Alternative substances to manage thrips population (Thrips tabaci Lind.) on onion, in an organic agriculture system were evaluated. The experiments were carried out in Ituporanga, Santa Catarina State, Brazil. Plants of onion cv. Crioula were transplanted into two fields on 9th September/96 and 13th August/97 and harvested respectively on 10th January/97 and 11th December/97. A randomized blocks with four replicates were used in both experiments. In 1996 the treatments included the anaerobic liquid biofertilizer at 50%, aerobic liquid biofertilizer at 5%, manganese sulfate at 1%, hydroalcoholic extract of propolis at 0,2%, macerate of herbs at 2% and 4%, tobacco extract (Nicotiana tabacum) 2 L ha-1 + neutral detergent at 1%, and no spray. In 1997, the treatments were: macerate of herbs 5% and 10%; sulfur waterable powder 0,25% + propolis hydroalcoholic extract 0,2% + extract of fern (Pteridium aquilinum) 3%; anaerobic liquid biofertilizer 50%; extract of wormseed goosefoot (Chenopodium ambrosioides) 10%; aerobic liquid biofertilizer 5%; extract of Ateleia glazioviana 0,5%; extract of fern (Pteridium aquilinum) 10%; extract of chinaberry (Melia zedarach) 10%; extract of camomile (Matricaria chamomilla) 5%; and control without spray. The products were applied using a CO2 sprayer with constant pressure. The different treatments did not cause significant reduction in the thrips population nor any increase in yield in comparison to control treatment, without spray.
Allium cepa; Thrips tabaci; organic agriculture; insect; agroecology
