Study of population dynamics and impact of abiotic factors on thrips, Scirtothrips dorsalis of chilli, Capsicum annuum and comparative bio-efficacy of few novel pesticides against it

Field experiment to study the population dynamics and bio-efficacy of some newer pesticides at various test concentrations against chilli thrips, Scirtothrips dorsalis Hood, on chilli crop was tested in field conditions. The highest incidence of thrips was observed during first week of October. The population of thrips showed significant positive correlation with maximum temperature and negatively correlated with rainfall, relative humidity. The bio-efficacy results revealed that the mean per cent reduction in thrips population over the untreated-control in Pyridaben 20% WP 125g a.i/ha was significantly superior over other treatments; with highest per cent reduction of 74.47%; closely followed by Fenpyroximate 5% EC 20g a.i/ha (70.58%). Pyridaben 20% WP 100g a.i/ha and Propargite 57% EC both were less effective than previous two treatments and were at par with a reduction of 68.08% and 65.45% respectively. However, the lower doses of Pyridaben 20% WP 50g a.i/ha and 75g a.i/ha gave the lowest performance with a mean percent reduction of 56.66% and 59.85% respectively against control. Such studies are helpful in developing prediction models against thrips for its efficient management with combining both conventional and newer pesticides.

The pesticides used have rarely been tested for control of Scirtothrips dorsalis Hood.

The result obtained was highly significant in the pest management and also enhance the yield.