Large Orchards Research Articles

Economic Analysis of a Low-cost Apple Harvest-assist Unit

A low-cost apple (Malus domestica) harvest-assist unit was recently developed to assist employees with fresh apple harvesting. This study reports on the economic analysis of this apple harvest-assist unit. Annual costs of the harvest-assist unit were calculated, including ownership and operational cost. Annual cost savings by increasing apple harvest efficiency, decreasing occupational injuries, improving work productivity in training, pruning, and thinning, and eliminating expenditures on purchasing ladders were calculated. When the annual costs are smaller than annual savings, the unit benefits apple orchard owners positively. Economic analysis results using orchard yields ranging from 25 to 45 Mg·ha−1 demonstrated that when the apple orchard area was larger than 7.6 ha, the unit always benefited orchard owners positively; when the orchard area was smaller than 4.2 ha, the unit always benefited orchard owners negatively. For large orchards, more than one unit was required to satisfy the operational needs. Of the top four U.S. apple production states, Washington, New York, and Michigan, benefitted from purchasing four units, three units, and two units, respectively, per typical farm. However, an average-sized orchard in Pennsylvania, would not benefit, due to small orchard size and low yield. A net present value (NPV) analysis was determined using data from Washington State, which yielded a return on the 8-year investment in the machinery of $888.44.

Automated online solid-phase extraction-liquid chromatography mass spectrometric analysis of dithianon in water.

An automated online solid-phase extraction-liquid chromatography mass spectrometry (SPE-LC/MS) method was developed for the quantification of dithianon in surface water samples, using warfarin as internal standard. The method was developed on a liquid chromatography (LC) system with Flexible Cube interfaced to a quadrupole time-of-flight (Q-TOF) mass spectrometer. A small volume of acidified water (1 mL) was spiked with internal standard, pre-concentrated online on polymeric cartridges and analyzed by full-scan MS in high-resolution conditions. The quantitative data were obtained by [M]-• of dithianon and [M - H]- of warfarin, used as internal standard. The chromatographic separation was performed on a C18 column with a gradient mobile phase consisting of acetonitrile and water containing 0.05% acetic acid. The method was validated to measure concentrations of dithianon in the range of 0.010-4 µg L-1 in surface water samples. Twenty real water samples, collected from Torrente Novella, Val di Non (TN, Northern Italy), during fungicide treatments of large apple orchards, were analyzed. All samples were kept in glass bottles and stored in the lab at -20°C until analysis. It was found that in all samples dithianon was undetectable: if it is present, its concentration was lower than the limit of detection (LOD) (0.008 µg L-1.To investigate the stability of dithianon, a series of water samples were spiked at different concentrations and analyzed after different storage conditions. Results suggested that dithianon is not stable in water stored at -20°C at neutral or basic pH, but the addition of acetic acid to pH = 3.5 increases its stability to at least two weeks.

Spatial distribution patterns of apple sawfly populations in two differently managed commercial apple orchards

An investigation on spatial distribution of apple sawfly (Hoplocampa testudinea Klug, 1816) populations was conducted in organically and conventionally managed apple orchards of Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2010–2013. The aim of this study was to examine population density patterns of within orchard spatial distribution of apple sawfly. White sticky traps Rebell ® bianco (Andermatt Biocontrol, Switzerland) were used to monitor apple sawfly population density. In order to determine aggregation extent in sawfly populations, coefficient k of the negative binomial distribution, serving as aggregation index, was computed using maximum-likelihood method. Additionally, in order to accurately evaluate distribution patterns of apple sawfly within orchards, spatial analysis using Kernel density function was performed. Spatial analysis was performed using program package ARCGIS 10. Results of the study on spatial distribution patterns of apple sawfly imagoes demonstrated strong tendency for aggregation of adult sawflies across the orchard area. Localisation of clumps was quite constant despite the size of the orchard. Such knowledge could be applied for optimization of apple sawfly control strategies, especially in large orchards. The highest infestation levels were recorded exactly in the aggregations of sawflies over the course of the study. Moreover, knowing exact locations of such aggregations could be useful for optimization of positioning of traps in the orchards and, ultimately, restricting insecticide applications only to places where it is really necessary.

