Stone Fruit Orchards Research Articles

The Effect of Phytoplasma Disease Caused by ‘Candidatus Phytoplasma prunorum’ on the Phenological and Pomological Traits in Apricot Trees

‘Candidatus Phytoplasma prunorum’, the causal agent of European stone fruit yellows (ESFY), is one of the most important pathogens causing considerable economic losses in stone fruit orchards. This study evaluated trees infected and noninfected by phytoplasma ESFY of 16 apricot varieties grown in an orchard in Lednice (Czech Republic) between the years 2008-2014. Pomological traits, phenophases, pollen germination and seed viability were analysed as well as the presence of ‘Ca. P. prunorum’ in pollen, flower organs, fruit flesh, immature seeds and seedlings by nested PCR. One of the most detrimental impacts was the decreased fruit set of infected trees which occurred in 12 out of 16 studied varieties reaching an average fruit set decrease of 16.1%. Pollen germination rates also suffered, showing an average decrease by 11.78% in infected trees. In the analysis of some traits, overall significant differences were observed between the infected and noninfected trees. However, for all analysed traits in different varieties, both positive and negative influences of phytoplasma ESFY were observed. The presence of ‘Ca. P. prunorum’ in infected trees was confirmed in flower parts (only in peduncle in 70.2% of cases) and fruit parts (immature fruit flesh in 42.0% and milky kernels in 26.2% of cases), however, neither in seedlings nor in pollen.

Screening for Polyphenol Compounds and Antioxidant Capacity of Sweet Cherry Fruits Infected with Monilinia Laxa

SummaryMonilinia laxa Aderh. and Ruhl. is the predominant causal agent of brown rot disease of stone fruit orchards, especially sweet cherries. The objective of this study was to identify reaction in response of nine genotypes cherry, with different pomological properties, against brown rot. These genotypes were harvested at commercial maturity from orchard in the Fruit Research Institute in Rimski Šančevi. The studied genotypes showed significant differences in terms of the occurrence of disease on fruits, both under artificial inoculation and infection in the field. Given the fact that sweet cherry fruits are prone to infection by a number of pathogens in the field, biochemical parameters were analysed on artificially inoculated fruits. Biochemical analysis of fruits determined significant differences in contents of total phenols, flavonoids and anthocyanins, as well as in antioxidant activity. It was genotype specificities and intensity of infection, as well as the interaction of the two that induced differences in the secondary biomolecules content and antioxidant activity. The majority of the genotypes examined showed high polyphenolics content, while under the infection, the content was significantly lower. Based on the results obtained, the secondary metabolites content can be used as one of the parameters for evaluating the resistance of sweet cherry genotypes to brown rot.

A Model for Temporal Dynamics of Brown Rot Spreading in Fruit Orchards.

Brown rot, caused by Monilinia spp., is a major disease of stone fruit and, in favorable environmental conditions and in the absence of fungicide treatments, it causes important economic losses. In the present work, we propose a modification of classical susceptible, exposed, infectious and removed compartmental models to grasp the peculiarities of the progression of brown rot epidemics in stone fruit orchards in the last stage of the fruit growth (i.e., from the end of the pit hardening to harvest time). Namely, we took into account (i) the lifespan of airborne spores; (ii) the dependence of the latent period on the cuticle crack surface area, which itself varies in time with fruit growth; (iii) the impossibility of recovery in infectious fruit; and (iv) the abrupt interruption of disease development by the elimination of the host fruit at harvest time. We parametrized the model by using field data from a peach Prunus persica orchard infected by Monilinia laxa and M. fructicola in Avignon (southern France). The basic reproduction number indicates that the environmental conditions met in the field were extremely favorable to disease development and the model closely fitted the temporal evolution of the fruit abundance in the different epidemiological compartments. The model permits us to highlight crucial mechanisms undergoing brown rot build up and to evaluate the consequences of different agricultural practices on the quantity and quality of the yield. We found that winter sanitation practices (which decrease the initial infection incidence) and the control of the fruit load (which affects the host fruit density and the single fruit growth trajectory) can be effective in controlling brown rot in conjunction with or in place of fungicide treatments.

