Species of Penicillium causing decay of stored fruits and vegetables in Israel

Penicillia species were isolated from postharvest decays of fruits of pear, apple, grapes, strawberry, melon, pepper, eggplant and tomato, after 3–5 days' shelf-life following cold storage.Penicillium cyclopium was the most common species in storage and was isolated from all fruits except eggplants. Next in frequency wereP. expansum, P. puberulum, P. viridicatum andP. brevi-compactum, naturally occurring on various types of stored fruits.P. expansum, P. stecki andP. cyaneo-fulyum showed the highest pathogenic potential, being capable of infecting all inoculated tested fruits.P. cyclopium, P. puberulum, P. viridicatum, P. crustosum andP. granulatum were also among the non-selective species, capable of infecting all fruits except eggplant or pepper.P. citrinum, P. purpurogenum, P. frequentans, P. chrysogenum, P. stolonifer, andP. italicum constitute a category characterized by both limited natural distribution and selective pathogonicity after artificial fruit inoculations. Fruit tissues of pears, grapes and tomatoes were found the most suitable for colonization and development of the Penicillia, whereas those of eggplant and pepper were most resistant to infection.     

Comparative content of some bioactive compounds in apples,peaches and pears and their influence on lipids and antioxidant capacity in rats

The aim of this study was to compare some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. The content of total polyphenols (g/100g) was 0.23 +/- 0.03; 0.22 +/- 0.03 and 0.68 +/- 0.1 in peeled fruits and 0.48 +/- 0.04, 0.47 +/- 0.04 and 1.2 +/- 0.12 in peels of peaches, pears and apples, respectively. Caffeic, p-coumaric and ferulic acids and the total radical-trapping antioxidative potential (TRAP) values in peeled apples and their peels were significantly higher than in peaches and pears, respectively. Contrarary, no significant differences in the content of dietary fiber among the studied fruits were found. The content of all studied indices in peels was significantly higher than peeled fruits (p < 0.05 ). A good correlation between the total polyphenols and the TRAP values was found in all fruits. Diets supplemented with apples and to a less extent with peaches and pears have improved lipid metabolism and increased the plasma antioxidant potential especially in rats fed with added cholesterol. The highest content of biologically active compounds and the best results in the experiment on rats makes apple preferable for dietary prevention of atherosclerosis and other diseases.     

番石榴实蝇寄主选择性试验

番石榴实蝇Bactrocera correcta(Bezzi)是一种为害多种水果的害虫,近年来在云南的元江暴发成灾。本试验选择番石榴实蝇的常见寄主:梨、芒果、苹果、桃、橙及芒果的不同品种进行室内试验,比较番石榴实蝇雌虫产卵对寄主的选择性及不同寄主对番石榴实蝇生长发育的影响。结果显示,番石榴实蝇雌虫对5种供试水果的寄生选择性大小依次为桃>梨>芒果>橙>苹果;番石榴实蝇对芒果不同品种的寄生选择性为三年芒>台农行1号>虎豹牙>胭脂芒>鹰嘴芒;番石榴实蝇在不同寄主上的蛀果期(卵及幼虫的历期)具有极显著的差异,以寄生桃和芒果的最短;从梨和苹果上饲养出的蛹最轻,且极显著低于其它寄主上饲养出来的蛹重;苹果上寄生的番石榴实蝇蛹重与蛀果期呈显著的正相关,而寄生梨的番石榴实蝇蛹重与蛀果期呈极显著的负相关。结果表明,番石榴实蝇雌虫产卵对不同寄主或同一寄主不同品种有明显的选择性,且该选择行为与其后代的生长发育有关。     

Fungicide residues in pears, apples and grapes after post harvest treatments by thermonebulization

