd March 2013) on sorghum. It was also observed that during these peaks the population of prey (Oligonychus indicus Hirst) was also highest. The correlation studies with abiotic factors suggested that there were a significant positive correlation existed between predator S. pauperculus with the prey mite (O. indicus) (r = 0.964). With the predator maximum, minimum and average temperature had positive correlations whereas morning, evening and average relative humidity had a negative correlations which are statistically significant. The rainfall had negative significant correlation (r =-0.283) with the predator in sorghum. The observations on the Baru grass, a very common weed in sorghum as well as found on bunds is an alternative host of O. indicus indicated that the predator remained active throughout the year and it showed two peaks. The first peak was recorded during 43rd SMW (last week of October 2012) (3.33 predators/plant), while the second peak was observed during 17th SMW (last week of April 2013) (4.67 predators/plant). The prey mite, O. indicus was also higher during the period. The correlations between predator and its prey worked out revealed that a positive correlation (r = 0.974). There was a positive significant correlation between predator and maximum, minimum and average temperature (r = 0.615, 0.498 and 0.703) whereas a non-significant positive correlation existed between morning, evening and average relative humidity. A negative correlation existed between predator population and rainfall (r =-0.156). Top Keywords Stethorus pauperculus, Oligonychus indicus, sorghum, Baru, abiotic factors. Top |