Infestation and population dynamics of striped flea beetle Phyllotreta striolata Fabricius in cruciferous vegetables in Kashmir

Abstract

Field surveys to study the infestation and population dynamics of the most abundant striped flea beetle, Phyllotreta striolata Fabricius, on two abundantly grown cruciferous crops viz., kale (Brassica oleraceae L. var.acephala) and turnip (Brassica rapa L.) revealed that these suffered with moderate and severe infestation, respectively. The maximum infestation was at cotyledonary stage as compared to true leaf stage. The pooled data of two year study revealed the maximum mean % infestation, severity, and number of flea beetle catches/sweep on turnip as compared with kale. Southern zone revealed the highest mean % infestation, severity and number of beetle catches/sweep followed by the Central and Northern zones. The extent of damage, severity and population build-up was more during 2012 compared to 2013. Emergence of the overwintering generation started from the second fortnight of March up to the end of May in kale while the subsequent generations started emerging at the beginning of June and the maximum trap catches were obtained during the second fortnight of July i.e. from 27th to 29th standard weeks and the minimum catches by the end of October. In turnip, the pest started its activity in the first week of August i.e. from 32nd standard week, immediately after sowing and remained active until end of October. Maximum catches of flea beetles were observed in the second fortnight of September i.e. in the 38th standard week and thereafter it decreased to its lowest during the end of October. The study further revealed that the temperature influenced the activity of the flea beetles significantly.