1 3

Übersichtsartikel

Abstract  Dose expressions are highly variable within  the european  Union.  recommended  doses  in  high  growing crops  are  expressed  in  various  ways  on  product  labels. therefore  it  is  necessary  to  harmonize  the  dose  expres-sion in high crops. in future one model should be favored, preferably  the  leaf wall  area  (lWa)  approach. the  doses in the lWa model are expressed in kg or l per 10.000 m² leaf wall  area. this  is  the  basis  for  canopy-adjusted  dose determination in all high crops.

the  leaf wall  area  (lWa)  is  a  function  of  the  canopy height and the row spacing. the canopy height will be de-fined  as  the  average  distance  from  the  highest  leaf  to  the deepest leaf of a tree.

in  this  publication  first  results  of  the  determination  of lWa in different German fruit farms with commercial ap-ple plantations are presented and discussed.

the  lWa  as  well  as  the  incremental  growth  depends on  the  rootstocks  and  the  varieties. the measured figures vary  from  approx.  8000  m²  for  new  planting  to  approx. 19000 m² for older orchards.

Keywords  leaf wall area · Dose rate expression · Dose rate determination · spray volume · Fruit crops

Dosiereinheiten – Notwendigkeit zur Harmonisierung und der Konsequenzen des Laubwandflächenmodells 

Zusammenfassung  Die Dosiereinheiten sind in der euro-päischen  Union  sehr  unterschiedlich.  Die  empfohlenen 

aufwandmengen  in raumkulturen sind  in verschiedenster Weise in den Produktinformationen ausgedrückt. eine har-monisierung der Dosiereinheiten in raumkulturen ist drin-gend erforderlich. Zukünftig wäre eine einheitliche Dosier-angabe  wünschenswert,  vorzugsweise  die  laubwandflä-chen berechnung (lWa). Die Dosis wird  im lWa Model als  kg  je  10.000  m²  laubwandfläche  angegeben.  Dieses stellt die Grundlage für die Dosierung in allen raumkultu-ren dar. Die laubwandfläche (lWa) ist eine Funktion aus laubwandhöhe  und  reihenentfernung.  Die  laubwandhö-he kann als durchschnittliche entfernung vom niedrigsten zum höchsten blatt eines baumes definiert werden.

in dieser Veröffentlichung werden erste ergebnisse von laubwandflächenbestimmungen  aus  verschiedenen  deut-schen Obstbetrieben mit professionellen apfelanlagen vor-gestellt und diskutiert.

Die  laubwandfläche  wie  auch  der  jährliche  Zuwachs hängen  von  den  sorten  und  den  verwendeten  Wurzel-unterlagen  ab. Die  gemessenen Werte  schwanken  von  ca. 8.000  m²  bei  Neupflanzungen  bis  hin  zu  19.000  m²  bei älteren anlagen.

Schlüsselwörter  laubwandfläche · Dosiereinheit · Dosis bestimmung · spritzvolumen · Früchte

Introduction

the  unit  and  the  dimension  of  the  dosage  are  extremely important  for  carrying  out  and  assessing  field  trials—this is  relevant  for  professional  applications  as well. the  trial results  collected  over  several  years  are  important  for  the registration  and must  reflect  the  practical  application  sce-narios in orchard plantations. the data from the registration trials of plant protection products (PPP) influences primar-

erwerbs-Obstbau (2012) 54:49–53DOi 10.1007/s10341-012-0161-z

Dose Rate Expression—Need for Harmonization  and Consequences of the Leaf Wall Area Approach

Ralph-Burkhardt Toews · Reinhard Friessleben

r.-b. toews () · r. Friesslebenbayer cropscience aG, alfred-Nobel-str. 50,  40798 Monheim, Germanye-mail: burkhardt.toews@bayer.com

received: 13 april 2012 / accepted: 17 april 2012 / Published online: 1 June 2012© springer-Verlag 2012

