bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vector transmission of Banana streak virus in the screenhouse in Uganda
Authors: KUBIRIBA J , LEGG J P , TUSHEMEREIRWE W , ADIPALA E 
Published: July 2006

SummaryAlthough mealybug transmission of Banana streak virus.(BSV) by Planococcus citri and Saccharicoccus sacchar has been demonstrated elsewhere, these mealybugs have not been identified on bananas in Uganda and their role and that of other agents in BSV transmission is not well documented. Insect samples were collected from banana farms in sites with low, moderate and high BSV infections in Uganda. Subsequently, live mealybugs and aphids were again collected and used in acquisition, retention and transmission tests, and BSV diagnosed using TAS‐ELISA. Dysmicoccus brevipes (pineapple mealybug), S. sacchari (sugarcane mealybug) and Pentalonia nigronervosa (banana aphid) were the most abundant insect species from banana fields sampled. Abundance of D. brevipes was positively and significantly correlated with BSV incidence unlike that of. P. nigronervosa. Transmission studies in the screenhouse showed that mealybugs acquired BSV one day after feeding on virus sources and approached optimum acquisition after the third day. Pineapple and sugarcane mealybugs retained BSV up to 5 days from the day of transfer from the virus source. BSV was first detected in the recipient banana plants 4 wk after transmission using pineapple mealybug and 6 wk after inoculation using sugarcane mealybug. Under screenhouse conditions, both mealybugs therefore appear to transmit BSV semipersistently.
The effect of Banana streak virus on the growth and yield of dessert bananas in tropical Australia
Authors: DANIELLS J W , GEERING A D W , BRYDE N J , THOMAS J E 
Published: July 2006

SummaryWe have examined the effect of a strain of Banana streak virus (BSV‐Cav) on the growth and yield of dessert bananas (Musa AAA group, Cavendish subgroup cv. Williams) in north Queensland, Australia. Healthy and infected plants were compared in a replicated field experiment over plant and first ratoon crops. In both crops, symptom expression followed a similar pattern, increasing to a maximum near the estimated time of bunch initiation, then decreasing in the period prior to bunch emergence. There was no evidence of plant‐to‐plant spread of virus, but the rate of transmission through suckers was 100%. In the plant crop, the mean bunch weights of healthy and infected plants were not significantly different. However, BSV‐Cav infection resulted in an 18 day delay in harvest, causing a 6% reduction in yield per annum. In the ratoon crop, the mean bunch weight of infected plants was 7% less than that of healthy plants, and the interval between the harvest of plant and ratoon crops was delayed by 9 days, resulting in a 11% reduction in yield per annum. Also, the mean length of fruit from infected plants was 5% less than that of healthy plants, resulting in a smaller percentage of fruit in the extra large size category. We conclude that in horticulturally favourable conditions typical of the tropical Australian banana industry, the effects of BSV‐Cav infection on the growth and yield of Cavendish bananas are small.
Assessment of variation in Aceria cajani using analysis of rDNA ITS regions and scanning electron microscopy: implications for the variability observed in host plant resistance to pigeonpea sterility mosaic disease
Authors: KUMAR P LAVA , FENTON B , DUNCAN G H , JONES A T , SREENIVASULU P , REDDY D V R 
Published: July 2006

Summary Aceria cajani on pigeonpea (Cajanus cajan) is the vector of the agent of pigeonpea sterility mosaic disease (PSMD), a very damaging virus‐like disease in the Indian subcontinent. PCR was used to amplify A. cajani nuclear ribosomal DNA (rDNA) internal transcribed spacers (ITS) and associated rDNA genes. They were assessed for variation in this genome region by nucleotide sequencing and RFLP. A. cajani‐specific rDNA primers are described. Several A. cajani populations were collected from pigeonpea plants from various PSMD endemic locations in India, Nepal and Myanmar. No significant variation was identified in rDNA regions, or in morphological features. These results suggest strongly that A. cajani on pigeonpea across the Indian subcontinent constitutes one species and that no other Aceria species and probably no A. cajani biotypes that differ in vectoring ability are involved in the transmission of the agent of PSMD. The implications of these findings for the variability observed in PSMD‐resistant pigeonpea genotypes across various locations in India are discussed.
The diversity of earthworms in 200 Scottish fields and the possible effect of New Zealand land flatworms (Arthurdendyus triangulatus) on earthworm populations
Authors: JONES H D , SANTORO GIULIO , BOAG BRIAN , NEILSON ROY 
Published: July 2006

