Introduction. Damage caused by tephritid fruit flies has been identified as a major limiting factor to citrus production in Nigeria. Presently, no control measure is applied by the majority of the farmers. This study therefore seeks to evaluate the efficacy of locally-made protein bait sprays and the differences in the susceptibility of sweet orange varieties in reducing fruit fly damage. Materials and methods. In 2006 and 2007, one, two and three spot applications of locally-made protein bait mixed with chlorpyrifos insecticide were administered to Agege, Parson Brown and Valencia Late sweet oranges. Treatments were arranged in a randomized complete block design. Efficacy of the bait sprays in reducing fruit attack was assessed by randomly sampling 10 ripe or ripening fruits per stand as well as dropped fruits. Results and discussion. The bait sprays significantly (p < 0.05) reduced damage of sweet orange by lowering the infestation level of Bactrocera invadens Drew Tsurata & White, and consequently reducing the number of dropped fruits. Application of three spots of bait was most effective in reducing damage due to B. invadens on sweet orange varieties. The infestation level of B. invadens and the number of dropped fruits of the variety Agege were significantly (p < 0.05) higher than those of the varieties Parson Brown and Valencia Late. Conclusion. Our study shows that three spot applications were most efficacious in reducing fruit damage, and that the Valencia Late variety was the least damaged, followed by Parson Brown.

Introduction. L’orange (Citrus aurantium sinensis) est une source de composés bioactifs : vitamines C et E, flavonoïdes (flavanes et flavanones glycosylés et polyméthoxylés). Pour valoriser les déchets des peaux d’orange, nous avons mesuré l’activité antiradicalaire du jus et des peaux sèches et fraîches de cinq variétés d’orangers de Tunisie afin d’évaluer leur concentration en composés antioxydants utilisables dans l’industrie. Matériel et méthodes. Le pouvoir antiradicalaire du jus et des extraits des peaux a été évalué en suivant, en fonction du temps, la disparition du radical stable DPPH• par spectrophotométrie d’absorption UV-visible à 515 nm. L’activité antiradicalaire mesurée a été exprimée en concentration efficace (CE50). La détermination du volume V50 de vitamine C d’une solution d’acide ascorbique de concentration connue et d’un volume V50 des extraits de jus et des peaux sèches et fraîches d’orange a permis d’estimer la concentration molaire et massique de vitamine C équivalente dans les extraits. Résultats. Les jus d’orange contiennent environ 400 mg·L–1 d’équivalent de vitamine C. Dans le cas de réactions très rapides avec le radical DPPH•, la totalité de l’activité antiradicalaire peut être attribuée à la vitamine C. Dans le cas de réactions plus lentes, en plus de la vitamine C, ce sont les polyphénols (citroflavonoïdes) qui contribuent à l’activité antioxydante totale. Les extraits méthanoliques des peaux fraîches (flavédo) contiennent plus de vitamine C que les extraits de peaux sèches. Conclusion. Les peaux d’oranges constituent d’immenses sources d’antioxydants qui peuvent trouver leur application dans différents domaines : agroalimentaire, cosmétique, pharmaceutique et autres.

Introduction. The citrus industry is one of the main activities of Brazilian agriculture. Several pests and diseases have threatened citrus culture in recent years. Genetic mapping is one of the most efficient strategies for conducting advanced genetic studies by facilitating plant selection guided by markers. The objective of this study was to construct an integrated genetic map between Citrus sinensis (L.) Osbeck cv. ‘Pêra’ and C. reticulata Blanco cv. ‘Cravo’ using two different types of segregation of markers. Materials and methods. The linkage analyses were conducted with segregation data obtained from 256 RAPD markers in a population of 94 hybrids. Analyses were performed through the software JoinMap, LOD ≥ 6.0, θ ≤ 0.25, and the Kosambi function. Results and discussion. The linked map between the two cultivars had 217 markers defined by 15 linkage groups, covering 527 cM. This map had five linkage groups with common markers of ‘Pêra’ and ‘Cravo’. The inclusion of new markers would increase the number of linkage groups with markers from both parents, thus making their number equal to the haploid chromosome number. The alterations in the order and in the distances among the markers, due to the presence or absence of bridging markers in the linkage map, are discussed.

