Hart. Sci. (Prague) Vol. 37, 2010, No. 4: 139-144 Vol. 37, 2010, No.4: 127-138 Hart. Sci. (Prague)

SA LVAD OR DE F.R ., PlTITTO A., GlORGI ONl M., FOLONl 1., USENIK V, FAJT N., STA MPAR F., 2006. Effects of rootstocks BASSI G., LONGO 1., 2008. Performance of 'Lapins' sweet and training system on growth, precocity and productiv­ cherry on several rootstocks in italy. Acta Horticulturae, ity of sweet cherry. Journal of Horticultural Science & Control ofHoplocampa testudinea using the extract 795: 311-316. Biotechnology, 81: 153-157. SIMAIW V., 2005. Six Vase-training systems: description and \VEBSTER A.D., 1996. Rootstocks for sweet and sour cher­ from in organic apple growing effect on fruit ripening and quality. Acta Horticulturae, ries. In: WJ;BSl'ER A.D., LOONEY N.t . (eds.), Proceedings 667: 353-359. Cherries: Crop Physiology, Productions and Uses. Oxon, 3 Stehr R., 2005. Experiences with dwarfing sweet cherry UK, CAB International: 127-163. V. P SOTA \ J. OUREDNicKOVA?, V. FALTA rootstock in Northern Germany. Acta Horticulturae, 667: Received for ~,ubJic a tion June 26, 2010 173-177. lFaculty OfAgronomy, Mendel University in Brno, Brno, Czech Republic STEHl( R., 2008. Further experiences with dwarfing sweet Accepted after corrections July 16,2010 cherry rootstocks in northern Germany. Acta Horticul­ 2Research and Breeding Institute ofPomology Holovousy, Ltd., Holovousy, Czech Republic turae, 795: 185-190. 3Crop Research Institute, Praha-Ruzyne, Czech Republic

Abstract

Corresponding author: PSOTA v., OURED NlCKOVA J., FALTA V, 2010. Control of Hoplocampa testudillea using the extract from Quassia amara in or ganic apple growing. Hort. Sci. (Prague), 37: 139-144. Lng. JITKA BL AZKO VA , Research and Breeding Institute of Pomology Holovousy, Ltd., Holovousy 1, 50801 Horice, Czech Republic In 2008 and 2009 the effects of quassin and neoquassin (oxygenated triterpenes) on apple phone: + 420 493 692 821, fax : + 420 493 692 833, e-mail: [email protected] (Hop/ocampa tes­ tudinea K1 ug, 1814) were studied. In the Czech Republic, monitoring was carried out in small-plot trials and in one laboratory experiment. The extract containing quassin and neoquassin was made by boiling wood chips of a tropical Quassia amara 1. (: Simaroubaccac). The experimental dosages were 3, 4.5, 6, and 9.25 kg of wood chips/ha. Spray treatment with the quassia extract was carried out just before most larvae hatched out. It was statisti­ cally proven that the extract from the wood of Q. amara reduced the apple sawfly infestation of fruitlets. Extract in the dosage corresponding to 3-4.5 kg of quassia wood chips for 1/ha appeared as optimal. The efficacy of these dosages was approximately 40-50%, and the efficacy above 80% was record.

Keywords: apple orchard; organic farming; Malus domestica; pest control; apple sawfly

Apple sawfly ( Klug, tained in the wood of of the 1814) (: ) overwinters family (Guo et al. 2005). The source of quassin and as a prepupa within the cocoon in the soil (AL­ neoquassin is a shrub Quassia amara L. (Sapin­ FORD 2007). It has one generation per year. Imagos dales: Simaroubaceae), its wood contains, depend­ hatch out during the blossom time of early and mid ing on the age, 0.14-0.28% of quassinoids (quassin early apple varieties (GHAF et al. 2001). This and neoquassin) (VILLALOB OS et al. 1999). pest causes significant losses and damages on apple In 2002-2003 a series ofexperiments with a stand­ fruits in organic orchards in Europe (KI ENZ LE et al. ard solution containing quassin were performed in 2006a; GR AF et a1. 2002). Germany. Dosages of pure quassin of 2, 3, 4, 6, and The possible method acceptable in organic grow­ 9 g/ha/m tree height were tested. The efficacy in most ing is spraying 9n the basis of natural bitter com­ cases was over 80%; 6 g of quassin/ha/m tree height pounds quassirf and neoquassin (WUNE N et al. being determined as the optimal dosage (KIENZLE ct 1994; ZIJ P, BL OMMERS 2002). These substances al. 2006a). In Ger many and Switzerland a commer­ bel o~lg among oxygenated triterpenes and are con- cial preparation with standardized quassin content

