bluuebunny/crossref_metadata_2025 huggingface dataset:
Cultivated and wild host plants supporting populations of the cabbage root fly
Authors: FINCH S. , ACKLEY CHRISTINE M.
Published: February 2008

To determine the relative importance of different potential host plants for supporting populations of the cabbage root fly, wild and cultivated crucifers were sampled for pupae at four locations during 1971‐3. In addition, eighty‐three species of Cruciferae native to or naturalized in the British Isles were inoculated with cabbage root fly eggs in a glasshouse to determine which species could support the larvae.

In the field, most pupae (28‐7/plant) were collected from untreated cauliflowers. Fewer pupae (i‐7–8‐6/plant) were obtained from untreated crops of Brussels sprout, cabbage and swede. Applications of chlorfenvinphos reduced populations to two or less pupae per plant on all crops. Of five common weed species sampled, only Raphanus raphanistrum produced as many pupae as certain of the untreated brassica crops. Pupae did not occur in samples from Capsella bursa‐pastoris but Sisymbrium officinale, Thlaspi arvense and Sinapis arvensis usually supported low numbers.

In the glasshouse, only forty‐four of the eighty‐three cruciferous species tested supported larval development. Most pupae were obtained from 12‐wk‐old plants of Barbarea intermedia. B. stricta, Brassica napus, Cochlearia officinalis and R. raphanistrum and from 24‐wk‐old plants of Brassica rapa, Erysimum aureum, Cochlearia anglica and C. officinalis. Plant age considerably affected pupal production. Plants within a genus often gave similar results, pupae not being recovered from any of the Diplotaxis or Arabis species tested, or from young plants of Erysimum spp. In other families, Reseda lutea and R. luteola supported larval development, but the widely‐separated Plantago major did not.

Arguments for and against the removal of cruciferous weeds from the vicinity of cruciferous crops are discussed.
Glitoria yellow vein virus, a tymovirus from Kenya
Authors: BOCK K. R. , GUTHRIE E. J. , MEREDITH GINA
Published: February 2008

Clitoria yellow vein virus (CYW) was found in Clitoria ternatea and Abrus precatorius in coastal districts of Kenya, but was not detected in food legume crops. When transmitted by inoculation of sap, CYW infected many species in the Papilionaceae, commonly causing yellowing of secondary and smaller leaf veins. All the economically important food legumes grown in the area of occurrence were very susceptible, so that CYW is potentially very important. The virus also infected okra (Hibiscus esculentus) and species in the Solanaceae, but none of many species of Cucurbitaceae.

CYW is serologically closely related to cocoa yellow mosaic and kennedya yellow mottle viruses, and more distantly to okra mosaic and desmodium yellow mottle viruses. Other properties of CYW^ typical of the tymoviruses include particle morphology (particle diameter c. 28 nm; two components) with sedimentation coefficients of 50S (top) and 109S (bottom); molecular weight of protein sub‐units c. 20000; thermal inactivation point c. 72 oC; and longevity in vitro c. 3 wk.
Chemical control of onion fly, Delia antiqua
Authors: SAYNOR M. , HILL D. S.
Published: February 2008

In nine trials done in 1972‐4 seed treatments reduced attacks of onion fly larvae very effectively and most of the organophosphorus formulations gave protection up to harvest, 12–17 wk after sowing. Pirimiphos‐ethyl and isofen‐phos each at 10 or 20 g a.i./kg seed controlled onion fly larvae well and they were not seriously phytotoxic in any of the trials. Chlorpyrifos, trichloronate, ethion, iodofenphos, chlorfenvinphos wettable powder or triazophos all at iog a.i./kg seed were also effective, but they were tested in fewer trials. Diazinon at 10 or 20 g a.i./kg seed, carbophenothion and chlorfenvinphos liquid seed dressing at 10 g a.i./kg seed controlled onion fly well, but in some trials they were phytotoxic; methiocarb, mecarphon and oxamyl were much less effective.