Introduction. Cropping systems of the mango trees in West Africa are very varied. Each one of them developed in a specific context where the agronomical practices and the varietal composition of the orchards contribute to the diversity observed. The study undertaken should make it possible to better understand the influence of the potential outlets on the evolution of the regional mango production. Principal cropping systems. In the studied area, the main part of the mango orchards has less than 10 ha; their production is extensive and uses few inputs. They belong in majority to growers whose principal activity is centred on agriculture. Certain plantations close to 100 ha, found in Senegal or in Côte.d'ivoire, belong to exporters and profit from a technical assistance. Agronomical practices. The study of the agronomical practices used in mango orchards of West Africa made it possible to analyze the aspects of seedling production, choice of the site, installation of the orchard before plantation, plantation and maintenance of the trees, fire protection, water management, as well as the effect of the export market on the varietal choice and the varietal offer during a harvest campaign. Diseases and enemies. An inventory of the pathological problems and physiological diseases likely to devalue the production were carried out. Marketing. This part made it possible to distinguish intercontinental exports, requiring a specific harvest and conditioning organization, and the local, national and regional markets. Processing. Today, the share of transformed mangos into West Africa uses only one negligible proportion of the total production. Conclusion and prospects. Beside a traditional production which presents signs of brittleness appear modern orchards. More than a necessary intensification of the orchards, a rationalization of the agronomical practices, plant health protection, fruit harvest or handling are impossible to circumvent. Downstream, the export path is confronted with a fast evolution of the exogenous regulations, based on qualitative and sanitary standards increasingly strict.

Introduction. In Algeria, the Mediterranean fruit fly Ceratitis capitata Wiedmann constitutes the main obstacle to production and exportation of many fruits. In studies of the genetic structure differences of medfly populations, certain authors, using molecular markers, observed the existence of different patterns among the pest Mediterranean populations. A clear understanding of the source and migration of the Mediterranean fruit fly would be useful for undertaking a successful eradication or control program. For this reason, preliminary work sought to compare the genetic structure of Algerian populations of C. capitata with that of other populations situated either in the western Indian ocean or on the northwestern Mediterranean coast. Materials and methods. The study of enzyme polymorphism allowed the comparison of the genetic structure of four Algerian populations of Ceratitis capitata with one from Reunion Island and five other populations collected from the northwestern Mediterranean coast (France and Spain). Enzyme analyses were performed on ground pest adults electrophoresed on a starch gel. Fifteen loci were analyzed for each population. Results and discussion. In spite of a wide geographic distribution of the analyzed populations (from a latitude of 24° to 44° N), no gradient of allelic frequencies was observed for any of the polymorphic loci. A higher genetic variability was observed in the population of Reunion Island than in the populations of Algeria or the northwestern Mediterranean coast. No genetic differentiation was observed among the populations of southern Algeria (Djanet and Ghardaïa) and northern Algeria (Boufarik and Oran).

Introduction. Costa Rica’s pepper production (Piper nigrum L.) is relatively low, but for the farmers involved it presents an interesting cash cropping activity. This paper aims to analyse whether contracts with processing firms offer an incentive for farmers to invest in pepper production and thereby increase their income. We analysed the characteristics of farmers with formal and informal contracts to see if this influences their way of producing pepper, their yields and income. The second goal of our work was to study whether market conditions (one or more buyers) influence contract uptake and pepper production. Materials and methods. A survey was conducted in 2000 among 63 farmers, 32 of whom had access to only one buyer and 31 of whom could sell to three potential purchasers. Characteristics of farmers, farms and pepper production were compared in terms of market conditions and forms of contract. A subsample of 24 farmers was revisited in 2008. Results. Overall, the effects of contracts in terms of improving access to inputs and increasing yield and productivity were limited. However, formal contracts were endorsed by income-constrained farmers, especially in the early phase of establishing themselves in the market. In subsequent phases, and under more competitive market conditions, producers seemed to prefer verbal commitments to formal contracts. In situations where a monopsony situation prevailed, there were lower yields. Conclusion. Contracts are important in the start-up phase, and competitive market conditions favour a process of moderate intensification which stimulates high returns at relatively low costs to the most established pepper producers.

