Alternaria fruit rot on Minneola tangelos and navel oranges can reach economically important levels in central Arizona. The objective of this study was to test the efficacy of a new fungicide in development, BAS 500, for disease management. A trial was conducted in a commercial Minneola tangelo grove with a history of Alternaria fruit rot. Within this grove, nine trees were sprayed monthly from August to December 2000 with BAS 500 at a rate of 0.25 lb active ingredient per acre. Another nine trees were not sprayed and served as controls. Disease severity was evaluated monthly from September 2000 to March 2001 by counting the number of infected fruit that had dropped from trees. No disease was evident on fruit from August through November, when fruit were green. By December the fruit had matured and turned color; additionally, the first fruit were detected with Alternaria fruit rot. In December and January there was little difference in the number of infected fruit on treated compared to nontreated trees. On the other hand, by February and March the cumulative number of infected fruit from trees treated with BAS 500 was 3.0 and 3.7 %, respectively, whereas the cumulative number of diseased fruit from nontreated trees during the same months was greater at 4.9 and 6.4 %, respectively. This study will be repeated next year with an adjusted spray schedule with the goal of increasing the level of disease control.

This experiment was initiated in March 2000 to study the feasibility of growing organic lemon in the desert southwest of Arizona. A ten-acre field planted to lemons in 1998 was selected on Superstition sand at the Yuma Mesa Agricultural Research Center. The initial soil test in top 6 inches was 5 parts per million (ppm) NO₃⁻ and 4.9-PPM NaHCO₃⁻-extractable P. Soil pH was 8.7 in the top 6 inches. Seven treatments were applied in randomized complete block design repeated three times. The treatments were control, compost and clover, compost and perfecta, compost and steam, manure and clover, manure and perfecta and manure and steam Leaf tissue analysis indicated that nitrate level was significantly influenced by treatment. Organic insect control treatments for citrus thrips were as equally effective as the non-organic commercial standards.

A small plot trial was conducted to evaluate the benefit of applying insecticides for citrus thrips management pre-petal fall. Because of low thrips densities during the pre-petal period, we were not able to discern tangible benefits from making prepetal applications. However, in situations where fruit is present and petal fall has not fully occurred, these applications may be useful to protect these fruit. Of the acute toxicants evaluated pre-petal fall (Assail and Success), Assail appeared to be the best choice. However, if temperatures are approaching 95°F, Assail should be avoided. Pre-petal fall applications of Surround and Snow are beneficial in respect that several applications of these products may be required to obtain adequate coverage, and by making these applications during the pre-petal fall period, thrips can be managed before many susceptible fruit are present.

Surround WP was evaluated at various spray volumes to determine if volumes lower than the label recommended volume of 250 gallon per acre would provide equivalent citrus thrips control and yield enhancement potential. All the spray volumes evaluated (50, 100, 150, and 250 gpa) appeared to be equally effective. It appears that as long as the spray coverage appears to be visually adequate, then coverage is sufficient. Application of Surround WP led to some increase in fruit size, particularly for the first harvest.

An attempt was made in 1997 to rejuvenate neglected, mature 'Wichita' pecan trees in a commercial Pinal County grove by applying two types of heading back pruning cuts. The treatments were applied during the dormant season prior to the growing season. The trees were pruned using proven horticultural techniques which included dehorning (cutting main scaffolds to within 2 feet of the trunk) and cutting main scaffolds by 50%. After four years of data, the trees receiving no pruning treatments are producing as well or better than trees to which the pruning treatments were applied. The data suggests that a return to normal irrigation and fertilization practices alone will return neglected, water-stressed trees to normal productivity as early as trees that have been headed-back.

No description available.

The fruits of elderberry - Sambuci fructus are used in the pharmaceutical and food industry. Fruits contain anthocyanins and flavonoids in addition to cyanogenic glycoside sambunigrin, organic acids, vitamins, sugars. Fruits from cultivated varieties are not used in pharmaceutically yet. The content of anthocyanins in the fruits of Sambucus nigra L. varieties Alessö, Bohatka, Haschberg, Mammut, Sambo, Sambo, Samdal, Sampo, Samyl, Weihenstephan and wild elderberry was determined by spectrophotometry. The amount of anthocyanins was recalculated for dried fruits and expressed by percentage of cyanidin chloride. Cultivated varieties shown lower values of anthocyanins than wild elderberry excerpt for Samyl variety. Statistically significant differences were found between contents of anthocyanins of varieties.

