Tropical and subtropical fruits in florida (other than citrus)

Avocado and mango are the leading commercial fruits of South Florida. Lychee, guava, pineapple, bananas, papayas, and persimmon, are of minor economic value, while sapodilla, macadamia nut, Barbados cherry and the Mysore black raspberry show promise of commercial development. All of these fruits and many more are grown as dooryard plants. The fact that such a large number of tropical and subtropical fruits can be grown in South Florida has made the subject of tropical pomology a very important one for this area.     

植物果实、颜色和形状对橘小实蝇产卵选择的影响

橘小实蝇Bactrocera dorsalis(Hendel)是近几年入侵江苏南部地区,严重危害当地水果、蔬菜的重要害虫。为深入了解其在该地区果树、蔬菜上的产卵特性,进行植物果实、颜色和形状对其产卵选择影响的研究。实验室中"纸杯法"的产卵选择试验结果表明,橘小实蝇对不同水果的产卵偏好性由高到低依次为:柑橘、香蕉、芒果、枣、石榴、苹果、桃子、梨、李、葡萄、柿;对不同蔬菜的产卵偏好性由高到低依次为:丝瓜、豇豆、苦瓜、黄瓜、茄子、南瓜、青椒、番茄。对不同寄主颜色和形状的产卵选择特点为,雌虫常选择桔黄色、绿色,以及圆球形的寄主产卵,而较少选择黑色、方形的寄主产卵。从试验结果可以看出,寄主果实散发出的气味,及其颜色和形状对橘小实蝇的产卵选择有影响。     

Management of Fruit Flies (Diptera: Tephritidae) of the Most Perishable Fruits

We investigated to minimize the dependency on the use of chemicals and thus develop safe and environmental friendly control program for the most perishable fruits i.e., apple,‘ber’, guava and mango. Our findings on the composition of fruit fly species reveal that Bactrocera dorsalis was dominant on apple (33.96% existence), Corpomya incompleta on‘ber’(51.91% existence) and Bactrocera zonata on guava (49.62% existence) and mango (74.66% existence). The correlation between population and infestation percentage was non‐significant in apple orchards, whereas positive and highly significant in between population and infestation, as well as on the cumulative basis in‘ber’, guava and mango orchards during 1998‐1999. Hoeing, baiting and methyl eugenol were statistically equal resulting about 77% decrease in infestation. The maximum control of 91.68% was observed where all four‐control operations including Dipterex® were integrated together. Weather factors, when computed together, had maximum effect on population fluctuation and infestation with rainfall contributing the major role. For guava fruits, the months of August (14.06A individuals/trap/day) and September (13.81A individuals/trap/day) were important, resulting in maximum infestation percentage of 10.76 to 14.74%, respectively.     

Volatile host fruit odors as attractants for the oriental fruit fly (Diptera: Tephritidae)

We examined the responses of oriental fruit flies, Bactrocera dorsalis Hendel, to the odors of different stages and types of fruit presented on potted trees in a field cage. Females were most attracted to odors of soft, ripe fruit. Odors of common guava were more attractive to females than papaya and starfruit, and equally as attractive as strawberry guava, orange, and mango. In field tests, McPhail traps baited with mango, common guava, and orange captured equal numbers of females. Traps baited with mango were compared with 2 commercially available fruit fly traps. McPhail traps baited with mango captured more females than visual fruit-mimicking sticky traps (Ladd traps) and equal numbers of females as McPhail traps baited with protein odors. Results from this study indicate that host fruit volatiles could be used as lures for capturing oriental fruit flies in orchards.     

不同成熟度菠萝贮藏特性的差异

随着菠萝果皮由绿转黄,果肉硬度及可溶性固形物含量降低,可溶性糖醛酸含量增加,多聚半乳糖醛酸酶(PG)活性持续升高,而果胶脂酶(PE)活性在过熟期达到高峰并开始下降。研究表明,同一菠萝不同部位果肉硬度、PG活性及可溶性糖醛酸含量差异较大。     