Supported by the Internal Grant Agency of the Faculty of Agriculture, Mendel University in Brno, Czech Republic, Project No. IG29014112102 /224 and NAZV, Project No. QH92179.

139 138 Vol. 37, 201 0, No. 4: 139-144 Hart. Sci. (Prague) Hort. Sci. (Prague) Vol. 37, 2010, N o. 4: 139- 144 is used; however, its high price is a li miting factor One replication included 4 in location 1, and with apple sawfly eggs we re counted and then com­ May4). The conventional insecticide Mospilan 20 $P for wider use. A non-standardized extract prepared 5 trees in location 2. Flight of apple sawfly adults pared to a number of fr uitlets infested by hatched was applied only in one dosage of 0.25 kg /ha on directly from wood of the shrub Quassia amara is was monitored using white sticky traps based on apple sawfly larvae. May 4. The control was treated only with water a cheaper altern ati ve. This wood is readily available the method of LUKAS and KOCOUREK (1998). containing the wetting agent. The eval uation was in Europe for a favorable price. The ai m of our ex­ The selected dosage of application water vol ume performed on May 12 and within each replication periments was to evaluate the efficacy of the simply was 400 II ha. Volumes of the concentrated extracts Experiment conducted in 2009 100 fr uitlets were evaluated, i.e. 400 fruitlets/va.ri­ prepared, non-standardized extract. applied corresponded to the dosages of 3, 4.5, 6, ant. Again, the numbers of non-infested fruitlets and 9.25 kg of boiled quassia wood l/ha. The wet­ The level of apple sawfly infestation was high. and those damaged by sawfly larvae were deter­ ting agent Silwett L-77 (0.1 I/ha) was added to the Therefore in 2009 the experiments were carried out mined. MATERIAL AND METHODS spray solution. with natural level of infestation without any artifi­ The spray treatment was applied with a knapsack cial infestation. Locations motor sprayer. Location 1: The fi rst apple sawfl ies on white sticky Laboratory trial In both seasons, the embryonic development of traps were recorded on April 16 and on April 20 The research was carried out in a for m of a small­ larvae in egg was monitored. Treatment dates were the infestation nearly fin ished. From April 20 the Blossoms with hatched eggs of apple sawfly were plot field trial in two locations in the Czech Repub­ scheduled according to the embryonic phase of lar­ embryonic development of larvae in eggs was daily collected in location 2 on May 4, 2009. The blos­ lic and one experiment was conducted under the vae so that spraying could cover a maximal possible evaluated. The first spray treatment was applied on soms were incubated in a climabox under a long­ laboratory conditions. number of hatching larvae. The efficacy of the extract April 23, it means when most of the larvae (78%) day regime and at the temperature of 20°C in the Location 1 was situated in a typical fruit area in was calculated from the acquired data by applying the had finished their embryonic development. The Crop Research Institute, Prague-Ruzyne. On May 7 South Moravia. The orchard was situated 20 km Abbott's formula (AB BOTT 1925). Data were statisti­ second spraying was carried out on April 24 when most of the larvae were just before hatching accord­ south from Bmo (49°0' N, 16°39' E). In 2008 and cally evaluated using the analysis ofvariance (ANOVA) most of the larvae were just before hatching or had ing to the embryonic development and the treat­ 2009 two experiments were performed in an apple in programs UPAV GEP 1.6 (State Phytosanitary Ad­ already started hatching. The third spraying was ment was carried out with an apparatus for manual orchard of the Idared variety in spacing 3 x 4.5 m. ministration) and Statistica 8 (StatSoft). Statistical performed on April 25, it means on the day when spraying. The spray treatment was performed in Location 2 was situated in Eastern Bohemia in difference among the treatments was determined ac­ most of the larvae had already hatched. Variants concentrations corresponding to the dosage 3 and the orchards owned by the Research and Breeding cording to the Tukey's test. with one spray treatment (3 or 4.5 kg /hal were ap ­ 4.5 kg quassia wood chips/ha. The spray solution Institute of Pomology in the village of Holovousy plied on April 23. On April 24 treatment dosage did not contain any wetting agent to assess its effi­ (50 0 22'N, 15°34' E). The experiment was carried out was 6 kg/ha. On April 23 and April 25, variants