New Insights into Mango Malformation Disease Epidemiology Lead to a New Integrated Management Strategy for Subtropical Environments.

Mango (Mangifera indica) is regarded as the king of fruits in India, where it has been cultivated for at least 4,000 years and has great cultural and religious significance. Many Indian mango cultivars originated in the fifteenth century when the best selections of mango seedlings were propagated by grafting and planted in large orchards, in some cases numbering 100,000 trees. With the arrival of voyagers to India from Europe, mango was soon established throughout the tropics and subtropics. Mango malformation disease (MMD) is one of the most important and destructive diseases of this crop. It affects inflorescences and vegetative portions of the plant. Although trees are not killed, the vegetative phase of the disease impedes canopy development and the floral phase reduces fruit yield dramatically; substantial economic losses can occur since malformed inflorescences do not bear fruit. Significant advances have been made in understanding the etiology of MMD, which is caused by more than one agent. However, until recently little progress had been made on the epidemiology of this disease. The results that are discussed in this article are only for MMD caused by F. mangiferae.

Modeling and optimization of CO2 emissions for tangerine production using artificial neural networks and data envelopment analysis

The aims of this research were to scrutinize CO2 emissions based on different size levels of orchards, modeling and optimization of CO2 emissions using artificial neural network (ANN) and data envelopment analysis (DEA) for tangerine production in Guilan province, Iran. The results revealed that the total CO2 emissions and yield were calculated about 622 kgCO2eq. ha-1 and 49 ton ha-1, respectively. Also, the large orchards had the highest emissions and yield among all of the groups. The results of ANN modeling indicated that the best topology was 8-4-1 for prediction of tangerine yield based on emission inputs. Also, the R 2 , RMSE and MAPE (%) of the best structure was computed as 0.964, 0.111 and 0.312, respectively. Based on DEA approach, the mean of technical, pure technical and scale efficiency was found to be 0.802, 0.890 and 0.894, respectively. In optimal units, the total CO2 emissions were calculated as 483.83 kgCO2eq. ha -1 . The results indicated that optimization of CO2 emissions by the DEA can reduce the total emissions about 138 kgCO2eq. ha-1 and the reduction of electricity consumption had the highest positive effect in CO2 emissions reductions.

The effects of different maturity times of fruit ripening and limb connection heights on the percentages of fruit removal in mechanical harvesting of hazelnut (Cv. Yomra)

In this research, the effects of maturity times of fruit ripening (MTR) and limb connection heights of shaker on efficacy of eccentric type shaker which is calculated by the percentages of fruit removal (PFR) in hazelnut (Corylus avellana L.) harvesting were assessed. Also, work efficiency of mechanical harvesting was evaluated. Three different timing strategies were determined for shaking and collecting the maturing hazelnuts. The first harvest time was chosen as August 28th which is indicating the approximately half of the matured hazelnuts. The second harvest time (September 7th) includes the term which nearly all the hazelnuts were matured. The natural fruit dropping time was considered as third harvest time (September 15th). Experiments were performed at four different limb connecting heights from the ground (LCH, 0.5 m, 1 m, 1.5 m and 2 m). Effects of maturity times of fruit ripening, limb connecting heights of shaker and their interactions on PFR were found significantly (P<0.01). The first harvest time (26.90%) decreased (P<0.01) the PFR as compared to the second (64.13%) and the third harvest time (69.83%). The LCH of 0.5 m (40.71%) and LCH of 1 m (43.43%) had a lower PFR value as compared to the LCH of 1.5 m (53.50%) and 2 m (57.41%). The effects of harvest times and LCH on the PFR were found to be linear (P < 0.01). The obtained results have showed that for larger orchards, the third harvest time which is used in the present study could be considered to be the best of the three ones with the LHC of 2 m.