Introduction. The production of `Tahiti' limes in southern Brazil has increased in the last 20 years and has become a good alternative for citrus growers in regions where Citrus Variegated Chlorosis has affected sweet orange groves. One of the main goals to insure success in growing `Tahiti' limes is to apply the right techniques to induce out-of-season flowering and winter fruit harvest when the fruit prices are the highest. This experiment evaluated the effects of gibberellic acid application on fruit set of `Tahiti' lime trees related to out-of-season flowering and accumulated degree days. Materials and methods. Eight-year-old plants were treated with five concentrations of gibberellic acid [ (0, 10, 25, 50 and 100) mg$\cdot$L-1] applied during anthesis of out-of-season bloom. Accumulation of degree days for fruit set and fruit development in the conditions of São Paulo State, Brazil, were calculated. The percentage of fruit set determined by weekly counts of the number of flowers from anthesis to the maturation of the fruits were determined on each previously marked branch. Data were submitted to regression analysis. Results and discussion. In regard to fruit set, it was observed that 10 mg gibberellic acid$\cdot$L-1 was enough to retain more than 10% of fruits in relation to the number of formed flowers. Starting from anthesis, (837.7 and 1 115.2) accumulated degree days were necessary for the stabilization of the fruit set and fruit maturation, respectively.

Introduction. In Malaysia, Limau Madu (Citrusreticulata Blanco; Citrus suhuiensis Hort.ex Tanaka) is commercially cultivated for local consumption. Itis a loose-peel mandarin with fruits that are spherical in shapewith shiny green or greenish yellow peel. In Malaysia, Limau Maduis vegetatively propagated, thus it is presumed to exhibit minimalvariability. In our study, the genetic variability and genetic relatednessamong cultivated samples collected from different states in Malaysiawere assessed using Simple Sequence Repeat (SSR) primers. Materialsand methods. Thirty pairs of SSR primers derived from Citrusunshiu were screened and 22 SSR primer pairs were utilizedto assess genetic variability and relatedness among 118 cultivatedsamples. Results and discussion. The percentage of SSR transferabilityfrom C. unshiu to C. reticulata (LimauMadu) was 73.33%, which indicated that the primer sequences flankingsimple sequence repeats were conserved among these Citrus species.Most SSR loci revealed a large excess of heterozygotes. In our study,low allelic diversity was shown, with an average of 5.227 allelesper locus. Polymorphic information content (PIC) ranged from 0.048to 0.674. Based on UPGMA clustering analysis, four groups were identifiedfrom these citrus genotypes with a mean genetic distance of 0.170. Lowgenetic variability within species was probably due to vegetativepropagation or inability to detect differences among samples usingthese primers.

Introduction. The Australian almond [Prunus dulcis (Miller) D.A. Webb] improvement program commenced five years ago with the main aims of developing scion and rootstock cultivars that are better adapted to local conditions, and that provide a superior product for Australian and overseas markets. Approaches used. The program has a number of approaches including breeding, virus detection and elimination, and biotechnology. The classical hybridisation approach aimed at generation of diversity is combined with research into the more targeted techniques of plant tissue culture, genetic fingerprinting, genome mapping and transformation. Cryopreservation research is important for genebank storage, and tissue culture for micropropagation of new rootstocks and for transformation. Material is screened for Prunus Necrotic Ringspot (PNRV) and Prune Dwarf (PDV) Viruses. In addition, work has commenced into identifying Australian isolates of Colletotrichum acutatum, the pathogen causing anthracnose disease of almonds. The work is conducted in collaboration with overseas research groups, to take advantage of the long experience of these programs, and to contribute to the international effort in Prunus improvement. Outcomes from the almond project. The important outcomes achieved after the first five years of the project by the research team are listed.