ciency. The control was left untreated. Each variant in 2009, on apple trees of the Sampion variety in Experiment conducted in 2008 with both spray treatments (3 and 4.5 kg/hal were had 15 blossoms . On May 13 the experiment was spacing 3 x 4.5 m. applied. The control was treated only with water evaluated, the num ber of fruitlets where sawfly lar­ In 2008 artificial infestation was performed. On containing the wetting agent. The eval uation was vae successfully hatched and continued to rear and April 17 the first apple were recorded on carried out on May 11. Within each replication, the number of fruitlets where larvae died after the Extract preparation white sticky traps. On April 25 trapping of the 150 fruitlets were assessed, i.e. 600 fruitlets/vari­ spray treatment were determined. Statistical evalu­ adults was carried out. Captured flies were closed ant. Numbers of non-infested ffuitlets and those ation was perfo rmed using a simple non- paramet­ Extract was prepared fro m wood chips of the Quas­ to monofilament isolators. One shoot at full blos­ damaged by sawfly larvae were determined. ric sign test. sia amara shrub. Quassia wood chips were supplied som (April 25) on each tree was covered with the Location 2: Flight of the apple sawfly adults was by the firm Keller GmbH & Co. KG (Freiburg, Germa­ isolator and two apple sawfly females and one male monitored using the white sticky traps from the be­ ny) . The supplier did not specify proportions of chips were placed to each isolator. The isolators were re­ ginning of April. From April 24 the embryonic de­ RE SULTS in the product description (our estimation of main moved on April 29. velopment of larvae in eggs was mon itored. In this fraction: length 0.5- 1 cm; width 0.3-0.5 cm; thickness Subsequently, the embryonic development oflar­ location in addition to the quassia extract, organic Year 2008 (small-plot trial) 0.2-0.3 cm). The extract was prepared shortly before vae was assessed on twenty blossoms with an apple insecticide NeemAzal T /5 (azadirachtin) and con­ its application (2-4 days). Quassia wood chips (100 g) sawfly egg each day. On May 5, it was determined ventional insecticide Mospilan 20 SP (acetamiprid) In this season, heavy apple sawfly infestation was were boiled in 2 I of water for one hour following that in 70% of eggs, the sawfly larvae were in the were applied. achieved by use of isolators. Infestation in the con­ the procedure described by D O OIA et al. (2008) and phase before hatching. One day later it was already The iirst spray treatment was applied on April 30 trol variant was 56.7% . The efficacy of the one spray Z IJP, BLOMMERS (2002) . During bOiling, chips slowly 90% and 5% of hatched larvae were recorded. Spray when most of the larvae were just before hatching. treatments of 3, 4.5, and 9.25 kg/ha was 55.03%, dropped to the bottom and fi nally they settled there. treatment was conducted the following day. The The second application was performed on May 4, 58.02%, and 65.43%, respectively. Surprisingly, the Subsequently, brown-colored solution was decanted tested dosages of quassia wood were 3, 4.5, and when most of the- larvae had already hatched. Quas­ variant with two spray treatments of 2 x 3 kg /ha and for a short period (max. 4 days) stored in a fridge. 9.25 kg wood/ha in one application (May 7) and sia wood extracts 3, 4. 5, and 6 kg/ha were applied in was the least efficient (only 37.92%) (Table 1). the dosage of 3 kg/ha which was applied twice, the two variants; ir#the variant with one spray treatment The dosage affected the level of infe station sta­ second spraying was carried out after five days, it (April 30) and the variant with two spray treatments tistically significantly (F = 23.8063, P = 0.05· ). All Small-plot trials means on May 12. The control variant was only (April 30 and May 4). The insecticide NeemAzal three dosages differe d from the control statistically treated with water containing the wetting agent. T /S 3 (l /ha) was applied in two variants, i.e. in the significantly and also the variant with two spray The experiments were established in randomized On May 16 the infestation on the marked shoots variant with one spray treatment (April 30) and in treatments differed statistically significantly from blocks with four replications of each treatment. was evaluated. Within each replication, fruitlets the variant with two spray treatments (April 30 and the variant with one treatment. No statistically sig­