八种水果中的多酚含量及其抗氧化性

测定了苹果、石榴、橄榄、芒果、香蕉、菠萝、葡萄和龙眼的壳、肉及核中的多酚含量及其抗氧化性。以70%丙酮(v/v)为提取溶剂,室温下超声波辅助浸提样品后得到提取液。采用普鲁士兰(Prussian blue)法测定了提取液中多酚和单宁的含量,利用FRAP法测定其抗氧化性。结果表明:提取液中多酚和单宁的含量均与其抗氧化性成正相关关系;石榴、橄榄、芒果、葡萄和龙眼等水果的壳与核有望成为天然抗氧化剂的新来源。     

Fruits of apple and sweet persimmon are not essential food sources for Riptortus pedestris (Hemiptera: Alydidae) which causes fruit-spotting

Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are unsuitable food for some fruit-spotting bugs, the dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated harvested fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, immature mortality, preovipositional period, fecundity, and adult size in the laboratory. No first instars of R. pedestris that were fed only apple or sweet persimmon fruits became third instar nymphs. When supplemented with soybean seeds, both fruits supported nymphal development and reproduction of R. pedestris. However, fruits combined with soybean seeds were not a better diet than soybean seeds only. Therefore, apples and sweet persimmons are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on fruit trees, thus explaining the absence of eggs and nymphs of this bug on fruit trees in orchards. Management of nearby vegetation of fruit orchards would be important for reducing damage by adult R. pedestris.     

Identification and Characterization of Colletotrichum spp. affecting Fruit after Harvest in Brazil

Colletotrichum spp. cause anthracnose in various fruits post‐harvest and are a particularly important problem in tropical and subtropical fruits. The disease in fruits of avocado, guava, papaya, mango and passion fruit has been reported to be caused by C. gloeosporioides, and in banana by C. musae. In subtropical and temperate crops such apple, grape, peach and kiwi, the disease is caused by C. acutatum. The variation in pathogenic, morphological, cultural and molecular characteristics of Brazilian isolates of Colletotrichum acutatum Simmonds and isolates from post‐harvest decays of avocado, banana, guava, papaya, mango and passion fruit was evaluated. The fruits were inoculated with mycelium of C. acutatum, Colletotrichum spp. and C. musae on a disc of potato dextrose agar. The morphological, cultural and molecular characteristics studied were conidia morphology, colony growth at different temperatures, colony coloration and PCR with primers CaInt2 and ITS4 for C. acutatum and CgInt and ITS4 for C. gloeosporioides. C. acutatum was pathogenic to avocado, guava, papaya, mango and passion fruit, but it was not pathogenic to banana. The morphological, cultural and molecular studies indicated that the avocado, papaya, mango and passion fruit isolates were C. gloeosporioides. The natural guava isolate was identified as C. acutatum, which had not been found previously to produce anthracnose symptoms on guava in Brazil.     

Stimulation of ethylene production by a cell wall component from mature green tomato fruit

Pectic (carbonate-soluble, covalently-bound pectin, CBP) material stimulated increased ethylene production when vacuum-infiltrated into whole, mature green tomato ( Lycopersicon esculentum Mill. cv. Rutgers) fruit. Activity was greatest if CBP was extracted from mature green tomatoes with jellied locules. CBP extracted from mature green tomatoes with immature seeds had no elicitor activity, while CBP from turning or red ripe tomatoes was only moderately active. Infiltration of CBP from normal mature green fruit into ripening inhibitor ( rin ) mutant tomato fruit stimulated ethylene production and attenuated red pigmentation in these fruits. Partial purification of the active material was accomplished using DEAE-Sephadex and BioGel P-100 chromatography. The most highly purified fraction is comprised of neutral carbohydrate (95%) with a relatively low content of amino acids (1%) and a uronic acid content of less than 5%. This material may be an endogenous trigger of ethylene production and ripening.     