Introduction. The genus Saissetia has 47 described species in the world, four of them in Mexico (S. oleae, S. miranda, S. neglecta and S. tolucana). These species attack different crops, including citrus, olives and ornamentals. Most introductions of natural enemies against S. oleae have been undertaken in North and South America, Australia and the Mediterranean countries. However, no natural enemy species have been purposedly introduced into Mexico against Saissetia spp. Materials and methods. During 1998–2003, samples of Saissetia spp. were collected in the States of Tamaulipas, Veracruz, Oaxaca and Guanajuato; all the emerged parasitoids were determined. Appropriate scientific publications were consulted to find out about any other Saissetia parasitoids recorded from Mexico. Results and discussion. Seventeen parasitoid species from five families of Chalcidoidea (Aphelinidae, Encyrtidae, Eupelmidae, Pteromalidae and Signiphoridae) were reared from Saissetia spp. in Mexico. Conclusions. In Mexico, the species of Saissetia prefer ornamental plants and are usually heavily parasitized by several chalcidoids. Native biological control of Saissetia spp. by different parasitoids has been effective for many years in Mexico. As a result, the species of Saissetia are not considered as primary or secondary pests of citrus and ornamentals.

Introduction. In the water-savingand income-generating agroforestry cropping systems developed andpromoted by the ICRISAT in the Sudano-Sahelian zone of West Africa, particularlyin Niger, fruits of domesticated Ziziphus mauritiana (“applesof the Sahel”) are severely damaged by fruit flies (Carpomya incompleta),and chemical pesticide application poses economic, environmentaland human health problems. In the Bio-reclamation of Degraded Lands (BDL)system, apple of the Sahel is the main high-value crop, while inthe Dryland Eco-Farm (DEF), it is grown alongside watermelon. Sclerocaryabirrea (marula plum) is presently being investigated asa dryland tree species for fruit and oil production, either in orchardsor such systems as BDL. Materials and methods. To completepreliminary results of earlier studies published elsewhere, we collectedand incubated in 2010 ripe fruits of marula plum and watermelonin Sadoré, Niger, where the above-mentioned agroforestry systemsare developed, and we recorded emerging fruit flies. We also conducteda spot-spraying experiment (using GF-120) in an apple of the Sahel orchardin Niamey in 2010; we recorded undamaged and damaged fruits and incubatedthe latter. In the same orchard, we set up in 2011 a fruit fly trappingsurvey targeting the invasive species Bactrocera invadens (Chempac®traps using methyl eugenol as the attractant). Results and discussion.The results showed that only Ceratitis cosyra emergedfrom marula plums, and only Dacus spp. from watermelon.The GF-120 spot-spraying experiment showed that C. incompleta was notattracted / intoxicated, contrary to Ceratitis spp.and Dacus spp.; the sprayed trees yielded significantly moremarketable fruits than unsprayed ones; only C. incompleta emergedfrom damaged fruit. Detection trapping revealed for the first timethe presence of B. invadens in the Sahelian zone ofNiger, including at the time of apple of the Sahel fruit production. Conclusion. This, alongside results of earlier studies,suggests a repellent effect of GF-120 on the monophagous C. incompleta species(Trypetinae), while it is attractive to oligophagous/polyphagousDacinae fruit flies; some of them (e.g., Dacus spp.)damage watermelon, which is part of the DEF system, and producefruit at the same time as the jujube tree. The prospects for harnessingthese two opposite regulation pathways are discussed.

