Low Volume Applications to Citrus Trees: Method for Evaluation of Spray Droplet Distributions2

Deposition, distribution, persistence and fate of bacillus thuringiensis variety kurstaki (BTK) in pecan orchards following aerial and ground appucations to control pecan nut casebearer larvae

“…The D max values found on the horizontal disc samplers in Plot 1 were generally high at all three canopy levels (76 to 102 urn) due to gravitational sedimentation of droplets, compared to the values found on the vertical cylindrical samplers (51 to 58 urn) ( (Roltsch et al, 1994;MacNichol, 1995) and other conventional insecticides (Carman and Jeppson, 1974;Yates et al, 1974;Spillman and Joyce, 1978;Armstrong and Yule, 1978;1989a;Barry, 1984;Sundaram, 1987). The gradation observed was due to the canopy levels (NMD, 10.7 ± 1.8 to 12.6 ± 2.7 urn; VMD, 32.8 ± 3.0 to 35.3 ± 3.0 urn) were similar to the corresponding values obtained for the discs (NMD, 10.6 ± 1.9 to 11.7 ± 2.4 urn; VMD, 31.9 ± 2.7 to 43.1 ± 3.2 urn) [ANOVA P > 0.05 (Ryan et al, 1985)].…”

Pesticide Spraying in Indian River Grapefruit: III. Opportunities for Improving Efficacy and Efficiency while Reducing Off-target Deposition

“…Interactions of application variables and weather conditions. In most published spray experiments, conditions are selected to minimize effects of complicating variables such as wind (e.g., Carman and Jeppson, 1974). Use of lower spray volumes, with concomitant smaller droplets, is likely to be more adversely affected by diffi cult spray conditions than would a higher volume spray (Dibble, 1983;Fleming, 1962;Hall, 1991).…”

“…In contrast, when trees are wet with dew or rain, spraying at 250-500 gal/acre is likely to greatly increase runoff in contrast to applications at 125 gal/acre or less (Hoffman and Salyani 1996). Where appropriate, standard air-blast orchard sprayers can be successfully adapted to provide a quality spray application at 125 gal/acre or even lower (Carman and Jeppson, 1974). These same sprayers can be quickly adjusted to make applications at higher spray volumes when necessary.…”

“…of non-orchard buffer areas and/or windbreaks appear to offer considerable opportunity for reducing off-site spray movement. I ndian River (IR) citrus growers are confronted with numerous pests and an environment conducive to disease development, in addition, citrus trees are also some of the most diffi cult of all tree crops to spray effectively (Carman and Jeppson, 1974;Juste et al, 1990). Environmental infl uences, such as wind and humidity, combine with large canopy size and limitations of sprayer capabilities to make spray coverage much less than ideal.…”

Condições operacionais de turboatomizadores na distribuição e deposição da pulverização em citros

“…A eficácia no controle de pragas e doenças está intimamente relacionada com a uniformidade de distribuição do produto qmm1co sobre a superfície (SHARP, 1973), tamanho de gotas e grau de cobertura da pulverização (SAL Y ANI & McCOY, 1989), volume de aplicação (McCOY & SAL Y ANI, 1989) e estrutura da planta (CARMAN, 1975). Por essas razões, a planta cítrica constitui-se num dos alvos mais difíceis de serem cobertos pela pulverização devido à densa distribuição de folhas na parte externa da copa, o que dificulta a penetração das gotas para o seu interior (CARMAN & JEPPSON, 1974).…”