Alternative disease management strategies for organic apple production in the United Kingdom

This paper provides an input–output (I/O)-based economic impact analysis for organic apple production in Washington State. The intent is to compare the economic ‘ripple’ effect of organic production with conventional production. The analysis is presented in two scenarios: first we compare the economic impact of organic versus conventional apple production for a final demand increase of US$1 million as measured in sales. In the second analysis, the economic impacts of organic and conventional apple production are compared in terms of a given unit of land (405 ha of production). Both state-wide output (sales) and employment (jobs) impacts are estimated under each scenario. Results are presented in terms of direct, indirect, and induced economic impact. Organic apple production was more labor intensive than conventional production. While the organic apple sector used less intermediate inputs per unit of output than conventional production, it also produced higher returns to labor and capital. As a result, the indirect economic effect was lower for the organic sector than the conventional sector, but the induced economic effect was higher for organic. Given the organic price premium, the economic impact (direct, indirect and induced) was larger for organic apple production than conventional apple production.

It is debated whether the ecotoxicity of active substances (ASs) contained in synthetic pesticides applied in conventional agriculture (conASs) differs from nature-based ASs used in organic agriculture (orgASs). Using the official pesticide use statistics, we evaluated the ecotoxicity of ASs used in apple and grapevine production in Austria. In 2022, 49 conASs and 21 orgASs were authorized for apple production and 60 conASs and 23 orgASs were authorized for grapevine production in Austria. Based on the latest publicly available data on the actual use of pesticides in apple and grapevine production (from the year 2017), we evaluated their ecotoxicity based on information in the freely accessible Pesticide Properties and Bio-Pesticides Databases. The results showed that although the amount of ASs applied per hectare of field was higher in organic farming, the intrinsic toxicities of ASs used in conventional farming were much higher. The number of lethal toxic doses (LD50) of ASs applied in conventional apple orchards was 645%, 15%, and 6011% higher for honeybees, birds, and earthworms, respectively, than in organic apple production. In conventional vineyards, lethal doses for honeybees, birds, and earthworms were 300%, 129%, and 299% higher than in organic vineyards. We conclude that promoting organic farming would therefore contribute to the better protection of biodiversity on agricultural land and beyond.

Nematode community structures in different deciduous tree fruits and grape in Colorado, USA and impact of organic peach and apple production practices

RESEARCH DIRECTIONS FOR ORGANIC TREE FRUIT PRODUCTION IN NORTH AND SOUTH AMERICA

With economic indicators from the full cost account and the cash flow statement it is possible to identify the return-risk profile for the organic and the integrated apple production in Switzerland. The full cost account and the cash-flow time line are composed with the managerial-economical software-tool Arbokost. Due to higher (more than 100%) prices in the organic production, growing organic satisfies more return-oriented producers than growing certified integrated. However, the higher return in the organic production is bound to a higher risk. With the certified integrated production (IFP), return and risk are lower. ‘Arbokost’ is an economic farm management software tool for fruit growers. Per orchard it reflects a full cost account, the cash flows collected during 15 years, the earned income for each year and other different key data which are important for certified integrated and organic apple production in Switzerland. Also, the cost differences between Swiss organic and certified integrated apple production can be calculated.

During the 2008–2010 growing seasons, an alternative ‘zero residue apple production system’ was compared with integrated apple production with cvs ‘Idared’, ‘Golden Delicious’, ‘Jonagold’ and ‘Gala’ in commercial orchards at several locations throughout Slovenia, using data envelopment analysis (DEA), and multi criteria assessment by an analytical hierarchical process (AHP). The principle of the ‘zero residue apple production’ is a combination of integrated (IP) and organic apple production. During the first 3 months of the growing season (1 April–30 June), pesticides used in IP with rapid degradation (8–10 applications) were used to control pests and diseases. During the second part of the season from 1 July to harvest, organic products (6–12 applications) were employed compared with 19–25 applications overall in IP. The goal of the alternative system was to reduce the amount of applied conventional pesticides by 40 % and to minimize pesticide residues in fruits to below the limit of 0.5 % of the legal maximum residue level (MRL) or below the residue concentrations of 0.005–0.01 mg/kg and to retain the high long-term level of yield, fruit quality, and net income per hectare. The number of pesticide residues was reduced from 4.2–5.5 in IP to 1.8–3.4 in zero residue cultivation, while 3 year average yields (class 1 fruit) were 4–9 % lower than in IP. The break even prices ranged from € 0.31 for Idared in IP, € 0.34 for ‘Elstar’ of both production systems to € 0.35/kg for zero residue cultivated ‘Golden Delicious’. Overall, a price increase of just € 0.02/kg for residue free apples would make this new ‘zero residue apple production’ profitable then representing a realistic alternative to the standard integrated apple production system.