Characterization of expression, and cloning, of beta-D-xylosidase and alpha-L-arabinofuranosidase in developing and ripening tomato (Lycopersicon esculentum Mill.) fruit

Modifications to the cell wall of developing and ripening tomato fruit are mediated by cell wall-degrading enzymes, including a beta-d-xylosidase or alpha-l-arabinofuranosidase, which participate in the breakdown of xylans and/or arabinoxylans. The activity of both enzymes was highest during early fruit growth, before decreasing during later development and ripening. Two beta-d-xylosidase cDNAs, designated LeXYL1 and LeXYL2, and an alpha-l-arabinofuranosidase cDNA, designated LeARF1, were obtained. Accumulation of mRNAs for beta-d-xylosidase and alpha-l-arabinofuranosidase was examined during fruit development and ripening. LeARF1 and LeXYL2 genes were relatively highly expressed during fruit development and decreased after the onset of ripening. By contrast, LeXYL1 was not expressed during fruit development, but was expressed later, particularly during over-ripening. The expression of all three genes was also followed in ripening-impaired mutants, Nr, Nr2, nor, and rin of cv. Ailsa Craig fruit. LeXYL2 mRNA was detected in the ripe fruits of all the mutants and its abundance was similar to that in mature green wild-type fruit. By contrast, LEXYL1 mRNA was expressed only in the ripe fruits of the Nr mutant, suggesting that the two beta-d-xylosidase genes are subject to distinct regulatory control during fruit development and ripening. LeARF1 mRNA was detected in ripe fruits of Nr2, nor and rin, and not in ripe fruit of the Nr mutant. The accumulation of LeARF1 in ripe fruit was restored by 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, while 1-MCP had no effect on the expression of LeXYL1 or LeXYL2. This suggests that LeARF1 expression is subject to negative regulation by ethylene and that the two beta-d-xylosidase genes are independent of ethylene action.     

Field infestation of rambutan fruits by internal-feeding pests in Hawaii

More than 47,000 mature fruits of nine different varieties of rambutan (Nephelium lappaceum L.) were harvested from orchards in Hawaii to assess natural levels of infestation by tephritid fruit flies and other internal feeding pests. Additionally, harvested, mature fruits of seven different rambutan varieties were artificially infested with eggs or first-instars of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), or oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) to assess host suitability. When all varieties were combined over two field seasons of sampling, fruit infestation rates were 0.021% for oriental fruit fly, 0.097% for Cryptophlebia spp. (Lepidoptera: Tortricidae), and 0.85% for pyralids (Lepidoptera). Species of Cryptophlebia included both C. illepida (Butler), the native Hawaiian species, and C. ombrodelta (Lower), an introduced species from Australia. Cryptophlebia spp. had not previously been known to attack rambutan. The pyralid infestation was mainly attributable to Cryptoblabes gnidiella (Milliere), a species also not previously recorded on rambutan in Hawaii. Overall infestation rate for other moths in the families Blastobasidae, Gracillariidae, Tineidae, and Tortricidae was 0.061%. In artificially infested fruits, both species of fruit fly showed moderately high survivorship for all varieties tested. Because rambutan has such low rates of infestation by oriental fruit fly and Cryptophlebia spp., the two primary internal-feeding regulatory pests of rambutan in Hawaii, it may be amenable to the alternative treatment efficacy approach to postharvest quarantine treatment.     

The developmental pattern of tomato fruit wax accumulation and its impact on cuticular transpiration barrier properties: effects of a deficiency in a beta-ketoacyl-coenzyme A synthase (LeCER6)

Cuticular waxes play a pivotal role in limiting transpirational water loss across the primary plant surface. The astomatous fruits of the tomato (Lycopersicon esculentum) 'MicroTom' and its lecer6 mutant, defective in a beta-ketoacyl-coenzyme A synthase, which is involved in very-long-chain fatty acid elongation, were analyzed with respect to cuticular wax load and composition. The developmental course of fruit ripening was followed. Both the 'MicroTom' wild type and lecer6 mutant showed similar patterns of quantitative wax accumulation, although exhibiting considerably different water permeances. With the exception of immature green fruits, the lecer6 mutant exhibited about 3- to 8-fold increased water loss per unit time and fruit surface area when compared to the wild type. This was not the case with immature green fruits. The differences in final cuticular barrier properties of tomato fruits in both lines were fully developed already in the mature green to early breaker stage of fruit development. When the qualitative chemical composition of fruit cuticular waxes during fruit ripening was investigated, the deficiency in a beta-ketoacyl-coenzyme A synthase in the lecer6 mutant became discernible in the stage of mature green fruits mainly by a distinct decrease in the proportion of n-alkanes of chain lengths > C(28) and a concomitant increase in cyclic triterpenoids. This shift in cuticular wax biosynthesis of the lecer6 mutant appears to be responsible for the simultaneously occurring increase of water permeance. Changes in cutin composition were also investigated as a function of developmental stage. This integrative functional approach demonstrates a direct relationship between cuticular transpiration barrier properties and distinct chemical modifications in cuticular wax composition during the course of tomato fruit development.     