140 141 Vol. 3 7, 2010, No.4: 139-144 Hort. Sci. (Prague) Hort. Sci. (Prague) Vol. 37, 201 0, No.4: 139-144

Table 1. Infestation, efficacy, and statistical difference of Table 3. Infestation, efficacy, and statistical difference of DISCUSSION are e.g. on the basis of p Lant oils and natural ten­ the treatments in location 1 in 2008 the treatments in location 2 in 2009 sides (STATE PH YTOSA NITAIl Y AOMIN IS TRAT ION The present results show that the extract pre­ 2010; ZEBIT Z 2005). In addition, quassia wood ex­ Efficacy (%) 95% Treatment Infestation (%) Treatment Infestation (%) Efficacy (%) 95% pared directly from wood chips of Quassia amara tract can be used in integrated production where Quassia 3 kg 25.5 55.03 A Quassia 3 kg 2.00 82.61 BC is statistically significantly efficient against apple a wide spectrum of wetting agents (including Sil­ Quassia 4.5 kg 23.8 58.02 A Quassia 4.5 kg 1.50 86.96 BC sawfly larvae. In 2009, in location 2 this extract was wett L-77) can be applied. Volume of water is also statistically equally effective as the conventional significant. KlENZLE et al. (2006b) determined that Quassia 9.25 kg 19.6 65.43 A Quassia 6 kg 0.75 93.48 BC synthetic insecticide Mospilan 20 SC (Table 3). the effi cacy increases with the volume of applied Quassia 3 kg - 2 x 35.2 37.92 B Quassia 3 kg - 2 x 1.25 89.13 BC The achieved efficacy results of the individual ex­ water and the optimal water volume appears to be Control 56.7 C Quassia 4.5 kg - 2 x 0.25 97.83 C periments show that the optimal dosage is 3-4.S kg SOO lIha. of Quassia amara wood chips/ha ofan orchard. Ac­ Based on the results achieved, it is possible to con­ Quassia 6 kg - 2 x 0.25 97.83 C Differences between the treatments were determined with cording to VILL ALOBOS et at. (1999) it corresponds clude that the use of the aqueous extract prepared the Tukey's test NeemAzal31 2.25 80.43 B to 4.2-8.4 g ofquassinoids (3 kg/hal and 6.3-12.6 g from 3 or 4.S kg quassia wood crups/ha reduced NeemAzal3 I - 2 x 1.75 84.78 BC of quassinoids (4.5 kg/ha). Alt hough releasi ng of the apple sawfl y infestation of apple fruitlets from nificant difference was found between the variants quassinoids to water solutions was already con­ SO-8S%. Extract prepared from higher dosages of Mospilan 20 SP 1.00 91.30 BC with one treatment (Table 1). fi rmed by ROA RK (1947) we do not suppose that all quassia wood chips or two consecutive sprays were Control 11.50 A the quassinoids contained in wood get into the ex­ not statistically significantly more efficient. Further Differences between the treatments were determined with tract. We can assume that the size of chips, i.e. size research should focus on the evaluation of quas­ Year 2009 - location 1 (small-plot trial) the Tukey's test of the active surface, affects the extraction rate and sia extract application in practice; the experiment quantity of the substance extracted into the solu­ should be tested in the scale of several hectares. In 2009 relatively high natural apple sawfly infes­ tion. However, the results indicate that under the tation occurred. In the contro!' 13.33% of fruitlets conditions of the method used by us, a sufficient Refe l'e n ce were damaged with apple sa'wfly larvae. The one Year 2009 - location 2 (small-plot trial) amount of the effective substances was extracted spray treatments with quassia extracts of 3, 4.5, and into the water solution. The treatment with higher ABBOTT W.S ., 1925. A method of computing the effective­ 6 kg/ha achieved the efficacy of SO.34%, 28.27%, Similarly to location 1, heavy natural apple sawfly dosages of Q uassia extract (6 kg/ha or 9.25 kg/ha) ness of an insecticide. Journal of Economic Entomology, and 39.86%, respectively. The two spray treatments infestation occurred here. In the control, I1.S% of did not achieve statistically significantly higher ef­ 18: 265-267. with 3 and 4.S kg/ha achieved the efficacy of 39.19% fruitlets were damaged with apple sawfly larvae. In ficacy. In 2009 in location 1 the most efficient dos­ ALFORD D.