SummaryEarthworm populations from 200 fields (132 pasture and 68 arable) in Scotland are compared. Earthworms populations from two pasture fields at a Scottish farm infested with the New Zealand terrestrial planarian,Arthurdendyus triangulates(a predator of earthworms), are compared with a subset of these 200 fields (none of which had planarians at the time of the survey). A variety of univariate and multivariate methods are used for comparison. Results from the 200 fields show that the number of individuals, number of species, richness and diversity decline eastwards and northwards across Scotland. There is an overall difference between pasture and arable fields at the same farm, with fewer anecic earthworms (Aporrectodea longa and Lumbricus terrestris), but moreAporrectodea rosea, in arable fields. Conversely, species richness and cumulative species diversity is greater in arable fields, and sample similarity is less. The planarian‐infested fields show differences from the subset of western Scottish pasture fields and from each other. Both have fewerAporrectodea caliginosa(and endogeic total) andA. longa(and anecic total) than the western pasture fields. One field has fewerL. terrestrisand fewer earthworms in total. Univariate factors show no significant differences between the infested fields and similar non‐infested fields, but multivariate analysis suggests differences. Waterlogging and recent growth of rushes in the infested fields are discussed in relation to the reduced population of earthworms and to rainfall.
Effects of carbonyl sulfide, methyl iodide, and sulfuryl fluoride on fruit phytotoxicity and insect mortality
Authors: AUNG L H , LEESCH J G , JENNER J F , GRAFTON‐CARDWELL E E 
Published: July 2006

SummaryThree potential chemical fumigants: carbonyl sulfide (COS), methyl iodide (MI) and sulfuryl fluoride (SF) were tested at selected dosages on lemons against California red scale (Aonidiella aurantii) and MI and COS were tested on nectarines against codling moth (Cydia pomonella). In nectarines, COS was tested at 0, 20, 40, 60 and 80 mg litre−1, MI at 0, 10, 15, 20 and 25 mg litre−1. Both fumigants intensified nectarine peel color, delayed fruit softening, but did not alter overall fruit quality. COS at 80 mg litre−1 resulted in 87% codling moth mortality, but the fumigant dosage was insufficient to reach the desired probits 9 level (99.9968%). MI gave 100% codling moth mortality at 25 mg litre−1. Lemons were treated with MI at 0,10,20,40,60 mg litre−1, SF at 0,10,20,40, 80 mg litre−1 and COS at 0,20,40, 60 and 80 mg litre−1. MI gave 100% red scale mortality at ≥40 mg litre−1 but caused significant fruit injury. Conditioning lemons at 15°C for 3 days before MI fumigation lessened lemon phytotoxicity. Forced aeration at 3.5 standard litres per minute of lemons for 24 h following MI fumigation at 20 mg litre−1 significantly reduced phytotoxicity compared to 2 h postfumigation aeration after MI treatment. SF at ≥40 mg litre−1 gave 100% red scale mortality but resulted in commodity phytotoxicity. Lemons treated with the highest selected dose of 80 mg litre−1 COS gave only 87% kill of red scale, but failed to reach the desired probit 9 level.
A mixture of begomoviruses in leaf curl‐affected tobacco in Karnataka, South India
Authors: PAXIMADIS M , MUNIYAPPA V , REY M E C 
Published: July 2006

