Organic Strawberry Research Articles

Organic and Conventional Strawberry: Nutritional, Physical‐chemical, Antioxidant, and Pesticide Residues Composition.

Conventional agriculture, based on the use of chemical, mechanical and biological inputs, can affect the environment and human health and, in view of this, sustainable models of organic production have been proposed. The objective of this study was to compare the nutritional, physical‐chemical and antioxidant properties and pesticide residues of strawberries grown under organic or conventional systems. Strawberries (Fragaria x ananassa Duchesne) cultivar Camarosa were produced in conventional or organic systems, under controlled agricultural conditions. Their compositions were analyzed regarding moisture, protein, carbohydrate, lipids, ash, pH, soluble solids, total solids, total titratable acidity, vitamin C, anthocyanin, total phenolic compounds, antioxidant capacity and pesticide residues (azoxystrobin, lambda‐cyhalothrin and thiamethoxam).The organic strawberries showed higher moisture (91.48 vs 91.03 mg/100g) and ash (0.43 vs 0.35 mg/100g) contents, while conventional strawberries had higher total solids (8.98 vs 8.53%), soluble solids (8.50 vs 8.13 °Brix), Protein (0.93 vs 0.75 mg/100g) and carbohydrate (6.80 vs 6.44 mg/100g). The pesticide residues in organic strawberry were below the limit of detection (<LOD) and the values in the conventional strawberries were below the limit of quantification (<LOQ). Under controlled crop production, the cultivation system did not affect substantially the nutritional, physical‐chemical and antioxidant properties and pesticide residues of strawberry.Acknowledgement: FAPES for financial support.

English

A two year study at Alexandria University compared ascorbic acid, β-carotene, total phenolic compound, nitrite content and microbiological quality of orange and strawberry fruits grown under organic and conventional management techniques to see if producers concerns are valid. Organically grown oranges and strawberries had lower titratable acidity (TA); whereas, there was no significant difference in total soluble solid (TSS) of oranges and strawberries between two production systems. Higher ascorbic acid and β-carotene content was found in organically grown oranges and strawberries, compared to conventionally grown ones. Total phenol content (TPC) was significantly higher in conventional oranges compared to its organic production. Conversely, TPC was significantly higher in organic strawberries than the conventional ones. Comparative analyses of the microbial counts of organic and conventional oranges and strawberries fruit showed that Escherichia coli ( E. coli ) were not detected in any sample. However, conventional oranges and strawberries fruits have greater counts of yeasts and mold than organic ones. Nitrites were detected in all samples. The nitrites levels from organic production varied between 0.13 and 0.16 mg/kg fresh weight (FW), whereas those from conventional production ranged from 0.20 to 0.25 mg/kg FW. Our results show that the ascorbic acid, β-carotene, TPC, TA, nitrite content and biological quality were dependent on the agricultural production system, while for TSS%, this dependency was not pronounced. Key words: Ascorbic, β-carotene, organic, orange, strawberry, yeasts and molds.

Nontargeted metabolite profiles and sensory properties of strawberry cultivars grown both organically and conventionally.

Strawberry (Fragaria × ananassa Duch.) contains many secondary metabolites potentially beneficial for human health, and several of these compounds contribute to strawberry sensory properties, as well. In this study, three strawberry cultivars grown both conventionally and organically were subjected to nontargeted metabolite profiling analysis with LC-qTOF-ESI-MS and to descriptive sensory evaluation by a trained panel. Combined metabolome and sensory data (PLS model) revealed that 79% variation in the metabolome explained 88% variation in the sensory profiles. Flavonoids and condensed and hydrolyzable tannins determined the orosensory properties, and fatty acids contributed to the odor attributes of strawberry. Overall, the results indicated that the chemical composition and sensory quality of strawberries grown in different cultivation systems vary mostly according to cultivar. Organic farming practices may enhance the accumulation of some plant metabolites in specific strawberry genotypes. Careful cultivar selection is a key factor for the improvement of nutritional quality and marketing value of organic strawberries.

