A test of fruit varieties on entry rate and development by neonate larvae of the codling moth,Cydia pomonella

The rate of entry by neonate larvae of the frugivorous codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), into fruit material was investigated. We used no‐choice bioassays in climate‐controlled rooms to assay larval entry across four host plant species (apple, pear, quince, walnut) and three varieties within a single fruit species (apple). Larvae successfully entering apples were reared to adulthood, and we collected tissue samples from apples which were successfully colonized in order to determine sucrose concentrations. This information was used to evaluate differences in adult moth size, development time, and pulp sucrose concentration due to apple variety. Four important findings emerged: (1) neonate larvae had the highest frequency of entry (86% of larvae) into apple fruits, compared with pear (78%), quince (56%), and walnut (32%); (2) the frequency of larval entry into immature apples differed across apple varieties, and larval entry rate was highest in variety Golden Delicious (72%), compared with Granny Smith (46%) and Red Delicious (64%); (3) on average, adult moths were larger and development times were shorter on the variety with the highest entry frequency (Golden Delicious); and (4) apple pulp sucrose concentrations were higher for Golden Delicious (17.5 μg mg^?1) than for either Granny Smith (15.9 μg mg^?1) or Red Delicious (15.1 μg mg^?1) varieties, which correlates positively with entry and development data. We conclude that host fruit species and varietals within a species affect the entry rate of neonate codling moth larvae in no‐choice assays. We hypothesize that larval development is influenced by mean sucrose concentrations or other phytochemical differences associated with host fruit varieties.     

Demography and mass-rearing of Carposina sasakii Matsumura (Lepidoptera: Carposinidae) reared on Golden Delicious and Red Fuji apples in the laboratory

Carposina sasakii Matsumura (Lepidoptera: Carposinidae), is one of the most serious fruit-boring pests in over ten species of fruit trees, and is especially damaging apples in the northern of China. The application of new planting systems, i.e., high-density and dwarfing rootstock orchard systems with mixed apple varieties, makes it important to study the fitness of C. sasakii on these apple varieties to gain fundamental knowledge for use in pest management involving this insect. In this study, life table data of C. sasakii were collected using Golden Delicious and Red Fuji apples as hosts. The egg-larva duration of male C. sasakii reared on Golden Delicious apples (22.81 d) was significantly shorter than that reared on Red Fuji apples (24.27 d). The egg-larva mortality in Golden Delicious apples (59.00%) was lower than that in Red Fuji apples (72.49%). The mortality of the pupal stage, however, was higher in Golden Delicious (10.51%) than in Red Fuji (0%). The total oviposition period (TPOP) on Golden Delicious apples (32.94 d) was significantly shorter than in individuals reared on Red Fuji apples (34.19 d). The intrinsic rate of increase (r = 0.0581 d⁻¹), net reproductive rate (R₀ = 7.57 offspring), and finite rate of increase (λ = 1.0598 d⁻¹) were all higher on Golden Delicious than those on Red Fuji. When the net reproductive rate (R₀) was used, the harvest rate of pupae was higher (0.8678) when reared on Golden Delicious apples than when reared on Red Fuji apples (0.8398). When a large cohort size (n = 200) was used for effective bootstrap sample, the P_E values for C. sasakii reared on Golden Delicious apples and Red Fuji apples were both almost equal to 1. For C. sasakii culturing purposes, Golden Delicious apples would be more productive than Red Fuji.     

Laboratory tests carried out onMicrothrix inconspicuella [Lep.: Pyralidae], a biological control agent forEmex australis in Australia

Host specificity tests of the moth,Microthrix inconspicuella Ragonot in Australia, indicated that larvae could feed and develop on young apple leaves. Additional tests in South Africa on leaves and fruit of the 4 apple varieties, Jonathan, Starking (Red Delicious), Granny Smith and Golden Delicious, showed that apples were not a preferred food. Little feeding occurred and pupation happened infrequently. No 2^nd generation resulted whenM. inconspicuella colonies were confined on apple fruit or leaves.      