Climate change is a complex and contentious public issue, but the risk-management options available to us are straightforward and have well-characterized strengths and weaknesses.

Based on data of a survey among 18 organic apple producers in Northern Germany and complementary expert judgements the rentability of transition from conventional to organic production is analysed. It is hypothesized that changing from conventional to organic production is an investment because specific capital items are necessary for such a step. It is further hypothesized that in view of the limited experience and the very restricted availability of extension materials such investment is particularly prone to risk. The methodology applied to investigate the question of rentability and risk of the investment for the transition to organic apple production includes four steps. First, economic parameters of the 18 existing organic apple producers are being analyzed. Second, the net present value and the annuity of net benefits from transition to organic apple production is calculated. Third, the risk of such investment is analyzed by applying Monte-Carlo type stochastic simulation. This method was also used to investigate the relative advantage of different apple varieties. Finally, the effect of varietal diversification on the mean and the variance of income is investigated by using a MOTAD approach. Choices about varieties are especially important in organic apple production as this is a major tool to control pests and to achieve high prices on the market. The analysis of the survey data confirmed the observation of previous studies that a distinction between extensive and intensive organic producers is reasonable. Results showed that only intensive apple producers are likely to be economically successful. The results of investment analysis for a model farm representing the group of intensive producers showed that at a price above 1 DM per kg of apples and a yield of at least 15 t per ha put to transition is economical. Comparing these data with those from the current producers in Northern Germany, transition to organic apple may be recommended to conventional farmers if they are prepared to take the extra risk. Results of the stochastic simulation confirms the result of the analysis under certainty. When risk is taken into account organic apple production remains an interesting option for farmers who are willing to learn and innovate. Comparing four apple varieties reveals that 'Topaz', a variety resistant to apple scab, is dominating all other varieties frequently grown by organic producers. Nevertheless, planting several varieties makes economic sense when risk is taken into account. Results of the MOTAD model show the trade-off between average annuity and its variance for different portfolios. At an annuity of less than 9 000 DM per ha high diversity can be observed. On the other hand, as income expectations rise, the number of varieties in the portfolio decline. In the extreme case of more than 11 000 DM only one variety, i.e. the variety 'Topaz' remains. The paper also draws some preliminary conclusions as regards the possibilities for further economic studies on organic horticulture. It is concluded that aside from the severe data problem innovative model approaches are necessary to capture some of the real questions which are asked by the practitioners of organic farming as well as by policy makers. It appears that extending the neo-classic economic approaches by some elements of ecological economics can advance the analysis of organic farming.

Climate change will affect both the quality and the quantity of water in freshwater environments. Changes in air temperature and precipitation will alter the annual water temperature cycle and the annual water level cycle. Initial assessments of the effects of climate change on freshwater fishes of North America have focused on the potential thermal effects of climate change because of the strong influence of water temperature on the life histories of temperate fishes. Paralleling the influence of water temperature on temperate fishes is the influence of water quantity on tropical fishes, especially on riverine fishes. The extreme seasonal fluctuations in discharge of tropical rivers, through the effects on fish habitat availability and habitat conditions, have produced a range in preferred habitat types among riverine fishes. We suggest that initial assessment of potential effects of climate change on tropical freshwater fishes should focus on changes to water quantity variables in riverine environments. Assessments should begin at a coarse level of resolution. A useful starting point would be comparative analyses of the sensitivity of blackfishes and whitefishes to changes in habitat availability, oxygen levels and desiccation stress that will likely accompany changes in the seasonal flow regimes of tropical rivers.