At 1–12 kg a.i./ha chlorfenvinphos granules applied over the rows shortly before the attack was expected was the best granular formulation, but it was not as effective as the better seed treatments.
Root and shoot development in peas
Authors: ALI‐KHAN S. T. , SNOAD B.
Published: February 2008

Seven root and shoot characters of young pea (Pisum sativum and Pisum fulvum) seedlings were analysed to study genetic variability and to obtain measures of heritability in the broad sense. Considerable genetic variation was noted in all characters studied in the thirty genotypes with the length of the main root showing the greatest variability. Estimates of heritability exceeding 50 % were noted for the number of laterals, length of shoot, weight of root and weight of shoot. Seed weight was significantly correlated only with length of longest lateral and weight of root. The length of the longest lateral and the length to the last lateral were correlated with most other characters.
Performance of carbendazim formulations injected for the control of Dutch elm disease
Authors: CLIFFORD D. R. , COOKE L. R. , GENDLE P. , HOLGATE M. E.
Published: February 2008

Formulations of carbendazim, containing varying mineral acid concentrations, injected into elm trees were evaluated for their protectant and eradicant activities against Dutch elm disease. Those with high acid contents were the best protectants but none was entirely successful as an eradicant.

The distribution of carbendazim within elm trees was erratic and there was a large fall‐off in available fungitoxicant within the twigs 55–97 days after injection.
Bioassay of residues on Cox's Orange Pippin apples following summer sprays of benomyl
Authors: MURRAY R. A.
Published: February 2008

Bioassay of residues of benomyl applied as orchard sprays has demonstrated the persistence of fungicide on apple fruits. Surface concentrations of fungicide from June applications were 60 % of those from July and August applications; this difference may be related to the relative sizes of fruits and leaves. The harvest residues were low and even after post‐harvest dipping, were well within acceptable levels.
The control of Gloeosporium storage rot of apple by reduced spray programmes
Authors: EDNEY K. L. , BURCHILL R. T. , CHAMBERS D. A.
Published: February 2008

Single sprays of benomyl (0.025 % a.i.) applied to Cox's Orange Pippin apple in either June, July or August, controlled rotting in store by Gloeosporium spp. Post‐harvest dips of either benomyl (0.05 % a.i.) or thiabendazole (0.025 % a.i.) effectively controlled any infection surviving orchard treatment.
Virus‐induced necrosis in white cabbage
Authors: Walkey D. G. A.
Published: February 2008

Turnip mosaic virus was found to be a major cause of internal necrosis in white cabbage. The extent of the disorder in heads in store could be correlated with the severity of virus symptoms on the outer leaves of the plants in the field.
Effects of organomercury treatment of wheat seed on Fusarium seedling disease in inoculated soil
Authors: BATEMAN G. L.
Published: February 2008

In growth room experiments, treatment of wheat seed with phenyl mercuric acetate significantly reduced seedling disease caused by soil‐borne Fusarium culmorum, F. nivale and F. avenaceum in inoculated soil. Seed treatment improved the low germination caused by F. culmorum, but did not affect the reduced seedling vigour caused by F. nivale. Seed treatment was normally as effective in conditions favouring disease as it was in less favourable conditions. Conditions favouring disease in soil inoculated with F. culmorum were high inoculum level, deep sowing and dry soil.
Seed treatment for the control of halo‐blight of beans (Pseudomonas phaseolicola)
Authors: TAYLOR J. D. , DUDLEY C. L.
Published: February 2008

Streptomycin and kasugamycin were applied as soaks, slurries or dusts to dwarf bean seeds either naturally (internally) infected or externally contaminated with Pseudomonas phaseolicola. Slurries of streptomycin (2–5 g a. i./kg seed) or kasugamycin (0–25 g a.i./kg seed) were the most effective treatments against both types of infection and were generally non‐phytotoxic at these rates. Combined analysis of eight field experiments made over a 3 yr period showed that on average both compounds applied in slurries reduced primary infection from infected seeds by 98 %. The method thus shows considerable promise as a commercial control treatment.
The effects of rootstock and scion on tobacco mosaic virus infection in susceptible, tolerant and immune cultivars of tomato
Authors: ARROYO A. , SELMAN I. W.
Published: February 2008