Susceptibility of selected apple cultivars to the Mediterranean fruit fly

Ceratitis capitata (Wiedemann), the Mediterranean fruit fly, is one of the key pest species affecting deciduous fruit orchards along the Mediterranean coasts. Because of global warming, C. capitata is gradually spreading north and is becoming a major pest of apples. Determining the susceptibility of the main apple varieties grown in the region will serve as a cornerstone to the management of this pest. In this study, we show the results of a field and laboratory no‐choice test conducted to determine the Medfly preferences on different apple cultivars. The seven main varieties of apples (Gala, Red Delicious, Golden Delicious, Granny Smith, Kanzi, Morgen Dallago and Fuji) were tested. The results demonstrate that C. capitata lays eggs on all apple cultivars in both field and laboratory conditions. The Granny Smith, Red Delicious and Morgen Dallago varieties showed the lowest susceptibility in laboratory conditions, (0.75, 1.55, 2 oviposition punctures/fruit, respectively), with significant differences in oviposition compared to the Golden Delicious, Kanzi and Fuji (3.27, 3.31, 3.1 oviposition punctures/fruit, respectively) varieties, which were shown to be the most susceptible to Medfly attack in laboratory conditions. On the other hand, only slight and not statistically significant differences emerged from the field trials. In relation to the physico‐chemical characteristics, the apple cultivars showing the lowest susceptibility (Granny Smith, Red Delicious and Morgen Dallago) had harder peels and pulps and lower sugar contents than the most susceptible cultivars (Golden Delicious, Fuji and Kanzi). These results were also confirmed through evaluation of larval development on different varieties. In fact, Granny Smith, Red Delicious and Morgen Dallago were the three varieties that did not allow adequate larval and adult development and reduced the possibility of the emergence of a new generation.     

Growth of Escherichia coli O157:H7 in bruised apple (Malus domestica) tissue as influenced by cultivar, date of harvest, and source

Four of five apple cultivars (Golden Delicious, Red Delicious, McIntosh, Macoun, and Melrose) inoculated with Escherichia coli O157:H7 promoted growth of the bacterium in bruised tissue independent of the date of harvest (i.e., degree of apple ripening) or the source of the apple (i.e., tree-picked or dropped fruit). Apple harvest for this study began 4 September 1998 and ended 9 October, with weekly sampling. Throughout this study, freshly picked (<2 days after harvest) McIntosh apples usually prevented the growth of E. coli O157:H7 for 2 days. Growth of E. coli O157:H7 did occur following 6 days of incubation in bruised McIntosh apple tissue. However, the maximum total cell number was approximately 80-fold less than the maximum total cell number recovered from Red Delicious apples. When fruit was stored for 1 month at 4 degrees C prior to inoculation with E. coli O157:H7, all five cultivars supported growth of the bacterium. For each apple cultivar, the pH of bruised tissue was significantly higher and degrees Brix was significantly lower than the pH and degrees Brix of undamaged tissue regardless of the source. In freshly picked apples, changes in the pH did not occur over the harvest season. Bruised Golden Delicious, McIntosh, and Melrose apple tissue pHs were not significantly different (tree-picked or dropped), and the degrees Brix values of McIntosh, Macoun, and Melrose apple tissue were not significantly different. Single-cultivar preparations of cider did not support growth of E. coli, and the cell concentration of inoculated cider declined over an 11-day test period. The rate of decline in E. coli cell concentration in the McIntosh cider was greater than those in the other ciders tested. The findings of this study suggested that the presence of some factor besides, or in addition to, pH inhibited E. coli growth in McIntosh apples.     

