title: The contribution of spray formulation component variables to foliar uptake of agrichemicals.
abstract: BACKGROUND
  The objective of the present study was to determine the contribution of the active ingredient (AI) and surfactant, and their concentrations, to the foliar uptake of agrichemicals, and to examine the physical properties that would need to be included in a model for foliar uptake.
  
  
  RESULTS
  All spray formulation component variables significantly affected uptake, explaining 73% of the deviance. The deviance explained by each factor ranged from 43% (AI concentration nested within AI) to 5.6% (surfactant). The only significant interaction was between AI and surfactant, explaining 15.8% of the deviance. Overall, 90% of the deviance could be explained by the variables and their first-order interactions.
  
  
  CONCLUSIONS
  Uptake increased with increasing lipophilicity of the AI at concentrations below those causing precipitation on the leaf surface. AI concentration had a far greater (negative) effect on the uptake of the lipophilic molecule epoxiconazole. The uptake of 2-deoxy-D-glucose (DOG) and 2,4-dichlorophenoxyacetic acid (2,4-D) increased with increasing hydrophile-lipophile balance (HLB) of the surfactant, the effect of HLB being far greater on the hydrophilic molecule DOG. However, the differences observed in epoxiconazole uptake owing to the surfactant were strongly positively related to the spread area of the formulation on the leaf surface. For all AIs, uptake increased in a similar manner with increasing molar surfactant concentration.
authors.affiliation: Plant Protection Chemistry NZ Ltd, Rotorua, New Zealand.
authors.forename: W Alison
authors.initials: WA
authors.lastname: Forster
authors.affiliation: Scion, Rotorua, New Zealand.
authors.forename: Mark O
authors.initials: MO
authors.lastname: Kimberley
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D027463:Chenopodium album / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D005659:Fungicides, Industrial / Q000378:metabolism; D006540:Herbicides / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D018515:Plant Leaves / Q000378:metabolism*; D013501:Surface-Active Agents; D014230:Triazoles / Q000378:metabolism*
chemical_list: D004852:Epoxy Compounds; D005659:Fungicides, Industrial; D006540:Herbicides; D013501:Surface-Active Agents; D014230:Triazoles; D015084:2,4-Dichlorophenoxyacetic Acid; D003847:Deoxyglucose; C109476:epoxiconazole
keywords: Chenopodium album; decaethylene glycol monododecyl ether; hexaethylene glycol monododecyl ether; triethylene glycol monododecyl ether; trisiloxane ethoxylate