Comparison of Single- and Double-chisel Injection Methods for the Control of Rotylenchulus reniformis in Pineapple

The efficacy of 1,3-dichloropropene (1,3-D) applied with one or two chisels was determined for control of Rotylenchulus reniformis on pineapple. The soil was fumigated with 1,3-D at 157 liters/ha with either a single chisel 46 cm deep or two chisels 41 cm deep in replicated experiments conducted in four commercial fields. Soil samples were collected before fumigation and 45 days afterward from three depths and three positions. The three depths were 0-15, 16-30, and 31-45 cm; and the three positions were the center of the bed, plant line, and interbed area. The single-chisel injection was comparable to the two chisels in percentage control of R. reniformis. Satisfactory control was achieved in three fields (percentage reduction from untreated = 79, 81, and 83) but not in the fourth field. The highest level of control was at the lowest soil depth (31-45 cm) nearest the points of injection. Among the sampling positions, control in the interbed area was generally the lowest. A single-chisel injection may be recommended because of the slightly enhanced control.