In the context of trials conducted in cold store, in order to investigate efficacy of fruit protection applying agrochemicals, the fate during the storage of two active ingredients (a.i.): pyrimethanil and imazalil, have been studied. The experimental trials were done on eight varieties of apples and pears and two of grapes. Only field use of named pesticides was already authorised on fruits and maximum residue limits (MRL) fixed. In the present biennial experimentation (apples and pears in the first year; grapes in the second one). Two fungicides formulations were applied and treatments have been executed by thermonebulization technique. The storage cell, had a volume of 110 m3 filled up with the fruits until 80% of its capacity. Each fruit variety constituted one thesis of 4 replicates. For each trial, only one treatment was performed at the beginning of conservation period (72 days for pears and apples, and 57 days for grapes). In order to estimate fungicides persistence, residues determinations have been carried out. From results obtained especially on grape, not homogenous residues distribution on treated commodities was observed. For all theses, residue level has not evidenced statistically significant decrement as function of time, behaviour not as observed in field tests. The following average values of residues have been determined: in apples and pears, 0.7 mg/kg of imazalil much lower than 5 mg/kg (RML fixed for field use), and 1.2 mg/kg of pyrimethanil little higher than 1 mg/kg (RML fixed for field use); in grapes 0.5 mg/kg pyrimethanil much lower than 3 mg/kg (RML fixed for field use).     

Activity of the Yeasts Cryptococcus laurentii and Rhodotorula glutinis Against Post-harvest Rots on Different Fruits

More than 200 yeasts were selectively isolated from microbial populations on the surface of different fruits. Fifty of these isolates were tested against blue mould ( Penicillium expansum ) on wounded apples. Isolates LS-11 of Rhodotorula glutinis and LS-28 of Cryptococcus laurentii were the most effective antagonists. They were further evaluated at 20IC on different fruits (apples, pears, strawberries, kiwi fruits and table grapes) against several of the main post-harvest pathogens ( Botrytis cinerea, Penicillium expansum, Rhizopus stolonifer and Aspergillus niger ) and at 4IC on apples inoculated with P. expansum . At 20IC the antagonists significantly reduced rot incidence and showed a wide range of activity on different hostpathogen combinations; isolate LS-28 exhibited a higher and more stable activity than LS-11. Both yeasts were also effective against P. expansum in cold storage conditions. Populations of the two yeasts were assessed on wounded and unwounded surfaces of apples kept at both 20 and 4IC. At either temperature, isolate LS-28 reached greater densities in wounded tissues than LS-11, but had a lower ability to colonize unwounded apple skin. The two yeasts were able to grow in culture at temperatures ranging from 0 to 35IC. In assays performed in vitro at 24IC, the antagonists showed low sensitivity towards several fungicides commonly applied on fruits and vegetables.     

Ceratitis capitata: Effect of host fruit size on the number of eggs per clutch

A laboratory strain of Ceratitis capitata (Wiedemann) was presented with grapes, plums, apples and peaches for oviposition. Fruit diameter was highly correlated with the number of eggs/oviposition. Clutch size was 3.9±0.3 for grapes (20 mm) compared with 14.0±0.7 for apples (70 mm). When Parafilm^®-enveloped whole peeled fruits and smaller spheres of fruit flesh were offered, fruit size proved more important than fruit type in determining egg clutch sizes. Ovipositions that required the puncture of fruit skin gave larger clutches than ovipositions through Parafilm or into punctured fruit.

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Zusammenfassung Einem Laboratoriumsstamm von Ceratitis capitata (Wiedemann) wurden Trauben, Pflaumen, Aepfel und Pfirsiche zur Eiablage vorgelegt. Der Fruchtdurchmesser war stark korreliert mit der Eizahl pro Eiablage. Die Grösse der Eihaufen war 3,9±0,3 bei Trauben (20 mm) und 14,0±0,7 bei Aepfeln (70 mm). Wenn geschälte und mit Parafilm^® eingehüllte ganze Früchte und Fruchtscheiben vorgelegt wurden, war die Fruchtgrösse wichtiger als der Fruchttyp für die Grösse der Eiablage. Eiablagen, bei denen die Fruchthaut durchbohrt werden musste, waren grösser als Eiablagen durch Parafilm oder in perforierte Früchte.