Introduction In Morocco the olive growers rely totally on pesticides to control the black scale Saissetia oleae, although this technique has adverse effects on natural enemies, on product quality and on the environment. However, the pesticides are not used efficiently because of ignorance of the developmental cycle of the insect, and of the periods of vulnerable instar presence. We studied these two parameters. Next, we tested the efficacy of the pesticide and we studied the effect of pruning on the scales as an alternative to chemicals. Materials and methods The seasonal trend of the black scale was studied in two olive orchards near Essaouira, in the west of Morocco, during 2005 and 2006. One of these orchards was subject to chemical treatment in 2007, while two new orchards were selected to study the effect of pruning on the scales. The evolution of crawler and nymph density on different olive tree organs was followed in order to discover their preferences for these different organs. Results and discussion The seasonal trend study showed the presence of one generation of S. oleae per year and the tendency to colonise young organs rather than old ones. The optimum of mobile instar population coincided with the beginning and the end of July. On the organs of the chemically-treated samples, numbers of crawlers and nymphs were highly reduced. The results showed a small-scale infestation in pruned trees compared with the unpruned trees (control). Conclusion. Though the chemical control has good results, pruning remains very efficient and can help improve the control of the black scale populations without harming the environment

Introduction. Bananas are traditionally propagated by suckers: nevertheless, the advantage of using tissue-cultured plants for banana production has been demonstrated in recent years. Despite the large-scale use of micropropagated plants in the subtropical regions, little information is available on the performance of these crops in tropical countries. So we compared the yield potential of some Cavendish banana cultivars propagated either by traditional suckers or by tissue culture. Materials and methods. A randomized complete block experiment was established in a commercial plantation in Cameroon to compare the performance of three tissue-cultured banana plants of Grand Nain, Williams and Zelig cultivars and two conventionally-propagated plants of Grand Nain and Williams. Morphological, phenological and yield component data were collected for six crop cycles. Results. All the plants grew vigorously and produced quality exportable fruits. However, the tissue-cultured plants consistently produced heavier bunches and higher yields than the conventionally-propagated plants. The highest yields (65.92 t·ha–1 for Grand Nain, 64.60 t·ha–1 for Williams and 65.58 t·ha–1 for Zelig) were obtained for the tissue-cultured plants in the third crop cycle compared with 51.43 t·ha–1 and 59.02 t·ha–1 obtained for the traditionally-propagated Grand Nain and Williams plants, respectively. There were no significant yield differences between the plants of different origin in the second and fourth cycles, respectively. However, the tissue-cultured Williams and Zelig plants outperformed the other plants in the sixth crop cycle. Conclusion. The tissue-cultured plants of the three Cavendish cultivars studied performed better than the plants resulting from conventional suckers. The best cultivar for commercial plantation used, that is located in a tropical environment, was Williams. In general, to obtain an optimum benefit, we would recommend the use of tissue-cultured plants over a period of 6–7 years with good management practices.

Introduction. Figs of the variety ‘Roxo de Valinhos’ are currently cooled in a cold room at a temperature between (1 and 3) °C, and it is unknown how long it takes to cool the fruits to that temperature. The work was based on the need to determine the parameters of forced-air precooling of figs packed in a carton box used for exportation and commercialization in São Paulo State, Brazil. Materials and methods. The fruits were harvested at the harvest rami stage (3/4 of maturity) and at size “type 8”, corresponding to eight fruits per box, making up a total of 24 fruits per package. Forty-eight packages were utilized, 24 on each side to form a Californian tunnel. The airflow was 2.8 L·s–1 per kg of product, with an average velocity of the air of 2.0 m·s–1. The initial interior temperature of the fruits was 20 °C and the final temperature was 1 °C. The evolution of the fig interior temperature was registered. Results. The cooling curve was drawn and the exponential analytical model to predict the precooling parameters was made based on the experimental data. The cooling curve of fig showed a typical behavior; the average fruit temperature during precooling presented a rapid fall at the beginning of the cooling, and slowly declined when it was close to the final temperature. Conclusion. The cooling time was 110 min, the cooling coefficient was 0.0344 min–1, the Biot number was 1.3 and the convective heat transference coefficient was 23.8 °C·W–1·m–2.

