bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiplication of Xanthomonas campestris pvs secalis and translucens in host and non‐host plants (rye and barley) and development of water soaking1
Authors: EL‐BANOBY F. E. , RUDOLPH K. W. E.
Published: April 2008

Multiplication of the rye‐specific and barley‐specific pathovars secalis and translucens, respectively, of Xanthomonas campestris (earlier named Xanthomonas translucens f. sp. cerealis) was determined in two rye and two barley cultivars. Fresh bacterial cultures were suspended in boiled tap water, adjusted to about 3 × 107 cfu ml−1 and infiltrated into the mesophyll of young leaves. In the compatible combinations, a generation time of 1.7–2.1 h was determined. Significantly higher multiplication rates than in incompatible combinations were not observed before 3 or 4 days after inoculation. At this time, the first small water‐soaked areas appeared. Bacteria multiplied up to the seventh day after inoculation, reaching a maximum of at least 109 cells per cm2, the same time at which the water‐soaked areas had reached their maximum size. Thus, the rate of bacterial multiplication paralleled with the development of the water‐soaked areas. In the incompatible combinations, nearly the same generation times were detected during the exponential growth phase. However, water‐soaked areas did not appear, and the final bacterial concentration ranged from 1:1000 to 1:100 of that determined in compatible combinations. A distinct early lag phase, characterized by a decrease of the bacterial population down to 1:100 of the starting concentration, was detected in all cases.
Basal glume rot (Pseudomonas syringae pv. atrofaciens) on wheat and barley in FRG and resistance screening of wheat1
Authors: TOBEN H. , MAVRIDIS A. , RUDOLPH K. W. E.
Published: April 2008

A survey in 1987 and 1988 revealed that basal glume rot, caused by Pseudomonas syringae pv. atrofaciens, occurred nearly everywhere in FRG. The symptoms of the disease usually consisted of water‐soaked dark green to brown lesions on unripe wheat heads, mainly at the basal end of the glumes, which later became dark brown. Forty‐six isolates of P.s. atrofaciens were obtained from glumes, seeds and leaves of wheat and barley. For a fast identification of the isolated bacteria, a bio‐assay was developed. Four to five‐day‐old wheat seedlings, grown on wet filter paper in Petri dishes, were pricked at two‐three sites with a dissecting needle contaminated with bacteria. After 2–3 days, pathogenic isolates induced brown to black spots. The bacterial isolates from wheat inhibited the growth of several fungi grown on potato dextrose agar. In contrast, an authentic isolate of P.s. syringae obtained from wheat showed no inhibitory effect. During screening for resistance, several cultivars of spring and winter wheat were tested in the greenhouse and/or field tests. The results revealed marked differences in the susceptibility of different cultivars.
Maladies bactériennes des graminées en Espagne1
Authors: NOVAL C.
Published: April 2008

Bien que la culture des graminées soit trés importante en Espagne, nous n'avons constaté que quelques problèmes posés par des bactéries phytopathogènes, sur maïs et orge. En 1980 nous avons étudié une maladie du maïs dans une culture porte‐graines du cv. Rx‐90, à partir duquel nous avons isoléErwinia chrysanthetni. La même maladie était connue depuis quelques années sur cultivars ayant un cycle de 700 FAO, cultivés dans des champs arrosés par aspersion. Ľaddition de chlore àľeau ďirrigation a empêché la propagation de la bactérie. A une seule occasion, nous avons isolé une bactérie, identifyée comme ‘Xanthomonas translucens”, dans un champ ďorge provenant de semences importées. Les études sur le potentiel pathogène de la souche, réalisées par inoculation sur différents hôtes, ont permis ďidentifier la forme spécifique áľorge (Xanthomonas campestris pv. translucens).
Experiments with a non‐pathogenic strain of Xanthomonas campestris pv. graminis1
Authors: SCHMIDT D.
Published: April 2008

Isolates of Xanthomonas campestris pv. graminis are known to vary in pathogenicity, which may be lost more or less rapidly in culture on artificial media. Inoculation of Lolium multiflorum with mixtures of a highly pathogenic strain and increasing proportions of a nonpathogenic strain of X. c. graminis resulted in a decreasing disease expression and mortality. Re‐isolation from plants inoculated with 1% pathogenic and 99% non‐pathogenic bacteria resulted mostly in highly pathogenic monobacterial colonies. Of about 200 colonies, 3% were non‐pathogenic. A few isolates had an intermediate pathogenicity. It has not been established whether they were pure strains or mixtures of pathogenic and non‐pathogenic bacteria. All isolates from plants inoculated with the non‐pathogenic strain were non‐pathogenic. The nonpathogenic bacteria multiplied inside the plants, but they were mostly found in the inoculated leaves. Thirty pots containing each about 20 plants of Italian ryegrass were pre‐inoculated with non‐pathogenic strains and, 4 weeks later, they were cut with scissors contaminated by pathogenic X. c. graminis. The disease was highly reduced in about half of the pots. Further experiments are needed to judge the expediency of such a ‘premunition’ of grasses.
Potato wart disease in Newfoundland: a review of current research studies1
Authors: HAMPSON M. C.
Published: April 2008

Research includes studies on germination of resting spores, substances affecting infection, eradication, bioassay for Synchytrium endobioticum, and sub‐surface vectoring of the fungus. The sequence of events in germination has been exposed and the mechanisms of germination are currently being studied. Chitin and in particular crabshell induce zero infection, and there is promise in using these materials as eradicants. Using the bioassay so far developed, it is possible to assay for 0.1 spore per g of soil. There is evidence that the fungus can migrate in soil through the agency of vector animals. Problems long posed by this disease now seem soluble.
Viruses transmitted by nematodes1
Authors: BROWN D. J. F.
Published: April 2008