Limitations to adopting regulated deficit irrigation in stone fruit orchards: a case study

Fruit production development is resulting in large commercial orchards with improved water management standards. While the agronomic and economic benefits of regulated deficit irrigation (RDI) have long been established, the local variability in soils and climate and the irrigation system design limits its practical applications. This paper uses a case study approach (a 225 ha stone fruit orchard) to unveil limitations derived from environmental spatial variability and irrigation performance. The spatial variability of soil physical parameters and meteorology in the orchard was characterized, and its implication on crop water requirements was established. Irrigation depths applied during 2004-2009 were analysed and compared with crop water requirements under standard and RDI strategies. Plant water status was also measured during two irrigation seasons using stem water potential measurements. On-farm wind speed variability amounted to 55%, representing differences of 17% in reference evapotranspiration. During the study seasons, irrigation scheduling evolved towards deficit irrigation; however, the specific traits of RDI in stone fruits were not implemented. RDI implementation was limited by: 1) poor correspondence between environmental variability and irrigation system design; 2) insufficient information on RDI crop water requirements and its on-farm spatial variability within the farm; and 3) low control of the water distribution network.

Noninvasive Water Stress Assessment Methods in Orchards

In large orchards up-to-date information is needed on water capacity and possible water stress of the fruit trees because the physiological reactions against the changing water capacity appear much earlier than the water stress. These physiological changes cannot be observed visually in the early period of water stress. One of the most sensitive indicator of photosynthetic activity, mutations, stress the chlorophyll content of the vegetation, which can be monitored by photometry. Thus, combining airborne remote-sensing technology and reflectance measurements of leaves can be the solution for detection of changing water content. With the use of remote-sensing technology, a large amount of agroecologic information can be achieved on sites such as orchards. The examined intensive apple and the extensive pear orchards, established on sandy soils, are situated in the northeastern part in Hungary. The apple orchard has a microirrigation system. Hyperspectral image was taken by AISA Dual airborne hyperspectral camera. The full spectra range of this system is 400–2450 nm, which was set to the maximum 498 spectral channels at the 2.25-m2 spatial resolution. Parallel to the flight campaign, leaf samples were also taken. Samples of different kind of apple species were analyzed by ALTA II and AvaSpec 2048 hand portable spectrometers. Based on the hyperspectral image, vegetation indices were also calculated to detect the effect of water stress. The normalized difference vegetation index (NDVI), which is sensitive to changes in biomass, and the water band index (WBI), which is sensitive to changes in canopy water status, were calculated to measure the water supply of the leaves. As a result, the reflectance of 886 and 937 nm can result more accurate WBI (WBI = δ886/δ937) in the case of pear trees. The water-stressed samples showed a greater reflectance in near-infrared spectrum and a lower reflectance in the red spectrum.

MANAGEMENT OF PEACH TREE REFERENCE COLLECTIONS: ONGOING RESEARCH &amp; DEVELOPMENT PROGRAM RELEVANT TO THE COMMUNITY PLANT VARIETY RIGHTS PROTECTION SYSTEM

Peach/nectarine is an important fruit tree crop in Europe and indeed world-wide. The registration of new cultivars, either for Plant Breeders' Rights or National Listing (PBR/NL) purposes in the European Union (EU), requires the completion of a distinctness, uniformity and stability (DUS) test in one of the EU Member States. The number of candidate cultivars and potentially required example cultivars entered for DUS testing is steadily increasing annually. Moreover, DUS testing of this type of tree crops requires the maintenance of large orchards, particularly with the aim of having a complete reference collection. In France, Hungary, Spain and Italy, peach tree breeding activity is characterized by an important number of cultivars available and a short turn-over of the cultivars. This situation will extend to new EU members states in the coming years, with the development of the European trade. However, although the diversification increases the number of segments, for each segment, new released cultivars are genetically closer and closer. The consequence is that it is now difficult in some cases to distinguish between cultivars. Clearly, developing means of managing reference collections is highly desirable in order to be able to compare candidate cultivars with the closest cultivars of common knowledge in the reference collections prior to planting them, and so reduce the number of cultivars that need to be grown, without eroding the strength of PBR and the relevance of DUS tests. Effective means of such a management include the definition of a standardised way to compare phenotypic data and to use molecular markers to eliminate the reference cultivars which do not need to be compared to the candidate cultivars. In peach tree, various molecular markers such as DNA microsatellites (SSR) have been developed and evaluated, but they have not yet been used for the characterization of large collections. Therefore, this project will generate a database compiling both phenotypic data, including standardised morphological descriptions and digital pictures, and a large data set of DNA profiles for 522 peach tree cultivars selected among the EU granted and listed cultivars.