Efficacy of Anaerobic Soil Disinfestation for Control of Prunus Replant Disease.

Prunus replant disease (PRD) is an important soilborne complex that suppresses growth and productivity of replanted stone fruit and nut orchards. It is effectively managed with preplant soil fumigation but, due to regulatory challenges, nonfumigant-based control strategies for PRD and other soilborne disease problems may become increasingly important, especially in California. We examined the potential of preplant anaerobic soil disinfestation (ASD) for control of PRD in four repeated orchard replant trials on sandy loam soil near Parlier, CA. After removal of the old orchard trees, alternative ASD treatments, all using rice bran as the main carbon source, were implemented, starting in late September. The alternative treatments incorporated rice bran at (i) 20 t ha-1, alone, in 3.0-m-wide row strips; (ii) 20 t ha-1, preceded by incorporation of a sudangrass cover crop and followed by drip application of molasses (10 t ha-1), in 3.0-m-wide row strips; (iii) 20 t ha-1, alone, in 1.8-m-wide strips; or (iv) 12 t ha-1, alone, in 1.8-m-wide strips. All ASD-treated areas were covered with clear tarp and drip irrigated with 25 cm of water. Tarps remained for 6 weeks, during which the soil moisture level was kept at or above field capacity by drip irrigation. All trials included nontreated control and fumigated standard treatments. ASD raised temperature and reduced redox potential in soil at 15- and 46-cm depths for 6 weeks. Fumigation and ASD treatments both nearly eradicated bioassay inoculum of Pythium ultimum in the soil before almond trees were replanted and significantly affected almond tree root communities of fungi and oomycetes after planting. Fumigation treatments and ASD treatments with rice bran at 20 t ha-1 in 3.0-m strips increased tree growth significantly and by similar magnitudes. Among repeated experiments, mean increases in trunk cross-sectional area growth due to fumigation ranged from 137 to 264%, while the increases due to ASD at 20 t ha-1 in 3.0-m strips ranged from 148 to 214%, compared with controls. ASD offers effective control of PRD and is worthy of further optimization and testing for management of PRD and additional orchard replant problems.

Pheromone Research and Development in Israel 1975–2015

The review describes the history of pheromone research in Israel in 1975–2015. The research focused on sex pheromones of moths that were important agricultural pests. Identification, synthesis and field application of sex pheromones was performed. Synthetic procedures of several known sex pheromones were developed. Monitoring and control of key pest moths was evaluated. The interactions of pheromone components of closely related species were studied in field and laboratory experiments. The sex pheromones of three scale insects, two mealybug species and Matsucoccus josephi were studied. New syntheses were developed and the pheromones were implemented in pest management. Structure activity relationship of the pheromonal and kairomonal of the M. josephi pheromone was investigated. Different pherotypes of P. ficus were identified and evaluated. The aggregation pheromone of sap beetles in combination with food baits was evaluated. The aggregation pheromone of the almond bark beetle was identified and a stereospecific synthesis of its enantiomers was developed. Monitoring the pest in stone fruit orchards was implemented. The activity of the pheromone biosynthesis activating neuropeptide (PBAN) was studied in Helicoverpa armigera and Heliothis peltigera. The ligation technique was used to assess the effect of PBAN on the production of female and male pheromones. A structure-activity relationship study of PBAN indicated that shorter peptides display activity as the full length PBAN. A series of linear and cyclic peptide analogs was prepared, resulting in the discovery of a lead antagonist. The research and development activity facilitated the intensive integration of pheromones in the pest management regimes in Israeli agriculture.

One-Step Detection of Monilinia fructicola, M. fructigena, and M. laxa on Prunus and Malus by a Multiplex Real-Time PCR Assay.

