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1.
Anthracnose disease caused by Colletotrichum horii (C. gloeosporioides), results in considerable economic damage to sweet persimmon in southern Korea yearly. This study deals with the life cycle of the pathogen in terms of seasonal fluctuations of spore dispersal and the development of disease based on field surveys, spore potential and fungal isolation. Anthracnose disease was observed first on twigs in the last week of May and reached an incidence of 1.2%. Subsequently, the disease increased rapidly and reached an incidence of 86% by the end of July. Infection of fruits started in mid‐June (2.8%) and increased gradually to 64.4% by the end of July. In severely infected orchards, 46.2% of diseased fruits were dropped. The pathogen began releasing conidia in the first week of May and continued until the end of September. The maximum release of spores was observed in mid‐July. To determine the optimal use of chemicals for control of anthracnose, the following spray programme was evaluated. Spraying two or three times resulted in 89.4 and 93% control, respectively, whereas spraying more than four times led to 100% control. In comparison, the disease rate of unsprayed trees was 89.8%. To control anthracnose effectively, it is recommended to take steps to eliminate inoculum sources in sweet persimmon orchards before spraying chemicals.  相似文献   

2.
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.  相似文献   

3.
涩柿生长,脱涩及返涩单宁细胞形态的变化   总被引:12,自引:1,他引:11  
以甜柿为对照,观察了涩柿(牛心柿)、脱涩和返涩中单宁细胞的形态变化,结果表明:涩柿单宁细胞在生长期体积不断增大,数量不断增多,涩味加强,在9月初细胞停止生长;4种不同方法脱涩的柿,其单宁细胞的变化基本相同,都是体积缩小,最后变成疏散的小颗粒;返涩的柿,单宁从单宁细胞中溢出,呈网状结构分布于果肉组织中。  相似文献   

4.
The dietary importance of sweet persimmon fruit (SPF) was determined in adult bean bug, Riptortus pedestris, by investigating the effect of feeding SPF and soybean seeds and peanut on longevity, weight change, fecundity and ability for pheromone production in the bean bug. Adult female R. pedestris fed on SPF had significantly shorter lifespans than those fed on soybean, while in males there was no significant difference. Males and females fed on SPF were significantly lighter than those fed on soybean seeds. Females fed on SPF did not lay eggs at all, but those fed on soybean laid 155.8 eggs, and those fed on soybean seed complemented with peanut seed laid 120.8 eggs in 50 days. The amount of pheromone components (E)‐2‐hexenyl (E)‐2‐hexenoate and (E)‐2‐hexenyl (Z)‐2‐hexenoate produced by male R. pedestris fed on SPF was significantly less than that produced by males fed on soybean. Other pheromone components, tetradecyl isobutyrate and octadecyl isobutyrate, were not produced by adult males fed on SPF. This difference was apparent at one week after emergence and was more at three weeks after emergence. In the present study, we demonstrated that SPF had adverse effect on female survivorship, reproduction of female adults and production of the aggregation pheromone by adult males, compared to soybean food. These results suggested that SPF is unsuitable for adult R. pedestris. Management of nearby vegetation of fruit orchards may play an important role in reducing damage by adult R. pedestris.  相似文献   

5.
Leucoanthocyanidin reductase (LAR) converts leucoanthocyanidin to (+)-catechin, a precursor of proanthocyanidins abundant in Japanese persimmon (Diospyros kaki Thunb.) fruits. A putative LAR gene (DkLAR) was isolated by rapid amplification of cDNA ends from young fruits. The full-length cDNA of DkLAR gene was 1 356 bp long and encoded an open reading frame of 349 residues. The deduced DkLAR protein was closely related to the homolog in other plant species. The expression of the DkLAR gene in Chinese pollination-constant non-astringent (PCNA) genotype was coincident with the tannin cell development, but was not in Japanese PCNA and Chinese pollination-variant astringent (PCA) genotypes.  相似文献   