Introduction. R.heudelotii (Euphorbiaceae) est un arbre fruitier des forêts denses humides, exploité par les populations locales. L’espèce est dioïque. La régénération par graines actuellement utilisée n’est pas aisée et elle entraîne une hétérogénéité génétique des descendants. Jusqu’à présent, la multiplication végétative horticole a surtout été basée sur l’utilisation de plantules issues des graines. Le but principal de notre travail a été de développer une méthode de multiplication conforme in vitro d’arbres adultes de R. heudoletii sélectionnés. Matériel et méthodes. Les boutures de 2 cm (un œil + un bourgeon axillaire) ont été prélevées sur une plante adulte de R. heudelotii, puis mises en culture, après stérilisation, sur un milieu de Murashige et Skoog dilué de moitié. Différentes concentrations de kinétine ont été ajoutées à ce milieu de base (MB) pour étudier l’effet de cette cytokinine sur le débourrement et le développement des bourgeons axillaires. De même, les effets de la benzylaminopurine (BAP) ajoutée à MB ont été parallèlement étudiés sur la prolifération des bourgeons présents au niveau des nœuds des boutures. Enfin, l’enracinement des boutures après culture soit sur milieu avec kinétine, soit sur milieu avec BAP a été testé par repiquage des boutures sur MB enrichi en acide naphtalèneacétique (ANA). Résultats. La BAP à 4,5 mg·L–1 a permis la prolifération de 91 % des bourgeons présents au niveau des nœuds sur boutures avec un maximum de 4,8 bourgeons néoformés par bouture. Cependant, l’isolement de ces bourgeons sur milieu enrichi en ANA n’a pas permis d’observer la différentiation de racines. La kinétine à 2,5 mg·L–1 a favorisé le débourrement et le meilleur développement des bourgeons axillaires (71 %). Le repiquage sur MB + 2 mg ANA·L–1 a favorisé l’enracinement de 72 % des boutures mises en cultures au départ sur MB + kinétine, avec un maximum de 6,3 racines formées par bouture. Le taux de réussite de l’acclimatation des vitroplants régénérés a été de 52,7 %. Discussion et conclusion. En utilisant la kinétine et l’ANA, un maximum de 36 vitroplants enracinés de R. heudelotii ont été régénérés en 22 semaines à partir de 50 boutures mises en culture. Ce taux de multiplication reste faible et, pour une multiplication conforme efficace de l’espèce, il devra être amélioré par la production complémentaire de vitroplants à partir de la prolifération des bourgeons obtenus sur milieu avec BAP.

Introduction. Conventional evaluation of Musa through multilocation trials has often been carried out to ascertain the yield stability and ecological range of new varieties but, for prospective growers, it is equally important to know the fruit characteristics and ripening pattern of the genotypes. Indeed, fruit characteristics determine consumers’ attitudes towards the new varieties, and the associated market value of these varieties. Materials and methods. The metric traits and ripening pattern of fruits from nine Musa hybrids and one local variety of plantain were evaluated during two cropping seasons in a sub-humid environment in Nigeria. Results. All the traits measured varied with the genotype, but cropping cycle influenced only fruit weight and days to complete senescence of fruits. The interaction between genotype and cropping cycle was significant on fruit weight, fruit length and days to attain four different ripening stages. Most genotypes had better values in the ratoon harvest than in the plant crop. Fruit length and shape of PITA 21 were comparable with those of the local check, but the index of edible proportion was highest in PITA 22. PITA 21 and PITA 26 had the longest green life and total shelf life. Conclusion. The genotypes evaluated in our study revealed different utilization potentials. Also, the better postharvest life of some of the hybrids and comparable metric traits with the local check suggested the high adoption potential of the hybrids.