“The Strawberry Caper”

Achieving a deep understanding of the many topics covered in middle school biology classes is difficult for many students. One way to help students learn these topics is through scenario-based learning, which enhances students’ performance. The scenario-based problem-solving module presented here, “The Strawberry Caper,” not only meets but connects ecological and genetic concepts that are required standards in middle school. Here, students are required to provide expert witness for a patent-infringement claim against an organic strawberry farmer by a large neighboring company. The students must think critically and formulate and test hypotheses to provide evidence for the case. Through phenotypic and genotypic analyses, the students are immersed in an inquiry-driven investigation that provides a real-world context for topics covered in the classroom. This, interspersed with integration of concepts, promotes understanding and application of these topics.

Assessing soil health : A perspective from organic strawberry fields in California, U.S.A.

Assessing soil health : A perspective from organic strawberry fields in California, U.S.A.

Comparison of mineral and trace element contents between organically and conventionally grown fruit

Introduction. Many consumers buy organic foods because of their alleged greater nutritional benefits. However, studies investigating the effect of the agricultural farming system on minerals and toxic elements content are scarce. This study compared the content of minerals (P, Ca, Mg, Na and K) and trace elements (Fe, Mn, Cu, Cr, Se, Zn, Mo, Ni, Cd and Al) of four organically and conventionally grown fruits in Brazil. Materials and methods. Mango (Mangifera indica L., var. Palmer), persimmon (Diospyros kaki L., var. Rama Forte), acerola (Malpighia punicifolia L., var. Olivier) and strawberry (Fragaria vesca L., var. Oso Grande) were produced by organic and conventional farming in the same geographic region, under the same climatic conditions and same type of soil. Mineral analysis was performed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Results and discussion. Organic mango contained higher amounts of Mg and K, and Cr content was higher in conventionally grown mangos. Organic persimmon contained higher amounts of Cu and Zn, and Mg, P, Na, and K concentration was higher in conventional persimmon. Conventionally grown acerola contained higher amounts of Ca, Fe, Mn, Mo, Al, and Ni than the organic acerola. The concentrations of Mo and Al were higher in organic strawberry when compared to conventional strawberry. Conclusion. Organic farming did not result in a clear superiority of the mineral quality of fruit nor did it provide fruit free of toxic elements.

Effect of Chlorella vulgaris CHK0008 Fertilization on Enhancement of Storage and Freshness in Organic Strawberry and Leaf Vegetables

