bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resistance of the German cockroach (Blattella germanica) to bendiocarb
Authors: BARSON G. , McCHEYNE N. G. 
Published: February 2008

SUMMARYTwo field strains of the German cockroach Blattella germanica (L.) were collected in England from survivors of treatments with bendiocarb wettable powder, and bred in the laboratory. These and a laboratory susceptible strain were compared by a tarsal contact method to test for resistance to bendiocarb, fenitrothion and dieldrin. The field strains after exposure to the insecticide for 24 h were resistant to bendiocarb in terms of mortality by factors of 5.6 and 6.2 at the LC50 level, but at the LC95 level the resistance factors were only 1.7 and 2.0; however knockdown resistance was detected, with resistance factors at the KD50 level of 10.6 and 8.1. At shorter exposure times of 5 min and 60 min, 2–20% of cockroaches from the field strains survived 55 or 110 mg bendiocarb/m2; there were no survivors from the susceptible strain. Some cockroaches from the field strains were able to recover from knockdown after and during exposure to 110 mg bendiocarb/m2. Both field strains showed some resistance to dieldrin; however, there was no resistance to fenitrothion. When all three strains were exposed to 55 mg fenitrothion/m2 for 5 min, all the insects were knocked down within 3 h, and all had died within 96 h. There was no recovery from knockdown to fenitrothion or dieldrin.
Field control of sore shin (Rhizoctonia solani) of tobacco with benomyl and benodanil*
Authors: COLE DESIRÉE L. , COLE JAMES S. 
Published: February 2008

SUMMARYBenomyl and benodanil, applied to tobacco seedlings before transplanting, reduced sore shin infection. Benodanil was the more effective, sometimes restricting damage to 5% of the surface area of the buried portion of stems, compared with 50–60% in untreated plants. The fungicides were applied either as a seedbed drench or a root‐stem dip. The dip method used less fungicide and was generally more effective than the drench at equal concentration but was less practical. Benodanil was over three times as active as benomyl against Rhizoctonia solani in liquid culture.
Competitive ability and ethirimol sensitivity in strains of barley powdery mildew
Authors: HOLLOMON D. W. 
Published: February 2008

SUMMARYStrains within field populations of barley powdery mildew (Erysiphe graminis f. sp. hordei) varied greatly in their response to ethirimol. Each strain remained stable whether the fungicide was present or not, and no evidence for adaptation was obtained. Strains of intermediate sensitivity were the most frequent within the pathogen population, and these also dominated model populations maintained in the laboratory. Ethirimol eliminated sensitive strains from laboratory mixtures, and increased the relative fitness of insensitive ones, but not sufficiently to oust the intermediate strains. Mildew from treated field plots was less sensitive than that from untreated plots, but only early in the epidemic. Insensitivity was not related to the level of ethirimol used and, at four times the rate used commercially, insensitive strains were no more frequent than at lower rates. As the complexity of mildew populations increased, changes in ethirimol sensitivity in response to selection became less pronounced, and it is suggested that strains of intermediate sensitivity to ethirimol exert a stabilising effect within natural populations. This could alter if the fitness of insensitive strains were to increase, perhaps through recombination. Consideration should be given to the effect ethirimol might have on the composition of the pathogen population if applied when sexual recombination occurs, and to the role ascospores play in disease development.
Components of adult plant resistance to powdery mildew (Erysiphe graminis f. sp. avenae) in oats
Authors: JONES I. T. 
Published: February 2008

SUMMARYThe adult plant reaction to mildew (Erysiphe graminis f. sp. avenae) of four oat genotypes was studied. A negative relationship existed in these genotypes between length of latent period and the percentage leaf area with mildew. The very susceptible CI 4877 had the shortest latent period and the largest area of leaf infected, while the highly resistant Cc 4761 had the longest latent period and the least leaf area covered with mildew.The same association also occurred between leaves within a genotype, particularly those genotypes with adult plant resistance, i.e., Maldwyn and Cc 4761. The more recently developed upper leaves showed the longest incubation period and least percentage area affected compared with lower leaves.A visual score of pustule sporulation indicated that CI 4877, Milford and Maldwyn had similar well‐sporulating foci, but in Cc 4761 the pustules showed significantly less sporulation.Estimates of the relative number of spores produced per day over a 15 day period reflected the level of resistance. Thus the most susceptible genotype CI 4877 released over 50 times more spores than Cc 4761, while Milford and Maldwyn respectively produced 9 and 4.5 times more spores than the highly resistant Cc 4761.The longer latent period of Cc 4761 was reflected in the delay this genotype showed in reaching its relatively low peak production of spores.The possible use of the latent period as a factor when selecting for adult plant resistance in early growth stages is discussed.
Effect of nitrogen deficiency on photosynthesis and the partitioning of 14C‐labelled leaf assimilate in unshaded and partially shaded plants of Lolium temulentum
Authors: POWELL C. E. , RYLE G. J. A. 
Published: February 2008