The transmission of plant viruses by nematodes is remarkable in involving only two distinct groups of viruses, nepo viruses and tobraviruses, and being limited to longidorid, Paratrichodorus and Trichodorus nematodes respectively. Tobraviruses and their associated vector nematodes are not discussed here. Only 11 of the 36 described nepoviruses are transmitted by nematodes, and 6 of these 11 viruses are present in Europe naturally associated with 8 virus‐vector longidorids. Specific relationships exist between the serologically distinct viruses and their vector nematode species. Specificity is largely determined by the virus coat protein and by an inherited ability of the nematode to retain virus particles at specific sites within its oesophagus. This specific relationship can be quite subtle, extending to populations of vector nematodes and also to virus isolates which apparently are serologically indistinguishable. Several serological and/or symptomatological variants of nepoviruses may be present at a field site in association with one or more vector nematode species. The exposure of different crops and new cultivars to these virus and vector combinations will probably result in the occurrence of further nematode‐transmitted virus diseases. New methods for suppressing damage to crops caused by these diseases are required including the likely use of transgenic resistant cultivars.
The occurrence and distribution of nepoviruses and their associated vector Longidorus and Xiphinema nematodes in Europe and the Mediterranean basin1
Authors: BROWN D. J. F. , TRUDGILL D. L.
Published: April 2008

Six nepoviruses are transmitted by five Longidorus and three Xiphinema species in Europe. The virus and vector associations are: L. apulus and L. fasciatus with artichoke Italian latent nepovirus, L. attenuatus and L. elongatus with tomato black ring nepovirus, L. elongatus and L. macrosoma with raspberry ringspot nepovirus, X. diversicaudatum with arabis mosaic and strawberry latent ringspot nepoviruses and X. index and X. italiae with grapevine fanleaf nepovirus. The distributions of the viruses and their vectors in Europe and the Mediterranean basin are described. The following points are commented: presence of non‐indigenous nematode‐transmitted nepoviruses in Europe; occurrence of vector nematodes in European countries in the absence of their associated nepoviruses; the possible vectors of serologically distinct strains of grapevine fanleaf nepovirus.
Sugarbeet rhizomania in England1
Authors: HILL S. A.
Published: April 2008

Concern about the introduction of rhizomania to UK heightened when the disease was confirmed in The Netherlands in 1983. A series of precautionary measures supported by legislation was quickly enacted to reduce this risk. Extensive surveys of harvested beet and of growing crops failed to reveal any infection until 1987 when a single isolated outbreak was found near Bury St Edmunds in Suffolk. Plants in the affected field showed typical rhizomania symptoms and laboratory tests confirmed the presence of beet necrotic yellow vein furovirus (BNYVV). Further investigation of isolates from the outbreak field revealed the presence of beet soil‐borne furovirus in addition to BNYVV and sometimes both were present in mixed infections. Intensive surveys in the immediate area of the outbreak, both by field inspections of growing crops and by soil bait testing, confirmed infection only in the one field and the margin of the adjacent field. Immediate containment measures were followed by soil sterilization with methyl bromide to minimize the movement of infection from the area. Surveys of beet will continue, but results to date suggest that the distribution of the disease is limited in extent.
Polymyxa betae zoospores as vectors of beet necrotic yellow vein furovirus1
Authors: PETERS D. , GODFREY‐VELTMAN A.
Published: April 2008

When beet seedlings exposed as bait plants in infested soil were placed in a nutrient solution, they released Polymyxa betae zoospores, infected with beet necrotic yellow vein furovirus. The roots produced the first zoospores 5 days after the start of soil baiting. When seedlings were inoculated with zoospore suspensions, infection occurred within 5 min and reached a maximum in 30 min. The suspensions remained infectious for at least 2 h after removal of the bait plants from which the zoospores were released. So many spores were released into the suspension that disease transmission could be obtained within half an hour from an infected plant to a healthy plant, placed together into fresh medium. Suspensions could be diluted 1/16 with nutrient solution without any loss of infectivity, whereas 1/4 dilution with tap water resulted in a complete loss of infectivity.
Inoculum potential and host range of Pofymyxa graminis1
Authors: BASTIN V. , BOUTE C. , MARAITE H.
Published: April 2008

The inoculum potential of Pofymyxa graminis was studied for 48 samples of Belgian soils and 8 samples from other European countries. After growing barley bait plants in tubes under controlled conditions on increasing dilutions of the samples in sterile sand, P. graminis was detected in 77% of the Belgian soils, the number of infection units calculated per g of soil ranging from 0.004 to 5.6. The inoculum potentials for the other origins were within these limits. The host range of P. graminis was studied by growing various Gramineae in the presence of cystosori extracted from barley roots cultivated on five soils. Barley was infected by all the isolates. Some isolates infected oat and/or rye but none wheat.
Management of yellow mosaic‐inducing viruses on barley by selection of resistant cultivars1
Authors: HUTH W.
Published: April 2008

