The objective of this work was to evaluate the efficiency of different nozzle types and volume of the insecticide solution in controlling thrips (Thrips tabaci) in onions. The work was carried out from August to December, 1996 and 1997. The treatments consisted of different nozzle types (fan and cone) and different flow rates. Fan nozzles were XR 110 015 VS® - 236 L/ha, XR 110 02 VS® - 316 L/ha, XR 110 03 VS® - 472 L/ha, XR 110 04 VS® - 632 L/ha, XR 110 05 VS® - 788 L/ha, TJ 60 110 02 VS® - 316 L/ha, TJ 60 110 04 VS - 632 L/ha; and cone nozzles were Conejet TSVS® - 236 L/ha, Conejet TXVK 18® - 472 L/ha, Conejet TXVK 26® - 632 L/ha, D6 Difusor V5® - 600 L/ha. Besides these treatments there was an untreated check. The experimental design was of randomized complete blocks with four replications. The insecticide used was chlorpyrifos 0.72 g.a.i./ha. The evaluation of the number of nimphs of T. tabaci was made weekly in the field using five plants per plot. The fan or cone nozzle applying 236 L/ha to 788 L/ha of the insecticide solution (chlorpyrifos) gave similar thrips control.
Allium cepa; thrips; chemical control; nozzles; volumes