6.
The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), poses a new threat to soybean, Glycine max (L.) Merrill (Fabaceae), production in the north central USA. As H. halys continues to spread and increase in abundance in the region, the interaction between H. halys and management tactics deployed for other pests must be determined. Currently, the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is the most abundant and damaging insect pest of soybean in the region. Aphid‐resistant soybean, mainly with the Rag1 gene, is commercially available for management of A. glycines. Here, experiments were performed to evaluate the effects of Rag1 aphid‐resistant soybean on the mortality, development, and preference of H. halys. In a no‐choice test, mortality of H. halys reared on Rag1 aphid‐resistant soybean pods was significantly lower than when reared on aphid‐susceptible soybean pods (28 vs. 53%). Development time, adult weight, and proportion females of surviving adults did not differ when reared on Rag1 aphid‐resistant or aphid‐susceptible soybean pods. In choice tests, H. halys exhibited a preference for Rag1 aphid‐resistant over aphid‐susceptible soybean pods after 4 h, but not after 24 h. Halyomorpha halys exhibited no preference when tested with vegetative‐stage or reproductive‐stage soybean plants. The preference by H. halys for Rag1 aphid‐resistant soybean pods and the decreased mortality when reared on these pods suggests that the use of Rag1 aphid‐resistant soybean may favor this emerging pest in the north central USA.  相似文献   

7.
Halyomorpha halys Stål (Hemiptera: Pentatomidae) has recently become a major orchard pest in the Mid‐Atlantic, USA. Large H. halys populations can develop on wild tree hosts adjacent to orchards, posing an ongoing threat to fruit. Adults and nymphs feed on tree fruit, causing economic injury. Understanding the seasonal patterns of nymphal host use among trees at the orchard‐woodland interface may aid the development of integrated pest management strategies for this pest. In laboratory and field experiments, modified versions of published trap designs – ‘Circle’, ‘Hanula’, ‘M&M’ (after Moeed & Meads) traps – were compared for their effectiveness for capturing H. halys nymphs walking up and down tree trunks. In the laboratory, second instars were released at the top and bottom of ailanthus (tree of heaven), Ailanthus altissima (Mill.) Swingle (Simaroubaceae), logs and captures were recorded after 24 h. Circle and M&M traps, respectively, were most effective for capturing nymphs walking up and down. In the field, traps were deployed on ailanthus trees next to apple orchards and captures were recorded weekly from 24 July to 11 September 2013. As in the laboratory, Circle and M&M traps captured the greatest number of upward‐ and downward‐walking nymphs. Hanula traps were least effective in both experiments. In the field, 88% of total captures were of nymphs walking up trees. This was at least partially explained by behavioral assays in the laboratory demonstrating that nymphs exhibited negative gravitaxis and positive phototaxis. Stage‐specific trends in captures of instars walking up during field sampling were observed. These results suggest that trunk traps can be used to address important ecological questions about seasonal patterns of host use by H. halys nymphs.  相似文献   

8.
Performance of nymphs and adults of the southern green stink bug,Nezara viridula (L.) (Heteroptera: Pentatomidae) feeding on immature fruits of radish,Raphanus raphanistrum L. (Brassicaceae) was poor compared with feeding on immature soybean [Glycine max (L.) Merrill] pods, but a change from radish to soybean from nymph to adult alleviated some of the detrimental effects of this food on adult performance. Over 50% of nymphs died on radish, while only 15% died on soybean. To complete nymph development (stadia 2 through 5), male and female nymphs required 9.5 and 13.3 days longer on radish compared to soybean. Fresh body weight of 1-d-old adult females and males was ≅65% greater for those reared as nymphs on soybean than on radish, with females being significantly heavier than males on both foods. Survivorship and longevity of females, however, was greater for those fed on radish as nymphs and as adults, as compared to those that fed on soybean or radish followed by soybean. Males lived longer when fed exclusively on soybean. In general, reproductive performance and percentage gain in adult body weight was greatest for insects fed on soybean only, and were better for those whose food was switched from nymph to adult, as compared to those insects fed on radish solely.  相似文献   

9.
Control of Halyomorpha halys (Stål) adults by combined spraying of pyrethroid and neonicotinoid insecticides has been investigated in apple orchards in northern Japan in 2008 and 2009. Insecticides were selected to control not only H. halys but also the common lepidopteran pests Carposina sasakii Matsumura, Adoxophyes orana fasciata Walsingham, and Phyllonorycter ringoniella Matsumura. Dinotefuran was sprayed in mid-May and early July, fenpropathrin in late June, and bifenthrin in late July. H. halys adults were released into apple trees at 3–5-day intervals from mid-May to mid-August. In this spraying program, survival of the adults increased 6 days after spraying, but relatively few injury marks were noted throughout the growing season. On the other hand, in the conventional spraying program, the survival ratio of the adults increased rapidly 3 days after spraying—especially after the organophosphate applied in mid-May, late June, and late July—and increases in the number of injury marks synchronized well with survival in both years. This spray program reduced the number of fruit injury marks to one-fifth that of the conventional spraying program and one-tenth that of fungicides alone.  相似文献   