During the last ten years yellow mosaic of barley has been spreading more and more in European countries and in some infested areas yield loss can only be prevented by growing resistant cultivars. Breeding of such cultivars is one of the most important goals of small‐grain breeders. To select resistant cultivars, several methods are available such as mechanical inoculation, growing of plants in infested soil in the field or in growth chambers as well as using root powder of infected plants. The situation has recently been complicated by the discovery that yellow mosaic is caused by at least two distinct but closely related viruses (barley yellow mosaic virus and barley mild mosaic virus). Inoculation methods are not equally effective for these two viruses. Although it appeared initially that resistance to the two viruses was linked, there are now indications that some barley cultivars respond differently, and there may even be a third virus involved. Programmes for selection of resistant cultivars now have to take account of this.
National and local spread of barley yellow mosaic virus in the United Kingdom1
Authors: HILL S. A. , WALPOLE B. J.
Published: April 2008

Barley yellow mosaic virus was first reported in the United Kingdom in 1980. Since then cumulative records of reports of disease, confirmed at the laboratory of the Agricultural Development and Advisory Service of the Ministry of Agriculture, Fisheries and Food, show how infection has spread from the east of England where it first occurred in quantity, to the west. Areas of concentrated infection appear to relate to areas of intensive winter‐barley cultivation. Records suggest that infection may have occurred as early as 1976. Patterns of local spread in fields as defined in aerial photographs reflect the means by which the viruliferous vector may be passively moved in the soil. Other patterns reflect previous cropping. The higher frequency of infection on the sites of long‐removed hedgerows is not explained.
Fungally‐transmitted viruses of cereals in the UK1
Authors: ADAMS M. J. , BATISTA M. DE F. , SWABY A. G. , ANTONIW J. F.
Published: April 2008

The distribution of two UK strains of barley yellow mosaic virus has been studied and both have been transmitted experimentally by Polymyxa graminis. cDNA hybridization studies support the suggestion that the strains should be considered distinct viruses. Oat mosaic and oat golden stripe (OGSV) viruses also occur in the UK. OGSV is a furovirus related to wheat soil‐borne mosaic furovirus: it has particles of two lengths and a bipartite genome.
Reaction of potato cultivars to primary and secondary infection by potato mop‐top furovirus and strategies for virus detection1
Authors: KURPPA A. H. J.
Published: April 2008

Potato cultivars in elite seed production in Finland were tested for susceptibility to primary and secondary infection by potato mop‐top furovirus (PMTV) in field and pot experiments during 1987 and 1988. The tubers of all 22 cultivars tested became infected under favourable conditions in naturally infested soil, and most of them showed external and internal spraing symptoms when stored first at 18°C for 2 weeks and then 2 weeks at 8°C. The second incubation cycle increased the percentage of tubers manifesting symptoms and the halving of tubers also favoured symptom development. The cultivars most tolerant to primary infection were Pito, Hertha and Record, and the most susceptible were Sabina, Olympia, Saturna and Matilda. The same cultivars, excluding Saturna, were also the most susceptible to secondary infection, which decreased tuber yield up to 37%. The virus could be detected fairly reliably in soils by the bait‐plant method, and in the tubers after a repeated cycle of incubation at 18 and 8°C. Electron microscopy and serological methods are useful in both virus detection and identification but they still have severe limitations.
The association between serotypes of tobraviruses and Trichodorus and Paratrichodorus species1
Authors: BROWN D. J. F. , PLOEG A. T. , ROBINSON D. J.
Published: April 2008

New procedures developed for studying virus transmission by Trichodorus and Paratrichodorus species permit accurate characterization of the virus and identification of the nematode species. Results obtained using this virus transmission system show that serologically distinct isolates (serotypes) of tobraviruses are transmitted by different vector species. Furthermore, one species may be associated with the same virus serotype in several countries. These results suggest that a high degree of specificity occurs between tobraviruses and their vector nematodes. These new methods also permit the application of stringent criteria which are considered necessary to establish that a Trichodorus or Paratrichodorus species is a vector of a tobravirus. Only 11 of 36 published associations between Trichodorus or Paratrichodorus and tobraviruses fulfil these criteria.
Occurrence of insects in coniferous roundwood imported to Sweden from France and Chile
Authors: SCHROEDER L. M.
Published: April 2008

Sweden requires all coniferous roundwood from countries outside Europe to have been debarked but makes no requirement for European wood. Six shipments of unbarked roundwood ofPinus pinasterfrom France and 14 shipments of debarkedP. radiatalogs from Chile were inspected in Sweden during 1988 and 1989. The imported wood from France yielded 92 insect species (90 Coleoptera and 2 Hymenoptera). Seventeen of these species do not occur in Sweden. All six consignments were thoroughly attacked by bark‐ and wood‐boring insects, representing 25 species. The logs from Chile had been well debarked; less than 1% of the inspected logs contained living insects. Nevertheless, a total of 49 insect species (46 Coleoptera, 1 Isoptera, 1 Hymenoptera and 1 Orthoptera) were found in the 14 shipments. Of these species 21 are not indigenous to Sweden.
Present status of Phytophthora species in the Mediterranean area, especially in relation to citrus1
Authors: LAVIOLA C. , SOMMA V. , EVOLA C.
Published: April 2008

Of the 44 currently accepted species of Phytophthora, 18 have been reported in the Mediterranean area. The status of each is briefly reviewed. On citrus, P. citrophthora and P. nicotianae var. parasitica are mainly responsible for foot rot and gummosis, and in addition P. hibernalis, P. syringae, P. cifricola and P. cactorum for brown rot of fruits. The incidence of these species is closely linked to their temperature requirements. The use of sour orange as a resistant rootstock has long provided satisfactory control of foot rot and gummosis, while chemical treatments are effective against brown rot. However, there are indications that, with changingcultural practices, the resistance of sour orange is less well expressed, and the species is incidentally also susceptible to citrus tristeza closterovirus. Alternative rootstocks are therefore being sought.
Caractères compareés des espèces de Phytophthora pathogènes des agrumes1
Authors: RICCI P. , POPE‐DE‐VALLAVIEJLLE C. , PANABIÈRES F. , MARAIS A. , AUGÉ G.
Published: April 2008