Reciprocal grafts were made between tomato cultivars Potentate, susceptible, and Virocross, tolerant (heterozygous for resistance gene Tm‐i) to tobacco mosaic virus (TMV) isolates of Pelham type o and between isogenic lines of cv. Craigella, susceptible and homozygous for gene Tm‐i. The grafted plants were inoculated with a type o isolate; both scion and stock inoculation were studied in the former, scion inoculation only, in the latter. With scion inoculation the virus content of a tolerant scion was greater on a susceptible stock than on a tolerant one, but that of a susceptible scion was unaffected by the type of stock: in contrast, the virus content of a tolerant stock was unaffected by the type of scion but that of a susceptible stock was less with a tolerant than with a susceptible scion. With root inoculation the virus contents of both tolerant and susceptible scions were greater on a susceptible than on a tolerant stock.

With cv. Craigella the genotype Tm‐1/Tm‐1 was found to be immune to the type o isolate used, but in grafts the leaves of Tm‐1/Tm‐1 scions became tolerant to leaf inoculation when on susceptible stocks and the virus entered the stock. Tm‐1/Tm‐1 stocks became infected when attached to infected, susceptible scions and did not affect the virus content of those scions.

The results indicate that a susceptible healthy stock may change the reaction of a tolerant or immune scion to infection by a strain of TMV.
Some pathological aspects of narcissus basal rot, caused by Fusarium oxysporum f. sp. narcissi
Authors: PRICE D.
Published: February 2008

Excavations of ridge‐grown narcissus showed that most roots were beneath the bulbs and that few extended sideways to the next ridge. Root senescence preceded leaf senescence and moribund roots were available for colonization by Fusarium oxysporum f. 8p. narcissi when soil temperatures became favourable for the pathogen. Inoculation experiments with 1 and 2 yr crops showed that some inoculum is redistributed during the first season to allow increased disease incidence in the second. In 2yr crops, some bulbs rot without trace so that true disease incidence in a stock is greater than is indicated by examination of lifted bulbs.
The development of silver scurf (Helminthosporium solani) disease of potato
Authors: JELLIS G. J. , TAYLOR G. S.
Published: February 2008

The main source of inoculum of Helminthosporium solani was the seed tuber; the fungus was not detected in soils in which infected potatoes had been grown the previous year. Lesions spread rapidly on seed tubers after planting, so that within a few weeks the entire surface was covered. As lesions aged they lost the capacity to sporulate, so most inoculum was produced in the first few weeks after planting. Infection of progeny tubers was first detected at the heel (stolon attachment) end soon after their initiation. Once established, lesions spread slowly on the surface of progeny tubers when in the soil; more rapid spread took place during storage. Potatoes which seemed unaffected at lifting became diseased during storage.
Race non‐specific resistance of oats to primary infection by mildew
Authors: CARVER T. L. W. , CARR A. J. H.
Published: February 2008

A range of oat species, species hybrids and derived addition lines, varied in their level of race non‐specific resistance to mildew. This resistance prevented attempted primary penetration by a proportion of spores. It was generally expressed more strongly in fifth than in first formed leaves and thus appeared to be a component of adult plant resistance. Penetration was most frequently arrested at the infection peg stage, implicating the papilla formed by the host as a defence mechanism. Epidermal cells close to stomata were more commonly invaded than others, but only in two of ten lines examined was preferential stomatal subsidiary cell infection observed. Where penetration was successful, host resistance could operate by arresting infections prior to the establishment of functional host/pathogen relations. In hybrids between resistant wild species and a susceptible cultivated oat, the level of both forms of resistance was reduced, indicating a similar effect of the susceptible host genome on genes conditioning both resistances.
Control of silver scurf (Helminthosporium solani) disease of potato with benomyl and thiabendazole
Authors: JELLIS G. J. , TAYLOR G. S.
Published: February 2008

Benomyl and thiabendazole, applied as dusts to seed potatoes before chitting (sprouting), reduced the incidence of silver scurf disease on the progeny at lifting and during subsequent storage. Treatment of seed tubers 4 months prior to planting almost completely suppressed sporulation during storage, even under conditions very favourable for the growth of the fungus.