This study aimed to enhance storage and freshness of strawberry fruits and foliage vegetables by spray treatment with Chlorella vulgaris as a bio-fertilizer. The tested strain, C. vulgaris CHK0008, was isolated from an organically cultivated rice paddy and identified as C. vulgaris by its morphology and 18S rDNA and 23S rDNA sequence homology. We successfully cultured C. vulgaris CHK0008 in BG11 modified medium (BG11MM) and adjusted 2.15 × 10 6 cell/mL C. vulgaris CHK0008 to one OD value by measuring the optical density at 680 nm using a UV-vis spectrophotometer. The soluble solid content of ‘Seolhyang’ and ‘Yukbo’ strawberry fruits treated by spray application with C. vulgaris CHK0008 was enhanced by 22.2% and 11.5% respectively, compared to untreated controls. Additionally, the decay rates of treated ‘Seolhyang’ and ‘Yukbo’ strawberry fruits decreased 63.8% and 74.4% respectively, compared to untreated control. Surface color changes and chlorosis of leaves in leaf vegetables such as lettuce, kale, red ornamental kale, white ornamental kale and beet were observed in samples treated with water spray for 10 days after cold storage. However, the decay rate of leafy vegetables treated with foliar application of 25% C. vulgaris CHK0008 liquid culture was significantly decreased compared to that of the untreated control during storage at 4°C. Additional key words: freshwater algae, fresh-cut vegetable, Seolhyang, spray and soil drenching application, Yukbo *Corresponding author: ckshim@korea.kr ※ Received 16 June 2014; Revised 9 July 2014; Accepted 14 July 2014. 본 연구는 2014년도 농촌진흥청 공동연구사업(PJ00912702)의 지원에 의해 수행되었음. C 2014 Korean Society for Horticultural Science 서 언 최근 생활수준의 향상으로 웰빙(wellbeing) 문화가 바람 을 일으키면서 건강에 대한 관심이 날로 증가하고 있다. 이 로 인해 일반 농작물보다 유기농작물 및 유기농 식품을 선 호하는 추세로 변화되고 있다(Kim et al., 2011, 2012, 2013). 특히, 우리나라 소비자들의 유기농 식품에 관한 인식 조사 에서 유기농 식품구매의 가장 큰 이유를 본인과 가족의 건 강(71.9%)이라고 답할 만큼 유기농산물과 유기식품이 차지 하는 비중이 빠르게 성장할 것으로 추산되고 있다(Kim and Lee, 2013; Lee and Kim, 2012). 이러한 소비자들의 식생활 변화는 건강에 대한 관심이 집 중됨에 따라 신선편의 샐러드류와 유기농 채소류의 소비가 증가하고 있으며, 이런 신선편의 샐러드류는 상추, 치커리, 청경채, 트레비소 등 엽채소류와 과일 등을 주 원료로 하여 다양한 형태로 판매되고 있다(Lee et al., 2009). 그러나 신선 편의 채소들은 대부분 별도의 조리과정 없이 바로 섭취하기 때문에 원료의 신선도와 저장성을 증진시키는 노력이 중요 김민정, 심창기, 김용기, 박종호, 홍성준, 지형진, 한은정, 윤종철 873 하기 때문에 다양한 연구들이 이루어지고 있다(In and Kim, 2008; Kim et al., 1995). 딸기는 풍미가 좋고 비타민과 무기영양분이 풍부하며 국 내에서 재배되는 과채류 중 생육 적온이 낮아 난방비 부담 이 적어 고수익의 시설재배 작물로 적합하다. 또한 국내 소 비뿐만 아니라 싱가폴, 홍콩, 및 말레이시아 등 동남아시아 지역으로 수출이 활성화되어, 2009년 총 딸기 수출액이 19,200천 달러가 되었다(KREI, 2010). 그러나 딸기는 물리 적 손상 및 조직의 연화 등으로 과육의 표면이 물러지고 과 숙으로 인한 변색으로 상품성이 낮아지고 수확 후 선별, 저 장 및 유통 과정에서 물리적 손상으로 부패되기 쉬워 이를 해결하기 위한 다양한 연구들이 이루어졌다(Hwang and Ku, 2004; Jeong et al., 1990; Park and Hwang, 2010). 클로렐라(Chlorella vulgaris)는 담수식물이자 미세조류 (microalgae)로 담수, 해수, 공기, 토양 등 다양한 생태계에 서 생존하고 있다. 클로렐라는 축산사료첨가제(Kang et al., 2013), 양어장의 치어사료(Bai and Cha, 1997; Becker, 1994), 식품첨가물(Park et al., 2002), 유산균발효촉진제(Heo et al., 2006), 폐수 중의 중금속 처리제(Travieso et al., 2002) 등으 로 널리 사용되고 있으며 사람에게는 영양학적인 우수성이 확인되었다(Kim et al., 2003). 클로렐라 배양액 및 추출물의 농업적 활용사례는 적으나 클 로렐라 실내배양 조건을 빛과 암 상태를 14:10h(Light:Dark) 로 조절하거나 암 상태에서 glucose(5g・L -1 )를 첨가하여 배 양할 경우 식물생장조절제(plant growth regulators)인 내생 옥신(auxin)과 사이토키닌(cytokinin)이 증가하는 것으로 보고 되었다(Stirk et al., 2014). Raposo et al.(2011)은 클로렐라와 식물생육촉진근권세균(plant growth-promoting rhizobacteria, PGPR)을 혼합 배양하여 레드클로버(meadow clover)에 처 리하였을 경우 뿌리의 신장이 길어지고 지상부와 지하부의 건물중이 증가하는 것으로 보고하였다. 따라서 본 연구는 유기농 딸기와 엽채소의 신선도와 저장 성 향상을 위해 클로렐라(C. vulgaris, CHK0008)를 처리하 였을 때 나타나는 효과를 조사하여 보고함으로써 다양한 기 능성을 지닌 클로렐라의 농업적 활용도를 높이고자 하였다.