\!., 2007. Pests ofFruit Crops: a Colour Handbook. and 41.22%, respectively (Table 2). this experiment surprisingly very high efficacy in age was 3 kg/ha. This result could be affected by London, M anson Publishing: 461. Similarly to 2008, the dosage affected the level of all the dosages tested was achieved. considerably uneven infestation of the individual DODIA D.A., PATEl. 1..5., PATEl. G.;"!.' 2008. Botanical Pes­ infestation statistically significantly (F =: S.033, P =: The one spray treatments with quassia extracts of replications. ticides for Pest Management. Jodhpur, India, Scientific O.OS*). Statistical differences were not detected be­ 3,4.5, and 6 kg/ha achieved the efficacy of 82.61 %, KIEN ZLE et aL (2006a) recommended the optimal Publishers: 354. tween the variants with one treatment with quassia 86.96%, and 93.48%. The two spraying treatments dosage of 6 g of pure quassin/ha. This dosage can GRAF B., HOPLI u., HONI H., 2001. The apple sawfly, Hoplo­ extracts of 4.5 or 6 kg/ha and variants with two spray with 3, 4.S or 6 kg/ha achieved the efficacy of be achieved with standardized commercial prepa­ campa testudinea: temperature effects on adult life·span treatments of 3 and 4.5 kg/ha. The one spray treat­ 89.13%,97.83%, and 97.83%, respectively (Table 3). rations containing quassin without any problems, and reproduction. Entomologia Experimentalis et Appli· ment of 3 kg/ha was the only one that differed sta­ The dosage had a statistical significant effect on the however acquisition costs are high. In the case of cata, 98: 377-380. tistically significantly from the control and the other infestation level (F =: 13.081, P =: O.OS*). All the treat­ simply prepared wood extract, not only quassin Gl< AF B., HOPLl u., HON! H., 2002. The apple sawfly, Hop­ treatments (Table 2). ments tested differed statistically significantly from but also neoquassin get into the extract. Both these locampa testudinea: egg development and forecasting of the control (Table 3). The insecticide NeemAzal T /S substances are effective to newly hatched larvae. egg hatch. Entomologia Experimentalis et Applicata, 105: Table 2. Infestation, efficacy, and statistical difference of achieved the efficacy of 80.43% in the variant with In the laboratory trial, the efficacy of only 36.36% 55 - 60. the treatments in location 1 in 2009 one treatment and the efficacy in the variant with was achieved in the variant with one spray treat­ Guo Z., VANGAPANDU S., SINDELAR R.W., \ VAl.KER L.A., two spray treatments was 84.78%. The efficacy of ment of 3 or 4.5 kg/ha. In the small-plot trials, the SIND ELAR R.D., 2005. Biologically active quassinoids and Treatment Infestation (%) Efficacy (%) 95% the insecticide Mospilan 20 SP achieved 91.30%. efficacy achieved with these dosages was consider­ their chemistry: potential leads for drug design. Current Quassia 3 kg 6.l3 50.34 B ably higher. This difference could be caused by the Medicinal. Chemistry, 12: 173-190. K IENZLE J., ZI MME.R J., MAX IN P., RANK H., BATH ON H., Quassia 4.5 kg 8.79 28.72 AB absence of the wetting agent in the laboratory trial. Laboratory trial TIlerefore, we assume that the wetting agent plays ZEBITZ c.P.W., 2006a. Efficacy of QLi<'ls sia extract on Quassia 6 kg 7.42 39.86 AB an important role in the case of the use of quas­ the ap ple sawfly Hoplocampa testudinea Klug. In: Boos Quassia 3 kg - 2 x 7.50 39.19 AB The variants with one treatment (3 or 4. 5 kg/ha) sia wood extrlct. It was also confi rmed by KIE NZLE M . (ed.), Proceedings 12th International Conference on Quassia 4.5 kg - 2 x 7.25 41.22 AB achieved the same efficacy of 36.36% under the et al. (2006b) who determined higher effi cacy of Culti vation Technique and Phytopathological Problems controlled conditions of the laboratory trial. Dam­ qJassin in case a wetting agent was added to the so­ in OrganiC Fruit-Growing. \Veinsberg, Germany, January Control 13.33 A age of the control treatment was 73.33%. lution. Silwett L-77, the wetting agent used, is not 31-February 2: 239-242. Differences between the treatments were determined with The tested dosages clid not differ statistically from permitted by the Czech law for organic agr iculture. KI ENZ LE J., ZIMMER J., MAXIN P., RANK H., BATH ON H., the Tukey's test the control (P > O.OS ). The possible wetting agents for organic agriculture ZI"B ITZ c.P.W., 2006b. Control of the apple sawfl y Hoplo·