     

Distribution of the oriental fruit moth Grapholita molesta Busck (Lep., Tortricidae) infestation on newly planted peaches before and during 2 years of mating disruption

Abstract:  Oriental fruit moth (OFM) Grapholita molesta Busck (Lep., Tortricidae) is one of the most important pests of commercial stone fruit orchards in the Goulburn-Murray Valley region of Victoria, Australia. OFM populations have been successfully controlled by the use of the mating disruption (MD) technique for many years, but damage to shoot tips and fruit has now started to increase. The most severe damage under MD is found at the edge of peach blocks, adjacent to the pear blocks under insecticide treatment. In 1997–98, OFM infestation levels were examined in a newly planted peach block surrounded by older peaches, pears, apples and pasture. The infestation distribution was followed up for four consecutive years. No treatments were used against OFM for the first 2 years in the newly planted peaches, but in years 3 and 4 the whole block was treated with MD. At the end of year 2, shoot tip damage was randomly distributed throughout the newly planted peach block with no 'edge effect'. After MD was applied in year 3, the damage was confined to the edges of the block adjacent to insecticide-sprayed apples and pears. No 'edge effect' was detected along the border with an older peach block treated with MD or on the border with pasture. Extending the MD treated area for 25–30 m into the neighbouring apples and pears in year 4 reduced the 'edge effect'.     

The <Emphasis Type="Italic">defH9-iaaM</Emphasis> auxin-synthesizing gene increases plant fecundity and fruit production in strawberry and raspberry

Background  

The DefH9-iaaM gene fusion which is expressed specifically in placenta/ovules and promotes auxin-synthesis confers parthenocarpic fruit development to eggplant, tomato and tobacco. Transgenic DefH9-iaaM eggplants and tomatoes show increased fruit production due mainly to an improved fruit set. However, the weight of the fruits is also frequently increased.     

蔷薇科植物果实花青苷积累研究进展

蔷薇科植物是植物界重要组成成员,除了观赏类植物月季、玫瑰等,还包含苹果、梨和桃等食用类果树。蔷薇科果实因为富含花青苷而具有丰富多彩的颜色,深受消费者喜爱。近年来,果树学家们围绕果实花青苷积累进行了较为深入的研究,主要探究环境因素或激素信号参与花青苷积累的分子机制。综述了蔷薇科果实着色的分子调控机制,对如何提高果实花青苷积累进行了思考总结,旨为提高蔷薇科果实的商品性和内在品质作出理论支持。     

Potential of patulin production by Penicillium expansum strains on various fruits

In this study, we investigated the pathogenicity and patulin production by ten strains of Penicillium expansum on various fruits (apples, apricots, kiwis, plums and peaches) at two (4°C and 25°C) different temperature regimes. All strains caused the infectious rots on all fruits at 4 and 25°C except one strain (PEX 09) at 4°C. Two strains (PEX 20 and PEX 12) out of ten produced the highest amounts of patulin on all fruits tested. The patulin production by P. expansum is high at 25°C compared to 4°C. All strains of P. expansum accumulated patulin ranging from 100–13,200 μg/kg and nine strains ranging from 100–12,100 μg/kg in all fruits at 25°C and 4°C, respectively. Among ten strains of P. expansum, strain PEX 20 produced the greatest amount of patulin on apricots (13,200 μg/kg of rotten fruit) and on apples (12,500 μg/kg) at 25°C after 9 days of incubation. At 4°C, this strain produced 12,100, 12,000, 2,100 and 1,200 μg/kg of patulin on apricots, apples, plums and peaches, respectively, after 45 days of incubation. Strain PEX 12 produced the highest amount of patulin on kiwis (10,700 μg/kg) at 25°C and 10,300 μg/kg at 4°C. Patulin production by P. expansum on peaches and plums at both temperatures were lower than other fruits. The results of this study showed that careful removal of rotten fruits is essential to produce patulin-free fruit juice, since high patulin levels in apricots, apples and kiwis could result in a level greater than 50 μg/kg of this mycotoxin in finished fruit juices, when one contaminated fruit occurs in 264, 250 and 214 fruits, respectively. So, the fruit processors should take care in not using rotten fruits for juice production to avoid the patulin problem worldwide, since this study proved that most important fruits being used for juice production and direct human consumption are susceptible to P. expansum and subsequent patulin production even at low temperatures. This is the first comprehensive report regarding patulin production by different strains of P. expansum on various fruits from Italy at different temperature regimes.     