1 3

50 r.-b. toews, r. Friessleben

ily label instructions, which are legally binding for the user (koch 2007). these dose expressions differ substantially in europe for the time being. this can influence residues and can  have  effects  on  the  environment,  so  harmonization  is necessary to improve mutual data exchange for PPP regis-tration  und  practical  use.  a  harmonized  dose  expression method ensures also complete and identical information for growers (koch 2007).

the ePPO guidelines of 2005 permit various dose  rate expressions (ePPO 2005). the Zonal registration and the revision  of  the  ePPO  guidelines  expedite  the  process  of harmonizing dose rate expression in high growing crops in europe. the  intention  is not only  to make  test  results and registrations more  comparable  and  usable  in  the  registra-tion zone, but also to establish a understandable and simple calculation  for  practical  use  that  replace  the  older,  more insufficient models like % concentration, kg/ha or kg/ha* m canopy height. in future it’s recommended that the dose rate expression should be defined by the leaf wall area model.

therefore, the following questions have to be answered:

1.   What is the right method to measure the leaf wall area?2.   how increases the lWa during the vegetation period?3.   how large are the actual leaf wall areas in professional 

orchards?

in  this  publication  selected  German  orchard  plantations have been evaluated to answer these questions.

Definition of Dose Rate Expression LWA

the dose  rate  determination  is  one of  the most  important and most difficult  steps during  the development of a PPP. the dose rate defines the amount of an active ingredient pla-ced as an initial deposit on the target area, which is adequate to control a certain target organism.

We must distinguish between:

•   Dose expression: the unit in which the dose is expressed on the label

•   Dose adjustment: the determination of a crop and or pest adjusted  dose,  i.e.  the  quantity  of  product,  necessary to achieve requested efficacy results under specific cir-cumstances (koch and Weisser 2002; Friessleben et al. 2007)

Dose  expression  and  dose  adjustment  are  two  related  but different tasks (koch 2007). the determination of crop-ad-justed  dose will  not  be  considered  by  changing  dose  rate expression.

spraying machines deliver a certain water volume  to a virtual treated area of e.g.10.000 m². in high crops this area cannot be the ground area like in arable crops.

sprayer calibration formula:

the  treated area  is defined by  the area  that  is  covered by working  nozzles.  the  nozzles  overspray  a  vertical  plane, defined  by  row  length  and  spray  swath  height  (koch  and Weisser 2000)  from both  sides of  the  tree  row. the over-sprayed area is the treated area (Fig. 1).leaf  wall  area  is  expressed  by  the  following  formula    

(Friessleben et al. 2007): 

row distance and canopy height are the key figures for cal-culating the leaf wall area. each change of 10 cm causes a 3–5 % change of the lWa. Due to this the determination of the canopy height  should be described exactly  in order  to establish a uniform and reproducible method. the canopy height can be defined as  the distance between  the highest and lowest leaf or fruit of a tree (Fig. 2). in some crops like e.g.  bush  berries  also  the  stem or  cane  can  belong  to  the target area and thus to the canopy height.

Water volume (L 10 000 m−2)

=Nozzle flow rate (L min−1) × number of nozzles × 600

Working width (m) × travel speed (km h−1)

Leaf Wall Area (LWA) m2 = 2 × Canopy height (m)

×ground area (m2)

row distance (m)

Fig. 1  treated area—defined as the area that  is covered by working nozzles. (source: koch, h., Dlr bad kreuznach)

            

1 3

51Dose rate expression—Need for harmonization and consequences of the leaf Wall area approach

Due to the fact that orchards are not always uniform, we recommend to measure the canopy height on 20 randomly distributed orchard trees and to calculate the average. the measurement is preferred compared to an estimation or stan-dard assumption. the size of the sample (amount of measu-red trees) determines naturally the accuracy of the average value. in view of an acceptable, feasible procedure for the growers or advisors this sample size should be sufficient.

Seasonal Change of the Leaf Wall Area

During the vegetation period in 2011 three varieties (‘Gol-den  Delicious’,  ‘red  boskoop’,  ‘Pinova’)  in  7  different orchards were  assessed  at  the bayer cropscience  experi-

mental farm in höfchen. a summer pruning was not carried out. the row spacing amounts to 3.5 m.

an increase of the leaf wall area from april to the end of august of approx. 20–30 % was observed by varieties with the weak root-stock M 9 irrespective of varieties.