Introduction. Le plantain constitue une importante denrée alimentaire pour de nombreuses populations au sud du Sahara. Sa production dans les systèmes traditionnels de culture par les petits paysans est menacée par la maladie des raies noires, une maladie foliaire due à Mycosphaerella fijiensis Morelet responsable de pertes importantes de récolte. Pour faire face à cette maladie, des hybrides tétraploïdes de type plantain, résistants à la maladie, ont été créés au Cameroun puis sélectionnés à l’issue d’une première phase d’évaluation. Après multiplication végétative, les hybrides ainsi sélectionnés ont été évalués en station de recherche afin de déterminer leurs caractéristiques agronomiques et leur rendement potentiel en conditions de culture semi-intensive. Matériel et méthodes. De 1996 à 2000, trente hybrides sélectionnés ont été évalués, en comparaison avec leurs parents femelles, sur deux cycles de production à la faveur de trois essais mis en place suivant un dispositif expérimental en blocs de Fisher complètement randomisés avec deux répétitions de 10 bananiers chacun. Chacun des bananiers a été étudié à partir de caractéristiques agronomiques portant sur la croissance et la production. Résultats et discussion. Sept hybrides ont été sélectionnés sur la base de leur rendement potentiel élevé, de leur précocité de floraison et de leur pouvoir rejetonnant. Cependant, ce matériel végétal tétraploïde présente plusieurs défauts qui constituent un frein à leur diffusion. Certains de ces hybrides sont utilisés comme produits intermédiaires dans un nouveau schéma d’amélioration variétale au CARBAP.

Introduction. Bacterial canker, caused by Pseudomonas syringae pv. syringae, is a destructive disease where stone fruit trees are cultivated. The efficacy of nitrogen and calcium fertilization on bacterial canker susceptibility was evaluated in stone fruits. Materials and methods. Field experiments were conducted to study the efficacy of foliar applications of calcium nitrate, and ground fertilization with CAN-17 plus low-biuret urea foliar spray on bacterial susceptibility in ‘Riegel’ peach, ‘French’ prune and ‘Nonpareil’ almond growing in ring nematode-infested and nematicide-fumigated soils. Host susceptibility was evaluated by measuring the length of lesions developed following inoculation with P. syringae pv. syringae. Results and discussion. Foliar applications of Ca(NO3)2 significantly increased leaf nitrogen and bark calcium concentrations in peach trees growing in both fumigated and nonfumigated areas. Peach trees growing in nonfumigated areas developed significantly longer lesions than trees growing in fumigated areas. However, Ca(NO3)2 foliar applications had no effect in decreasing peach susceptibility to bacterial infection in both nonfumigated and fumigated areas. After inoculation, diseased prune trees developed significantly longer lesions than healthy trees. Leaf and bark calcium concentrations of diseased prune were significantly increased after Ca(NO3)2 foliar sprays, but again the treatments did not significantly affect prune susceptibility to bacterial infection. However, nitrogen fertilization with CAN-17 and urea significantly increased the bark nitrogen concentration of almond trees, and these trees had significantly smaller lesions than those not receiving nitrogen fertilization. Foliar application of calcium (Nutri-Cal) did not affect almond susceptibility to bacterial canker. Collectively, these data support the previous hypothesis that increased susceptibility of stone fruits to P. syringae pv. syringae under nematode infestation conditions is mediated by both nitrogen effects and nitrogen-independent effects, and application of ammonium nitrogen may have some beneficial effects in reducing stone fruit susceptibility to bacterial canker where ring nematode infestation prevails.

Introduction. We present some protocols aiming at partially characterizing banana fruit quality through measurement of some key biochemical parameters. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials and the steps necessary for achieving four protocols making it possible to measure sugar, organic acids and free ACC contents, and in vitro ACC oxidase activity. Results. Standard results obtained by using the protocols described are presented in the figures.