Huit espèces differentes de Phytophthora sont capables de parasiter les agrumes en donnant des attaques sur racines, sur tronc et branches charpentières (gommose) et sur fruits (pourriture brune), y compris après récolte. Les trois espèces les plus importantes sont P. citrophthora, P. nicotianae var. parasitica et P. palmivora, avec une prédominance qui varie selon les régions climatiques. La taxonomie classique repose sur la morphologie des spores sexuées et asexuées, parfois sur celle du thalle, et aussi sur des critères physiologiques: homoou hétérothallisme, températures cardinales de croissance. Sur ces bases, l'appartenance spécifique des isolats peut le plus souvent être déterminée, mais certaines ambiguïtés demeurent. La validité des taxons ne peut être éprouvée que par l'étude de populations d'isolats et en ayant recours à des critères supplémentaires, de nature biochimique. L'analyse des protéines solubles totales ou d'isoenzymes, d'origine mycélienne ou extra‐cellulaire, séparées par éectrophorèse ou isofocalisation, a maintenant bien prouvé son intérêt. De nouvelles méthodes, s'adressant non plus à l'expression des gènes mais à leur organisation, sont en train de voir le jour. L'enjeu n'est pas seulement taxonomique; il concerne aussi la structure des populations et leur évolution.
Identification and differentiation of Phytophthora by electrophoresis of mycelial proteins and isoenzymes1
Authors: NWAGA D. , NORMAND M. LE , CITHAREL J.
Published: April 2008

Total proteins (both native and denatured) and three isoenzyme systems (esterases, malate dehydrogenases, superoxide dismutases) were analysed for eight Phytophthora species and for eight strains of P. nicotianae. The results obtained showed low intraspecific variability (62‐100% of similarity index) for P. nicotianae and allowed the characterization of P. capsici, cinnamomi, cryptogea, megakarya, megasperma, nicotianae, palmivora and citrophthora by the polyacrylamide gel electrophoretic profiles of native proteins and isoenzymes. The interspecific variability between these eight species is high (27‐49% of similarity index). The results obtained support the use of these macromolecular criteria as an aid to the identification of Phytophthora spp.
Les maladies àPhytophthora des agrumes au Portugal: caractéristiques des espèces isolées
Authors: TELHADA J. A.
Published: April 2008

Une prospection a été entreprise dans les plus importantes régions citricoles portugaises afin d'obtenir une information préliminaire sur la population de Phytophthora spp. parasites des agrumes au Portugal. Au cows de cette prospection cinq espèces ont été isolées et identifiées: P. citricola, P. citrophthora, P. hibernalis, P. nicotianae var. parasitica et P. syringae. Leur caracterisation a été effectuée d'après les aspects bio‐morphologiques et éco‐géographiques les plus importants. La population de Phytophthora spp. inféodées aux agrumes s'est répartie entre une espece majoritaire‐P. citrophthora (60,9%)—et quatre minoritaires: P. citricola (15,2%), P. hibernalis (15,2%), P. n. parasitica (4,3%) et P. syringae (4,3%). P. citrophthora a été repérée dans tout le territoire continental portugais; P. citricola et P. hibernalis ont été isolées dans les régions du centre et du nord; par contre, P. n. parasitica n'existe que dans la région de Sintra (environs de Lisbonne) et P. syringae que dans la région de Coimbra, montrant une petite dispersion géographique. Hormis P. hibernalis, toutes ces espèces ont été signalées pour la premiere fois au Portugal.
Effect of irrigation on the dynamics of Phytophthora citrophthora populations in soil of citrus orchards1
Authors: DI SAN LIO G. MAGNANO , MESSINA F. , GRECO G. , PERROTTA G.
Published: April 2008

Effects of irrigation on the dynamics of soil populations of Phytophthora citrophthora have been studied in three citrus orchards in East Sicily (Italy). Significant increases of inoculum levels were detected 24 h after irrigation. In one orchard throughout summer, population of P. citrophthora beneath the tree canopy was more than 15 propagules g‐1 soil, a value which is considered a threshold level for root rot infections.
Role of Phytophthora spp. in citrus decline in Apulia and Basilicata, Italy1
Authors: IPPOLITO A. , DE CICCO V. , SALERNO M.
Published: April 2008

The results of field surveys carried out in citrus groves of Apulia and Basilicata in Italy to clarify the etiology of a decline condition associated with root and foot damage of citrus are reported. Field observations and laboratory tests have shown that the most frequent causes of citrus decline are root and foot infections by Phytophthora spp. The species isolated were P. nicotiunae var parasiticu and P. citrophthora; the former was the species most often isolated from both the soil and the feeder roots. Less frequently, ArmiNuria sp., frost damage and rodents were identified as additional causes ofdecline. Finally the role ofcultural factors in the decline caused by Phytophthora spp. is discussed.
Search for resistance to phytophthora root rot in West Indian avocado rootstocks in the Canary Islands1
Authors: LLOBET L. GALLO
Published: April 2008