Le groupe des agrumes d’acidité intermédiaire (orange, clémentine et mandarine) perd l’acidité au cours de la maturation (stade III), mais cette chute semble plus forte depuis quelques années dans la zone méditerranéenne. Il a été suggéré que cette perte d’acidité serait liée au climat (automnes plus doux) ce qui entraînerait une augmentation de la respiration des fruits avec une photopériode plus courte à cette période et se traduirait par un déséquilibre carboné. Pour tester cette hypothèse, nous avons choisi d’étudier l’effet d’un déséquilibre carboné, induit par une défoliation partielle, soit en début soit en fin de stade II, qui est la phase de grossissement cellulaire où les sucres et les acides organiques s’accumulent dans la vacuole des cellules des sacs à jus. Nous avons établi un bilan sucres-acides des fruits soumis aux différentes réductions d’apport carboné et identifié la ou les périodes où la réduction de l’apport carboné a le plus d’impact sur les teneurs en sucres et en acides organique. Puis, nous avons regardé l’impact de ce déséquilibre sur le métabolisme du fruit en étudiant l’activité spécifique d’enzyme spécifiques (phosphofructokinase, invertase acide, phosphoénolpyruvate carboxylase, isocitrate déshydrogénase cytoplasmique) et l’expression de gènes d’intérêts (CsCit1, succinate semialdéhyde déshydrogénase, Δ1-pyrroline-5-carboxylate synthétase) et identifié les mécanismes biochimiques impliqués dans la réponse à la limitation des apports carbonés.Les résultats obtenus montrent que les fruits ne sont pas capables de compenser la réduction des apports carbonés (poids et calibre) que la réduction foliaire soit précoce ou plus tardive au cours du stade II. Lorsque la réduction foliaire est précoce et à court terme (48h et une semaine), l’apport carboné n’est pas affecté puisque les teneurs en saccharose sont similaires à celles du témoin. Nous avons observé une augmentation de l’activité enzymatique de la PFK qui est envisageable grâce au déstockage de la vacuole par l’action de l’invertase acide. La PEPC permet la synthèse d’oxaloacétate et maintient la production d’acide citrique, qui sera dégradé dans le cytoplasme par la NADP-IDH en α-cétoglutarate qui va donner du glutamate et du GABA. La voie du GABA « shunt » semble favorisée puisque l’expression du gène codant pour la SSADH est augmentée. A long terme (7 semaines), l’apport carboné a été affecté puisque les teneurs en saccharose ont fortement diminué par rapport au témoin. Il y a un déstockage de l’acide citrique de la vacuole par CsCit1 mais pas d’activation de la voie du GABA shunt ce qui est compatible avec l’hypothèse que cette voie serait activée par un stress. Lorsque la cellule est en phase d’accumulation des acides organiques, elle privilégie la synthèse d’acide citrique. En revanche, lorsque la réduction foliaire est tardive, les teneurs en sucres sont fortement affectées 48h après la réduction, le flux glycolytique est ralenti et il ne semble pas y avoir un déstockage de la vacuole. Les teneurs en acide malique et en acide malique chutent également mais l’activité de la PEPC est augmentée pour favoriser la synthèse d’acide citrique. Nous avons observé une formation importante de proline qui provient du glutamate. Comme nous n’avons pas observé, 48h après la réduction foliaire, une augmentation des niveaux de transcrits de la P5CS, la voie de l’ornithine serait impliquée. Il serait intéressant de confirmer ou non l’hypothèse de la formation de ROS lors des deux réductions foliaires ce qui nous permettrait de savoir si la voie du GABA « shunt » lors de la réduction foliaire précoce ou bien la formation de proline lors de la réduction foliaire tardive sont fortement sollicitées afin de lutter contre le stress oxydatif provenant de la réduction des apports carbonés. / The intermediate acidity group of citrus (orange, clementine and mandarin) loses acidity during maturation (stage III). But this decrease seems to get stronger since several years in the mediterranean basin. It has been suggested that the wider loss of this acidity could be linked to climate (warmer autumns) which would increase fruit respiration at the time when photoperiod is short inducing a carbon imbalance. To check this hypothesis, we chose to study the effect of a carbon imbalance induced by partial defoliation, either at the beginning or at the end of stage II, which is the phase of cell enlargement where sugars and organic acids accumulate in the juice cells bags vacuole. We have established a sugar-acid balance of fruit submitted to different carbon reductions and identified the period or periods for which the reduction of the carbon input had the greatest impact on sugars and organic acids contents. Then, we watched the impact of this imbalance on fruit metabolism studying specific enzyme activity (phosphofructokinase, acid invertase, phosphoenolpyruvate carboxylase, cytoplasmic isocitrate dehydrogenase) and genes of interest expression (CsCit1, succinate semialdehyde dehydrogenase genes Δ1-pyrroline-5-carboxylate synthetase). We also identified the biochemical mechanisms involved in the response to the carbon inputs limitation.The obtained the results showed that fruits are not able to offset the limitation of carbon inputs (weight and size) whether the leaf reduction is early or late during stage II. When the leaf reduction is early, for a short-term (48 hours and one week), the carbon contribution is not affected since sucrose contents are similar to those of the control. We observed an increase in PFK enzymatic activity of which is suitable through the destocking of the vacuole due to the action of acid invertase. PEPC allows oxaloacetate synthesis and maintains citric acid production, which will be degraded in the cytoplasm by the NADP-HDI in α-ketoglutarate which will give glutamate and GABA. The GABA "shunt" response seems to be promoted since the expression of the gene encoding the SSADH is increasing. In long-term (7 weeks), the carbon contribution was affected since sucrose contents decreased significantly compared to control fruit. Citric acid is destocked from the vacuole by CsCit1 but no activation of the GABA shunt occurs which is consistent with the hypothesis that this pathway would be activated by stress. Thus, when the cell is in the process of organic acids accumulation, it seems the synthesis of citric acid. In return, when the leaf reduction is late, the sugar contents are strongly affected 48h after reduction, the glycolytic flux is slow and it does not seem to have remobilization of sugars from vacuole. The contents of malic acid and citric acid also fall but PEPC activity is increased to promote the synthesis of citric acid. A significant formation of proline from glutamate is observed. Since we did not observe, 48 hours after foliar reduction, an increase in P5CS transcript levels, ornithine pathway could be involved. It would be interesting to confirm or not the hypothesis of ROS inducing in both foliar reductions in order to see if the GABA "shunt" for early leaf reduction or the proline formation for late leaf reduction are heavily involved in oxidative stress response that might be induce by carbon inputs limitation.