MYCOTOXIN CONTAMINATION OF DRIED GRAPES AND STRATEGIES TO CONTROL THE DAMAGES

Grape is a fruit appreciated by consumers as fresh, dried (raisins), or as processed products, such as grape juice and wine. Sometimes these products are heavily infected with chemical composition and secondary metabolites such as mycotoxins. Several factors affecting mycotoxin production include the fruit or vegetable type, geographical location, climate, harvest treatments and storage management. Relevant mycotoxins are signaled in fruits, with major problems in dried fruits as compared to fresh fruits. Iran has large orchards of various grape cultivars and potential to improve the cultivation and production. Also, it is one of the important producers of raisins in the world with more than 240,000 MT annually. Raisins are one of the significant products with rich nutrient and extremely high calories. They may carry a significant mycological load contaminated via cultivation, post-harvest processing and drying process. Mycotoxins are toxic in trace amounts therefore assays must be extremely sensitive. Temperate climates are the biggest risk with respect to mycotoxins from climate change in developed countries. The most prevalent genera from which mycotoxins were isolated from raisin samples are Aspergillus and Penicillium spp., including ochratoxin A., aflatoxins, patulin, and citrinin. Although, these toxins are associated with a wide range of lower optima temperatures, surveys for ochratoxin A have been carried out in many countries and it is the main toxin in grape and dried vine. In contrast to the significant work on ochratoxin A, there are fewer reports on the presence of aflatoxins in dried vine fruits. Different storage conditions with water activity and temperature levels below 0.930 and 15°C, respectively, allow limiting the ochratoxin A production in raisins. This discussion explains postharvest strategies and the use of natural and chemical agents are important in the prevention of mycotoxin contamination.

HORTICULTURE IN ANTIQUITY, WITH EMPHASIS ON THE GRAECO-ROMAN ERA

The evolution of horticulture (gardening) in antiquity, as distinct from largescale agriculture and forestry, is traced from its humble origins in ancient Egypt and Mesopotamia, to the Graeco-Roman era. Little is known about horticulture in the Greek Bronze Age and Homeric period, but from the 5th century onwards, public rather than private gardens became popular. In Athens a market garden was planted on the agora, and public parks (containing trees without flowers or decorative shrubs) like the Academy and Lyceum, appeared on the outskirts of the cities. Orchards and vegetable gardens were usually placed outside city walls and domestic gardening in and around homes were virtually unknown. The Greeks used wild flowers rather than cultivated flowers. Graveyards were planted with trees, and sacred groves, often in idyllic settings, were associated with shrines and divinity. During the Hellenistic era, exotic gardens based on the Persian paradeisos, were introduced by the affluent. The Romans made extensive use of private and domestic horticulture. In their homes (domus) built on the Greek model, the peristyle in particular, was converted into a garden containing trees, shrubs, flowers and vegetables. Further walled gardens were often attached to the domus. In large cities where the majority of citizens lived in multi-storied apartments (cenaculae), domestic gardening was restricted to occasional climbing plants and potted flowers decorating pillars, balconies and window sills. Wealthy Romans erected villas on country estates where indoor gardens and outside horticultural projects often included large orchards, gardens and vegetables shrubs and flowers, as well as tree-lined walking lanes, shrines, statues and water features. Facilities for horse riding were common, as well as pleasure gardens on the paradeisos model.