SUMMARYThe effect of a deficiency of applied nitrogen on the rate of leaf photosynthesis, and on the subsequent partitioning of 14C‐labelled leaf assimilate between new leaf, stem, tillers and root, was investigated in single plants of Lolium temulentum L., grown normally in controlled environments, or grown with collars shading the base of the plant. The nitrogen deficiency reduced the rate of leaf photosynthesis, increased the retention of assimilate in the leaf, suppressed the export of assimilate to tillers, and generally increased the export of assimilate to roots and to new leaves. Shading the base of the plant generally had little effect on the rate of leaf photosynthesis, reduced the export of assimilate to roots, and increased the export of assimilate to new leaf and to the stem, which elongated when shading was imposed.
Growth, reproductive development and yield of effectively nodulated cowpea plants in contrasting aerial environments
Authors: SUMMERFIELD R. J. , MINCHIN F. R. , STEWART KATRINE A. , NDUNGURU B. J. 
Published: February 2008

SUMMARYEffectively nodulated cowpea plants were grown to reproductive maturity in growth cabinets set to simulate factorial combinations of daylength (11 h 40 min or 13 h 20 min), day temperature (27 or 33°C) and night temperature (19 or 24°C) characteristic of humid tropical environments. The experiment was designed specifically to compare and contrast the growth, reproductive ontogeny and seed yield of these plants with data obtained earlier when the same symbiotic combination (cv. K 2809 and Rhizobium CB 756) received large amounts (197 mg/l) of inorganic nitrogen throughout growth. These comparisons have shown that effectively nodulated plants are potentially no less adaptable to the aerial environment than are plants depending on inorganic nitrogen, whilst producing equally as good, or even better, seed yields.
Host range and properties of potato black ringspot virus
Authors: SALAZAR L. F. , HARRISON B. D. 
Published: February 2008

SUMMARYPotato black ringspot virus (PBRV), obtained from cultivated potato in Peru, was found to have a very wide host range resembling that of tobacco ringspot virus (TRSV‐B), to which PBRV is distantly related serologically. However, PBRV caused the more severe symptoms in many species and, unlike TRSV B, infected Lycopersicon esculentum and Cyamopsis tetragonoloba. In Solanum tuberosum, PBRV caused necrotic spots and ringspots in systemically infected leaves in the year of infection and was readily transmitted through tubers to progeny plants, most of which developed no obvious symptoms although systemically infected. TRSV‐B infected non‐inoculated S. tuberosum leaves only sporadically, did not induce symptoms in them and was not transmitted through tubers to progeny plants.PBRV was cultured in Nicotiana clevelandii and infectivity was assayed in Cheno‐podium amaranticolor or C. quinoa. Virus particles were purified from leaf extracts, after clarification using chloroform, by precipitation with 6% polyethylene glycol and differential centrifugation. Purified preparations contained 25 nm diameter isometric particles with somewhat angular outlines, sedimenting as three components (T, M and B) at 49, 84 and 117 S, and containing a single protein species of mol. wt 59 000. Preparations of PBRV nucleic acid contained two species, estimated by polyacrylamide gel electrophoresis in non‐denaturing conditions to have mol. wt of about 25 106 (RNA‐1) and 15 106 (RNA‐2). Infectivity was associated with B particles, preparations of which contained RNA‐1 and RNA‐2, presumably in different particles. M particles contained RNA‐2, were not infective and enhanced infectivity only slightly when added to B particles. Similar relative amounts of RNA‐1 and RNA‐2 were extracted from unfractionated virus using phenol or Pronase, but preparations obtained using phenol were much the more infective.PBRV has properties typical of nepoviruses; its present cryptogram is (R/1):2–5/41 + 15/28 or 2 1 5/46:S/S:S/*, nepovirus group.
The relationship of potato black ringspot virus to tobacco ringspot and allied viruses
Authors: SALAZAR L. F. , HARRISON B. D. 
Published: February 2008

