A field study investigating the insecticidal efficacy against Diaphorina citri Kuwayama on Kinnow mandarin, Citrus reticulata Blanco trees

Quantification of insecticide spatial distribution within individual citrus trees and efficacy through Asian citrus psyllid reductions under different application methods

“…9,36 This may help control ACP populations and limit reproduction over time, but still allows for ACP to transfer CLas and infect the tree with HLB in the short term because these modes of action are not immediately lethal to the ACP. 30 Additionally, comparing imidacloprid concentrations on both sides of leaf between ground (side-and speed-sprayer) application methods revealed that bottom sides of leaves were not statistically different (diff conc = 0.01 μg cm −2 , diff = 0.39, P = 0.162), while top sides of leaves were statistically different (diff conc = 0.14 μg cm −2 , diff = 1, P < 0.001). Results also showed a greater difference between top and bottom leaf samples for the side-sprayer than the speed-sprayer ground application methods.…”

“…9 These results also agree with recent findings for imidacloprid (44%) applied to Kinnow mandarin plants via a knapsack sprayer. 30 However, several studies recommend repeated insecticide applications within a week in order to reach effective percent reductions (73% imidacloprid). 30,40,41 Although these findings reaffirm the percent reductions obtained during our field studies and align with previous studies showing initial ACP response to the a.i., they do not all fall within the effective percent reductions limit (73%) or offer realistic pest management improvements for a large commercial grove located in regions with specific US Environment Protection Agency (EPA) regulations.…”

“…30 However, several studies recommend repeated insecticide applications within a week in order to reach effective percent reductions (73% imidacloprid). 30,40,41 Although these findings reaffirm the percent reductions obtained during our field studies and align with previous studies showing initial ACP response to the a.i., they do not all fall within the effective percent reductions limit (73%) or offer realistic pest management improvements for a large commercial grove located in regions with specific US Environment Protection Agency (EPA) regulations. 42,43 High-management commercial citrus groves cannot use fitted knapsack sprayers, which may offer a more targeted application to individual trees in smaller farms or research facilities.…”

“…42,43 High-management commercial citrus groves cannot use fitted knapsack sprayers, which may offer a more targeted application to individual trees in smaller farms or research facilities. 30 In addition, recommended rotations of insecticide types to prevent ACP insecticide resistance development and meet EPA regulations inhibit high-management groves from repeated applications of the same insecticide within a week of the previous application. [44][45][46] Therefore, suggestions to increase application frequency or concentration do not offer realistic options for some of the large citrus producers.…”

“…Previous studies investigating ACP response to insecticides in the laboratory and field conclude that insecticides are effective at killing psyllids. 11,[29][30][31][32][33][34] The few studies assessing both insecticide application efficacy with ACP inspections either lacked the variety of application methods commonly used in high management groves or an effective ACP inspection method. 11,[29][30][31] To date, no studies have thoroughly examined insecticide efficacy by quantifying insecticide concentrations and spatial distribution, extensively sampling entire citrus trees while simultaneously quantifying ACP population response, from multiple insecticide spray methods in a high-management commercial field.…”