Sucrose phosphate synthase and other sucrose metabolizing enzymes in fruits of various species

Recent reports have suggested that sucrose phosphate synthase (EC 2.4.1.14), a key enzyme in sucrose biosynthesis in photosynthetic “source” tissues, may also be important in some sucrose accumulating “sink” tissues. These experiments were conducted to determine if sucrose phosphate synthase is involved in sucrose accumulation in fruits of several species. Peach (Prunus persica NCT 516) and strawberry (Fragaria x ananassa cv. Chandler) fruits were harvested directly from the plant at various stages of fruit development. Kiwi (Actinidia chinensis), papaya (Carica papaya), pineapple (Ananas comosus) and mango (Mangifera indica) were sampled in postharvest storage over a period of several days. Carbohydrate concentrations and activities of sucrose phosphate synthase, sucrose synthase (EC 2.4.1.13), and acid and neutral invertases (EC 3.2.1.26) were measured. All fruits contained significant activities of sucrose phosphate synthase. Moreover, in fruits from all species except pineapple and papaya, there was an increase in sucrose phosphate synthase activity associated with the accumulation of sucrose in situ. The increase in sucrose concentration in peaches was also associated with an increase in sucrose synthase activity and, in strawberries, with increased activity of both sucrose synthase and neutral invertase. The hexose pools in all fruits were comprised of equimolar concentrations of fructose and glucose, except in the mango. In mango, the fructose to glucose ratio increased from 2 to 41 during ripening as sucrose concentration more than doubled. The results of this study indicate that activities of the sucrose metabolizing enzymes, including sucrose phosphate synthase, within the fruit itself, are important in determining the soluble sugar content of fruits of many species. This appears to be true for fruits which sweeten from a starch reserve and in fruits from sorbitol translocating species, raffinose saccharide translocating species, and sucrose translocating species.     

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.     

A comparison of the ultrastructure and composition of fruits’ cuticular wax from the wild-type ‘Newhall’ navel orange (Citrus sinensis [L.] Osbeck cv. Newhall) and its glossy mutant

Key message

The altered ultrastructure and composition of cuticular wax from ‘glossy Newhall’ (MT) fruits lead to its glossy phenotype.

Abstract

A novel mutant derived from the wild-type (WT) ‘Newhall’ navel orange (Citrus sinensis [L.] Osbeck cv. Newhall), named ‘glossy Newhall’ (MT), which produced much more glossy fruits that were easily distinguishable from the WT fruits was characterized in this report. The total wax loads of both WT and MT fruits varied considerably during the fruit development. The most abundant wax fraction of WT mature fruits was triterpenoids, followed by aldehydes, alkanes, fatty acids, primary alcohol and cholesterol. The total wax load in MT mature fruits was reduced by 44.2?% compared with WT. Except for the minor wax components of primary alcohol and cholesterol, the amounts of all major wax fractions in MT mature fruits were decreased in varying degrees. The major reduction occurred in aldehydes that decreased 96.4?% and alkanes that decreased 81.9?%, which was consistent with scanning electron micrographs of MT mature fruit surfaces that showed a severe loss of wax crystals. Hence, aldehydes and alkanes were suggested to be required for wax crystal formation in ‘Newhall’ navel orange fruits.     

Studies on the latent infection of Botryodiplodia theobromae Pat. on Citrus sinensis (Li.) Osbeck fruit

The latent infection caused by Botryodiplodia theobromae on Citrus sinensis fruit was investigated. Isolations from washings from mature green fruit surfaces showed the occurrence of B. theobromae, Rhizopus stolonifer and Trichoderma sp. The histological studies on fruit tissues revealed some structural and physiological changes between ripe and unripe fruits while investigations on the host-parasite relations could not detect any propagule of B. theobromae at the early stage of infection. The effects of rind extracts obtained at 60°, 80° and 100°C from mature green, half ripe and full ripe fruits when cooled were tested on the growth of three fruit moulds. Extracts from healthy mature green fruit rind obtained at 80°C showed significant inhibition of growth of B. theobromae while R. stolonifer and C. paradoxa could not grow in this medium.     