SUMMARYThe relationship between potato black ringspot virus (PBRV), isolates of tobacco ringspot virus from blueberry (TRSV‐B), cherry (TRSV‐C) and calico‐diseased potato (TRSV‐P), and eucharis mottle virus (EuMV) was examined in tests of three types. In gel‐diffusion precipitin tests, the reaction end‐points of antisera, and spur formation, indicated that PBRV and TRSV‐P are very closely related but not identical antigenically, as are TRSV‐B and TRSV‐C, and that these two pairs are more distantly related to each other and to EuMV. In plant‐protection tests in Nicotiana angustifolia, PBRV, TRSV‐B and EuMV conferred protection against the homologous virus but not against one another. PBRV, but not TRSV‐B, conferred protection against TRSV‐P. In tests with the two RNA species of PBRV, infectivity increased greatly when preparations of RNA‐1 and RNA‐2 were mixed, and both species are probably needed for infection. Infectivity did not increase when RNA‐1 or RNA‐2 of PBRV was mixed with RNA‐2 or RNA‐1, respectively, of TRSV‐B; the two viruses seem too distantly related to form pseudo‐recombinants.It is concluded that PBRV and tobacco ringspot virus should be considered separate viruses, and that TRSV‐P should be considered a strain of PBRV. EuMV should perhaps be recognised as a virus distinct from, but related to, PBRV and tobacco ringspot virus.
Effects of root residues on growth ofPinus radiata seedlings and a mycorrhizal fungus
Authors: CHU‐CHOU MYRA 
Published: February 2008

SUMMARYThe height of Pinus radiata Don seedlings grown on soils incorporating different proportions of root tissues (25 and 50%) was shown to be reduced by 20–80%. Seedlings watered with aqueous extracts from soil/root mixtures also showed a significant reduction in growth. This growth‐retarding effect was partially overcome by the addition of nutrients or by soil sterilisation. It is postulated that growth retardation was caused not only by nutrient deficiency resulting from the addition of organic matter with a high C/N ratio, but also by phytotoxic substances present in the root tissue.The effect of water extracts of roots from old P. radiata trees on the growth of young P. radiata seedlings and on a mycorrhizal fungus (Rhizopogon sp.) under aseptic conditions was also studied. Extracts from the inner bark of roots caused complete growth inhibition of the mycorrhizal fungus as well as root necrosis and wilting of P. radiata seedlings. A water‐soluble substance or substances, toxic both to the roots of P. radiata and to its mycorrhizal fungus, is postulated as the causal agent.
Survival and duration of development of Oscinella spp. (Diptera: Chloropidae) on different Gramineae in the laboratory
Authors: Vickerman G. P. 
Published: February 2008

SUMMARYThe duration of development and survival of Oscinella frit, O. nitidissima and O. nigerrima at different growth stages of several plant species was investigated in the laboratory. The effect of the infestation on the growth of plants was also quantified. Survival of O. frit larvae was significantly lower (P < 0.01) on barley than on either oats or wheat, between which there was no significant difference. Survival was usually highest when plants were infested at the two‐leaf stage and lowest when plants were infested at the five‐leaf stage. The duration of development of both male and female O. frit was longer on barley than on either oats or wheat and generally increased when older plants were infested. The proportion of male flies was greatest when older plants were infested. Duration of development and survival of O. frit was similar on oats and Lolium multiflorum, but larvae did not survive on Dactylis glomerata.Of the other Oscinella species, O. nitidissima larvae did not survive on oats, wheat and barley and O. nigerrima larvae did not survive on either oats or barley.The main shoots of cereal plants infested at the two‐, three‐ or four‐leaf stages were rapidly killed by O. frit larvae whereas many of those infested at the five‐leaf stage continued to grow slowly. In response to attack proportionately more tillers were produced by oat plants than by either wheat or barley plants.When cereals were infested with O. nigerrima larvae the central shoots were damaged, but most recovered and continued to grow. Damage symptoms were most obvious when cereals were infested at the two‐leaf stage, oats being more severely affected than either wheat or barley.
Studies on virulence of the take‐all fungus, Gaeumannomyces graminis, with reference to methology
Authors: Deacom J. W. , Henry Christine M. 
Published: February 2008