New strawberry genotypes tested for organic production on a Verticillium-infested site

Nineteen new strawberry breeding clones, bred at the Institute for Breeding Research on Fruit Crops in Dresden-Pillnitz, Germany, were evaluated for their suitability for organic production at a Verticillium-infested site in Vienna, Austria. Soil cover, plant vitality, resistance to leaf spot diseases as well as flower damages by the strawberry blossom weevil (Anthonomus rubi) and by spring frost were recorded. In two consecutive years, marketable yield and fruits infested by Botrytis cinerea were assessed. Three breeding clones, P-7189, P-8043 and P-8071, were considered as suitable for organic strawberry production. P-7189 and P-8043 showed high tolerance to Verticillium wilt. The breeding clones P-8155 and P-8166 performed well under organic management but had very soft fruits that were not acceptable for commercial fruit production. The rest of the breeding clones were low-yielding, however, some of them could be of interest for home gardens due to their good flavour and high plant vitality.  

Composition of commercially produced organic and conventional strawberries

Purpose – The purpose of this study was to determine differences in taste-related and bioactive compounds of organically (OR) and conventionally (CONV) cultivated commercially produced strawberries (Fragaria × ananassa Duch.). Addresses the question if the consumers buying OR strawberries are likely to purchase fruits with better taste and richer in bioactive compounds than those buying CONV fruits. Design/methodology/approach – Only information commonly available to the consumers [cultivar, quality class, product origin (country) and eco-labelling], was considered in selecting experimental material. “Polka” strawberries from 14 farms (7 OR and 7 CONV) from South Estonia were used for analyses. Findings – No evidence was found that OR strawberries contain more bioactive compounds or have higher soluble solids content and titratable acids ratio (associated with better taste) compared to CONV strawberries. There were significant differences in content of total phenolics, anthocyanins, ascorbic acid, vitamin E, total antioxidant capacity, titratable acids and soluble solids between strawberries from individual farms irrespective of cultivation system. Research limitations/implications – Our study was limited to strawberry “Polka” and some other cultivars might response differently to production systems. Social implications – Consumers get information that by choosing an organic product in the marketplace, it is not guaranteed that this product has higher content of bioactive compounds. Originality/value – Comparative studies of organic and conventional products are preferably performed with products grown at the same location with the same amount of nutrients etc. However, information of production site’s microclimate, soil texture or the amount of plant available nutrients is never available to the consumers. Therefore, our consumer-oriented approach might be valuable.

Effects of organic vs. conventional farming system on yield and quality of strawberry grown as an annual or biennial crop in southern Italy

Organic foods represent a significant market segment within the global food industry, since these products are often believed to be safer and more nutritious than their conventional counterparts. Due to the growing importance of organic strawberry cultivation for several agricultural areas in Italy, we carried out a four year research (2008–2011) on Fragaria×ananassa grown under tunnel in Campania (southern Italy), with the purpose of assessing the effects of two farming systems (organic or conventional) combined with propagation material (fresh or cold stored plants) and crop duration (annual or biennial) on yield and quality. The experimental treatments were randomized in a split-plot design, assigning the farming systems to the main plots and the propagation material in factorial combination with the crop duration to the subplots, with three replicates.The conventional system produced the highest yield, as a consequence of the higher fruit number per plant, while the organic management resulted in increased berry mean weight. Organic fruits showed higher values of dry and optical residue and higher content of glucose, sucrose, vitamin C and ß-carotene but lower nitrate. Fresh plant crops produced a lower yield than the cold stored ones; moreover, the fruit production of fresh plants was higher when grown as an annual crops compared with a biennial cycle, independently on the farming system. In the case of cold stored plants, no yield differences were recorded between annual and biennial cultivations under conventional management, whereas organic crops from cold stored plants showed higher yields as annual crops compared with the biennial cycle. Fruit dry residue as well as sucrose, malic acid and mineral element content attained higher values in the fruits harvested from biennial crops than from the annual ones.The choice of organic system as an alternative to the conventional practice could be justified by the better fruit quality, lower environmental impact and higher market prices. Moreover, the biennial crop duration could be a cost effective option when the crop is started from cold stored plants under organic management.