Brown rot is an economically important fungal disease affecting stone and pome fruit orchards, as well as harvested fruit during storage and on the market. Monilinia fructicola, M. laxa, and M. fructigena are the main causal agents of this disease and each have a different regulatory status depending on regional regulations. In this study, a new multiplex tool based on real-time polymerase chain reaction was developed to detect the three pathogenic fungi in a single reaction on fruit, twigs, and flowers of Prunus and Malus spp. Species-specific primer-hydrolysis probe combinations were designed to amplify a region located in a previously described MO368 sequenced characterized amplified region marker, and used in a quadruplex format coupled with the 18S Uni universal primer-probe test in order to check the quality of the DNA template. The assay was designed and optimized with the objective to provide high performance values. Experimental data supported its sensitivity, specificity, reproducibility, and robustness. In addition, a set of quality controls was implemented to minimize the risk of false-positive and false-negative results, thus making this new test fit for use in serial analyses and reliable in the framework of official controls.

Going beyond sprays and killing agents: Exclusion, sterilization and disruption for insect pest control in pome and stone fruit orchards

Because of their perennial nature, orchards harbor one of the most complex ecosystems in agriculture. Nevertheless, crop protection programs still mainly focus on pesticides (synthetic or organic-approved) to prevent or limit the action of so-called noxious species in these systems. Killing agents represent the dominant paradigm and have been used in agriculture for decades. This paper synthesizes the available literature about the other approaches, more suited to organic farming, which recognize that the radicalness of killing is not necessary to prevent crop losses. Exclusion barriers represent one of the most readily available means of protecting the crop that way, but other behavior-based techniques have been developed, such as sterile insect technique and mating disruption. While there are many other possibilities, these are the three approaches that are currently getting the most interest in tree fruit production, due to ecological and agronomical characteristics, some of which will be detailed in this review.

Comparative in vivo and in vitro study on Monilia fructicola causing brown rot of stone fruit in Brazil and California

Stone fruit production plays an important economical role in southern Brazil as well as in California, United States. In both countries, brown rot caused by Monilinia fructicola is the most important stone fruit disease, responsible for significant pre- and post-harvest fruit losses. The United States is among the main importers of stone fruit to Brazil. Imported fruit carrying the pathogen may introduce isolates with greater ability to infect stone fruit orchards in Brazil. In this study, 26 M. fructicola isolates from Brazil and California, recovered from commercial stone fruit orchards, were randomly selected and compared based on in vitro (optimum growth temperature, mycelial growth rate, germination, spore production and germ tube rate) and in vivo (sporulation, area under disease progress curve, incubation and latent period) studies on brown rot infection components. The isolates behaved similarly for most of the studied variables, except for germ tube length and sporulation on fruit, which were higher in isolates from California and Brazil, respectively. The negative correlation between these variables may be disadvantage for isolates from California to cause infections in the main peach cultivar grown in South Brazil. Significant differences in incubation and latent period and the area under disease progress curve were found among isolates from a same country. Such differences may be due to intraspecific diversity associated with the occurrence of the perfect stage in California, and by the broad sampling area from where isolates from Brazil were obtained. It is still difficult to determine the effect of isolates arising from imported California fruits in Brazilian stone fruit orchards. Further genetic variability studies and comparative epidemiology in the field may help to understant the real threat that foreign isolates represent.

Suppressing Mediterranean fruit fly (Diptera: Tephritidae) with an attract-and-kill device in pome and stone fruit orchards in Western Australia

Attract-and-kill is a possible alternative to the conventional control of Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann (Diptera: Tephritidae) with bait or cover sprays of organophosphate insecticides. In this study, we determined if an attract-and-kill device (MagMED®) could be applied alone at the recommended rate (80 devices/ha), or needed to be combined with other conventional control tactics to suppress medfly in deciduous fruit orchards (apple, nectarine, peach, pear, plum). We also determined if attract-and-kill had any detrimental effects on naturally occurring beneficial insects. Based on an acceptable level of crop loss of 2–5% (the level of crop loss growers can tolerate), attract-and-kill suppressed medfly and reduced crop loss below the acceptable level in orchards with additional controls. Attract-and-kill was most effective when combined with either bait spraying, cover spraying or both. Combining attract-and-kill with cover sprays of fenthion resulted in a drop in crop loss of apples from 2.5% to 0.5%. By combining attract-and-kill with weekly bait sprays and two cover spray applications, crop loss fell from 13.7% to 4.3% in peaches, from 6.3% to 5% in nectarines and from 6.3% to 3.7% in pears. Twice weekly bait spraying was the most effective technique at suppressing medfly, providing acceptable control when applied alone, which further improved by combining with attract-and-kill. By combining attract-and-kill with twice weekly bait spraying crop loss fell from 2% to 1% in nectarines and from 4% to 2% in apples. In laboratory trials, attract-and-kill devices killed 100% of brown lacewings (Micromus tasmaniae Walker) and 94% of transverse ladybeetles (Coccinella transversalis Fabricius) 24 h after contact. However, orchard samples suggest that it may not pose any significant negative impact on naturally occurring beneficials such as Neuroptera, Hymenoptera, Coleoptera, Thysanoptera and Syrphidae in the field.