10.
The invasive Halyomorpha halys (Heteroptera: Pentatomidae) is a key pest of fruits in the Emilia‐Romagna region of Italy. For the development of a sustainable management programme, knowledge of its native natural enemy community and its efficacy is essential. A three‐year field survey was conducted exposing H. halys egg masses in different types of habitats to investigate the efficacy of native natural enemies in reducing the H. halys populations in the Emilia‐Romagna region, where the stinkbug was first detected in 2012. Over the first year of the study, sentinel eggs from laboratory cultures were stapled to the underside of leaves in various host trees, whereas in following years H. halys adults were directly caged on branches in sleeve cages to allow natural oviposition. Over the examined years, low rates of parasitism (1%–3%) and predation (2%–5%) were observed. Parasitism was caused exclusively by the generalist parasitoid Anastatus bifasciatus.  相似文献   

11.
The brown marmorated stink bug, Halyomorpha halys, is an invasive agricultural pest of fruit trees and vegetables. Egg parasitoids play a key role in the reducing of H. halys populations. Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyrtidae) can parasitize H. halys and complete its life cycle in this host species. Many factors can influence this parasitoid–host relationship. Of these factors, we evaluated the effect of female age, exposure time, and host species on the biological characteristics and fecundity of O. kuvanae reared on eggs of H. halys as well as another previously known host Philosamia ricini (Lepidoptera: Saturniidae). In this study, we used a 3-year-old laboratory colony of O. kuvanae. Parasitism rates positively affected by exposure time in P. ricini. The highest parasitism rates were obtained in 5- and 7-day-old females of both hosts. The highest emergence rates were recorded on P. ricini for 5- and 7-day-old female P. ricini (81.8% and 84.8%, respectively). The development time of O. kuvanae ranged from 18.4 to 19.1 days on H. halys and 17.7 to 18.3 days on P. ricini. The longevity of O. kuvanae that were provided honey was 38.5 and 47.8 days on H. halys and P. ricini, respectively. The longevity of O. kuvanae that were not provided honey was 2.3 and 2.8 days on H. halys and P. ricini, respectively. The sex ratio was male-biased (36.5% female) on H. halys and female-biased (55.2% female) on P. ricini. Fecundity of O. kuvanae was 37.7 and 59.6 progeny per female for H. halys and P. ricini, respectively. The performance of O. kuvanae was lower when compared with its performance on the host P. ricini. Our results suggest that O. kuvanae has potential as new biological control agent for H. halys.  相似文献   

12.
Halyomorpha halys is native to Asia, but was recently accidentally introduced to North America and Europe. This species was recorded for the first time in Russia in 2013 (2014) and in both Serbia and Abkhazia in 2015. In 2015–2017, we conducted surveys in Russia, Serbia, and Abkhazia and found that H. halys had not only successfully survived its first winters in new regions, but also started to establish locally, spread, increase populations, and damage local crops. In Sochi (Russia) and Abkhazia, H. halys was recorded to feed on 32 species and cultivars from 16 plants families. In Serbia, it has so far been observed on only four species from four plant families. H. halys is already widely spread in Abkhazia and causes serious damage to many crops: in 2016, the yield of peach, mandarin orange, persimmon and other crops fell down by 13.2–87.4% if compared to the long-term means of yield. The losses are likely to be mostly caused by feeding of H. halys. We conclude that H. halys was accidentally introduced to Russia in 2012–2013 most likely with woody plants imported to Sochi from Italy or Greece for urban landscaping before the 2014 Winter Olympics. The species established in Sochi and quickly moved to Krasnodar (Russia), Abkhazia, and beyond—to Georgia. Populations in Serbia most likely arrived in 2015 traveling on railway cars or in commodities on the Bucharest–Belgrade railway line. We discuss phenology and prospects of further expansion of H. halys in Europe.  相似文献   

13.
Extending the shelf life of fruits during post‐harvest storage and eradicating pests associated with quarantine issues could together comprise the key steps toward expanding the exportation of sweet persimmon in South Korea. Here we firstly investigated the concurrent application of ethyl formate (EF), a methyl bromide alternative fumigant, which is currently considered a beneficial and safe fumigant in quarantine use, and 1‐methylcyclopropene (1‐MCP), an anti‐ethylene compound that is broadly used in post‐harvest systems, on sweet persimmon. We also suggest the proper fumigation methods to be follow when using these compounds. Tetranychus urticae, an important quarantine pest, was inoculated under the calyx of sweet persimmon, and the fruits were then fumigated using 35.0 mg L?1 of EF for 6 h before and after treating with 1.0 μL L?1 of 1‐methylcyclopropene for 24 h under storage conditions of 5°C. Our results showed that concurrent treatments with 1‐MCP and EF could be suitable for commercial purposes by extending shelf life, delaying color changes and softening, and offering complete control of the target pest, Tetranychus urticae.  相似文献   