Certified organic farm area in Poland increased 8.5 fold during the 2003-2010 time period to 518 thousand ha, which constituted 2.8% of the arable land. The production costs and profitability of the organic fruit production of apples, strawberries, and sour cherries were evaluated and compared to conventional production of those fruits. The research was based on data from thirty-two commercial fruit farms; twenty farms with conventional production, and twelve with organic production. The main problems associated with organic production were the costs of weed control and soil cultivation. The conventional production of apples turned out to be slightly more profitable than the organic production. The organic production of sour cherries was not profitable. In the case of strawberries, it was the opposite - the organic production gave a better financial outcome than the conventional one

Apple replant disease (ARD) is a common problem in major apple planting areas, and biological factors play a leading role in its etiology. Here, we isolated the bacterial strain QSB-6 from the rhizosphere soil of healthy apple trees in a replanted orchard using the serial dilution method. Strain QSB-6 was provisionally identified as Bacillus amyloliquefaciens based on its morphology, physiological and biochemical characteristics, carbon source utilization, and chemical sensitivity. Maximum likelihood analysis based on four gene sequences [16S ribosomal RNA gene (16S rDNA), DNA gyrase subunit A (gyrA), DNA gyrase subunit B (gyrB), and RNA polymerase subunit B (rpoB)] from QSB-6 and other strains indicated that it had 100% homology with B. amyloliquefaciens, thereby confirming its identification. Flat standoff tests showed that strain QSB-6 had a strong inhibitory effect on Fusarium proliferatum, Fusarium solani, Fusarium verticillioides, Fusarium oxysporum, Alternaria alternata, Aspergillus flavus, Phoma sp., Valsa mali, Rhizoctonia solani, Penicillium brasilianum, and Albifimbria verrucaria, and it had broad-spectrum antibacterial characteristics. Extracellular metabolites from strain QSB-6 showed a strong inhibitory effect on Fusarium hyphal growth and spore germination, causing irregular swelling, atrophy, rupture, and cytoplasmic leakage of fungal hyphae. Analysis of its metabolites showed that 1,2-benzenedicarboxylic acid and benzeneacetic acid, 3- hydroxy-, methyl ester had good inhibitory effects on Fusarium, and increased the length of primary roots and the number of lateral roots of Arabidopsis thaliana plantlet. Pot experiments demonstrated that a QSB-6 bacterial fertilizer treatment (T2) significantly improved the growth of Malus hupehensis Rehd. seedlings. It increased root length, surface area, tips, and forks, respiration rate, protective enzyme activities, and the number of soil bacteria while reducing the number of soil fungi. Fermentation broth from strain QSB-6 effectively prevented root damage from Fusarium. terminal restriction fragment length polymorphism (T-RFLP) and quantitative PCR (qPCR) assays showed that the T2 treatment significantly reduced the abundance of Fusarium in the soil and altered the soil fungal community structure. In summary, B. amyloliquefaciens QSB-6 has a good inhibitory effect on Fusarium in the soil and can significantly promote plant root growth. It has great potential as a biological control agent against ARD.

The purpose of this study was to compare organic and conventional apple production systems in terms of energy, economics and greenhouse gas emissions at an orchard located at Egirdir Fruit Research Institute Isparta-Turkey, where ’Williams Pride’ apple variety were grafted on M9 rootstock. The results showed that the total energy consumptions for organic and conventional apple orchards were 25,937.58 and 29,199.61 MJ ha−1, respectively (P 0.01). The renewable energy consumed in organic farming (30.19%) was higher than that of conventional farming system (13.58%). Benefit to cost ratio of apple produced organically (1.74) was higher than that of conventional groves (1.46) (P > 0.01). The value of total greenhouse gas emission of organic production was estimated at 1344.27 kg CO2eq ha−1 while conventional production was 1464.07 kg CO2eq ha−1 (P < 0.01). In conclusion, organic apple production systems can reduce the non-renewable energy consumption, protect the environment, and maintain soil quality with comparable apple outputs while yielding higher profits and greater energy efficiency.