Monitoring of the exotic fly Drosophila suzukii in stone, pome and soft fruit orchards in NW Italy

After its introduction in Europe, Drosophila suzukii Matsumura (Diptera: Drosophilidae), an invasive pest native to South-East Asia, has rapidly spread into many European countries, including Italy, causing several economic losses on stone fruits and berries. Therefore, monitoring of fly adults and fruit damage was carried out in stone, pome and soft fruit orchards in two areas in NW Italy in 2011–2012. In 2012, different types of vinegars and traps [apple cider vinegar (ACV), mixture of wine vinegar and ACV, rice vinegar in transparent traps; ACV in red traps] were also used in the field; moreover, the responses of females to these vinegars were evaluated in the laboratory through a two-choice olfactometer. In the two-year field surveys, adults of D. suzukii were trapped in all orchards. In both years, after few specimens were caught in early spring, adults were no longer found until June. The captures increased in late summer, reaching higher peaks in October and November. In winter, the population decreased severely, but a few adults were still caught. At harvest, no damage was found on stone and pome fruits. Instead, severe yield losses occurred on berries, especially on later cultivars. In the field, the numbers of adults sampled by the tested vinegars fluctuated highly during the season, but significant differences were found only between red traps and the other ones. In the laboratory, ACV was the most attractive substance for fly females in the two-choice olfactometer.

A survey of entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae (Nematoda: Rhabditida) in Damascus countryside of Syria

A survey of entomopathogenic nematodes was conducted in Damascus countryside from January 2011 to December 2013. Soil samples were tested for the presence of steinernematid and heterorhabditid nematodes by baiting with Galleria mellonella larvae. Of the 189 soil samples studied 17 were positive for entomopathogenic nematodes (9%), with 11 of these positive samples (65%) containing Heterorhabditis and 6 (35%) Steinernema isolates. Morphological studies were carried out to characterize eight isolates. The Heterorhabditis isolates collected in Syria were identified as Heterorhabditis zealandica (Poinar, 1990), Heterorhabditis indica (Poinar et al., 1992) and Heterorhabditis bacteriophora (Poinar, 1990). Heterorhabditis zealandica was isolated from 4 sites. Heterorhabditis indica and H. bacteriophora were isolated from two sites each. Entomopathogenic nematodes were mainly found in stone fruit orchards and apple orchards but also in citrus groves, vineyards, and walnut orchards.