On the other hand, an increase of the lWa of 65 % was determined by varieties grafted on  invigorating  root-stock M 7. the  leaf wall  area was  still  in april  in  all  orchards approx.  11.000  m².  the  lWa  after  shoot  growth  of  the varieties  grafted  on  M  9  varied  only  little  and  was  bet-ween 13.486 m² (‘red boskoop’) and 14.114 m² (‘Golden Delicious’).

comparing the influence of the root-stocks on the deve-lopment of the lWa of ‘red boskoop’ on M 7 was around 4.000 m² higher  than on M 9.  ‘red boskoop’ showed  the highest  leaf wall  area  of  about  17.000 m² with M 7. the lWa  of  ‘Golden  Delicious’  on  MM  106  increased  from 14.171 m² up to 16.571 m² on root-stock M 7.

the increase of the lWa is based predominantly on the shoot growing upwards. the tree height increased between 20 and 48 cm on root-stock M 9. the root-stock M 7 cau-sed  an  increase  of  65–115  cm  canopy  height. Due  to  the increase of fruit weight the lower branches bend down bet-ween 2 and 20 cm.

Fig. 2  Measurement of canopy height

m canopy height,distance from highest leaf to the lowest leaf

            

Table 1  increment of lWa of apple orchards 2011, bayer cropscience trial station höfchenQuartier Planting year rootstock Variety Date of  

assessmentbbch row  

spacingcanopy  height (cm)

lWa (m²) rel

Qu 30 1999 M 9 Golden Delicious 15. apr 52 3.50 190 10.743 10017. Mai 65 3.50 210 11.714 10915. Jul 71 3.50 210 12.171 11326. aug 77 3.50 250 14.114 131

Qu 5c 1969 M 9 red boskoop 15. apr 52 3.50 190 11.029 10017. Mai 65 3.50 200 11.429 10426. aug 77 3.50 240 13.486 122

Qu 5c 1969 M 7 red boskoop 15. apr 52 3.50 190 10.571 10017. Mai 65 3.50 230 12.857 12226. aug 77 3.50 310 17.429 165

Qu 5c 1969 MM 106 Golden Delicious 15. apr 52 3.50 190 11.029 10017. Mai 65 3.50 210 12.000 10926. aug 77 3.50 250 14.171 128

Qu 5c 1996 M 7 Golden Delicious 15. apr 52 3.50 190 10.857 10017. Mai 65 3.50 220 12.457 11526. aug 77 3.50 290 16.571 153

Qu Xii 2005 M 9 Pinova 15. apr 52 3.50 200 11.429 10017. Mai 65 3.50 220 12.686 11126. aug 81 3.50 240 13.657 119

Qu Vi 2010 M 9 Pinova 15. apr 52 3.50 110 6.286 10017. Mai 65 3.50 140 7.829 12526. aug 81 3.50 150 8.286 132

1 3

52 r.-b. toews, r. Friessleben

a ‘Pinova’—new planting  (block Qu Vi) was  included into  table  1.  here  the  lWa  increase  to  approx.  6.300–8.300 m² at the end of the growing season (32 %).

the measurements will be continued in the next year and supplemented by additional locations.

Determination of the LWA of a Professional Fruit Farm

in  the  most  important  German  orchard  growing  areas determinations of the lWa in professional fruit farms have been conducted. in table 2 the data are shown for a larger fruit-growing  farm  in  the  region of thuringia  in 17 apple orchards with seven varieties and two root-stocks. the leaf wall  area  of  M  9  root-stocks  differs  variety-dependently between approx. 12.000 and 18.000 m². the highest lWa was measured in ‘Golden Delicious’. the root-stock M 26 showed a 11 % higher leaf wall area in relation to M 9 with ‘idared’ and around 24 % with ‘Pinova’, despite the wider row spacing of 3.5 m for the M26 rootstock. the maximum lWa was  measured  in  ‘Pinova’  on M  26  rootstock  with 19.429 m².

it was  shown  that  the  leaf wall  area  differs  depending on variety and root-stock. therefore the dose determination has to be different for each variety depending on the lWa, which  has  effects  on  the  adjustment  of  the  spray  equip-ment. these requirements are not only relevant for the lWa approach but concern all dose expression calculations.

a successful implementation and acceptance of the lWa method by farmers and advisors depends on a good educa-tional advertising and training.