Growth of Escherichia coli O157:H7 in Bruised Apple (Malus domestica) Tissue as Influenced by Cultivar, Date of Harvest, and Source

Four of five apple cultivars (Golden Delicious, Red Delicious, McIntosh, Macoun, and Melrose) inoculated with Escherichia coli O157:H7 promoted growth of the bacterium in bruised tissue independent of the date of harvest (i.e., degree of apple ripening) or the source of the apple (i.e., tree-picked or dropped fruit). Apple harvest for this study began 4 September 1998 and ended 9 October, with weekly sampling. Throughout this study, freshly picked (<2 days after harvest) McIntosh apples usually prevented the growth of E. coli O157:H7 for 2 days. Growth of E. coli O157:H7 did occur following 6 days of incubation in bruised McIntosh apple tissue. However, the maximum total cell number was approximately 80-fold less than the maximum total cell number recovered from Red Delicious apples. When fruit was stored for 1 month at 4°C prior to inoculation with E. coli O157:H7, all five cultivars supported growth of the bacterium. For each apple cultivar, the pH of bruised tissue was significantly higher and °Brix was significantly lower than the pH and °Brix of undamaged tissue regardless of the source. In freshly picked apples, changes in the pH did not occur over the harvest season. Bruised Golden Delicious, McIntosh, and Melrose apple tissue pHs were not significantly different (tree-picked or dropped), and the °Brix values of McIntosh, Macoun, and Melrose apple tissue were not significantly different. Single-cultivar preparations of cider did not support growth of E. coli, and the cell concentration of inoculated cider declined over an 11-day test period. The rate of decline in E. coli cell concentration in the McIntosh cider was greater than those in the other ciders tested. The findings of this study suggested that the presence of some factor besides, or in addition to, pH inhibited E. coli growth in McIntosh apples.     

Carotenoids of Some Apples

Three varieties of crab apples and two varieties of eating appleshave been investigated for their carotenoid contents. ß-caroteneis not always the major carotenoid and epoxy-carotenoids arefound in fairly large amounts. There are relatively more carotenesthan xanthophylls in two of the crab apples while the reverseis observed in the eating apples studied. Cox's Orange Pippincontains 33 I.U. of vitamin A activity, Golden Delicious 3.6,while the crab apple Golden Hornet has 132 I.U. per gramme dryweight. Further, the peel has a greater concentration of carotenoidsthan the flesh except in the crab apple Pyrus baccata wherethe ratio is 1: 1     

Genetics of phytopathogenic fungi XIX. Responses of four apple varieties to inoculation with auxotrophic mutants of Penicillium expansum

Summary Variations in content and/or availability of the amino acids methionine, cysteine, arginine, leucine, and histidine in the apple varieties, Jonathan, McIntosh, Red Delicious, and Golden Delicious influence the fruit's susceptibility to amino acid-dependent mutants ofPenicillium expansum. Differences among these varieties in the levels of several vitamins, or of the purines, adenine, or hypoxanthine, do not alter susceptibility. The growth in vitro of 7 arginine-requiring mutants at 1×10^–4 M arginine and the decay they cause in apples were directly correlated.     

Phenolic acid content – a criterion for selection of resistant apple cultivars against Podosphaera leucotricha (Ell. and Ev.) Salmon

Development of powdery mildew (Podosphaera leucotricha) on five popular cultivars of apple, viz., Scarlet Gala, Golden spur, Mollies Delicious, Red Fuzi and Red Chief was studied to determine incidence–severity relationship. The disease was confined primarily to the vegetative terminal shoots early in the season which also traversed later onto other leaves. Several biochemical changes occur in the trees due to fungal/microbial infection. We studied the qualitative/quantitative changes in phenolic acids in apple-powdery mildew pathosystems. Scarlet Gala and Red Chief are very rich in phenolic acids, and had shown resistances to the pathogen but those with low amount of phenolic acids, viz., Golden spur, Mollies Delicious, and Red Fuzi, were highly susceptible. Thus, the quantity of phenolic acids (secondary metabolites) has been taken as a biochemical parameter in screening apple cultivars for resistance/susceptibility against powdery mildew of apple.     