Continuous planting of apple in the same area leads to reduced growth vigor and subsequent crop losses, i.e., apple replant disease (ARD) syndrome. Several soilborne plant pathogens including Pythium, Fusarium, and Cylindrocarpon spp. are often proposed as candidate causal organisms for ARD. In addition, the presence of root lesion nematodes and the lack of beneficial groups of bacteria are believed to exacerbate or ameliorate the effects of the plant pathogens. The importance of these proposed causal and auxiliary agents seems to vary with site. Using a spatially explicit sampling strategy to minimize spatial variability we collected rhizosphere soil samples from neighboring pairs of healthy and putative ARD trees to identify candidate causal organisms of ARD. Amplicon-based metabarcoding was used to obtain community-level profiles of the bacteria, fungi, oomycetes and nematodes in the soil samples. Total bacterial and fungal biomass in each sample was estimated using qPCR to adjust the raw sequence reads data. The results suggested that ARD is not ameliorated by enhanced rhizosphere biodiversity per se. We identified 25 bacterial operational taxonomic units (OTUs), 16 fungal OTUs, 18 oomycetes OTUs, and one nematode OTU group with differential abundance between healthy and putative ARD trees. All 25 bacterial OTUs had lower abundance in samples from ARD symptomatic trees than from healthy trees. One AMF OTU had lower abundance in samples from ARD symptomatic trees. None of 13 fungal OTUs that had higher abundance in samples from ARD symptomatic trees is a known plant pathogen; but at least one Pythium OTU (probably Pythium intermedium) is a candidate for causing ARD. The abundance of one nematode OTU was much higher in samples from ARD symptomatic trees than in healthy trees. The results suggest that, apart from the use of broad spectrum fumigants, the complexity of ARD may necessitate the combined use of multiple management strategies with the success of these measures expected to vary considerably between sites because of the varying importance of ARD causal agents among sites.

Apple replant disease (ARD) is a severe problem in apple production worldwide. It is caused by a complex of soil biota, leading to small discolorated roots, as well as increased biosynthesis of phytoalexins, total phenolic compounds and antioxidants. We sampled soil from randomized field plots with either apple trees affected by ARD, which were five times replanted every second year, or with healthy trees growing in plots, which had a grass cover during this period. We investigated the contribution of nematodes to ARD by dissecting the soil biota from plots infested with ARD and non-infested control plots into a nematode and a microbe fraction. Nematode communities significantly differed between ARD and control soil as revealed by high-throughput sequencing of 18S rRNA genes. Plant-parasitic nematodes were too low in abundance to explain root damage, and did not significantly differ between ARD and control soil. Their separate and synergistic effect on ARD symptoms of susceptible M26 apple rootstocks was analyzed 4 and 8 weeks after inoculation in three greenhouse experiments. Inoculants were either nematodes from ARD plots (NARD), NARD plus microbes from ARD plots (MARD), NARD plus microbes from control plots (MCon), nematodes from control plots NCon plus MARD, NCon plus MCon, MARD, or MCon, or non-inoculated control. In all three experiments, the combination NARD plus MARD had the strongest adverse effect on the plants, with respect to growth parameters of shoots and roots, total phenolic compounds and phytoalexins in roots, and antioxidants in leaves. NARD also induced ARD but less than NARD plus MARD. NARD plus MCon had delayed effects on the plants compared to NARD plus MARD, suggesting that detrimental nematode-microbe interactions built up with time. Effects of MARD or NCon plus MARD were minor or not distinguishable from those of MCon or non-inoculated control. Overall, the source of the inoculated nematodes -ARD or control soil- and the interaction between ARD nematodes and microbes were highly significant factors determining ARD. In conclusion, exploring the associations of nematodes and microbes in ARD soils will give the chance to unravel the etiology of ARD.

Environmental considerations are becoming increasingly important and, as a consequence, interest has turned from conventional to organic fruit production, including apple. In this production system, synthetic products are banned e.g. in plant protection and nutrient supply, only natural products are permitted according to organic production standards. As a result, disease control is less effective in organic apple orchards than in conventional ones with the consequence that epidemics of key diseases are likely to be more serious in such a system. The majority of sprays in organic apple production are consumed for apple scab control. Therefore, improvement of fungal disease management in organic apple production is largely dependent on apple scab control. This review will provide novel epidemiological aspects and season-long management options against apple scab in organic orchards. This will include several topics (i) risks of early scab epidemics in organic apple orchards initiated by sexual and asexual forms of fungi, (ii) specific features of apple scab epidemics in organic orchards, (iii) possible control strategies to reduce primary inoculum sources, (iv) appropriateness of various sanitation practices against scab in organic production, and (v) some aspects of efficacy and phytotoxicity of approved fungicidal products against scab in organic orchards. Based on the above examples, a theoretical and practical decision-making approach for apple scab and future trends for organic disease management will be provided for organic orchards based on mechanical, agro-technical and chemical control options.