Thanks to Taiwan¡¦s geographic advantage of being located in subtropics, tropical fruits in Taiwan have high quality. There is never shortage of variously fresh and high-quality fruits in four seasons of a year in Taiwan, which should have gained Taiwan competitive advantages in international markets and should have made Taiwan nominated to be a standard for international markets. However, a large number of problems and difficulties in production and marketing system of the fruit industry have caused tropical fruits in Taiwan unable to get into foreign markets. The prospect of this research is to find out the influential marketing factors by carefully examining export and other related difficulties; consequently, the purpose of this research is to find out the most effective solutions among a large number of marketing factors to help the fruit industry in Taiwan out of difficulties. The research methods used in this study are interviewing fruit production and marketing professionals to analyze the fruit export difficulties, assisted with marketing 4P and STP structure, brand thesis, and real case studies. With the above mentioned methods, I structurally analyze difficulties and problems. According to the findings of this research, tropical fruits in Taiwan evidently have powerful competitive advantages; however, the ¡§Product¡¨ aspect of 4P is still the major factor that should be solved at first when tropical fruits in Taiwan confront export competition. All of the followings, fruit classification, production capacity management, packing, freezing, inspection, brand and the other related factors, are the main problems mentioned consistently by professionals. This research also finds that ¡§brand¡¨ makes industry, government, schools reach one accord; therefore, it should be taken as our long-term developmental direction and the best strategy to resuscitate Taiwan¡¦s fruits in international markets. Nevertheless, as it is shown on the related documents, Council of Agriculture¡¦s brand identification system is nothing more than just providing a name to a species of fruit, which is unable to build up its fame to domestic consumers and much less to foreign markets. According to the above findings of this research, four suggestions are proposed as follows: 1. Establishment of national brand series: to take advantage of Taiwan¡¦s great fame, using its name to sell our tropical fruits, and to take rural towns¡¦ or Co-operatives¡¦ brand as the sub-brand or the extensive brand. 2. Brand clock: to promote and cross sell fruits in different seasons based on different fruit periods. To construct brand life span with brand clock by taking national brand as the principal axis and assisted with season fruits¡¦ production periods; as a result, Taiwan¡¦s fruits can be sufficiently provided to export markets all the year around, keeping out from unstable supply that Taiwan has confronted for a long time. 3. Market Segmentation and Positioning: tropical fruits enjoy the advantage of freshness and numerous species, but they are difficult to keep fresh. Although freezing technology has been improved a lot, keeping tropical fruits fresh during a long distance transportation is always a real challenge. Consequently, choosing a proper market to do marketing according to the feature of every kind of fruit is highly recommended. This will avoid fruit quality from declining caused by blindly selling all fruits to uncompetitive markets or caused by a long distance transportation. Both of the above situations will cause a negative impact on brand. 4. Fruit identification: to take fruits that agricultural units can easily promote as the major products, to enhance production, to abandon uncompetitive species of fruits, to effectively manage and control fruit cultivating technology (Intelligent property right and species control), and to promote fruit identification system. All of the above methods will help Taiwan¡¦s fruit industry have their competition in the market.

Thèse de doctorat : Procédés biotechnologiques et alimentaires : Vandoeuvre-les-Nancy, INPL : 2006. / Titre provenant de l'écran-titre. Bibliogr.