Orchard Factors Associated with Resistance and Cross Resistance to Sterol Demethylation Inhibitor Fungicides in Populations of Venturia inaequalis from Pennsylvania

Orchard management practices, such as destroying of overwintered inoculum and limiting the number of fungicide applications, are often recommended as tactics for slowing the development of resistance to sterol demethylation-inhibitor (DMI) fungicides in populations of Venturia inaequalis. However, there is little quantitative evidence relating the use of such practices to levels of resistance in orchards. The aim of this study was to evaluate the sensitivity of V. inaequalis isolates from Pennsylvania to DMI fungicides, and to identify orchard management factors related to the incidence of resistant isolates. In total, 644 single-spore V. inaequalis cultures obtained from 20 apple orchards in 2008 or 2009 were tested for sensitivity to myclobutanil, fenbuconazole, or difenoconazole. Growers provided management history of the sampled plots. Widespread shifts toward resistance to the three fungicides were noted, with mean effective concentration for 50% inhibition (EC(50)) values of 2.136, 0.786, and 0.187 μg/ml for myclobutanil, fenbuconazole, and difenoconazole, respectively. Cross resistance to the three fungicides was documented in high correlation (Spearman's r > 0.6) between mean EC(50) values for 14 orchards. Based on a 0.5-μg/ml threshold, 66 and 26% of isolates were resistant to myclobutanil and fenbuconazole, respectively, and 22% were cross resistant to the two fungicides. A significant between-year shift toward increased resistance was noted in two of three orchards surveyed in both years. Failure to use dormant copper sprays, older trees, larger orchards, orchards with ≤10 cultivars, and application of >4 DMI sprays were positively correlated (0.0001 < P < 0.05) with the incidence of resistant isolates. Isolates from orchards with >4 DMI sprays were four times as likely to be resistant to fenbuconazole (odds ratio = 4.57; P = 0.015). Isolates from orchards without dormant copper sprays were twice as likely to be cross-shifted toward resistance to all three fungicides (odds ratio = 1.76; P = 0.048). Results identify management practices that can reduce the risk of V. inaequalis developing resistance to DMI fungicides.

Ecological influence of the entomopathogenic nematode, Steinernema carpocapsae, on pistachio orchard soil arthropods

Abstract The entomopathogenic nematode, Steinernema carpocapsae, can reduce pesticide reliance in pistachios by controlling overwintering larvae of the navel orangeworm, Amyelois transitella (Lepidoptera: Pyralidae). But, beyond this, their influence in pistachio soil food webs is unclear. Given soil food webs’ complexity, S. carpocapsae likely interact with more species than just their intended target, infecting alternate hosts or providing food for native predators. This study quantifies the nematodes’ effects on soil arthropod and surface arthropod diversity in two large orchards in Madera County, California. We found significantly more isotomid collembolans, predatory anystid mites and gnaphosid spiders under trees where nematodes were applied indicating either direct predation or indirect trophic effects. Significantly fewer Forficula auricularia (Dermaptera: Forficulidae) and Blapstinus discolor (Coleoptera: Tenebrionidae) were found under treated trees, suggesting a possible non-target infection. Nematode persistence was limited but positively correlated with pitfall catches of the tenebrionid beetles, Nyctoporis cristata and B. discolor.

