A new device has been developed and tested on 30 hectares in 2007, to protect apples

from codling moth Cydia pomonella damages. Different meshes, dates and strategies

have been tested, and observations on various orchards give an outstanding efficacy with

very few damages at harvest

Romet, L.

Severac, G.

English

Organic Eprints

291An innovative strategy to control codling moth:“ALT'CARPO” Concept Romet L. 1, Severac G.2AbstractA new device has been developed and tested on 30 hectares in 2007, to protect apples from  codling  moth  Cydia  pomonella  damages.  Different  meshes,  dates  and  strategies have been tested, and observations on various orchards give an outstanding efficacy with very few damages at harvest.Keywords: codling moth, Cydia pomonella, net, physical control IntroductionCodling moth remains the most damaging pest on apples in southern France (Sauphanor, 2007).The  “Alt'carpo”  concept  was  created  and  tested  for the first time in 2005, then validated experimentally on 9 tests in 2006.  In 2007, it was set up to : -  assess the performance of this method for the first  year  of  development  in  commercial orchards,-  make some targeted tests on some questions: behaviour  of  codling  moth  (CM)  under  nets, influence  of  the  nets  closing  date  and  the damages caused, as well as  the importance of the  size  of  the  net's  mesh  (Severac  et  al.,2008).“Alt’carpo” installed on apple trees Material and methods About 60 acres (30 hectares) of apple orchards in southern France were enveloped in“Alt'  carpo”  nets.  Most  of  those  covered  orchards,  conducted  in  organic  (2/3)  and integrated (1/3), showed some important CM damages the previous year (between 3 and 40% according to plots). For the trials shown below, observations were made at the end of every CM generation, as well as at picking time, on 1000 fruits per treatment, chosen randomly.  The closing of nets was generally done around April 20th, just before first egg layings. For technical reasons, some nets have been set up after this date, and one treatment with granulosis virus (GV) had to be applied just before.1 Romet Lionel, Research Group for Organic Farming, lionel.romet@grab.fr 2 Guilhem Séverac, Chambre d’Agriculture du Vaucluse, guilhem.severac@fr.oleane.com Archived at http://orgprints.org/13717/2921) Effectiveness in 2007 Protection  by  the  « Alt’carpo»,  was  compared  to  a  classical  grower’s  plant  protection programme :-  GV + Bt every 8 days for organic orchards, -  Synthetic insecticides every 10 days for conventional ones. The net was the only protection against CM ; however, in case of a late set up of the net, some producers used GV at the beginning of season.  No untreated plot could be associated to the trial, because of a high level of CM risk. The  counting  of  all  the  covered  orchards  (around  3000  m²  each)  at  the  end  of  each generation of CM was done.2) Influence of the net's set up date. The orchards were protected with “Alt'carpo” (only protection against CM) ; 3 orchards have been observed, per date : - date 1: nets set up at the right time. - date 2 : nets set up the month following the right date, with an additional GV treatment. - date 3: nets set up more than a month after the right date, with one or two additional GV treatments. 3) Influence of net's mesh : Alt'carpo “4*4” (ie 2,2 x 5,4 mm) was compared to a classical hail net (3 x 7,4 mm).Results 1) efficacy in 2007 : 99.94% We compared the protection with simple nets to growers protection strategies. Evaluation led to the conclusion that nets provide a much better protection against CM damages than treatments,  either  in  organic  or  integrated  production  (IP).  IP  suffered  11%  damages, probably because of an acquired resistance to registered pesticides. 0123Alt' Carpo organic% damagesFigure 1 : efficacy of protection with net compared to organic or integrated production 04812Alt' Carpo IP% damagesFigure 1 : efficacy of protection with net compared to organic or integrated productionArchived at http://orgprints.org/13717/2930,00,10,20,30,40,50,60,7G1 G2 G3%right timewithin 1 monthafter 1 month0/1000n=101/1000n=32/1000n=13/1000n=1The  development  of  the  technique  in  2007  allowed  a  global  overview  of  the  method suitability on 15 different orchards. Figure 2 shows the damage rate at harvest, and the number of orchards with such damages. It shows that on a total of 15 orchards controlled, 10 had no damages on 1000 fruits checked on each, at harvest. Only one orchard got up to 3%odamages.Figure 2 : efficacy of « Alt' Carpo » at harvest 2007, number of orchards per damage rate (%o)2) influence of net’s set up date It seems like GV treatments shall be done in any case, if nets are set up at the right time, or later (for thinning reasons for example). Light damages can be observed at the end of first generation, but bites are generally getting dry and negligible.Proportion of bites is proportional to the time needed to set up the net. At the end of Generation 1, no new bites has appeared. At the end of G2 and G3, only old and dry bites could still be found.Figure 3 : Influence of set up date on CM damages under net 3) influence of net’s mesh No difference was found in 2006 between both meshes.  In 2007, a trial on a big plot was carried out, on Granny Smith, with a high 2006 pressure (40%) and a low 2007 bearing.Archived at http://orgprints.org/13717/294Hail net (with bigger mesh) seemed to compress trees under, and possibly led to more egg layings through the net. Its efficacy was therefore lower, with regular damages throughout the season, on fruits in direct touch with the net, or with neighbouring leaves touching the net.Results obtained (figure 4) with hail net remain very satisfying with 2% of damaged fruits at harvest, but this result is still below the optimum. 00,511,522,533,544,5avr-07mai-07mai-07mai-07juin-07juin-07juil-07juil-07août-07août-07sept-07%2,2x5,4mm 3x7,4mmFigure 4 : Influence of net’s mesh on CM damages The fruits protected by the other net (smaller mesh) suffered from no CM damages.  ConclusionWithdrawal of some insecticides, climate change favouring pests, resistance encountered to  more  and  more  molecules  (including  GV),  restricting  legislation  on  treatments  and residues, poor efficacy of natural alternatives  such  as  mating  disruption, lead to major difficulties for growers.  In  such  a  context,  we  assume  “Alt’carpo”  strategy  provide  a  relevant  and  successful alternative  to  growers.  Results  obtained  in  commercial  orchards  on  various  situations confirm the first preliminary trials carried out since 2005.The  results  gathered  in  2007  give  additional  information  to  propose  a  more  accurate protection strategy.  References Séverac G., Romet L. 2008. Avec Alt’Carpo, des arbres bien protégés… Phytoma, sous presse Sauphanor B., Berling M, Toubon JF, Reyes M, Delnatte J, Allemoz P. 2006. Carpocapse des pommes : cas de résistance au virus de la granulose en verger biologique. Phytoma, 590, 24-27.00,511,522,533,544,5avr-07mai-07mai-07mai-07juin-07juin-07juil-07juil-07août-07août-07sept-07%2,2x5,4mm 3x7,4mmArchived at http://orgprints.org/13717/

An innovative strategy to control codling moth: “ALT'CARPO” Concept

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