The fungicides appeared not to act systemically because developing tubers grown from treated seed were just as susceptible to infection after inoculation as those from untreated. Control was due to effective inhibition of sporulation on the surface of diseased seed tubers after planting.

There was no reduction in the amount of disease in subsequent generations of potato crops without further fungicidal treatment. Seed virtually free from silver scurf, produced from seed treated with fungicide in the previous year, yielded progeny with as much disease as progeny from untreated seed stocks.
Accumulation and metabolism of aldicarb by the free‐living nematodes Aphelenchus avenae and Panagrellus redivivus
Authors: BATTERBY S. , LE PATOUREL G. N. J. , WRIGHT D. J.
Published: February 2008

The accumulation and metabolism of aldicarb has been compared in two species of free‐living soil nematodes, Aphelenchus avenae and Panagrellus redivivus, which differ considerably in their sensitivity to this and other pesticides. Similar levels of aldicarb were found to accumulate in the two species. The results showed that although the rate of uptake of aldicarb was greater in P. redivivus, so also was the rate of metabolism and elimination. Levels of toxic metabolites of aldicarb were two to three times higher in the more susceptible species A. avenae after 24 h incubation than in the less susceptible P. redivivus. The toxicological significance of these findings is discussed in relation to previous work with the organophosphorus pesticide phorate and its effects on the same two nematode species.
Effects of Poa trivialis, Stellaria media and Rumex obtusifolius on the growth of Lolium perenne in the glasshouse
Authors: GIBSON D. I. , COURTNEY A. D.
Published: February 2008

In glasshouse experiments shoot dry weight, leaf area and tiller number of Lolium perenne, cv. S. 24, were compared when grown in monoculture and in competition with Poa trivialis, Stellaria media or Rumex obtusifolius at a range of densities and for different time intervals. The results showed that S. media and R. obtusifolius were more competitive than P. trivialis. Competition effects with S. media and R. obtusifolius appeared between the 4 and 6 wk stage, coinciding with the production of the first S. 24 tillers. Spraying with 2,4‐D (0·84 kg acid equivalent/ha) for control of R. obtusifolius did not decrease grass yield whereas mecoprop (2·80 kg a.e./ha) for control of S. media damaged young L. perenne. It appeared that the optimum time for mecoprop treatment was between 4 and 6 wk after sowing when tillering had commenced. At this stage weed competition was only beginning and crop tolerance to the herbicide was adequate.
Beetle, contact and potato true seed transmission of Andean potato latent virus
Authors: JONES R. A. C. , FRIBOURG C. E.
Published: February 2008

A species of the flea beetle (Epitrix sp.) transmitted Andean potato latent virus (APLV) from Datura stramonium to D. stramonium, Nicandra physalodes and potato, and from N. physalodes to N. physalodes and D. stramonium. Although the acquisition and inoculation feeding times used were varied, this transmission always occurred at low efficiency. By contrast, APLV was very readily transmitted in tests in which infected plants of D. stramonium, N. physalodes, Nicotiana bigelovii and potato were brushed against healthy plants of one or more of these species. A low level of seed transmission of APLV occurred in potato.
Studies on the effect of gamma radiation (from Cobalt 60 source) on storage life of white yam (Dioscorea rotundata var. efon) infected with Scutellonema bradys
Authors: ADESIYAN S. O.
Published: February 2008