14.
The brown marmorated stink bug, Halyomorpha halys, a native of Asia, has become a serious invasive pest in the USA. H. halys was first detected in the USA in the mid 1990s, dispersing to over 41 other states. Since 1998, H. halys has spread throughout New Jersey, becoming an important pest of agriculture, and a major nuisance in urban developments. In this study, we used spatial analysis, geostatistics, and Bayesian linear regression to investigate the invasion dynamics and colonization processes of this pest in New Jersey. We present the results of monitoring H. halys from 51 to 71 black light traps that were placed on farms throughout New Jersey from 2004 to 2011 and examined relationships between total yearly densities of H. halys and square hectares of 48 landscape/land use variables derived from urban, wetland, forest, and agriculture metadata, as well as distances to nearest highways. From these analyses we propose the following hypotheses: (1) H. halys density is strongly associated with urban developments and railroads during its initial establishment and dispersal from 2004 to 2006; (2) H. halys overwintering in multiple habitats and feeding on a variety of plants may have reduced the Allee effect, thus facilitating movement into the southernmost regions of the state by railroads from 2005 to 2008; (3) density of H. halys contracted in 2009 possibly from invading wetlands or sampling artifact; (4) subsequent invasion of H. halys from the northwest to the south in 2010 may conform to a stratified-dispersal model marked by rapid long-distance movement, from railroads and wetland rights-of-way; and (5) high densities of H. halys may be associated with agriculture in southern New Jersey in 2011. These landscape features associated with the invasion of H. halys in New Jersey may predict its potential rate of invasion across the USA and worldwide.  相似文献   

15.
The influence of canopy development in soybean on the survival of corn earworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), egg and larval stages and population dynamics of arthropod fauna were evaluated in field trials during 1986–88 in eastern North Carolina. Soybean canopy size decreased as soybean cyst nematode, Heterodera glycines Ichinohe (Nematoda: Heteroderidae), initial population densities increased. Plant species composition of the soybean canopy was affected by weed population densities. Mortality of H. zea larvae due to parasitism and infection with entomopathogens was greater in closed canopy and (or) weedy soybeans than in very open and (or) weed free soybeans. Predation and parasitism of corn earworm eggs were similar across nematode and weed density treatments. Natural enemy populations increased to highest levels during July in closed canopy and (or) weedy soybeans, coinciding with availability of largest prey population reservoirs. A delay in colonization of very open and (or) weed free soybeans by beneficial arthropods until mid to late August allowed greater H. zea larval survival than in closed canopy and (or) weedy soybeans. Arthropod species richness was generally greatest in closed canopy and (or) weedy soybeans during mid to late July, with differences becoming nonsignificant in August and early September. Mean and maximum ambient temperatures were higher and relative humidities lower in open canopy than in closed canopy plots. These conditions were less favorable for development of pathogens and natural enemies.  相似文献   

16.
We describe a unique microsporidian species that infects the green stink bug, Chinavia hilaris; the brown marmorated stink bug, Halyomorpha halys; the brown stink bug, Euschistus servus; and the dusky stink bug, Euschistus tristigmus. All life stages are unikaryotic, but analysis of the consensus small subunit region of the ribosomal gene places this microsporidium in the genus Nosema, which historically has been characterized by diplokaryotic life stages. It is also characterized by having the reversed arrangement of the ribosomal gene (LSU –ITS‐ SSU) found in species within the “true Nosema” clade. This microsporidium is apparently Holarctic in distribution. It is present in H. halys both where it is native in Asia and where it is invasive in North America, as well as in samples of North American native C. hilaris collected prior to the introduction of H. halys from Asia. Prevalence in H. halys from mid‐Atlantic, North America in 2015–2016 ranged from 0.0% to 28.3%, while prevalence in C. hilaris collected in Illinois in 1970–1972 ranged from 14.3% to 58.8%. Oral infectivity and pathogenicity were confirmed in H. halys and C. hilaris. Morphological, ultrastructural, and ecological features of the microsporidium, together with a molecular phylogeny, establish a new species named Nosema maddoxi sp. nov.  相似文献   

