PEST-CONTROL ON DWARF APPLES WITH A TUNNEL SPRAYER

A tunnel sprayer equipped with either two opposing pairs of Curtec(R) cross-flow fans, or two sets of three opposing Proptec(R) fans, was ev aluated for pest and disease control on three dwarf apple cultivars, a nd compared to a conventional airblast sprayer, in a full-season (12 a pplication) spray programme. Spray systems were evaluated in 20 compar isons of pest and disease control for each of two experiments. Curtec( R) and Proptec(R) fans provided control that was equal or superior to the airblast sprayer in 85% of insect and disease comparisons. There w ere no differences in performance between the Curtec(R) and Proptec(R) fans in 65% of comparisons; the Curtec(R) was superior in 15% of comp arisons, while the Proptec(R) was superior in 20% of comparisons. Curt ec(R) spray volume (187 or 700 l/ha) did not effect performance in 60% of comparisons; however, the 700 l/ha volume provided superior contro l in six out of eight comparisons where performance differed. Pest and disease control with the tunnel sprayer (Curtec(R) fans) travelling a t 8 km/h was equal to or better than that at 4.8 km/h in 80% of compar isons. (C) 1997 Elsevier Science Ltd.