Efficacy of a physical method for control of direct pests of apples and peaches

Two studies were conducted to test the feasibility and efficacy of using physical barriers (Maggot Barrier^® nylon mesh bags) for control of three internal pests of tree fruit (codling moth (Cydia pomonella L.), apple maggot (Rhagoletis pomonella (Walsh)) and peach twig borer (Anarsia lineatella Zeller)) and three groups of external direct pests (stink bugs (Pentatomidae), plant bugs (Miridae) and birds). Two types of Maggot Barrier^® were tested (regular and heavy duty), and two methods of securing the bags: knotting the bag on itself (‘self‐ties’) and using plastic‐coated wire ‘twist‐ties’. Bags were applied to eight cultivars of both apples and peaches, selected to give a range of maturity dates. Apples were bagged when fruit was approximately 27 mm in diameter, and peaches when the fruit was approximately 36 mm in diameter. Unbagged fruits served as controls. On apples, bagging had no effect on damage due to birds, stink bugs or apple maggot (which was present only in very low numbers), but reduced codling moth damage by 20–25% compared with unbagged controls; there were no significant differences due to bag type or tie type. In apples, a significantly higher proportion of the heavy duty bags were reusable after harvest, but on peaches, which were bagged for a shorter time, there was no difference between bag types in this respect. Bagging significantly reduced the percentage of peach fruits damaged by twig borer, birds and stink bugs, but increased the percentage of fruit with skin marks; there were no significant differences between bag or tie types. In peaches, there were significant effects on the time taken to apply bags due to both tying method and differences between individual operators. Cultivar affected pest‐related damage in both fruit types, underlining the importance of appropriate cultivar choice in pest management, particularly for organic growers and home gardeners.     

Studies on fungi associated with tomato fruits and effectiveness of some commercial fungicides against three pathogens

Among 39 fungal species and one variety belonging to 16 genera isolated from 116 healthy tomato fruits collected from markets in Assiut, Egypt, during 1994,Aspergillus niger was found to be the most prevalent, being isolated from 84.6% of the samples. Of 11 species recovered from 156 diseased tomatoes,Alternaria alternata, Rhizopus stolonifer andA. niger were the most common and isolated from 52.7%, 35.9% and 25.0% of the samples, respectively. Experiments for comparison of the effects of medium containing tomato juice with synthetic medium on the mycelial growth of nine fungal species indicated that, the tomato juice medium was more suitable for growth of all fungal species. The effect of five commercial fungicides and sodium hypochlorite when applied as post-harvest dips after inoculation was studied in laboratory againstA. alternata, A. niger andR. stolonifer. At 10 and 100 µg ml^–1, neither of the fungicide caused a noticeable inhibition ofAlternaria rot. At 1000 µg ml^–1 benlate, rovral and sumisclex completely preventedAlternaria andAspergillus rot, whereas cuprosan and ridomil were ineffective against rotting caused byA. niger. Rhizopus rot development was inhibited by over 50% with one treatment only (rovral at 1000 µg ml^–1). Sodium hypochlorite has good curative properties against fruit rots especially those caused byA. alternata andA. niger.     

β-Glucosidase from Botrytis cinerea: Its Relation to the Pathogenicity of This Fungus

Cellulolytic enzyme activities in 11 strains of B. cinerea and their pathogenicity against apples, grapes, and lettuce were tested. A positive correlation was found between the β-glucosidase activity of B. cinerea cultured in PYA-medium and the pathogenicity, as expressed in the area of lesions. Further, this correlation was found to hold for the β-glucosidase activity of the apple fruit lesion caused by B. cinerea.

Since it was suggested that pathogenicity of B. cinerea depended on its β-glucosidase activity, the β-glucosidase was purified and characterized. The enzyme had its optimum pH at 3.0, and was very stable in a wide range of pH. These properties were extremely advantageous for B. cinerea to infect the apple fruit.     