Initiation of Rapid Ethylene Synthesis by Apple and Pear Fruits in Relation to Storage Temperature

The influence of storage temperature on the onset of rapid ethyleneproduction was investigated for fruits of Conference pear (Pyruscommunis L.) and five cultivars of apple (Malus domestica Borkh.).The time taken from harvest to rapid ethylene production wasshorter and more uniform at 3 ?C than at 18–20 ?C forConference pears and Golden Delicious apples. Increases in internalethylene concentration, 1-amino cyclopropane-1-carboxylic acidconcentration and ethylene production were simultaneous in GoldenDelicious apples at 3 ?C. When Golden Delicious apples wereheld at 3 ?C for 48 h and then kept at 20 ?C the mean time ofonset of ethylene production was similar to that for applesheld continuously at 20 ?C. However, two periods of 48 h at3 ?C caused earlier ethylene production. Conversely, ethyleneproduction at 3 ?C was delayed by transfer to 20 ?C for twoperiods of 48 h. Cox's Orange Pippin and other apple cultivarstended to show more synchronous ethylene production at 3 ?Cthan at higher temperatures but the mean time of onset was eitherunaffected by temperature or slighdy delayed at lower temperature.Acceleration of the onset of ethylene production by low temperaturewas never observed in Cox's Orange Pippin apples harvested atweekly intervals from 10 August to 17 September. Key words: Ethylene, Storage temperature, Pyrus communis, Malus domestica     

Revisiting within-tree trap positioning for apple maggot fly (Dipt., Tephritidae) behavioural control

Abstract:  Aiming to minimize visual competition between large red apples and red sphere traps from influencing effectiveness of traps for apple maggot fly (AMF) control, we compared AMF captures by red spheres in standard recommended position (no fruit within 15 cm), red spheres in similar position but with all fruit removed within a 30-cm radius (fruitless), red spheres with additional visual competition provided by three plastic red spheres hung 15 cm from sphere traps, and yellow panels. Traps were coated with adhesive, baited with synthetic fruit odour, and hung on trees of an apple cultivar bearing red fruit (Akeene) and trees of an apple cultivar bearing pale yellow fruit (Golden Delicious). On Akeene trees, red spheres in recommended position and fruitless red spheres caught more AMF than red spheres surrounded by plastic spheres and than yellow panels. Towards harvest, effectiveness of red spheres in recommended position decreased as reflectance of the surface of Akeene apples approached that of red spheres. By contrast, effectiveness of fruitless spheres increased over time. On Golden Delicious trees, fruitless spheres were the most effective, followed by spheres surrounded by uncoated plastic spheres and red spheres in recommended position. We conclude that removing all fruit within a 30-cm radius around red sphere traps results in similar or increased trap effectiveness relative to red spheres in recommended position.     

Variations and trends of birch pollen seasons during 15 years (1996–2010) in relation to weather conditions in Poznań (western Poland)

Birch (Betula) pollen seasons were examined in relation to meteorological conditions in Poznań (1996–2010). Birch pollen grains were collected using a volumetric spore trap. An alternate biennial cycle of birch pollen season intensity was noticed in Poznań. The main factors influencing birch pollen season intensity were average daily minimum temperatures during the second fortnight of May and the month of June one year before pollination as well as the intensity of the pollen season of the previous year. Most of the pollen grains are recorded during the first week of the season; the number of pollen grains recorded at this time is positively correlated with mean maximum temperature and negatively correlated with daily rainfall. The significant effect of rainfall in reducing the season pollen index was noticed only during weak pollen seasons (season pollen index <?mean). In addition, mean daily maximum temperature during the first two weeks of the birch pollen season markedly influences its duration. No significant trends in duration and intensity of the pollen season were recorded, however, a slight tendency towards early pollination was observed (?0.4 days/year, p?=?0.310).     

PP333对苹果幼树越冬期间过氧化物酶同工酶的影响

以越冬性强的元帅苹果幼树为对照,用PP333处理越冬性弱的金冠苹果幼树,测定越冬期间其枝条过氧化物酶同工酶的变化,并在翌年春季田间调查越冬情况。结果表明,PP333处理大大增加了过氧化物酶同工酶中与抗寒性有关酶的酶活,并提高了金冠苹果幼树的越冬性。     

Treatment with chlorous acid to inhibit spores of Alicyclobacillus acidoterrestris in aqueous suspension and on apples

