Effect of organic amendments on Thrips tabaci infestation in onion crop

Effect of organic amendments; organic compost + neem cake; cocopeat + neem cake; Pongamia cake + neem cake, vermicompost + neem cake; mustard cake + neem cake; linseed cake + neem cake; groundnut + neem cake and farm yard manure (FYM) + neem cake and with negative (without any fertilizer) and positive (synthetic fertilizer) substitution with soil was studied in contrast to evaluating their effectiveness in developing tolerance in onion plants against Thrips tabaci. The first dose of all organic amendments was applied in rows at the time of transplanting @ 1 kg/m² and later on sprinkled @ 1 kg/m² after 35 and 45 days of transplanting just after 2 days of irrigation with light turning of soils using spud. Based on the results of the organic amendment, Pongamia + neem cake (1:1) proved better in suppressing thrips incidence and gave a higher yield than the other treatments followed by ON and VN compared to SF and UN. Farmyard manure + neem cake also provided better yield compared to the control but didn't reveal a significant role in the reduction of T. tabaci. Significant differences were obtained in bulb yield among the treatments in both years. Bulb yield was 11.77 t/ha in VN compared to 10.44 in LN in 2016–17, while 12.33 t/ha in VN and 11.55 in CN in 2017–18.