DEVELOPMENT OF THE AUSTRALIAN WALNUT INDUSTRY

In Australia up to the 1970s there would have been only 6 to 10 walnut orchards to supply the demand for fresh, locally produced nuts in shell. From 1970 on, there has been an increasing interest in local production and when the Australian Walnut Industry Association (AWIA) was established in 1990, it had 14 financial members. Interested growers soon realized that for easy access of information on orchard establishment, production and methods of crop disposal, it pays to become a member of the Association. Within the first 10 years, membership increased to close to 100. At present the membership is fairly steady at just over 100. However, over the last 10 years tree numbers have increased quite dramatically because of large scale developments by corporations. Thus the structure of the industry changed from being mainly cottage industry to one based on corporations. Information transfer was always considered as one of the most important functions of the Association. AWIA produced a Newsletter, distributed 2-4 times yearly, had at least annually one weekend seminar with talks and orchard visits held at various walnut growing areas and established its own website. AWIA established the Standards for Marketing Walnuts in Australia. Members were asked to contribute a voluntary levy that will partly fund a new research project being considered at present. A survey on orchard size, production, aspects of management, marketing and operators' age was conducted among members in 2008. While only 25% of members returned the forms, data obtained provides a reasonably characteristic profile of the local walnut production - apart from the few, most recently established large scale orchards managed by corporations.

First Report of a New Phytoplasma Subgroup, 16SrIII-T, Associated with Decline Disease Affecting Sweet and Sour Cherry Trees in Lithuania

During July 2007, sweet (Prunus avium) and sour cherry (P. cerasus) trees exhibiting disease symptoms suggestive of possible phytoplasma infection were observed in a large orchard in the Kaunas Region of Lithuania. Samples of leaf tissue were collected from 13 sweet cherry trees that were affected by a decline disease (designated cherry decline, ChD) characterized by symptoms that included leaf reddening and premature leaf drop and two sour cherry trees exhibiting proliferation of branches and nonseasonal flowering. To assess the diseased trees for phytoplasma infection, DNA was extracted with a Genomic DNA Purification Kit (Fermentas, Vilnius, Lithuania) and used as template in nested PCRs, primed by phytoplasma universal primer pairs P1/P7 and R16F2n/R16R2 for amplification of 16S ribosomal (r) DNA sequences (1,2). The 1.2-kbp DNA sequences amplified from all 15 trees were subjected to restriction fragment length polymorphism (RFLP) analyses with AluI, MseI, KpnI, HhaI, HaeIII, HpaII, RsaI, HinfI, TaqI, Sau3AI, and BfaI. The collective profiles indicated that DNAs were derived from two different phytoplasmas. One of them, designated ChD phytoplasma, was found in 11 sweet cherry trees and two sour cherry trees and tentatively classified as a member of new subgroup designated 16SrIII-T in 16S rDNA RFLP group 16SrIII (X-disease phytoplasma group). It was observed that the ChD phytoplasma caused different symptoms in sweet and sour cherry. The amplified ChD phytoplasma 16S rDNA was cloned in Escherichia coli, sequenced, and the sequence deposited in the GenBank database (Accession No. FJ231728). The ChD phytoplasma 16S rDNA shared 98.4 and 98.6% sequence identity with the 16S rDNAs from stone fruit-infecting phytoplasmas associated with western X-disease (GenBank Accession No. L04682) and Canada X-disease (GenBank Accession No. L33733), respectively, indicating that the three strains are closely related. Interestingly, the ChD phytoplasma 16S rDNA shared 99.8% sequence identity with 16S rDNA from one operon (rrnB, GenBank Accession No. AF370120) from a phytoplasma previously found to be associated with dandelion virescence (DanVir) disease in Lithuania. The operon rrnA (GenBank Accession No. AF370119) shared 99.3% sequence identity (2). The high similarity of the ChD 16S rRNA gene sequence to that of DanVir rrnB suggests the possibility that ChD and DanVir may belong to a single phytoplasma species and that dandelion is possibly an alternate host of ChD phytoplasma. The other phytoplasma, found in two sweet cherry trees, was classified in subgroup 16SrI-B of 16S rDNA RFLP group 16SrI ('Candidatus Phytoplasma asteris' and related strains) and was designated cherry proliferation phytoplasma (GenBank Accession No. FJ231729). Thus, in Europe, cherry may be affected by diseases associated with phytoplasmas belonging to groups 16SrI, 16SrIII, 16SrX, and 16SrXII (3,4). The infections by diverse phytoplasma strains and species underscore the need for production of phytoplasma-free planting stock and for intensified research to reduce ecological and economic impacts of these phytoplasmas.

