Spatial and temporal distribution of trunk-injected imidacloprid in apple tree canopies.
BACKGROUND
Pesticide use in orchards creates drift-driven pesticide losses which contaminate the environment. Trunk injection of pesticides as a target-precise delivery system could greatly reduce pesticide losses. However, pesticide efficiency after trunk injection is associated with the underinvestigated spatial and temporal distribution of the pesticide within the tree crown. This study quantified the spatial and temporal distribution of trunk-injected imidacloprid within apple crowns after trunk injection using one, two, four or eight injection ports per tree.


RESULTS
The spatial uniformity of imidacloprid distribution in apple crowns significantly increased with more injection ports. Four ports allowed uniform spatial distribution of imidacloprid in the crown. Uniform and non-uniform spatial distributions were established early and lasted throughout the experiment. The temporal distribution of imidacloprid was significantly non-uniform. Upper and lower crown positions did not significantly differ in compound concentration. Crown concentration patterns indicated that imidacloprid transport in the trunk occurred through radial diffusion and vertical uptake with a spiral pattern.


CONCLUSIONS
By showing where and when a trunk-injected compound is distributed in the apple tree canopy, this study addresses a key knowledge gap in terms of explaining the efficiency of the compound in the crown. These findings allow the improvement of target-precise pesticide delivery for more sustainable tree-based agriculture.
Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, USA.
Srđan G
SG
Aćimović
Anthony H
AH
VanWoerkom
Pablo D
PD
Reeb
Christine
C
Vandervoort
Thomas
T
Garavaglia
Bert M
BM
Cregg
John C
JC
Wise
D007093:Imidazoles / Q000378:metabolism*; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000378:metabolism; D027845:Malus / Q000378:metabolism*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism*; D010573:Pesticide Residues / Q000032:analysis; D018515:Plant Leaves; D018547:Plant Stems / Q000378:metabolism*; D013997:Time Factors
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues; C082359:imidacloprid
apple leaf canopy; diffuse porous xylem; imidacloprid; spatial and temporal distribution; trunk injection