SUSTAINABLE STRAWBERRY PRODUCTION IN GEORGIA

In Georgia during the last five years there has been an increase of Organic Strawberry farmers’ interest towards strawberry and blueberry crops. These crops have large export potentials in Georgia and cultivation of them through diversification might develop as one of the most important branches of Sustainable Agriculture Development. Insufficient amounts of organic and virus-free plants of these crops is the principal problem in the development of this branch of agriculture. Farmers are interested in producing organically and biologically safe strawberry plant products without using artificial pesticides and fertilizers. Organic biomass mulches are used widely. Organic strawberry producers are struggling to address the challenges that have been intensified by harmful chemicals and oil-based fertilizers in conventional strawberry production. Three of the most pressing challenges facing sustainable organic strawberry growers are soil fertility, soil-borne diseases and pests. Organic fruit is produced without conventional pesticides, synthetic fertilizers or bioengineering. Choosing organic culture provides a tangible way which is beneficial for the environment, local economies, and public health, both on and off the farm. Our research provides sustainable strawberry organic methods. It also covers integrated pest management and weed control techniques that can reduce pesticide use in strawberry production.

Heat shock and salicylic acid on postharvest preservation of organic strawberries

Heat shock and salicylic acid have been studied on shelf-life extension of fruits. The benefits of these techniques have been related to their effect on inducing physiological defense responses against the oxidative stress and pathogen development. The objective of this study was to evaluate the effect of heat shock and salicylic acid on the postharvest preservation and contents of total phenolics, anthocyanins, ascorbic acid, fresh weight loss and microbiological quality of organic strawberries cv. Dover. Strawberries produced organically and stored at 5 ºC were subjected to heat shock (45 ºC ± 3 ºC for 3 h), application of salicylic acid (soaking in 2.0 mmol L-1 solution), heat shock in combination with salicylic acid and control. After treatment, the fruits were packed and stored in a climatic chamber at 5 ºC ± 2 ºC. At 1, 7 and 14 days, the experimental units were removed from refrigeration and kept at room temperature of approximately 20 ºC for two days. There was no effect of treatments on fresh weight loss, incidence of pathogens or chemical variations in strawberry fruits during the storage period. In natural conditions, organically grown strawberries remained in good condition for sale up to seven days of storage in all treatments.

Spatial density and movement of the Lygus spp. parasitoid Peristenus relictus (Hymenoptera: Braconidae) in organic strawberries with alfalfa trap crops.

Alfalfa trap crops are currently used to manage Lygus spp. in organic strawberry fields on the California Central Coast. The retention of Lygus spp. in alfalfa creates aggregated distributions that provide improved opportunities for biological control by the introduced parasitoid Peristenus relictus (Ruthe). The abundance and distribution of P. relictus between two trap crops separated by 50 strawberry rows were analyzed in 2008 and 2010. Parasitism of Lygus spp. nymphs by P. relictus (measured by larval abundance and % parasitism) was greatest in alfalfa trap crops compared with strawberry rows. A significantly positive correlation between host nymphs and P. relictus larvae in and between trap crops was found. Movement of P. relictus adults from a marked alfalfa trap crop into adjacent strawberry rows or trap crops was also studied in 2008 and 2009 using a chicken egg-albumin enzyme-linked immunosorbent assay mark-capture technique. In 2008 and 2009, 85 and 49% of protein-marked wasps were captured from central trap crops, respectively, indicating that alfalfa trap crops act as a concentrated "host-density anchor" in organic strawberry fields.