Nutrient and Nematode Status of Coffee and Soils from Orchards in Hawaii

Suboptimal nutrition and plant-pathogenic nematodes are two factors that are limiting coffee production in commercial orchards in Hawaii. A survey of the major coffee (Coffea arabica) production areas of the state was conducted in 2000–2001. Deficiencies of calcium (Ca) and zinc (Zn), and toxicity of manganese (Mn) were the main nutritional factors limiting coffee production. Nutritional levels in leaves averaged 8.1 g kg−1 Ca and 10 mg kg−1 Zn. Leaf Mn varied widely from 95 mg kg−1 for Andisol-grown coffee (Hawaii Island) to 363 mg kg−1 for Oxisol-grown coffee in the other islands. On average, Mehlich-3 extractable Ca (in mg kg−1) was 900 in many soils on Oahu and Maui, 1200 in soils from Hawaii Island, and 2000 in soils on Kauai and Molokai. Extractable Zn averaged 5 mg kg−1 in soils from Oahu and 15 mg kg−1 in soils from the other islands. In contrast, Mehlich-3 extractable Mn averaged 500 mg kg−1 from the Oxisols and Ultisols on Oahu, Kauai, and Molokai, but only 25 mg kg−1 from the Andisols on Hawaii. (The reported critical values of nutrient deficiencies in coffee were 12 g kg−1 for Ca, 15 mg kg−1 for Zn in leaves, and 1900 mg kg−1 Ca in Hawaiian soils as extracted with the Mehlich-3 solution.) As with the nutrients, plant-parasitic nematodes varied among the five islands, especially the highly pathogenic species. Spiral and pin nematodes were recovered from several islands. Reniform nematode occurred in coffee orchards in Hawaii, Kauai, and Oahu. Burrowing nematode was recovered only from the island of Hawaii. Meloidogyne incognita, common in two coffee germplasm collections, was found only in one commercial orchard sample. A highly damaging root-knot nematode species (Meloidogyne konaensis) was present in 34% of samples of the coffee roots and soils collected on the island of Hawaii but was absent from the other four islands. A variant of M. hapla was present in a large Maui coffee orchard.

INVESTIGATION OF THE RELIABILITY OF EASY-TO-USE METHODS TO PREDICT ERWINIA AMYLOVORA INFECTION RISK IN APPLE ORCHARDS

As a complement to a national fire blight monitoring network, such as the MARYBLYT system in Hungary, an accurate local prediction method would improve control in a large orchard or a micro-region. Data relating to temperature and wetting events in 1999-2001 were analysed by means of the Californian Mean temperature line, Smith's degree hour-based model (Cougarblight), Billing's integrated system (BIS95) and the MARYBLYT computer model. In two years, the start of the massive infection risk was predicted by three of four models on the same day: 28 April in 1999 and 25 April in 2000. However, there was a delay of one day with the Cougarblight model as compared with the BIS95 and MARYBLYT systems in 2001. The forecast of an infection risk via the Mean Temperature Line was consequently one day later than that with the BIS95 and MARYBLYT systems. The size of the epiphytic bacterial population in the flowers was variable from year to year, with no convincing difference between cultivars with high (e.g. 'Sampion') or low (e.g. 'Freedom') susceptibility. The incidence of fire blight was sporadic in 1999 and 2001, but epidemic in 2000. The proportion of trees of 6 apple cultivars with fire blight symptoms well reflected the differences in weather-related risks in the two years investigated. The findings indicate that both Cougarblight and BIS95 deserve to be tested in commercial orchards in Hungary.

Biological Control Agents for Fire Blight of Apple Compared Under Conditions Limiting Natural Dispersal.