SummaryTobacco leaf curl is widespread in several states in India including Andhra Pradesh, Gujarat, Karnataka, Bihar and West Bengal. Tobacco leaf curl virus (TbLCV) isolates collected from five different parts of India induced four distinct symptom phenotypes (group I, II, III & IV) on tobacco cultivars Samsun and Anand 119 (Valand & Muniyappa, 1992). PCR was performed on DNA extracted from group I and IV leaf curl‐affected tobacco from Karnataka, India using degenerate begomovirus‐specific primers. Subsequent cloning and sequencing of PCR products revealed preliminary evidence for the presence of at least three begomoviruses in the affected material following alignment of a 333 bp region of the coat protein gene (CP). The complete CP and common region (CR) of two putative begomoviruses, Tobacco leaf curl virus‐Karnataka1 (TbLCV‐Kar1) and Tobacco leaf curl virus‐Karnataka2 (TbLCV‐Kar2), were sequenced using PCR clones obtained with designed sequence‐specific primers. Phylogenetic analysis of the CP and CR of TbLCV‐Kar1 and TbLCV‐Kar2 placed them in the Asian Old World begomovirus cluster. The two viruses differed from each other significantly in both the CP gene and the CR (< 90% nucleotide sequence identity). This difference, in conjunction with distinct iterative sequences strongly suggests that these begomoviruses are distinct from one another. Group I and IV tobacco were also found to harbour a possible third begomovirus following the 333 bp CP alignment. Comparison of TbLCV‐Kar1 and TbLCV‐Kar2 with other geminiviruses, showed that both sequences shared high nucleotide sequence identity (> 90%) with other begomoviruses in either the CP or CR, thereby suggesting these viruses to be possible strains of other reported begomoviruses. Combined comparison of the CP and CR sequences however, suggests that the two viruses are not strains of other reported begomoviruses, but may be distinct begomoviruses that could have arisen through recombination events during mixed infections.Phylogenetic comparison demonstrated no significant homology between the Indian tobacco begomoviruses and a tobacco‐infecting begomovirus from Zimbabwe, again showing that as with other geminiviruses, there is a geographic basis for phylogenetic relationships rather than an affiliation with tobacco as a host.
Resource provision for farmland gamebirds: the value of beetle banks
Authors: THOMAS S R , GOULSON D , HOLLAND J M 
Published: July 2006

SummarySevere declines have occurred in the populations of wild game birds in Britain. This has been attributed to agricultural intensification, leading to the loss of invertebrates vital within chick diets, fewer feeding resources for adults, and inadequate provision of nesting and brood‐rearing habitat. This paper explores the potential value of simple sown grass strips – beetle banks – in providing these resources, and compares results with functionally similar conventional field margins. The data indicate that beetle banks can contribute useful, albeit lower, densities of chick‐food than conventional margins. These resources are more abundant later in the season, which may have implications for early hatched chicks. Beetle banks provide considerable quantities of nesting cover for adults, although sheltering conditions may never be as satisfactory as in well managed hedgerows. Given the ease and low cost of establishment of beetle banks, we suggest that they may be valuable components within a range of game management techniques on the farm, as a ‘spin‐off’ to their primary role as overwintering habitat for polyphagous predators. They may be important particularly where resources for game birds are impoverished, but clearly cannot substitute for suitably managed field margins.
Presence of Neotyphodium‐like endophytes in European grasses
Authors: LEYRONAS C , RAYNAL G 
Published: July 2006

SummaryIn order to improve knowledge of Neotyphodium‐likc fungi in European grasses, microscopic detection of endophytic mycelium was achieved in living grasses and in seeds. Samples of grasses were gathered near permanent pastures or along paths in France (93 samples, 13 genera, 22 species). Typical convoluted mycelium was found inside leaf sheaths of four genera, especially in Festuca and Lolium spp. The results suggest that endophytes were present most often in the southern regions where plants may suffer from summer drought. Endophytes were looked for in 489 seed samples (63 genera, 237 species) received from 24 European botanical gardens. Neotyphodium was found in seeds of only six genera (22 species), especially in Festuca (15 species) and Lolium (three species). No endophytic mycelium was found in the other 215 species, although other work had demonstrated the presence of the fungus in 39 of the species analysed. Neotyphodium‐likc mycelium was detected for the first time in Festuca juncifolia, F. trachyphylla, F. vaginata, F. pseudodalmatica, F. rupicaprina, F. arenaria, Vulpia ciliata and Micropyrum tenellum. Further studies are needed for the correct identification of the Neotyphodium species observed.
Canopy height and seed yield in winter linseed (Linum usitatissimum) can be influenced by proximity to pink canes
Authors: WILTSHIRE J J J , ANDERSEN M , ATHERTON J G , WRIGHT C J 
Published: July 2006

SummaryChanges to growth and development in a winter linseed crop were observed adjacent to pink canes used as markers in 1997. Notably, canopy height was increased in plants positioned up to 40 cm from the pink canes. In 1998 these effects were confirmed and further characterised in a replicated experiment: extension growth occurred approximately one week earlier and canopy height was increased by 14.5 cm in plants adjacent to pink canes. The number of seed capsules was 953 m−2 in control plots and 2567 m−2 in plots with pink canes. Seed yield, calculated from a 0.25 m2 quadrat, was 12.4 g m2 in control plots and 56.1 g m−2 in plots with pink canes. The R:FR (red:far red) ratio of light reflected from canes was approximately 1.7 compared with approximate R:FR ratios of 1.4 in incident daylight and 0.2 in light reflected from a linseed canopy (assessed using a spectral analysis system). Possible mechanisms to explain the changes in crop performance are discussed.
Ingestion, transmission, and persistence of Chino del tomate virus (CdTV), a New World begomovirus, by Old and New World biotypes of the whitefly vector Bemisia tabaci
Authors: IDRIS A M , SMITH S E , BROWN J K 
Published: July 2006