PRESENCE OF SHARKA DISEASE IN THE NORTH-HUNGARIAN COUNTIES

In the concerned region, such as Hungary Plum pox virus (PPV) causes the most serious yield loss in the stone fruit orchards. A survey of sharka disease was conducted in the north-Hungarian border region from 2010 to 2012. The main goals of the survey were to isolate the virus, to map the spreading and the actual status, to identify the PPV strains and inform the orchard owners and manufacturers about the results of the study. This survey was a part of the Hungary-Slovakia Cross-Border Co-operation Programme 2007-2012. Nearly 250 leaf samples were taken from 51 different settlements of the northern counties from stone fruit orchards, home gardens and natural environment, showing the symptoms of PPV. The surveyed species were plum, apricot, peach, sweet and sour cherry, and blackthorn. To identify the strains the following molecular methods were used: conventional RT-PCR with strain-specific primers, RT-PCR followed by RFLP analysis using EcoRI, DdeI and EcoRV restriction enzymes in the 3’P3-6K1-5’CI genomic region and RT-PCR followed by sequence analysis in the formerly mentioned region. The results show that the dominant strains were PPV-Rec in the central and PPV-D in the eastern region, but PPV-M was also identified. The apricot and peach orchards were less infected than plum orchards in the northern counties of Hungary. A suspected triple-mixed infection (M, D and Rec) is under further studies. After the survey a map was prepared, the dominant isolates, the infection rate, the host plants and the type of the sample collection places were marked. From the results a bilingual booklet was also published with the great help of the Slovak partners, for producers and orchard owners including all important knowledge about the virus and the disease prevention.

Similar worldwide patterns in the sex pheromone signal and response in the oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae)

The response of Grapholita molesta (Busck) males to three-component sex pheromone blends containing a 100% ratio of the major sex pheromone component, (Z)-8-dodecenyl acetate and a 10% ratio of (Z)-8-dodecenol, but with varying ratios of (E)-8-dodecenyl acetate (0.4, 5.4, 10.4, 30.4, and 100.1% E-blends) was tested with populations in eight stone and pome fruit orchards in Europe, Asia, and North and South America. Traps baited with the 5.4% E-blend caught significantly more males than traps with any other blend with all populations. Significantly more males were caught in traps baited with the 10.4% E-blend than in traps with the remaining blends, except with the 0.4% E-blend in Turkey. Significant differences in male moth catches occurred between the other blends with the 0.4>30.4% E-blend, and the 30.4>100.1% E-blend. Male moth catches with the 100.1% E-blend only differed from the hexane control in Chile. No apparent differences were noted to these blends in populations collected from pome or stone fruits. Flight tunnel assays to synthetic blends with a subset of populations were similar to the field results, but the breadth of the most attractive E-blends was wider. Flight tunnel assays also demonstrated a high level of male-female cross-attraction among field-collected populations. Female gland extracts from field-collected populations did not show any significant variation in their three-component blends. The only exceptions in these assays were that long-term laboratory populations were less responsive and attractive, and produced different blend ratios of the two minor components than recently collected field populations.

Frequency of brown rot fungi on blossoms and fruit in stone fruit orchards in Greece

Brown rot is a devastating disease of stone fruits caused by Monilinia spp. This study was conducted to investigate the disease aetiology on blossoms and fruit in peach, apricot, sweet cherry and plum orchards, in Greece. In total, 1433 isolates obtained from orchards located in the main stone fruit production regions of Greece were identified to species based on the presence/size of a cyt b intron. Monilinia laxa and M. fructicola were detected at frequencies of 59 and 41%, respectively, while M. fructigena was absent. Monilinia fructicola was more common on fruit whereas M. laxa occurred in similar frequency on blossoms and fruit. Monilinia laxa was replaced by M. fructicola in fruit infections of peach in both regions investigated and in fruit infections of plum in the Imathia region. Assessments of aggressiveness of 30 isolates of both species on the petals and fruits of the hosts showed that M. fructicola isolates were more aggressive. This suggests that the predominance of M. laxa on the blossoms cannot be explained by higher aggressiveness. Measurements of the effect of temperature on mycelial growth showed that M. laxa isolates had a higher growth rate than M. fructicola at the lowest temperature tested of 5°C, whereas M. fructicola isolates showed higher growth rates at higher temperatures. The observed high frequency of M. fructicola in Greece represents a major threat for stone fruit production. Furthermore, the information obtained about delineation of species and plant organ preference could be useful for the implementation of disease management strategies.