Studies on the effect of gamma irradiation on yam tubers infected with Scutellonema bradys showed that dosages between 5 and 15 krad did not eliminate the nematodes completely, but suppressed sprouting and signs of deterioration in the tubers. Dosages between 20 and 30 krad eliminated 70–80 % of the nematode population in yam peels. The appearance and taste of yams treated with between 7·5 and 15 krad were generally acceptable to a panel of tasters.
The effect on grain yield of adult plant resistance to mildew in oats
Authors: JONES I. T.
Published: February 2008

Lines were selected from progeny of the crosses Maldwyn × Milford and Maldwyn × Sun II which consistently exhibited small and large amounts of mildew in similar situations. These are referred to as ‘low’ and ‘high’ mildew lines respectively. In small plot field trials conducted in 1971, 1972 and 1973 the low mildew lines produced substantially more grain each year compared with the high mildew lines in plots where mildew was allowed to develop normally. In plots which were kept comparatively free from infection by spraying with tridemorph, both low and high mildew lines gave similar yield.

When the unsprayed plots were compared with the sprayed plots the low mildew lines invariably showed very small losses in grain yield and the high mildew lines usually very large losses. This same trend was evident also in the parent cultivars in 1972. Maldwyn, with only 7·9% mildew cover in the unsprayed plots due to its resistance, suffered a decrease of only 9·2% in grain yield compared with losses of 17·1 and 20·3% in the more susceptible cultivars Milford and Sun II.

Certain lines and cultivars sustained heavy levels of mildew without corresponding loss of grain yield, i.e. showed low sensitivity to the disease. The importance of combining low sensitivity (or tolerance) with adult plant resistance to mildew is discussed.
Genetic analysis of several traits in potatoes by means of a diallel cross
Authors: KILLICK R. J.
Published: February 2008

Genetic variation for nine traits of importance in potatoes was analysed in a half‐diallel set of crosses with six parents. General combining ability (GCA) effects were responsible for differences in maturity. For the other traits (yield, number of tubers, mean tuber weight, percentages of cracked and diseased tubers, texture and blackening following cooking and specific gravity) special combining ability (SCA) was important. The correlations between the traits were calculated. The implication for breeding is that trial crossing would be necessary to identify progenies with good potential. The analyses revealed associations between traits which are potentially useful to the breeder.
Host plant reactions, physical properties and serology of three isolates of Andean potato latent virus from Peru
Authors: FRIBOURG C. E. , JONES R. A. C. , KOENIG RENATE
Published: February 2008

Three isolates of Andean potato latent virus (APLV) (Caj, Hu, Ay) each infected twenty‐seven species of plants in the families Amaranthaceae, Chenopodiaceae, Cucurbitaceae and Solanaceae but differed somewhat in the symptoms they induced. Nicotiana bigelovii and N. clevelandii proved the most useful diagnostic hosts. Symptoms were sometimes produced by all three isolates in cultivated and wild potatoes. In sap from systemically infected N. bigelovii and N. clevelandii leaves, all three isolates remained infective when diluted to 10‐6 and when stored at room temperature for at least 3 wk. The thermal inactivation points were 65–70 °C for Hu and Ay, but 75–80 °C for Caj. All three isolates differed serologically from Col, the original isolate of APLV, forming spurs in gel diffusion tests. No serological difference was found between Hu and Ay, but both formed spurs in reciprocal reactions with Caj. The data from light absorption, particle morphology and protein molecular weight for Caj, Hu and Ay are similar to those reported for other tymoviruses. APLV was found widespread in Andean countries.
Effect of annual and perennial cropping regimes in microplots on the population density and vertical distribution of Xiphinema diversicaudatum and on soil porosity
Authors: COTTON J.
Published: February 2008

Long‐term trends in populations of Xiphinema diversicaudatum were measured in two microplot experiments in which annual and perennial crops of seven plant families were grown in monoculture.