142 143 Vol. 37, 2010, No.4: 139-144 Hart. Sci. (Prague) Ho rt. Sci. (Prague) Vol. 37, 2010, No. 4: 145- 154

campa testudinea Klug in organic fruit growing. In: Boos Ecological and Management Implications. Acta Horticul­ M. (ed.), Proceedings 12th International Conference on tmae, 502: 369-375. Cultivation Technique and Phytopathological Problems WlJNEN T., BLO KSMA )., BROU WER G., LAWANT Q., 1994. in Organic Fruit-Growing. Weinsberg, Germany, January Bestrijding van de appelzaagwesp (Hoplocampa testudinea) Effect of low oxygen storage conditions on volatile 31-February 2: 25-29. met het plantaardige middel Quassia [Apple sawfly (Hop­ emissions and anaerobic metabolite concentrations LUKAS J., KOCOU REK E, 1998. Monitorovani vyskytu pi­ locampa tesfudinea) control using botanical insecticide latky jablecne (Hopiocampa testudillea) pomoci bil ych Quassial. Driebergen, Lo uis Balk lnstitut: 39. in two plum fruit cultivars lepovych desek [Monitoring of apple sawfly (Hoplocampa ZEBITZ c.P.\V'., 2005. Untersuchungen zur Regulierwlg der testudinea) occurrence using white sticky traps]. Apfelsagewespe im Okologischen Obstbau (Possibilities of Protection Science, 34: 98-104. apple sawfly control in organic fruit growing). Available at J. GOLIA5, P. HIe, J. IUNovA ROAR KR.C., 1947. Some promising insecticidal plants. Eco­ http://orgprints.org/8594/ (accessed July 11,2010). nomic , 1: 437- 445. 21)1' J.P., BLOMM EHS L. H.M ., 2002. Apple sawfly Hoplocam­ STATE l'HYTOSANlTARY ADM INIST RATI ON, 2010: WWW pa testudinea (Hym., Tenthredinidae) and its parasitoid Department of Postharvest Technology of Horticultural Products, Fa culty ofHorticulture, list of plant protection products. Available at http://www. Lathrolestes ensator in Dutch apple orchards (Hym., M endel University in Brno, Lednice, Czech Republic srs.cz/pls1 /pp_public/ rpg10e$.startup (accessed July 11, Ichneumonidae, Ctenopelmatinae). Journal of Applied 2010). Entomology, 126: 265-274. V Il.tALoBOS R., MARMU l.OD D., O CA MPO R., M ORA G., Abstract ROJAS c., 1999. Variations in the quassin and neoquassi n Received for publication December 11,2009 content in Quassia amara (Simaroubaceae) in Costa Rica: Accepted after corrections October 4, 2010 GOLlAS J., Hie P., KANOV;' J., 2010. Effect oH ow oxygen storage condi tions on volat ile emissions and anaerobic metabolite concentrations in two plum fruit cultivars. Hort. Sci. (Prague), 3 7: 145-154.

