Soil fertility management and its impact on mustard aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae)

Maize-mustard cropping sequence is the most adopted cropping pattern in the rainfed belt of Jammu region, Jammu & Kashmir, India. Mustard is attacked by aphids, flea beetles, saw flies and painted bugs, among which aphids are of great economic importance. An experiment was conducted to assess the impact of various organic and inorganic fertilizers / pesticides on mustard aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae). During 2009-2010 and 2010-2011, mustard was sown applying Farm Yard Manure, Neem cake, Adhatoda vasica twigs, Di Ammonium Phosphate and Muriate of Potash (MOP) at different rates and their impact on mustard aphid incidence was studied. The lowest aphid population was noticed in MOP at 80 kg/ha. This was followed by MOP at 40 kg/ha or Neem cake at 5 quintals/ha. The aphid incidence was highest in plots treated with higher dose of DAP at 120 kg/ha (117.97 aphids per ten cm twig), showing the adverse impact of application of higher dose of nitrogenous fertilizer. Application of neem cake also acted as fertilizer and recorded highest yield of 7.34 q/ha along with MOP at 80 kg/ha (7.34 q/ha). The impact of application of various organic and inorganic fertilizers on available soil nutrients, was also recorded after the completion of two year experiment during 2010-2011 (post harvest soil samples).