Numbers of X. diversicaudatum increased under perennial ryegrass, raspberry and strawberry but decreased under hop, spring barley, potato, sugar beet, cabbage, winter wheat and winter beans; these effects probably reflected differences in the inherent host status of the crops. There were fewer X. diversicaudatum at 40–60 cm below annual crops than below perennial crops, and there were differences between perennial crops in nematode vertical distribution.

Soil pore space did not limit nematode population density; total pore space was uniformly large under all crops and there was no detectable instability to water slaking. Under ryegrass a greater proportion of soil volume was occupied by pores too small to accommodate X. diversicaudatum, but since ryegrass supported the second largest nematode population, it seems unlikely that this was seriously limiting.
The long‐term effects of four monocultural regimes on two field populations of the nematodes Xiphinema diversicaudatum and Longidorus spp.
Authors: McNAMARA D. G. , PITCHER R. S.
Published: February 2008

Population density changes of Xiphinema diversicaudatum and several Longidorus spp. were observed under four cultural regimes in long‐term field experiments. Numbers of X. diversicaudatum increased under strawberry and, to a lesser extent, ryegrass, but remained more or less unchanged in hop and fallow plots. A mixture of four Longidorus spp. increased in numbers under grass but stayed static, or declined slowly under the other cultural regimes.

All changes in population density were slow to occur, taking 3 or 4 yr for differences to become statistically significant. Fluctuations in larval numbers were mainly responsible for overall population changes; numbers of adults showed little difference over 5 yr.
Studies on plant growth‐regulating substances XLVII. Ultrastructural studies on emergent leaves of Avena sativa treated with 3,5‐(diiodo and dibromo)‐4‐hydroxyphenylmethylsulphone
Authors: SARMA R. , FLOOD A. E. , WAIN R. L.
Published: February 2008

Treatment of oat plants with the pre‐emergence herbicides ioxysone and bromoxysone leads to the production of albino leaves. Ultrastructural studies have indicated that this effect is associated with lipid‐like material outside the chloroplasts which themselves are in a proplastid state. The significance of these observations is discussed in terms of the possible mode of action of these chemicals.
Relationships, host‐ranges and symptoms of some isolates of phleum mottle virus
Authors: CATHERALL P. L. , CHAMBERLAIN JUDITH A.
Published: February 2008

Eleven isolates of phleum mottle virus, each from a different grass species, were grouped into five distinct strains: phleum mottle (PM), holcus transitory mottle (HTM), festuca mottle (FM), cocksfoot mild mosaic (CMM) and brome stem‐leaf mottle (BSM). Their interrelationship was expressed three‐dimensionally using serological differentiation indices.

When 105 species of Gramineae were inoculated with each strain, eighty‐one in forty genera became infected. These included festucoid, chloridoid, panicoid and andropogonoid species. Electron microscopy was more reliable than back‐inoculation for detecting infection in plants that remained symptomless. Annual species were usually more severely affected than perennials. PM, HTM, FM, CMM and BSM did not appear to differ in host range, but sometimes differed in the symptoms induced in a given host. Each was symptomless in some hosts, caused a mild or severe mottle in others and mottling plus necrosis in a few. HTM was symptomless in most, and BSM in fewest species: BSM caused necrosis in most and HTM in fewest hosts.
Changes in the oxygen consumption of cysts of Globodera rostochiensis associated with the hatching of juveniles
Authors: ATKINSON H. J. , BALLANTYNE A. J.
Published: February 2008

The oxygen consumption of single cysts (90–110 /tg dry wt) was measured with an oxygen electrode microrespirometer. The mean oxygen consumption of nine cysts after 7 days in tap‐water, was 0–48 + 0–05 mm3 02 mg dry wt‐1 h‐1. After transfer to potato root diffusate for 1 day the mean oxygen consumption of the same cysts showed a significant increase to 159±7% of the rate recorded before they were removed from water. After 3 and 7 days in diffusate the corresponding means were 131±9% and 127±12% respectively. Cysts that remained in water throughout the experiments did not show any significant change in their oxygen consumption from the rate recorded after 7 days. The initial increase in oxygen uptake after the addition of diffusate was shown not to be due to the presence of microorganisms.