SUMMARYCurrent methods for take‐all assessment in laboratory experiment were examined; it was shown that the extent of vascular discoloration may not reflect virulence of a fungal isolate or host resistance to the pathogen under some experimental conditions. A new assessment method for take‐all is described, based on the ability of transport eosin past infection sites. It enables hosts or isolates to be compared by ET50 values, the times from inoculation when 50% of plants fail in eosin‐uptake through the three oldest seminal roots. Use of this technique suggested that barley roots were less affected than were wheat roots by Gaeumannomyces graminis var. tritici.Further experimental results showed that an isolate of G. graminis that had lost part of its virulence in culture yielded some single‐conidium progeny more virulent than itself. When single‐condium isolates or a mycelial isolate and its single‐conidium progeny were jointly inoculated on wheat, the amount of disease was less than that caused by the more virulent isolate alone.
Host and environmental effects on the infection of maize by Puccinia sorghi. I. Prepenetration development and peneration
Authors: Mahindapala Ranjith 
Published: February 2008

SUMMARYGermination of urediniospores of Puccinia sorghi on leafves and on ager was sminilar over the range 5–25°C, being greatest at 15°C, At this temperature, maximum germination was attained withing 5 h. Germination on cover slips started at around 99% r. h. and increased with of humidity.Urediniospore germination was not affected by leaf age. In generalk, proportionally more spores germinated on the abaxial than on the adaxial surface. Maximum germination was observed on the abxial surface of the tip portion of the leaf.The optimum temperature for infection structure formation was about 15°C, A munimum period of 3–4 h was required for the initiation of infection. Increase in appressorium and sub‐stomatal vesicle formation with increase in dew perio ws observed, with the maxima being attained at about 24 h after inculation.
Some effects of benomyl and carbendazim on Aphis fabae and Acyrthosiphon pisum on field bean (Vicia faba)
Authors: Bailiss K. W. , Partis G. A. , Hodgson C. J. , Stone E. V. 
Published: February 2008

SUMMARYField bean plants were treated with benomyl in a glasshouse, then nymphs of Aphis fabae and Acyrthosiphon pisum were caged on the second pinnate leaf. Soil drenches at concentrations of 150 and 75 μg benomyl/ml or above increased mortality of A. fabae and A. pisum respectively; 250 μg a.i./ml increased mortality and decreased progeny production of alate A. fabae. The effect on mortality persisted for at least 16 days after treatment. Foliar sprays increased mortality at concentrations of 75 μg a.i./ml and above (A. fabae). Field populations of A. pisum were reduced when bean plants were drenched or sprayed at a concentration of 250 μg a.i./ml and A. fabae populations were reduced by drenches but not by foliar sprays. A commercial formulation of carbendazim (Bavistin) increased aphid mortality whereas the formulation medium did not. Under the experimental conditions, benomyl affected the distribution of both species on young bean plants but did not induce a repellent effect; aphids preferred untreated leaves. Mortality and preference tests, and a field experiment, indicated that A. pisum was affected more than A. fabae.
Rearing and transmission techniques for Haplaxius sp. (Horn: Cixiidae), a suspected vector of lethal yellowing disease of coconuts
Authors: EDEN‐GREEN S. J. 
Published: February 2008

SUMMARYAdult Haplaxius sp., identified from Jamaica as H. crudus or H. cocois, are common on coconut foliage in both Jamaica and Florida and are suspected vectors of lethal yellowing disease in both regions. Nymphs, which are subterranean, were mass‐reared on roots of the grasses Stenotaphrum secundatum, Axenopus compressus and Cynodon spp. Transmission of the disease was tested by feeding the nymphs on roots of diseased palms, rearing them on grasses and transferring the emergent adults to foliage of test palms for infection feeds. No transmission was proven.
Aphid‐injection experiments with carrot mottle virus and its helper virus, carrot red leaf
Authors: ELNAGAR S. , MURANT A. F. 
Published: February 2008