Integrated Biological and Cultural Practices Can Reduce Crop Rotation Period of Organic Strawberries

A team of researchers conducted a replicated on-farm experiment with the break period between strawberry crops (continuous strawberries with broccoli residue incorporation, one-year break, two-year break, three-year break, and seven-year break) as the main plot and cultivar as the split plot in Moss Landing, Central Coastal California. We hypothesized that the use of non-host rotation crops for Verticillium wilt plus bio-fumigation with broccoli, incorporation of mustard cover crop residues, use of relatively resistant strawberry cultivars, and compost application would suppress disease sufficiently to grow strawberries successfully in rotation every two or three years. Although a positive correlation between break period and marketable fruit yield existed, integrated use of biological and cultural practices allowed one to three-year breaks to have a statistically similar yield as seven-year break for this low Verticillium dahliae pressure field over a five-year period.

Dispersion, Distribution, and Movement ofLygusspp. (Hemiptera: Miridae) in Trap-Cropped Organic Strawberries

Alfalfa (Medicago sativa L.) is a highly attractive plant host to Lygus spp. and is used as a trap crop in California organic strawberries to influence the dispersion and dispersal of these pests, particularly Lygus hesperus Knight. The abundance and distribution of Lygus spp. nymphs between two trap crops separated by 50 strawberry rows was analyzed in 2008 and 2010. Nymphs demonstrated a bimodal distribution in strawberries between trap crops, where nymphs were most abundant and aggregated in alfalfa, when compared with interior strawberry rows, where nymphs were less abundant. The majority of nymphs were concentrated in trap crops and nymphal densities in interior strawberry rows were well below economic thresholds. The movement of Lygus spp. from a marked alfalfa trap crop into adjacent strawberry rows or trap crops was also studied in 2008 and 2009 using a chicken egg albumin enzyme-linked immunosorbent assay mark-capture technique. The majority of marked-captured L. hesperus adults and Lygus spp. nymphs remained in alfalfa trap crops, rather than dispersing out into strawberry rows at 24 h, 48 h, and 2 wk, postprotein application. The attenuation of Lygus spp. movement in alfalfa associated with organic strawberries is a key component of successful trap cropping. A small percentage of marked adults and nymphs were captured in neighboring alfalfa trap crops, located 62 m from the point of protein application, highlighting the dispersal capacity of this key pest.

Effect of Alginure® (seaweed extract), Myco-Sin®VIN (sulfuric clay) and Polyversum® (Pythium oligandrum Drechs.) on yield and disease control in organic strawberries

In 2011 and 2012 three commercial products Alginure® (seaweed extract), Myco-Sin® VIN (sulfuric acid clay with yeast and plant extracts) and Polyversum® (spores of Pythium oligandrum) were tested in field experiment with strawberry cv. ‘Induka’ under the conditions of organic growing system. The aim of the study was to determine the effect of the preparations on yield, fruit quality and diseases control. The preparations were applied five times during flowering. We assessed total yield, marketable and unmarketable yields, average fruit weight, grey mould incidence on fruits caused by Botrytis cinerea and leaf spot severity caused by Mycosphaerella fragariae. Efficacy (%) of preparations was calculated. Preparations did not show positive effect on yields parameters. Total and marketable yields were not significantly different to untreated control in both years. Nevertheless considerable increase of yields from 2011 to 2012 was observed in strawberries treated by biofungicide Polyversum®. Preparations did not significantly reduce the incidence of grey mould. Alginure® showed the best results by efficacy 39.6 % and 57.4 %, respectively. All preparations provided very low, less than 10% efficacy to control leaf spot severity.

Physical attributes and chemical composition of organic strawberry fruit (Fragaria x ananassa Duch, Cv. Albion) at six stages of ripening

Organic strawberry fruits (Cv. ‘Albion’) were harvested at six different ripening stages and evaluated for physical and chemical parameters. Biometrical characteristics and moisture content did not change significantly during ripening. Total soluble solids, pH and colour development increased while titratable acidity and fruit firmness decreased 14.7% and 91%, respectively. Fructose, glucose, and sucrose followed similar tendencies. Final contents of these sugars were 2323.4, 1988.5, and 1578.4mg/100g. Citric, malic, and ascorbic acids followed a descending, irregular, and increasing tendency during ripening, respectively. Final contents of these acids were 822.8, 245.8, and 78.1mg/100g. Total anthocyanins content (TAC) increased during ripening, while the opposite was observed for total phenolic content (TPC). TAC and TPC in ripe fruit were 56.4mg/100g and 196mg gallic acid equivalents (GAE)/100g. Twenty eight phenolic compounds, mainly glycosides, were identified and quantified by HPLC-DAD–MS analysis. The concentration of these compounds was ripening dependent.