Comparison of hatching data with the changes in oxygen consumption of similar cysts after 24 h in diffusate suggests that the increased oxygen uptake cannot be attributed solely to locomotor activity of the juveniles during the hatching process. The increased rate of respiration may precede other known changes that follow after the juveniles within a cyst are stimulated to hatch.
Changes in the adenine nucleotide content of cysts of Globodera rostochiensis associated with the hatching of juveniles
Authors: ATKINSON H. J. , BALLANTYNE A. J.
Published: February 2008

The content of AMP, ADP and ATP within single cysts of Globodera rostochiensis (60–80 fig dry weight) was determined as ATP to an accuracy of ± 10‐11 mol by a bioluminescent technique, after microenzymic methods had been used to phosphorylate AMP and ADP to ATP.

Results for a total of 120 cysts showed that a change occurs in the adenylate energy charge of their contents after they have been exposed to potato root diffusate. Cysts in water had a mean adenylate energy charge of 0–63 (s.E. ± 0–04), but a randomly selected group of cysts after 24 h treatment with potato root diffusate had a significantly lower mean of 0–49±0–04. In a second, similar experiment, cysts in diffusate for only 8 h had an energy charge of 0*55 ± 0–03, but this value was not significantly less than the corresponding mean of o‐6i ±0–03 of cysts that remained in water.

The results indicate an effect on the metabolism of the unhatched juveniles that occurs too soon after the addition of diffusate to be directly due to any increase in locomotor activity. Apparently, the primary action of the hatching factor had affected many juveniles within 24 h of the addition of potato root diffusate to the cyst.
The effect of partial defoliation on yield of sugar beet
Authors: FRENCH S. A. W. , HUMPHRIES E. C.
Published: February 2008

Sugar‐beet plants were defoliated during growth in seven experiments from 1968 to 1974 either (1) by removing each leaf as it became fully expanded or (2) by removing with scissors as soon as possible all leaves except certain groups up to leaf50, but mainly 6 to20, or (3) by treating the growing point chemically or mechanically in an attempt to stop the production of leaves after the twentieth.

Removing mature leaves decreased yields considerably, but removing all leaves except 6–20 did not decrease significantly total dry matter yield of the whole plant and in one experiment increased it by 7% and root weight by 15%. Remaining leaves had a greater photosynthetic efficiency as measured by growth analysis and a 14C02 feeding technique because they were less shaded or there was reduced competition for some nutrient or essential growth component.

Additional leaves formed beyond the twentieth resulted in a proportionately lower photosynthetic efficiency of all leaves, but attempts to treat the plant to stop production of new leaves beyond the twentieth were inconclusive.
Host‐ranges of cocksfoot mottle and cynosurus mottle viruses
Authors: CATHERALL P. L. , ANDREWS P. A. , CHAMBERLAIN J. A.
Published: February 2008

Cocksfoot mottle virus (CfMV) and cynosurus mottle virus (CyMV) had similar, but not identical, host‐ranges within the Gramineae. Each infected fifteen out of forty‐one species tested, considerably fewer than phleum mottle virus (PMV), but unlike PMV both infected Triticum aestivum (wheat), causing a lethal mottle. The species most useful for differentiating CfMV, CyMV and PMV are listed. Some species appear especially susceptible to virus infection.
Control of clubroot by soil partial sterilization with particular reference to the treatment of small natural foci of infection
Authors: WHITE J. G. , BUCZACKI S. T.
Published: February 2008