By harvest time, small amounts of acetaldehyde were accumulated in the flesh of plums, such as 0.31 mg/l for the cv. Stanley and 1.03 mg/l for the cv. Valjevka. This relative difference in concentrations remained constant throughout the whole period of storage in a regular atmosphere. The long-term effects of higher concentrations of CO are the 2 same as for very low oxygen concentrations; and significant amounts of ethanol accumulate in the tissue. Out of a total Corresponding author: number of 42 different odour compounds identified in the juice, there were 11 alcohols, 6 aldehydes, 17 esters, 2 ter­ lng. VA C1.AV PSOTA, Mendel University in Brno, Faculty of Agronomy, Zemedelska 1,62800 Brno, Czech Republic penes, 3 organic acids, and 1 lactone. Very low oxygen atmospheres slow down the production of esters and aldehydes, phone: + 420 545133247, e-mail: [email protected] but have little effect on the production of lactones and terpenes. It was shown that a very low oxygen concentration,

without much CO2 (Fluctuating anaerobiosis treatment), does not encourage the production of significant amounts of ethanol and acetaldehyde in the fruit flesh , but does significantly slow the biosynthesis of aromatic volatiles.

Keywords: plum fruit; volatiles; ethanol; acetaldehyde; firmness; headspace gas analysis

The quality of plum fruit fo llowing harvest is es­ 1977; NICHOLS, P AT T ERSON 1987; P ESIS 2005). If sentially influenced by the temperature and com­ oxygen levels drop below a certain critical point for position of the ambient atmosphere. The storage the aerobic conve rsion of storage substrates, then period is limited by fruit softening, visible signs of pyruvate is conver ted into acetaldehyde and etha­ wilting and a physiological disease manifested as an nol with adverse affects on fruit quality. internal browning adjacent to the stone (TAY LOR et Fermentation processes which proceed as a con­ al. 1993; GOLlAs 2004; TOIVONEN, BRUMMELL 2008). sequence of fruit ripening, even without low oxygen Knowing the lower oxygen limit for effective aero­ levels in the ambient atmosphere, also result in the bic metabolisnt is critical for managing the compo­ accumulation of ethanol and consequently the pro­ sition of the gaseous atmosphere (GRAN, BEAU DRY duction of ethyl esters in concentrations which may 1993; BEAUD RY 1999; ME NN ITI et al. 2006). A gas cause off-flavours. Specifically, an unpleasant odour atmosphere where the ethanol concentration does and taste results from the production of ethyl acetate, not increase over time is considered to be opti­ ethyl butanoate, ethyl 2-methylbutanoate, ethanol, mal for long-term storage (S MA GULA, BRAML AGE and acetaldehyde (LARA et al. 2007), wherea.s there

Supported by the Ministry of Agriculture of the Czech Republic, Project No. QH 81235.

144 145