SummaryTwo whitefly biotypes of Bemisia tabaci, from either the Eastern or Western Hemisphere, respectively, were compared with respect to their competency to ingest and their efficiency to transmit the New World begomovirus, Chino del tomate virus (CdTV). The AZ A biotype of B.tabaci originates from the arid southwestern USA and northwestern Mexico, while the B biotype has an origin in the Middle East or Northern Africa. The ability of these two vector biotypes to ingest and subsequently to transmit CdTV were evaluated for an acquisition‐access period (AAP) that ranged from 0 to 72 h, followed by a 48 h inoculation‐access period (IAP). Individual adult whiteflies were monitored for CdTV ingestion using polymerase chain reaction (PCR) to detect the viral coat protein gene (AV1 ORF), and transmission efficiency (frequency) was determined by allowing potentially viruliferous whiteflies access to tomato seedlings following each experimental AAP. PCR results for individual adult whiteflies indicated that CdTV was ingested from infected tomato plants by both biotypes 93% of the time. Transmission frequencies by both vector biotypes increased with longer AAPs. However, the AZ A biotype transmitted CdTV 50% of the time, compared to only 27% for the B biotype. Evidence that virus was ingested with equal competency by the A and B biotypes confirmed that both vectors were capable of ingesting CdTV from tomato at the same frequency, even when the AAP was 0.5 h. Consequently, either the acquisition and/or transmission stages of the pathway, rather than ingestion competency, were responsible for differences in vector‐mediated transmissibility. Detection frequency of CdTV, after 48 h AAP, by PCR in single females of AZ B biotype was significantly higher than males.
Identification of Rubus yellow net virus as a distinct badnavirus and its detection by PCR in Rubus species and in aphids
Authors: JONES A TEIFION , McGAVIN WENDY J , GEERING A D W , LOCKHART B E L 
Published: July 2006

SummaryRubus yellow net virus (RYNV) infects Rubus species and cultivars worldwide and is an essential component of raspberry veinbanding mosaic (RVBMD), a virus disease complex that causes serious decline in plant vigour and productivity. The virus is transmitted, probably in a semi‐persistent manner, by the large raspberry aphid, Amphorophora idaei in Europe, and A. agathonica in North America. The particles of RYNV are bacilliform in shape and measure 80–150 × 25–30 nm, similar to those of badnaviruses. A1.7 kb fragment of the viral DNA was amplified by PCR and then directly sequenced. Analysis of this sequence suggests that RYNV is possibly a distinct species in the genus Badnavirus and is most closely related to Gooseberry vein banding associated virus (GVBAV) and Spiraea yellow leaf spot virus, two other badnaviruses described recently. Using the sequence derived from the PCR‐amplified viral DNA fragment, RYNV‐specific primers were designed and used in PCR to assay for RYNV in a range of Rubus germplasm infected with RYNV, with other unrelated viruses and virus‐like diseases found in Rubus, and in healthy plants. RYNV was detected in all glasshouse cultures of RYNV‐infected plants, whether alone or in complex infections with other viruses, but not from healthy Rubus plants, nor from plants infected with other viruses. It was also detected in field‐grown raspberry plants with and without symptoms of RVBMD and in raspberry plants infected with RYNV by viruliferous A. idaei. RYNV was also detected by PCR in A. idaei following access feeds on RYNV‐infected plants of 1 h or more. PCR failed to amplify DNA from gooseberry infected with GVBAV confirming the specificity of the RYNV analysis. PCR detection of RYNV in dormant raspberry buds allows assays to be made outside the natural growing season, providing a useful application for plant introduction and quarantine programmes.
Effect of strain‐specific hypersensitive resistance on spatial patterns of virus spread
Authors: THACKRAY D J , SMITH L J , CHENG Y , PERRY J N , JONES R A C 
Published: July 2006

