Abstract:

Factors, such as diameter size of injection holes on trees, diameter size of injector blowholes, trees species, trunk basal diameter and season changes, which might affect the absorption to 4% Imidacloprid liquid formulation (ILF) by trees, were analyzed with auto flowing trunk injection. The results showed that the most important factors were diameter size of injection holes on trees and trees species, followed by trunk basal diameter and season, however, the diameter size of injector blowholes had no significant effect on absorbing efficiency. The amount of absorbed ILF reached to 6～8 mL in 10 h after injection with 5 mm diameter of injection holes on trees, which was much greater than that with 2 mm and 3 mm diameters. There were no significant differences in ILF absorbing efficiency between 0.5 mm and 1.0 mm diameters of injector blowholes. The absorbability for nine tree species were in turn as: Populus tomentosa > Pyrus bretschneideri > Prunus salicina > Platycladus orientalis > Metasequoia glyptostroboides > Platanus acerifolia, Sophora japonica and Salix babylonica > Albizia julibrissin. The trunk basal diameters had different effects on absorbability according to different tree species. For Sophora japonica the bigger trunk basal diameter had the higher absorbability whereas for Platycladus orientalis the smaller trunk basal diameter had the higher absorbability. There was no obvious difference in the absorbability over different trunk basal diameters for Populus tomentosa. As to the season factor, the absorbability in May was higher than that in September.

Key words: trunk injection, injection holes, blowhole, tree species, absorbability of pesti cide