Studies on the fungi associated with tomato fruit rots and effects of environment on storage

Seven fungi associated with fruit rot of tomato were isolated includingFusarium equiseti, F. chlamydosporum, Alternaria solani, Geotrichum candidum, Acremonium recifei, Aspergillus flavus andA. niger. They were all pathogenic on tomato fruits, most pathogenic beingGeotrichum candidum followed byA. niger. Least rot was caused byAlternaria solani. The optimum temperature for maximum rotting caused byG. candidum, A. niger andA. flavus was 30°C. The relative humidity for maximum rot ranged from 70–90%. Tomato fruits stored well at 0–10°C and rather poorly at 20–30°C. Fruits stored at 35°C showed blemishes. The best RH for storage ranged between 60 and 90%.     

Bacterial Communities Associated with the Surfaces of Fresh Fruits and Vegetables

Fresh fruits and vegetables can harbor large and diverse populations of bacteria. However, most of the work on produce-associated bacteria has focused on a relatively small number of pathogenic bacteria and, as a result, we know far less about the overall diversity and composition of those bacterial communities found on produce and how the structure of these communities varies across produce types. Moreover, we lack a comprehensive view of the potential effects of differing farming practices on the bacterial communities to which consumers are exposed. We addressed these knowledge gaps by assessing bacterial community structure on conventional and organic analogs of eleven store-bought produce types using a culture-independent approach, 16 S rRNA gene pyrosequencing. Our results demonstrated that the fruits and vegetables harbored diverse bacterial communities, and the communities on each produce type were significantly distinct from one another. However, certain produce types (i.e., sprouts, spinach, lettuce, tomatoes, peppers, and strawberries) tended to share more similar communities as they all had high relative abundances of taxa belonging to the family Enterobacteriaceae when compared to the other produce types (i.e., apples, peaches, grapes, and mushrooms) which were dominated by taxa belonging to the Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria phyla. Although potentially driven by factors other than farming practice, we also observed significant differences in community composition between conventional and organic analogs within produce types. These differences were often attributable to distinctions in the relative abundances of Enterobacteriaceae taxa, which were generally less abundant in organically-grown produce. Taken together, our results suggest that humans are exposed to substantially different bacteria depending on the types of fresh produce they consume with differences between conventionally and organically farmed varieties contributing to this variation.     

Patulin and aflatoxin in brown rot lesion of apple fruits and their regulation

Aspergillus flavus, A. niger, Penicillium expansum and Rhizopus stolonifer were the most frequently isolated fungi from healthy apple fruits. Alternaria alternata was the most common organism of rotten apple fruits, followed by A. niger, A. flavus, P. expansum and R. stolonifer. The prevalent type of decay, brown rot lesion, is caused by R. stolonifer followed by A. flavus, A. niger, A. alternata and P. expansum. Sodium hypochlorite had good curative properties against fruit rots. The main natural mycotoxins produced in rotten apple were patulin and aflatoxins. The optimum temperature for patulin production by P. expansum was 15 °C after 15 days. Complete inhibition of patulin formation was attained using 0.2% lemon oil and > 90% inhibition using 0.05% lemon and 0.2% orange oils. Also significant inhibition (> 90%) of aflatoxin production was observed with 0.2% lemon oil. This revised version was published online in July 2006 with corrections to the Cover Date.     

Botryosphaeria spp. isolated from apple and several deciduous fruit trees are divided into three groups based on the production of warts on twigs, size of conidia, and nucleotide sequences of nuclear ribosomal DNA ITS regions