The efficacy of Pantoea agglomerans strain E325 for control of fire blight of apple was determined in comparative field trials involving other bacterial antagonists. Concurrently, the importance of the natural dispersal of bacteria as a complicating factor was assessed. Tests were performed under two sets of conditions, those that allowed for the dispersal of bacteria via honeybee activity and those that minimized it through the use of translucent polyethylene enclosures around single trees. The enclosures also raised daytime temperatures and allowed for controlled wetting, two factors important to the development of blossom blight. Singleantagonist treatments with strain E325, Pseudomonas fluorescens strain A506, and P. agglomerans strain C9-1 were applied to open blossoms on each of 10 enclosed trees and 10 nonenclosed trees. During bloom, suspensions of antagonists (108 CFU/ml) were applied twice with a brush, and a suspension of Erwinia amylovora (107 CFU/ml) was subsequently applied once using the same method. Two days after inoculation with the pathogen, trees were misted to simulate precipitation. Flower-to-flower spread of antagonistic bacteria was less frequent on trees surrounded by plastic enclosures than on nonenclosed trees. The range and statistical separation of means for population size of E. amylovora and disease incidence among treatments were greater for enclosed trees than for nonenclosed trees. Based on these results, the natural spread of antagonists being compared may mask differences in their efficacy as biocontrol agents. Such distortions and resulting misinterpretations could be lessened by separating treatments widely in large orchard blocks and by monitoring microbial populations. Strain E325 from fresh or lyophilized cultures was consistently more effective than standard antagonists in suppressing E. amylovora and reducing disease incidence. To fully assess its potential use for fire blight, larger-scale trials under various conditions will be necessary.

Idiosyncrasies of Pecan Pollination

Pecan orchard productivity and yields often suffer due to pollination problems despite copious pollen produced within or near orchards. The problem is most acute in large block-type orchards of one or two varieties and can be due to pollen not being present at time of stigma receptivity or due to selfing. Fruit-set problems do not appear to be due to excessive pollen on stigmatic surfaces, as is the case in walnut. Pistillate flowers set best when pollen is received within about 1 day after becoming receptive. While stigma receptivity appears to lasts several days, pistillate flowers usually fail to complete development if pollinated after ≈2 days. Flowering dichogamy of given varieties varies with tree age and spring temperatures, thus often leading to poor pollination and low fruit-set. Orchards are therefore likely to benefit from the presence of two complementary pollinizers for the main crop variety. Trees in block-type orchards and are beyond about three rows or 50 m from pollinizers are likely to exhibit pollination related yield losses. Many orchards exhibit pollination problems because adherence to the standard two-class Type I/II flowering system often caused planting of noncompatible varieties. A recently developed 30-class Type I/II system allows for greater probability of avoiding pollination problems. Removal of “off-genotype” trees from orchards may reduce yields in block-type orchards.

Globalization of the Washington Apple Industry: Its Evolution and Impacts

A major challenge in the study of commodity systems is to discern the various local impacts of globalization. The objective of this paper is to do this by presenting evidence from the development of Washington's apple industry. Washington State, which for years has been the leading producer of apples within the United States, is also a dominant player in global apple markets. In general, the Washington apple industry has followed a Fordist path to success by producing in ever increasing quantity and quality a comparatively inexpensive and undifferentiated commodity, i.e. red and golden delicious apples. Evidence presented in this paper shows that steadily growing global sales of apples produced in Washington are associated with increasing vertical integration of packing with production and the partial replacement of family with waged migrant labor. The benefits of economies of size in warehousing and production are causing the production base to expand into nontraditional growing areas where large orchards are being planted. Local labor supplies are inadequate and larger numbers of low-income migrant and settled (first generation migrant) laborers are being employed in orchards and warehouses. These changes are occurring at a time when there is heightened labor and community conflict in apple growing areas. Our analysis of this industry demonstrates that globalization is not a recent phenomenon, that the state continues to play an important role in the process, that globalization is firmly embedded in local dynamics and processes, and that an associated element of globalization is an increased reliance on wage labor.