Aim: To test the efficacy of a chemical (chlorous acid) for reducing the numbers of viable Alicyclobacillus acidoterrestris spores in laboratory media and on apples. Methods and Results: Alicyclobacillus acidoterrestris spores in aqueous suspension and on apple surfaces of four different cultivars were treated with 268 ppm chlorous acid. Treatment with 268 ppm chlorous acid sharply reduced the numbers of spores of A. acidoterrestris in laboratory media by 1·6, 4·3, and 7·0 log₁₀ reductions for 5, 10, and 15 min treatments, respectively. Chlorous acid also effectively reduced the spore load on apple surfaces. Alicyclobacillus acidoterrestris spore counts were significantly reduced by about 5 log₁₀ after 10 min treatment on four different apple cultivars (‘Red Delicious’, ‘Golden Delicious’,’ Gala’, and ‘Fuji’). There was no synergistic effect on spore reduction when chlorous acid treatment was combined with heat. Conclusions: These results show that chlorous acid is highly efficacious against A. acidoterrestris spores on apple surfaces. Significance and Impact of the Study: Chlorous acid can be used as an alternative sanitizer of chlorine to control a major A. acidoterrestris contamination source in juice processing plants.     

Prediction of birch airborne pollen counts by examining male catkin numbers in Hokkaido,northern Japan

Birch pollen is a very common cause of pollinosis in Hokkaido, northern Japan. Birch airborne pollen concentrations vary each year; hence, the development of a method for predicting annual airborne pollen concentration is very important in preventing widespread symptoms of pollinosis. In the current study, we investigated airborne pollen counts and male catkin numbers (male flower index) of birch in four cities of Hokkaido between 2002 and 2008. Airborne pollen surveys were conducted using Durham’s sampler, and male catkin numbers determined for three major birch species (Betula platyphylla var. japonica, B. emanii, and B. maximowicziana). We found an annual variation in male flower index for all the three birch species investigated. This variation worked in combination with the amount of precipitation during the pollen season to influence total birch pollen counts. In conclusion, the male catkin numbers of three major birch species reliably predict airborne pollen counts in Hokkaido, but only when the effect of precipitation during pollen season is considered.     

Virulence Pattern of Venturia inaequalis Field Isolates and Corresponding Differential Resistance in Malus x domestica

All commercially important apple cultivars are susceptible in the field to scab caused by Venturia inaequalis. The scope of this study was to investigate variation in virulence in Venturia inaequalis populations towards commercial apple cultivars. For this purpose, primary lesions were sampled in orchards with different varietal compositions and diversities. The virulence pattern of monosporic isolates, obtained by isolation of single conidia, was assessed by cross inoculations of the cv. Ananas Reinette, Boskoop, Glockenapfel, Golden Delicious, Gravenstein, James Grieve, Jonathan, Maigold, Reinette de Champagne, Spartan and Yellow Transparent. All cultivars were susceptible to some isolates and resistant to others. No cultivar behaved the same way, which suggests the presence of differential resistance in each cultivar and corresponding virulence in some isolates. Isolates from a monoculture of Golden Delicious consisted mainly of a pathotype that was virulent to Golden Delicious but not to other cultivars. In the samples from cultivar mixtures, virulence pattern variation was considerable. The results give further evidence of the existence of a large pool of differential and ephemeral resistances in Malus, which were overcome by the local scab populations during co‐evolution.     

Impact of European red mite on Golden Delicious and Oregon Spur apples in Israel

To develop a damage threshold for the European red mite (ERM), Panonychus ulmi (Koch), the effect of ERM injury on fruit weight and return crop in the apple cultivars (CVs) Golden Delicious and Oregon Spur were studied in the Upper Galilee of Israel for two consecutive seasons. The ERM significantly affected the leaf colour, chlorophyll content, fruit weight and return harvest in both CVs. High population levels of 450 adult female cumulative mite days (ACMDs) reduced the fruit weight on Golden Delicious but not on Oregon Spur. Population levels above approximately 600 and 900 ACMDs in Golden Delicious and Oregon Spur, respectively, caused a substantial reduction in the return harvest. Because no damage was observed at low population levels, an action threshold of 150 ACMDs is recommended.