Asymmetrasca decedens (Cicadellidae, Typhlocybinae), a natural vector of ‘Candidatus Phytoplasma phoenicium’

Abstract‘Candidatus Phytoplasma phoenicium’ is associated with a lethal disease of almond, peach and nectarine named almond witches'‐broom disease (AlmWB). The disease spread rapidly in Lebanon from coastal areas to elevations exceeding 1200 m, killing over 150,000 trees in a span of two decades. The mode of spread suggested the involvement of efficient vector(s) and Asymmetrasca decedens (Hemiptera, Cicadellidae) was suspected as it is the most abundant leafhopper species present in Lebanese stone fruit orchards. Living A. decedens specimens were collected from fields heavily infested by AlmWB and used in transmission trials on healthy peach almond hybrid GF‐677 and peach GF‐305 seedlings with an inoculation‐access period of 30 days. PCR analysis supported by sequencing showed that A. decedens is a carrier of the phytoplasma, and that the phytoplasma was detected in insect salivary glands and in some inoculated GF‐677 and GF‐305 seedlings. One year post‐inoculation, ‘Ca. P. phoenicium’ was detected in newly emergent leaves of inoculated seedlings. However, the characteristic symptoms of witches'‐broom were not observed. PCR amplified fragments from phytoplasma‐positive seedlings and from A. decedens samples showed 99.9% nucleotide identity in their 16S RNA region and phylogenetic analysis using a neighbour jointing tree confirmed that the phytoplasmas detected in both insects and inoculated seedlings belonged to 16SrIX‐B (D). The present manuscript is the first known report for a leafhopper vector of ‘Ca. P. phoenicium’ and shows that the incubation period of the disease in plants may be longer than 1 year. The importance of phytosanitary control measures, the adoption of a national strategy and regional cooperation in order to contain the further spread of the disease are discussed.

Monitoring oriental fruit moth and codling moth (Lepidoptera: Tortricidae) with combinations of pheromones and kairomones

AbstractExperiments were conducted in North and South America during 2012–2013 to evaluate the use of lure combinations of sex pheromones (PH), host plant volatiles (HPVs) and food baits in traps to capture the oriental fruit moth, Grapholita molesta (Busck), and codling moth, Cydia pomonella (L.), in pome and stone fruit orchards treated with sex pheromones. The combination of the sex pheromone of both species (PH combo lure) significantly increased G. molesta and marginally decreased C. pomonella captures as compared with captures of each species with either of their sex pheromones alone. The addition of a HPV combination lure [(E,Z)‐2,4‐ethyl decadienoate plus (E)‐β‐ocimene] or acetic acid used alone or together did not significantly increase the catch of either species in traps with the PH combo lure. The Ajar trap baited with terpinyl acetate and brown sugar (TAS bait) caught significantly more G. molesta than the delta trap baited with PH combo plus acetic acid in California during 2012. The addition of a PH combo lure to an Ajar trap significantly increased catches of G. molesta compared to the use of the TAS bait or PH combo lure alone in 2013. Female G. molesta were caught in TAS‐baited Ajar traps at similar levels with or without the use of additional lures. Ajar traps baited with the TAS bait alone or with (E)‐β‐ocimene and/or PH combo lures caught significantly fewer C. pomonella than delta traps with sex pheromone alone. Ajar traps with 6.4‐mm screened flaps caught similar numbers of total and female G. molesta as similarly baited open Ajar traps, and with a significant reduction in the catch of non‐targets. Broader testing of HPV and PH combo lures for G. molesta in either delta or screened or open Ajar traps is warranted.

The efficiency of RNA interference for conferring stable resistance to plum pox virus

Plum transformed with an intron hairpin RNA CP (ihpRNA-CP) was resistant to plum pox virus (PPV) infection through the specific process of RNA silencing involving both small interfering-RNA (siRNA) and a methylated virus transgene. Silencing specifically targeted the PPV genome and led to the degradation of viral RNA in the model plant species Nicotiana benthamiana and the natural Prunus domestica host. Plums inoculated with the five major PPV strains, three widespread PPV strains (D, M, and Rec), and the atypical EA strain did not allow systemic spread of PPV in greenhouse-grown transgenic ihRNA-CP plum over multiple cycles of vegetative growth and cold-induced dormancy. PPV ihRNA-CP N. benthamiana displayed an immunity reaction and also allowed for the testing of PPV-C, a strain that was unable to infect P. domestica. This stable resistance demonstrated in plum based on the accumulation of siRNA can prevent PPV infection and can also act as a “curative” when PPV is inoculated through graft inoculation, through a recovery reaction. Regardless PPV strain variability based on geography, host species, epidemiology and serotypes of the CP protein and substitutions of nucleotides at the NH2-terminus of CP of the major five PPV strains tested, we show that the use of a PPV-CP intron hairpin (ihp) RNA is an effective strategy to specifically target the PPV genome. We provide methods and tools that demonstrate a reliable path towards developing PPV resistance suitable for protecting stone fruit orchards.