Outlook

the data analysis in professional farms has to be continued in the next year. the aim is to get a broad overview of the current lWa in europe and its consequences for the regis-tration  of  PPP,  field  trials  on  efficacy  and  growers  spray application. For this the use of geo data from the land sur-veying  has  to  be  proven.  some  approaches  like  the  “air-borne laser-scanning” might be able to determine tree height and row width. this method uses special laser scanner sys-tems mounted on manned or unmanned airplanes to scan the ground surface. Geo data can possibly supply huge data sets in a relative short time frame. Further investigations within europe and other crops than apple should follow.

For a successful implementation of the lWa method into the  registration process of PPP and also  into practical use it is necessary to clarify the determination of the lWa for special cultivation forms and crops. the main question is: how can the lWa concept be converted in all orchards, viti-culture and high growing vegetables?

training of trial officers, advisors and professional users are necessary for a broad consent. For this plan appropriate concepts must be still compiled.

Table 2  leaf wall area of apple orchards of a thuringia fruit farm 2011block Planting 

yearrootstock Variety Date of 

assessmentbbch highest  

leaf (cm)Ground  clearance (cm)

canopy height (cm)

row  spacing (cm)

lWa (m²)

3 2008 M 9 Jonagored 07. sept 87 260 32 228 330 138293 2008 M 9 elstar 07. sept 87 247 50 197 330 119399 1997 M 9 Pilot 06. sept 87 269 40 229 320 142815 1991 M 9 Pilot 06. sept 87 263 44 220 320 137195 1991 M 9 Golden Delicious 06. sept 85 290 30 261 320 162815 1991 M 9 elstar 06. sept 87 275 50 225 320 140638 1995 M 9 Golden Delicious 07. sept 85 320 30 290 320 181258 1995 M 9 Pinova 07. sept 81 295 30 265 320 165636 1989 M 26 idared 07. sept 85 303 23 280 400 140006 1989 M 9 idared 07. sept 85 283 30 253 400 126257 2003 M 26 Pinova 07. sept 81 370 30 340 350 194295 1991 M 9 Pinova 06. sept 81 287 36 251 320 156564 2010 M 9 shampion 07. sept 89 170 60 110 320   68752 2009 M 9 shampion 07. sept 89 266 60 206 350 117431 2009 M 9 shampion 07. sept 85 278 60 218 320 136255 1991 M 9 shampion 06. sept 85 276 41 235 320 146889 1997 M 9 shampion 06. sept 85 282 38 244 320 15250

1 3

53Dose rate expression—Need for harmonization and consequences of the leaf Wall area approach

References

ePPO  (2005)  efficacy  evaluation  of  plant  protection  products. Dose  expression  for  plant  protection  products.  ePPO  bulletin 35:563–566

Friessleben r, roßlenbroich h-J, elbert a (2007) Dose expression in plant protection field testing in high crops: need for harmoniza-tion. Pflanzenschutz-Nachrichten bayer 60:89–96

koch h (2007) how to achieve conformity with the dose expression and sprayer  function  in high crops. Pflanzenschutz-Nachrichten bayer 60:71–89

koch h, Weisser  P  (2000)  sensor-equipped  orchard  spraying—effi-cacy, savings and drift reduction. aspects of applied biology 57, advances in Pesticide application, pp 357–362

koch  h, Weisser  P  (2002)  expression  of  dose  rate  with  respect  to orchard sprayer function. aspects of applied biology 66, inter-national advances in Pesticide application, pp 353–358