Avocado root rot caused by Phytophthora cinnamoni is a major limitation for avocado expansion in the Canary Islands, as it is in other producing areas of the world. To date, no germplasm with resistance potential has been found among West Indian avocados, which would convert this type into an ideal rootstock for use in infested areas such as the Canary Islands. Our aim was a thorough screening of the local West Indian population, descendants of seedlings brought to the Canaries from the Caribbean in the early 1800s. Our selection methods were based on those used by Zentmyer in California (US) since 1960 (nutritivesolution tank, with controlled aeration, pH, and temperature, to which inoculum is added), which gave rise at that time to several resistant/tolerant Guatemalan and Mexican rootstocks. We also screened using pots filled with naturally infested soil. The plant material tested was: (a) West Indian seeds from the original, local population; (b) seeds of the Guatemalan x West Indian hybrid Gema, taken from 20‐year‐old local trees growing in highly infected groves; (c) seeds of the salt‐resistant Israeli West Indian cv. Maoz. Also tested for comparison purposes were seeds of Mexican and Guatemalan avocados. Inoculations were done using the P. cinnamomi A2 strain, taken from proved diseased trees found in the Canaries. At present, one West Indian plant has survived the selection in a first trial, while 38 have survived in a second trial. One Mexican plant (cv. Topa‐Topa) has survived in a third trial. Resistant material is now being reproduced both by tissue culture and by the etiolation technique.
A review of Phytophthora diseases of different Mediterranean crops in Turkey1
Authors: BİÇİCİ M. , ÇINAR A.
Published: April 2008

In the last 20 years, seven different Phytophthora species (P. cambivora, P. hibernalis, P. citrophthora, P. capsici, P. cactorum, P. drechsleri and P. infestans) have been determined in Turkey on chestnut, citrus, pepper, strawberry, melon, and potato respectively. Two of them, P. citrophthora and P. capsici, which attack citrus and pepper, are very destructive and have the greatest economic importance. P. citrophthora has caused approximately 15% fruit losses every year and 8–30% infection on a susceptible lemon cultivar in Cukurova region. P. capsici is very dangerous for pepper‐spice and pepper‐paste production because it causes up to 100% drying and killing of pepper plants under conditions of poor drainage and incorrect irrigation practices. P. cambiuora, which causes the ink disease of chestnut, has spread from the Black Sea coast to the Mediterranean; about 20 000 chestnut trees have been killed by this organism from 1952 to 1970. Recently, P. infestans on potato is achieving importance, as the potato area increases. The other species of Phytophthora do not have any economic importance and only first records have been noted.
Phytophthora species attacking strawberry and raspberry1
Authors: DUNCAN J. M.
Published: April 2008

Phytophthora frugariae causes red core root rot of strawberries. Although the disease is probably most acute in northern Europe, serious outbreaks have been reported from a number of Mediterranean countries, especially France and Italy. Leather rot of fruit and crown rot, which are caused by P. cuctorum, can also be severe problems in warmer climates. Both fungi survive in soil for long periods, but the most common form of spread is in diseased planting material. Sensitive tests have been developed to detect red core in planting material, and been used to effect in certification schemes. Root rot of raspberry has gained prominence in the last 10 years in Europe as raspberry growing has expanded, but the disease has been known for many years in France. Nine species of Phyfophthora have been recovered from affected plants, but two of these, one with affinities with P. megasperma, and P. cumbiuora, are responsible for most major outbreaks. The other species are only troublesome where drainage is poor. Again, spread is mainly in infected material. Few raspberries are resistant to root rot, but some wild RubuP spp., blackberries and raspberry x blackberry hybrids are resistant and may be useful in breeding programmes.
Genetics of resistance toPhytophthora capsiciin the Mexican pepper‘Line 291
Authors: ORTEGA R. GIL , ESPAÑOL C. PALAZÓN , ZUECO J. CUARTERO
Published: April 2008

In order to establish a genetic model of the resistance toPhytophthora cupsiciinCapsicum annuumgenotype‘Line 29′, three experiments were conducted which included, as well as‘Line 29′, the susceptible genotype‘Morron INIA 224’and several of its F1, F2, F3and backcrosses. Plants with 4–6 leaves were inoculated by irrigating the culture substrate with a zoospore suspension of isolate B 1. The F2test was applied to the segregating generations to test whether there were one, two, three or four genes involved in the resistance. Additivity and equal weight of all the genes in the final effect were assumed. The hypothesis that best explained the results obtained was the one that assumed three genes in‘Line 29′; at least four alleles had to be present in any genotype for it to behave as resistant. The possible influence of isolate aggressiveness and inoculation method on the results is discussed.
Quelques phytophthoroses des cultures dans la zone méditerranéenne du Monténégro (Yougoslavie)
Authors: MIJUŠKOVIĆ M. , VUČINIĆ Z. , TIODOROVIĆ J.
Published: April 2008

Trois phytophthoroses des cultures dans la région méditerranéenne du Monténégro sont présentées: la gommose des agrumes, maladie connue depuis longtemps, mais dont l'importance est devenue négligeable grâce à la pratique du greffage; Phytophthora capsici sur poivron, constaté pour la première fois dans le Monténégro il y a une dizaine d'années, et Phytophthora nicotianae var. nicotianae, provoquant le pied noir du tabac, connu en Yougloslavie seulement depuis 1983. Les phytophthoroses du poivron et du tabac restent toujours des maladies potentiellement importantes dues à la nécessité d'irrigation de ces cultures et á la difficulté d'une lutte chimique rationnelle.
A new Phytophthora disease of the aerial parts of Eucalyptus species1
Authors: BELISARIO A.
Published: April 2008