Color, anthocyanin pigment, ascorbic acid and total phenolic compound determination in organic versus conventional strawberries (Fragaria × ananassa Duch, cv Selva)

The CIEL*a*b* and sensory color and anthocyanin, ascorbic acid and total phenolic contents were determined in strawberries (Fragaria×ananassa Duch, cv Selva) grown in the same geographical area of Galicia (NW Spain) under organic and conventional farming methods. The cultivation system was significant for all of the CIEL*a*b* surface color parameters. The color of the organic fruits was darker, less vivid and frequently redder (lower L*, C* and H values). These differences were consistent with the higher scores given by assessors in the external color evaluation for organically grown strawberry. Furthermore, the organic strawberries had a significantly higher level of anthocyanins (19.3±6.8 versus 9.8±1.8μg/gfreshwt (fw) for Cyn-3-glu; 332.3±66.5 versus 254.1±33.6μg/gfw for Pgd-3-glub) and ascorbic acid (86.4±12.7 versus 71.2±4.9mg/100gfw); in contrast, the cultivation system (organic or conventional) did not affect the total phenolic content. The organic strawberries have a higher nutritional value, in terms of antioxidant compounds, which is also reflected in better sensory color characteristics.

Physical-chemical and Microbiological Characteristics of Organic Strawberries Conserved with Biofilms and Refrigeration

Biodegrabable and edible coatings were applied on fresh strawberries (<em>Fragaria </em>x <em>ananassa Duch</em>), ‘Camarosa cultivar’, produced in organic system and stored at 10ºC for nine days. Color, mass loss, incidence of rottenness and chemical analyses contents was evaluated. Suspension of cassava starch and grains of kefir milk reduced evolution of fruit coloration when compared uncoated fruits. Treatment associated cassava starch and kefir liquid resulted in a lower rottenness incidence and less mass loss of the fruits, is therefore recommended for postharvest organic strawberries. Anthocyanin and titrable acidity contents increased during storage, regardless of the treatments in general.

Effects of local vegetation and plantation age for the parasitoid Asecodes mento– a biocontrol agent in organic strawberry fields

Abstract The parasitoid Asecodes mento (Walker, 1839) (Hymenoptera: Eulophidae) is the most important biocontrol agent of the strawberry leaf beetle Galerucella tenella (L.) (Coleoptera: Chrysomelidae) in northern Europe. Here, I investigated whether natural parasitism in organic strawberry plantations was affected by the presence of the alternative host plant meadowsweet (Filipendula ulmaria), and whether parasitism rates differed between plantations of different ages (6 to 79 years). I also investigated whether parasitoid brood size, body size and sex ratio differed between the two host plants in the field. Parasitism was very low (0%) in newly established plantations and increased to a plateau (∼40%) in fields where strawberries had been grown for approximately 20 years or longer. Such an extended colonization process is unacceptable for commercial growers. It would thus be desirable to find a method to catalyze parasitoid population buildup in young plantations. Parasitoid brood sizes were larger in beetles collected from meadowsweet, while body size and sex ratio did not differ between parasitoids collected from the two plants. These findings suggest that meadowsweet can export parasitoids to neighboring strawberry fields. Although this is a possibility, I did not find any significant differences in parasitism rates between isolated strawberry fields and fields adjacent to meadowsweet stands, indicating that effects of local vegetation are small on parasitism rates. Releasing parasitoids in newly established strawberry plantations may be a better strategy for quickly obtaining high parasitism than intercropping with meadowsweet.