Comparison of macro-morphological and physiological methods for Monilinia species identification in Paraná State, Brazil

The aim of this study was to characterize 93 isolates of Monilinia from stone fruit orchards of Paraná State Brazil, and make inferences concerning their physiological aspects. A synoptic key was utilized at 10 days after incubation for morphological characterization, which allowed us to identify three Monilinia species (M. laxa, M. fructigena and M. fructicola). Molecular analysis was later performed for isolates representative of the morphological species. The polymerase chain reaction (PCR) confirmed only M. fructicola to be present for all isolates collected in Paraná State and contradicted the synoptic key identification. Additionally, isolates were tested physiologically in order to support Monilinia segregation. However, no significant differences were found among the isolates for optimum growth temperature and lesion size of inoculated pear fruit. We concluded that the synoptic key cannot segregate isolates of Monilinia species from southern Brazil and that PCR with specific primers was the best approach.

First report of Adoxophyes orana in northwestern Turkey: population fluctuation and damage on different host plants

This study reports the presence of the summer fruit tortrix moth, Adoxophyes orana , in pome and stone fruit orchards for the first time in northwestern Turkey. Based on growers' complaints about cosmetic damage to peach and pear fruits, pheromone traps were set up in mid-April of 2009 and 2010 to monitor the occurrence of the summer fruit tortrix moth. We conducted studies in conventional apple, pear, peach, and sweet cherry orchards in Bursa, northwestern Turkey. Moths caught in pheromone traps showed a trimodal flight pattern in all orchards. However, both moth emergence time and total flight period varied among host plants. The first moths were caught in peach and apple orchards on 13 May in 2009 and 3 May in 2010, corresponding to an average degree-day (DD) accumulation of 350-356 DD starting from 1 February. The 2nd and 3rd moth flights began in late June or early July (1003-1027 DD) and early August (1600-1690 DD), respectively. Moth captures continued until the end of September, lasting for an average of 2305 DD. The highest mean percentage leaf damage (9.3%) was found in sweet cherry orchards. However, neither sweet cherry nor apple fruits were injured in any way by A. orana larvae. Conversely, the mean percentage of fruit infested with larvae was 1.4% and 0.8% in peach and pear orchards, respectively. Because a level of fruit damage higher than 1% is considered the control threshold, A. orana is more likely to cause economic damage in peach and pear orchards in the near future.

Serological and Molecular Detection of Prune dwarf Virus Infecting Stone Fruits of Charmahal-va-Bakhtiari Province, a Central Region of Iran

Prune dwarf virus (PDV) is one of the major positive RNA viruses which cause economical damages in stone fruit trees. The symptoms of PDV vary between different stone fruits namely sour and sweet cherry, almond, peach, apricot and plum including leaf narrowing, leaf chlorosis, vein clearing, mosaic, leaf whitening, leathery leaf, bushy branches and stunt trees. During the years 2011 and 2012, 251 leaf samples were collected for detection of PDV in stone fruit orchards of Charmahal-va-Bakhtiari province. DAS-ELISA test proved PDV presence serologically. Then, total RNA were extracted and tested by two-step RT-PCR which replicated partial and full coat protein sequence of PDV. One hundred and eighty one out of total samples (251 samples) showed PDV infection using serological and two-step RT-PCR assays, hence, incidence of PDV in Charmahal-va-Bakhtiari province was confirmed. This is the first report of PDV in stone fruit orchards of Charmahal-va-Bakhtiari province and in Iran.