We examined the phytopathological and biological characters ofBotryosphaeria spp. isolated from apples and other deciduous fruit trees, and determined the nucleotide sequences of their rDNA ITS regions. TheBotryosphaeria isolates from deciduous fruit trees can be divided into three groups based on their production of warts on twigs, size of the conidia, and nucleotide sequences of rDNA ITS 1, ITS 2 and 5.8S rDNA. Isolates ofBotryosphaeria in ITS group A produced conidia of intermediate size and showed warts on infected twigs prior to the development of ring rot on fruit. This group was common on deciduous fruit trees in Japan as a causal agent of ring rot and wart bark diseases of apples and pears; and it appears similar to theB. dothidea from the US that was isolated from apple exhibiting white rot. The ITS group BBotryosphaeria produced small conidia and induced shoot blight without wart development prior to the development of ring rot on fruit. This group was localized on pear, persimmon, and kiwi fruit in restricted areas of Japan. The ITS group CBotryosphaeria consisted ofB. obtusa, the causal agent of apple black rot in the US, which produced large dark brown conidia.     

Prevalence of airborne Aspergillus flavus in Khartoum (Sudan) Airspora with reference to dusty weather and inoculum survival in simulated summer conditions

Khartoum air was scanned for airborne Aspergillus flavus for 12 months using the horizontal gravitational settling method. Frequency of occurrence was related to total fungal catch and dusty weather. The Aspergilli were prevalent (68% of total isolated/plate/month) and A. flavus constituted 31% of the total Aspergilli. In June (hot, dry & dusty) Aspergilli constituted 79% of the total isolates, whilst A. flavus represented 30% from amongst the other Aspergilli. A. flavus, A. niger, A. nidulans (conidial & ascosporic states), A. terreus, Eurotium amstelodami and A. fumigatus, in descending order of prevalence were isolated in June. Other pathogenic or potentially pathogenic forms, isolated, were Cladosporium, Curvularia and Penicillium. Amongst winter isolations A. flavus was sporadic to absent in occurrence. A. flavus spore inocula that underwent hourly intermitted exposure to 45 °C, showed a decrease in spore germinability as well as reduced germ length.     

A novel approach to the assessment of fruit damage caused by <Emphasis Type="Italic">Carposina sasakii</Emphasis> (Lepidoptera: Carposinidae) using pheromone trap catches in Korean orchards

This study reports a model that utilizes pheromone trap catches to assess the fruit damage caused by Carposina sasakii. The model consisted of four steps: (1) obtaining influx population density using pheromone traps, (2) estimating the actual female population within a defined area using an estimated conversion rate, (3) calculating the total number of eggs using the oviposition model of C. sasakii, and (4) estimating the proportion of fruits infested with eggs (potential damaged fruits) using the relationship between mean egg density per fruit and the proportion of fruits infested with eggs. The relationship between mean egg density ([`(x)] \bar{x} ) per fruit and variance (s ²) was well described by Taylor’s power law, and its parameters were successfully incorporated into the equation that estimates the relationship between mean egg density and the proportion of fruits infested with eggs. In peach orchards, the model accurately predicted the proportion of fruits infested with eggs at the beginning of C. sasakii emergence in early season, but overestimated it in the mid-season. The fitting ability of the model outputs largely increased when the factor of oviposition behavior of C. sasakii was incorporated into the simulation processes, applying the allocation module of total eggs between peaches and apples.     

Phytophagous preferences of the multicolored Asian lady beetle (Coleoptera: Coccinellidae) for autumn-ripening fruit

The objective of this study was to assess the potential pest status of Harmonia axyridis (Pallas) on autumn-ripening fruit. In autumn, H. axyridis has been observed feeding on pumpkins, apples, grapes, and raspberries in Minnesota. To determine whether H. axyridis can inflict primary feeding damage to fruit (i.e., breaking the skin of the fruit), we conducted laboratory feeding experiments with undamaged pumpkins, apples, grapes, and raspberries. The only fruit that H. axyridis was able to damage directly was raspberry. Laboratory choice tests were conducted to determine whether H. axyridis exhibits a preference between damaged and undamaged fruit, between cultivars of fruit, and between sugar water and water alone. For all fruits tested, H. axyridis showed a preference for damaged fruits over undamaged fruits. H. axyridis also exhibited a strong preference for sugar water over water alone. However, few differences were exhibited in preference between cultivars of fruit. In autumn, it seems that H. axyridis is an opportunist, taking advantage of previously damaged fruit, caused by other agents.