17.
Several North American trees are hypothesized to have lost their co‐evolved seed disperser during the late‐Pleistocene extinction and are therefore considered anachronistic. We tested this hypothesis for the American persimmon (Diospyros virginiana) by studying the effects of gut passage of proposed seed dispersers on seedling survival and growth, natural fruiting characteristics, and modern animal consumption patterns. We tested gut passage effects on persimmon seeds using three native living species, the raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), and coyote (Canis latrans), and two Pleistocene analogs; the Asian elephant (Elephas maximus) and alpaca (Vicugna pacos). Persimmon seeds excreted by raccoons, coyotes, and elephants survived gut transit. Gut passage did not affect sprouting success, but did tend to decrease time to sprout and increase seedling quality. Under field conditions, persimmon fruits were palatable on the parent tree and on the ground for an equal duration, but most fruits were consumed on the ground. Seven vertebrate species fed upon persimmon fruits, with the white‐tailed deer (Odocoileus virginianus)—a species not capable of dispersing persimmon seeds—comprising over 90% of detections. Conversely, potential living seed dispersers were rarely detected. Our results suggest the American persimmon evolved to attract a variety of seed dispersers and thus is not anachronistic. However, human‐induced changes in mammal communities could be affecting successful seed dispersal. We argue that changes in the relative abundance of mammals during the Anthropocene may be modifying seed dispersal patterns, leading to potential changes in forest community composition.  相似文献   

18.
Flowers on the ground of orchards can provide substantial resources for wild pollinators of orchard trees. Few studies, however, have examined the relative importance of groundcover flowers to orchard pollination by analyzing pollen on the body surface of pollinators. Oriental persimmon trees bloom within the longer blooming period of white clover, which is occasionally found as a flowering plant on the ground of persimmon orchards in Japan. The present study compared the insect species assemblage collected on persimmon flowers with that on clover. Before persimmon bloomed, Bombus ardens ardens and Apis cerana japonica were the major visitors of clover flowers. Once persimmon bloomed, the former was the most abundant bee that visited persimmon flowers over the flowering period. Apis mellifera was captured only on clover flowers. We found numerous clover pollen grains on the body surface of bumblebees captured on persimmon flowers, but far fewer persimmon pollen grains on bees that visited clover. These findings show that B. ardens ardens utilized the clover flowers under the orchards before persimmon bloomed.  相似文献   

19.
The ladybeetle Harmonia axyridis Pallas (Coleoptera: Coccinellidae), is a key predator of the scale insect Drosicha corpulenta (Kuwana), (Hemiptera: Coccoidea: Monophlebidae) in persimmon tree orchards. We used a Y-tube olfactometer and gas chromatograph/mass spectrometry to assess the possible role of volatiles from persimmon trees in attracting H. axyridis. The results showed more ladybeetles aggregated at odour sources from heavily damaged trees than from slightly damaged or undamaged trees. The relative amounts and types of terpenoid and alcohol compounds changed, usually increased, in the volatiles from damaged persimmon trees: α-pinene increased from 26 to 43%. The ladybeetle was attracted to α-pinene in a Y-tube assay at most tested concentrations.  相似文献   

20.
Y. F. Zhong    Y. W. Zhang    X. Y. Chen    Y. Luo    L.Y. Guo 《Journal of Phytopathology》2008,156(4):229-235
Survival of Monilinia fructicola on the surface of mummified fruit and in peduncles and shoots of stone fruit trees infected by M. fructicola in the previous season was studied from 2003 to 2006 in orchards in the agricultural region of Beijing. Viable conidia of M. fructicola were consistently detected on fruit mummies from mid‐March to the end of April. During flowering (in mid‐April), studies in five peach orchards showed that 33–87% of mummified fruit bore viable conidia. The germination rate of conidia on diseased fruit was about 64% in autumn. It decreased to 24% in mid‐winter when the fruit was completely mummified, and in the following year to 2–4% in early spring. Viable M. fructicola was consistently detected in peach and nectarine shoots collected in winter and spring. In general, viable M. fructicola in peduncles was detected from mummified fruit of 11–27% branches and from asymptomatic plant tissues of 3–20% branches. Sporulation of M. fructicola was observed on peduncles in seven of eight surveys, and the percentage of branches containing viable M. fructicola in peduncles in contact with mummified fruits ranged from 18% to 40%. This study demonstrates that the tree‐borne mummified fruit and the peduncles could be the parts of trees where M. fructicola can survive the winter in orchards in suburban Beijing.  相似文献   

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