Aerial damage on transplanted seedlings of Eucalyptus spp. was recorded in Italy for the first time. In 1987 a widespread infection was detected in the eucalyptus nursery of the Ovile Farm, Rome. It occurred only on E. globulus and was subject to sprinkler irrigation. In 1988 the disease occurred exclusively on E. delegarensis and E. regnans. The agent, which attacks leaves, petioles and shoots, was identified from the morphological and physiological characteristics of the isolates obtained in each year as Phytophthora nicotianae var. nicotianae.
Control of phytophthora gummosis of citrus with systemic fungicides in Brazil1
Authors: FEICHTENBERGER E.
Published: April 2008

Phytophthora gummosis and phytophthora root rot are the most important fungal diseases of citrus in the State of São Paulo, Brazil. Phytophthora citrophthora and P. nicotianae var. parasitica are the main species that incite both diseases in all the citrus‐growing areas of the State. Studies on the control of gummosis and root rot with systemic fungicides have been under way in the State since 1980. The efficacy of fosetyl‐A1 and metataxyl to control gummosis incited by both fungi in lemon and sweet orange trees was confirmed. The best control was achieved when foliar sprays of fosetyl‐A1 were combined with soil applications of metataxyl. The best timing was determined for application of these systemic products to control gummosis in the state.
Spread of phytophthora rot on stored citrus and its prevention by fungicide dips1
Authors: CHITZANIDIS A. , ARGYRI I.
Published: April 2008

Oranges and lemons infected with Phytophthora citrophthora and P. syringae were placed among healthy fruits in boxes kept at 5, 10 and 14°C. The spread of the rot by contact infection was assessed after 3,6,12 and 18 days and again after 7 days' shelf‐life at 17°C. P. citrophthora infected adjacent fruits after 12 days at 10°C and 3 days at 14°C. No infection occurred at 5°C. P. syringue infected the fruits at all the temperatures tested. On fruits kept for 6 days at 5°C, the rot developed after shelf‐life. The presence of Phytophthora‐infected fruits in orange and lemon packing boxes enhanced the development of penicillium rots. Post‐harvest dips in metalaxyl at 0.05 and 0.1% concentrations and fosetyl‐Al at 0.1,0.2 and 0.3% concentrations prevented the spread of P. citrophthora in packing boxes kept for 30,40 and 60 days at 11°C, but had no effect on penicillium rots. The mixture of the above fungicides with thiabendazole at 0.1%] or imazalil at 0.05%, concentrations gave best control against phytophthora and penicillium rots.
Efficacité de quelques fongicides dans la lutte contre Phytophthora capsici sur poivron1
Authors: PALAZÓN C. , GIL R. , PALAZÓN I. , DELGADO I.
Published: April 2008

Le dépérissement du poivron provoqué par Phytophthora capsici est capable de produire de graves dégllts dans les cultures espagnoles de plein champ présentes dans la Vallée de 1'Ebre (Espagne). En attendant une solution génétique qui à l'heure actuelle n'est pas encore arriveée, on a tenté de resoudre le probleme avec la lutte chimique en utilisant de nouveaux produits par rapport aux fongicides classiques. Les essais, situés à trois localités dans la Vallée de l'Ebre, ont été realists pendant 4 années successives sur des parcelles artificiellement contaminées avec l'agent pathogène. Tous les essais ont été réalisés en plein champ sur des poivrons cv. Morrón. La contamination a consistéà verser, au pied de chaque plante, 25 ml d'une suspension de zoospores à la concentration de 10000 zoosporés par ml. I1 a donc été appliqué au pied des plantes 25 ml d'une suspension fongicide en deux fois, la première 7 j avant I'inoculation et la deuxiéme 25 j aprés. L'ensemble des resultats obtenus permet de caractéariser l'efficacité des nouveaux fongicides (étridiazole, métalaxyl, propamocarbe, phoséthyl‐A1, oxadixyl) par rapport à celle du captafol et du propinébe, produits de référence, et de discuter leur intérêt respectif dans la lutte contre P. capsici sur poivron.
Phosphorous acid treatments control Phytophthora diseases in Australia1
Authors: DE BOER R. F. , GREENHALGH F. C. , PEGG K. G. , MAYERS P. E. , LIM T. M. , FLETT S.
Published: April 2008

Treatments with a partially neutralized formulation of phosphorous acid containing potassium phosphite were assessed for control of Phytophthora diseases in subtropical and temperate crops in Australia. In Queensland, trunk injections of phosphite (10% solution) controlled severe root rot (Phytophthora cinnamomi) of avocado trees and resulted in the recovery of trees. Single pre‐harvest sprays (2.5 kg ha‐1) of phosphite controlled root and heart rot (P. cinnamomi) of pineapples. Foliar sprays of phosphite (64 g per tree) controlled root rot (P. nicotianae var. parasitica) and trunk canker (P. citrophthora) of mandarin trees. In Victoria, a foliar spray of phosphite (300 g ha‐1) reduced root rot (P. clandestina) of subterranean clover and increased dry matter by 1.96 to 5.11 t ha‐1. Trunk injections of phosphite (10% solution) controlled trunk rot (P. cactorum) of peach trees and foliar sprays (10 kg ha‐1) reduced severity of root rot (P. nicotianae var. nicotianae) of tomatoes.
Fungicide resistance in soil‐borne Phytophthora species1
Authors: LUCAS J. A. , BOWER L. A. , COFFEY M. D.
Published: April 2008