Induction of Peroxidase during Infection of Unripe Persimmon Fruit by Alternaria alternata: a Possible Quiescence Mechanism

Limited black spot symptoms (Quiescent infections) develop on persimmon fruits as Alternaria alternata hyphae penetrate the pericarp of green‐immature fruit. Inoculation of persimmon with A. alternata or treatment with a commercial preparation of purified cellulase induced similar black symptoms and higher peroxidase activity in green‐immature fruits but not in orange‐mature persimmon fruits. Both treatments induced the development of new peroxidase isoforms only in immature fruits – however, no effect was observed on polyphenoloxidase activity. A. alternata was transformed with a construct expressing green fluorescent protein (GFP). Histological analysis of hyphal development using GFP‐transformed fungi indicated that symptoms are always found ahead of the leading edge of the hyphae. We suggest that peroxidase increase, induced by the directly penetrating A. alternata, might be involved in the induction of quiescence infection by the pathogen in immature fruits.     

Penetration by Botryosphaeriaceae species in avocado,guava and persimmon fruit during postharvest

Botryosphaeriaceae species have a wide host range and a worldwide distribution. These fungal species can colonize several plant organs, such as the trunk, leaves and fruit. Some Botryosphaeriaceae species cause important diseases on persimmon, avocado and guava fruit. However, there is a lack of information regarding the mechanisms of penetration by Botryosphaeriaceae species on these tropical and subtropical fruits. This study aimed to better understand the mechanisms involved in fungal penetration, host specificity and aggressiveness of Botryosphaeria dothidea, Lasiodiplodia pseudotheobromae and Neofusicoccum parvum on avocado (Persea americana), guava (Psidium guajava) and persimmon (Diospyros kaki) fruit. Scanning electron microscopy (SEM) image analysis showed that in avocado fruit, the three studied Botryosphaeriaceae species penetrated through lenticels. In guava fruit, penetration through stomata was verified for Botryosphaeria dothidea and Neofusicoccum parvum. In persimmon fruit, an appressoria-like structure was observed for B. dothidea, which suggests direct penetration. Disease incidence in wounded fruit was 24% higher than in non-wounded fruit. L. pseudotheobromae and N. parvum showed differences in aggressiveness in guava fruit. The longest incubation period was observed for N. parvum inoculated on guava, with an average of 4.5 days, and the shortest incubation period was verified for B. dothidea inoculated on avocado, with an average of 2.8 days. The area under the disease progress curve (AUDPC) did not differ between Botryosphaeriaceae species on avocado, whereas on guava and persimmon fruit, the AUDPC was lower for B. dothidea. The information regarding penetration mechanisms and aggressiveness is important to improve postharvest disease control strategies.     

Flight Tunnel Responses of Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) to Olfactory and Visual Stimuli

Cohorts of mass-reared, naive Diachasmimorpha longicaudata, parasitoids of tephritid fruit flies, were released in a laminar airflow wind tunnel to study their responses to visual and olfactory stimuli associated with their host habitat. Parasitoids were five times more likely to land on yellow plastic spheres emitting the odor of ripe, guava fruit (Psidium guajava L.) than to spheres emitting clean air. The rate of landing was not modified by the presence of green artificial leaves adjacent to the spheres in the tunnel or by the inclusion of green leaf volatiles emanating with the guava odors. However, hovering activity was twice as frequent around spheres adjacent to artificial leaves than around isolated spheres. Oviposition activity on spheres emitting guava odor was not affected by the presence of artificial leaves nor by green leaf volatiles. This suggests that inexperienced D. longicaudata may be instinctively attracted to foliage and to fruit odor but that landing (arrestment) and oviposition are influenced more by odor than by the appearance of fruit or foliage. D. longicaudata are not instinctively attracted to larvae of Bactrocera dorsalis in the absence of host-habitat stimuli. More wasp activity occurred around oviposition units containing larvae if the odor of ripe/overripe guava was present. Successful wasp reproduction occurred only in units with guava odor.