SUMMARYCarrot mottle virus (CMotV) and its helper virus, carrot red leaf (CRLV), were not transmitted by aphids (Cavariella aegopodii) that had fed through membranes on, or had been injected with, sap from mixedly infected chervil plants or partially purified preparations of CMotV. However, the viruses were transmitted by recipient aphids injected with haemolymph from donor aphids that had fed on mixedly infected plants but not by a second series of recipients injected with haemolymph from the first series. Some of the first series of recipients transmitted both viruses for up to 11 days but others transmitted erratically and many lost ability to transmit after a few days. The results confirm that both viruses are circulative but provide no evidence for multiplication in the vector.Non‐viruliferous aphids, or aphids that had acquired CRLV by feeding, did not transmit CMotV when they were injected with haemolymph from aphids that had fed on a source of CMotV alone, confirming that they can only transmit CMotV when they acquire it from a mixedly infected plant. When extracts from donor aphids were treated with ether before injection, recipient aphids transmitted both CRLV and CMotV, although the infectivity of CMotV grown in Nicotiana clevelandii in the absence of CRLV is destroyed by ether treatment. CMotV particles acquired by aphids from mixedly infected plants therefore differed in some way from those in singly infected plants. A plausible explanation of these results, and of the dependence of CMotV on CRLV for aphid transmission, is that doubly infected plants contain some particles that consist of CMotV nucleic acid coated with CRLV protein.
The influence of human and goshawk Accipiter gentilis activity on wood‐pigeons Columba palumbus at brassica feeding sites
Authors: KENWARD R. E. 
Published: February 2008

SUMMARYHumans caused more than half the disturbance of wood‐pigeons, Columba palumbus, from roadside brassica feeding sites. The birds always flew away from pedestrians, cyclists and horsemen, but often remained feeding when closed vehicles passed. The pigeons resettled immediately on the same feeding site after 23% of goshawk, Accipiter gentilis, attacks, and birds were feeding there later the same day after nearly half the attacks. They resettled immediately after a similar proportion (19%) of the times they were approached by humans on foot, and rarely fed in fields where people were working.The shorter the time pigeons had spent feeding before an interruption, the sooner they returned after it. This probably reflected the level of their crop food reserves. This behaviour should minimise the effect of short duration disturbance, as caused by goshawk attacks, on wood‐pigeons feeding at brassica sites. Goshawk attacks did not cause a reduction in pigeon pecking‐rate.Pigeons feeding in roadside fields tended to avoid the side nearest to the road, but not parts of fields adjoining walls and hedges which could have provided cover for predatory attacks. It is concluded that scaring techniques based on man himself are more promising than use of the goshawk in protecting crops against wood‐pigeons.
Effects of foliar sprays of daminozide on the incidence of potato common scab
Authors: MCINTOSH A. H. , BATEMAN G. L. 
Published: February 2008

SUMMARYSingle foliar sprays of the growth retardant daminozide (1.5–12 g/l) approximately halved the incidence of common scab, caused by soil‐borne Streptomyces scabies, on potted potato plants in the glasshouse. Two analogues of daminozide (N‐dimethylaminomaleamic and N‐(dimethylamino)‐methylsuccinamic acids) also decreased scab, but others were inactive. Of 22 other unrelated growth regulators and translocated chemicals tested as foliar sprays, only gibberellic acid (0.1 g/l) decreased scab incidence, but many of the tubers were distorted. Chlormequat chloride and chlorphonium chloride, as root treatments, were inactive.In other experiments with daminozide, scab incidence was decreased after application to soil. In tests with two plants per pot, spraying one of each pair decreased its rate of stem extension, but did not affect the other, indicating that little or no daminozide passed into the soil from the roots of the sprayed plant. The decrease in scab brought about by foliar sprays was not altered by varying their timing during the period before symptom development (1 to 5 wk after potting). In agar plate tests, daminozide was only weakly toxic to S. scabies.It is concluded that daminozide probably decreased scab by altering the physiology of the plants, so that scab symptoms did not develop.
Further studies on the effect of resistance to Amphorophora idaei in raspberry (Rubus idaeus) on the spread of aphid‐borne viruses
Authors: JONES A. T. 
Published: February 2008

SUMMARYThe rate of spread of viruses transmitted by the aphid Amphorophora idaei into genotypes of raspberry differing in resistance to infestation by A. idaei was studied in a field experiment which exposed plants to large numbers of infective aphids. Under these conditions, genotypes that are readily colonised by A. idaei were totally infected with virus after two to three growing seasons, whereas genotypes with a high degree of resistance were substantially free of virus after four growing seasons but 56% of plants were infected after seven seasons. Genotypes with intermediate resistance were also substantially free of virus after three seasons but 76% of plants were virus infected after seven seasons.The effectiveness of resistance to A. idaei in raspberry in restricting spread of viruses transmitted by this aphid is discussed.