Systemic fungicides such as the phenylamides and phosphonates have provided new opportunities for chemical control of soil‐borne Phytophthora species. Potential problems in their use include biodegradation in soils, and the emergence of pathogen isolates resistant to these compounds. Resistance to phenylamides is well known in leaf‐infecting Oomycetes, but less is known about the development and relative fitness of resistant isolates among populations of soil‐borne Phytophthora species. Experiments with P. capsici and P. palmivora have shown that stable resistant and virulent isolates can be selected under laboratory conditions. Some mutants resistant to both metalaxyl and fosetyl‐A1 have been recovered, with growth rates and sporulation equivalent to parental wild types. Selected mutants proved able to compete in vivo with fungicide‐sensitive wild types in the absence of the compounds. More information is required to fully evaluate the implications of these results for chemical control of soil‐borne Phytophthora species in the field.

Résistance des Phytophthora du sol aux fongicides
Interception of Colorado beetle in England and Wales, 1983–1987
Authors: BARTLETT P. W.
Published: April 2008

The policy of the British Government continues to be to maintain total freedom from Colorado beetle by preventing its introduction and eradicating any breeding colonies which are found. During the years 1983–1987, no breeding colonies have been found and there is no evidence that the Colorado beetle is established anywhere in the UK. Interceptions on imports during this period are analysed by country of origin and also by means of introduction. Total confirmed reports of live beetles are compared with those in previous reports; 250 were found in 1983–1987, 286 for the previous 5‐year period and 563 of known origin for the 20‐year period previous to 1978.
Ceratocystis species on Quercus robur with oak decline symptoms in southern Poland1
Authors: KOWALSKI T. , BARTNIK C.
Published: April 2008

In southern Poland during 1986–1989, six species of Ceratocystis were found on sick and dead Quercus robur. The frequency of their occurrence in above‐ground portions and roots of trees is given. The possibility is discussed whether oak decline, caused by a complex of abiotic and biotic factors, is intensified when trees are colonized by Ceratocystis.
Computer‐supported pest management systems in the USA1
Authors: JACKMAN J. A.
Published: April 2008

The use of computers in pest management is discussed by task and the implementation of computer programs is outlined. Tasks discussed include information retrieval, record keeping, diagnostic applications, event prediction, strategic planning and studying spatially referenced data. Appropriate applications of data base management systems, management information systems, decision support systems, expert systems and geographical information systems are defined and examples are given from the USA with special emphasis on Texas projects. The audience for pest management software is defined and problems of delivery and evaluation are emphasized.
L'utilisation en France des systèmes experts en protection des végétaux: l'aide au diagnostic1
Authors: DELHOTAL P. , LAMARQUE C.
Published: April 2008

Le diagnostic est une composante essentielle de l'aide à la décision en protection des cultures. Une gamme de systèmes experts destines aux cońseillers, techniciens ou producteurs est disponible en France afin d'aider au diagnostic de l'ensemble des désordres (maladies, ravageurs, phytotoxicité…) rencontrés sur une culture au champ et, éventuellement, en conservation. Etabli uniquement à partir de critères renseignables par l'utilisateur, le diagnostic s'accompagne si nécessaire d'indications permettant de le confirmer (chambre humide…) ou d'une préconisation d'envoi à un laboratoire. Testés en conditions réelles d'utilisation, ces systèmes entrent pour la plupart dans une phase de maintenance destinée à prendre en compte l'évolution phytosanitaire. La diffusion télématique choisie en France n'est pas la seule voie possible, ainsi certains systemes actuellement expérimentés aux USA seront diffusts autrement.
Diagnostic expert systems in US agricultural extension1
Authors: ADAMS S. S. , STEVENSON W. R.
Published: April 2008

Acurate identification of plant pest problems requires expertise in the agronomic or horticulture aspects of crop production and a sophisticated level of knowledge of the many problems (diseases, insects, toxicities, and deficiencies) that may affect crops. Diagnostic expertise developed over many years is lost almost overnight through changes in career or program direction or retirement. Expert systems which simulate the behavior of diagnostic consultants in interaction with users, offer the chance to capture this expertise before it is lost. Each system is composed of a knowledge base and an expert system shell. The knowledge base contains the collective diagnostic expertise (often encoded in the form of IF‐THEN rules) of interviewed specialists in plant pathology, entomology, and agronomy. The shell performs the reasoning and problem‐solving tasks (including searching the knowledge base for applicable rules) while directing questions and issuing diagnostic reports to the user. There are currently a large number of expert systems being developed, evaluated, and placed into use in the USA. These include systems for diagnosing disease and insect problems of apple, cotton, muskmelon, peach, peanut, potato, red pine, soybean, tomato, and turfgrass. Weed identification systems are also in progress. It will be necessary, if not crucial, for extension professionals to be actively involved in the ongoing development, evaluation, and implementation of such systems.
Utilisation de la diffusion multi‐média dans l'aide au diagnostic1
Authors: DELHOTAL P. , LUCAS P. , BOUDEVILLE J. L. , CONNIER C.
Published: April 2008