SummarySpatial patterns of spread were compared between strains of Bean yellow mosaic virus (BYMV) that differ in causing systemic necrotic (hypersensitive) or non‐necrotic symptoms in narrow‐leafed lupin (Lupinus angustifolius). Both types of BYMV were spread naturally by aphids from adjacent infected pasture into a large lupin block (‘natural spread site’), or from clover plants introduced as virus sources into two field experiments with lupin. Cumulative spatial data for plants with disease symptoms from a range of times in the growing period were assessed using Spatial Analysis by Distance IndicEs (SADIE). At the‘natural spread site’, with non‐necrotic BYMV, the extent of clustering of plants with symptoms increased gradually over time, while with necrotic BYMV there was less clustering and no increase over time. In both experiments, for the type of BYMV that was introduced into a plot, there was a gradual increase in clustering, but with this being greater with non‐necrotic BYMV. In the second experiment, there was also significant clustering of plants with symptoms of non‐necrotic BYMV in plots without introduced non‐necrotic foci but not for necrotic BYMV in plots without introduced necrotic foci. When clustering data for plants with newly recorded symptoms was tested for spatial association between successive assessment dates, association was positive for both BYMV types though stronger for the non‐necrotic type, declining as the temporal lag increased. Generally, association was strongest for assessments 2–3 wk apart, corresponding approximately to the period for BYMV to move systemically in plants and for obvious symptoms to appear in shoot tips. Contour maps for local association between dates showed that the strongest spatial associations were from coincidence of infection gaps rather than infection patches. The combination of information from clustering and association analysis showed that spread of non‐necrotic BYMV is less diffuse, with considerably more localised infection surrounding the infection sources. This work demonstrates how spatial virus spread can be diminished when hypersensitive (necrotic) resistance is deployed, and the limitations associated with employing hypersensitivity that is strain specific.
Identification and application of RAPD markers for anthracnose resistance in water yam (Dioscorea alata)
Authors: MIGNOUNA H D , ABANG M M , ONASANYA A , ASIEDU R 
Published: July 2006

SummaryAnthracnose, caused by Colletotrichum gloeosporioides, is the most severe foliar disease of water yam (Dioscorea alata) worldwide. The tetraploid breeding line, TDa 95/00328, is a source of dominant genetic resistance to the moderately virulent fast growing salmon (FGS) strain of C. gloeosporioides. Bulked segregant analysis was used to search for random amplified polymorphic DNA (RAPD) markers linked to anthracnose resistance in F1 progeny derived from a cross between TDa 95/00328 and the susceptible male parent, TDa 95–310. Two hundred and eighty decamer primers were screened using bulks obtained from pooled DNA of individuals comprising each extreme of the disease phenotype distribution. A single locus that contributes to anthracnose resistance in TDa 95/00328 was identified and tentatively named Dcg‐1. We found two RAPD markers closely linked in coupling phase with Dcg‐1, named OPI71700 and OPE6950, both of which were mapped on the same linkage group. OPI71700 appeared tightly linked to the Dcg‐1 locus; it was present in all the 58 resistant F1 individuals and absent in all but one of the 13 susceptible genotypes (genetic distance of 2.3 cM). OPE6950 was present in 56 of the 58 resistant progeny and only one susceptible F1 plant showed this marker (6.8 cM). Both markers successfully identified Dcg‐1 in resistant D. alata genotypes among 34 breeding lines, indicating their potential for use in marker‐assisted selection. OPI71700 and OPE6950 are the first DNA markers for yam anthracnose resistance. The use of molecular markers presents a valuable strategy for selection and pyramiding of anthracnose resistance genes in yam improvement.
Heat tolerance of strawberry tarsonemid mite Phytonemus pallidus
Authors: HELLQVIST SVEN 
Published: July 2006

SummaryThe heat tolerance of the strawberry tarsonemid mite Phytonemus pallidus ssp. fragariae was studied in northern Sweden by treating adult mites in hot water at temperatures 44°C, 46°C and 48°C. During the summer, the shortest exposure times required to kill all adult mites at these temperatures were 6, 2.5 and 1.25 min, respectively. It is concluded that hot‐water treatment of strawberry runners for 6.5 min at 46°C would suffice to kill all tarsonemid mites on infested runners. This exposure time includes the time needed to raise the temperature of the plant material to that of the water bath. In the autumn, from the middle of September and later, the mites became successively much more heat tolerant as they prepared for hibernation. It is expected that longer exposure periods are needed to kill mites on frigoplants.