L'aide au diagnostic repose sur une communication homme‐machine entre un consultant non expert et un logiciel apte à simuler la démarche d'un expert. Les validations de terrain montrent qu'un dialogue purement textuel peut suffire mais aussi que des illustrations bien choisies faciliteraient la compréhension et contribueraient à rendre plus attractive la démarche menant au diagnostic. Le diagnostic visuel intègre une vision globale et une analyse de critères précis devant tenir compte de la variabilité des expressions. Diversité des situations, d'une part, précision des descripteurs, d'autre part, relèvent de modes de représentation distincts. L'emploi conjoint de textes, schémas et photographies apparaît alors nécessaire afin d'améliorer les performances des systèmes et leur acceptabilité. Les nécessités de maintenance dans un domaine susceptible d'évolution brutale mènent à privilégier une diffusion centralisée, d'où le choix en France d'une solution télématique (réseau Télétel), excluant jusqu'à présent l'emploi d'images. La mise en service de Numéris (réseau numérique à intégration de services) autorise désormais une approche multi‐média techniquement et économiquement viable. Cette possibilité ouvre des perspectives supplémentaires d'enrichissement des systèmes (documentation, approche de l'aide à la décision).
Pest and disease monitoring and plant protection information systems in Denmark1
Authors: MURALI N. S.
Published: April 2008

At the Danish Research Centre for Plant Protection, under the Information System Program, a Pest and Disease Monitoring System (PDM) and a Plant Protection Information System (PPIS) are being developed and maintained with the objectives of recording the pest and disease status of the country and integrating information pertaining to optimal plant protection measures, pests and diseases, spraying techniques, pesticides and beneficial organisms. PDM was initiated in 1983 and covers five pests and 11 diseases in seven groups of crops. Monitoring is done regularly by voluntary participants during the growing season and the system includes individual farm recommendations. In 1989 there were 692 participants in the programme. PPIS was initiated in 1987 and will be tested in 1990. The system integrates optimal plant protection strategies for individual farms with all relevant information on plant protection.
Système informatisé d'aide aux arboriculteurs pratiquant la lutte intégrée1
Authors: MARCELLE R. D.
Published: April 2008

En Belgique, pour aider un groupe d'arboriculteurs désireux dappliquer des méthodes de protection intégrée et avec I'aide des autorités régionales wallonnes, un système vidéotex a été mis en place afin de diffuser rapidement une série d'informations utilisables dans ce type de protection des végétaux. L'article décrit brièvement les circonstances ayant donné naissance à cette initiative, le système informatique utilisé ainsi que quelques exemples des informations fournies aux utilisateurs.
Computer aids to integrated control in peach orchards in Emilia‐Romagna (Italy)1
Authors: CRAVEDI P. , MOLINARI F. , MAZZONI E.
Published: April 2008

An Integrated Pest Management (IPM) programme on vineyards and orchards has been applied since 1974 in Emilia‐Romagna (northern Italy). The Entomology Institute of Piacenza has the scientific responsibility for peach, plum and apricot orchards. Data is collected in the field by a team of technicians with province‐level co‐ordination. Directions for control are given directly to farmers or through answering machines, Videotel or weekly bulletins. Data from orchards, concerning the pest and disease situaton, are processed by two Hewlett Packard 9000 computers: an HP 9845B and an HP Vectra RS/20. With the latter, data exchange is possible with MS DOS operating systems, allowing data input from a regional computer network now at the development stage.
An integrated pest management approach to Colorado potato beetle control in the USA1
Authors: SCHRODER R. F. W.
Published: April 2008

An integrated pest management program utilizing the egg parasite Edovum puttleri for Colorado potato beetle control was developed at Beltsville (US). This program presents an alternative control that is environmentally safe, cost‐effective and energy‐efficient.
Control of Colorado beetle (Leptinotarsa decemlineata) in Poland1
Authors: PRUSZYńSKI S. , WĘLGOREK W.
Published: April 2008

Leptinotarsa decemlineata (Colorado beetle) was found in Poland for the first time in 1945 and a great invasion of this pest took place in 1950. It now plays a very important role in Polish plant protection, mainly because the acreage of potato in Poland amounts to about 1.8 million ha. The pest is controlled by repeated insecticide applications to a yearly total of 2 million ha, which is the highest amount of insecticides used in Poland. Research has been carried out in Poland on the following subjects: biology and ecology of Colorado beetle, influence of pest appearance and control on the biocenosis of fields, methods of control, biochemical factors influencing the life cycle, forecasts and warning of appearance, artificial diet, resistance of potato cultivars and reaction of leaf blades of potato to the eggs of Colorado beetle. Research is also carried out on chemical control, modernization of pesticide recommendations and resistance of Colorado beetle to pesticides. The influence of biotic and abiotic factors on the reduction of Colorado beetle numbers has been studied. With a view to possible biological control, predatory bugs (Perillus bioculatus and Podisus maculiventris) were introduced into Poland in 1959 and 1979. Research is also conducted on entomopathogenic fungi, parasitic nematodes, protozoans, spiroplasms and Bacillus thuringiensis.
Lutte contre le doryphore de la pomme de terre (Leptinotarsa decemlineata) en Normandie (France)1
Authors: VERGNAUD A.
Published: April 2008

Pour éviter l'introduction du doryphore de la pomme de terre dans les iles Anglo‐Normandes, le service français de la protection des végétaux méne, en collaboration avec les comités agricoles de Jersey et de Guernesey dans le cadrede I'OEPP, une lutte originale en Normandie. Cette lutte est baste sur la biologie de I'insecte (conditions d'hibernation et de vol) et sur I'étude des conditions climatiques (température, insolation, vent). La synthése journaliére des donnees permet de détecter les périodes critiques. Ces observations sont complétés par une surveillance des cultures de pommes de terre et des avis de traitements obligatoires sont envoyés dans 228 communes. 11s visent I'élimination du doryphore dam le Cotentin.