Experiments were made on field plots with four soil partial sterilants applied at different dose rates or as combination treatments. The effects of treatments on clubroot were assessed by growing cabbages on the field plots or in a glasshouse in soil removed from the plots. In two experiments, no plants grown on plots or seedlings grown in soil samples from plots treated with Dowfume M.C.2 or Telone were infected with clubroot, whilst only one infected seedling was found in soil samples from those plots treated with chloropicrin. Although relatively few infected plants were recovered from Basamid treated plots, many infected seedlings were found in soil samples from those plots. The effectiveness of these treatments as indicated by seedling survival was Dowfume M.C.2 < chloropicrin < Telone < Basamid. At five sites a combination of Dowfume M.C.2 at 98 g/m2 with 40 g/m2 Basamid resulted in all cabbage seedlings grown in soil samples being disease free.
The effect of Benlate and cytokinins on the content of tobacco mosaic virus in tomato leaf disks and cucumber mosaic virus in cucumber cotyledon disks and seedlings
Authors: BAILISS K. W. , COCKER F. M. , CASSELLS A. C.
Published: February 2008

Tomato leaf disks were inoculated with tobacco mosaic virus (TMV) and floated for 7 days on solutions of kinetin and benzyladenine in the range 20‐0‐002 mg/1. Virus content was reduced at the higher and increased at the lower concentrations. Benlate and benomyl showed a peak of cytokinin activity in the Amaranthus betacyanin bioassay equivalent to c. 0–002 fig/l kinetin. At concentrations above 25 and 100 mg a.i./l for Benlate and benomyl respectively, both compounds increased the TMV content of tomato leaf disks.

Cucumber mosaic virus (CMV) content in cucumber cotyledon disks was increased by Benlate and benomyl treatment (50–100 mg/1). Applied as a soil drench (50–500 mg a.i./l) when the plants were inoculated, Benlate increased the CMV content of infected seedlings. The number of starch‐iodide lesions (a measure of susceptibility) was unaltered in cotyledons treated with Benlate 7 days before or immediately after inoculation. Infectivity of crude infective cucumber sap was unaffected by benomyl incorporation, whereas Benlate reduced infectivity at higher concentrations (1000–5000 mg/1).

Under the experimental conditions described, Benlate, benomyl, benzyladenine and kinetin had no effect on the chlorophyll content of tomato leaf disks, and intact seedlings.
Regeneration from rhizome fragments of Agropyron repens
Authors: LEAKEY R. R. B. , CHANCELLOR R. J. , VINCE‐PRUE D.
Published: February 2008

Single‐node rhizome fragments from four swards of Agropyron repens were grown without added nutrients in Perspex growth‐boxes in the dark. Mean values for shoot length; shoot, root and rhizome dry weights; soluble sugar, starch, soluble nitrogen and total nitrogen contents were determined monthly, and the occurrence of ‘late spring dormancy’ noted. Regenerative capacity was greatest in winter and least in summer and often could be related to the rhizomes' total nitrogen content, as there was a correlation between total nitrogen content and shoot dry weight throughout the year. The amount of gibberellic acid in i‐yr‐old rhizomes was less than o‐i figjg in April and June, the months with the two extremes of regenerative capacity.
Regeneration from rhizome fragments of Agropyron repens
Authors: LEAKEY R. R. B. , CHANCELLOR R. J. , VINCE‐PRUE D.
Published: February 2008

Experiments were done with rhizome fragments of Agropyron repens with or without ‘late spring dormancy’. Increasing concentrations of KN03 from 1 to 210 ppm successively increased the percentage of buds released from dormancy, but the restriction of shoot extension was significantly lessened only when concentrations of nitrogen were 50 ppm or more. Solutions of sodium nitrite, ammonium chloride and glutamic acid with equal nitrogen contents were equally effective in releasing buds from dormancy. Larger amounts of nitrogen were required to stimulate growth in basal buds, than in apical buds. GA3, and chilling at – 2 oC slightly increased the percentage of buds growing but did not significantly affect the amount of extension growth, while ethephon (2‐chloroethylphosphonic acid) had no effect. The restoration of regenerative capacity was associated with increased utilization of rhizome sugars.

In single‐node rhizome fragments with ‘late spring dormancy’, chilling for 2 wk slightly increased the regenerative capacity but chilling for longer periods decreased it, possibly because respiration during the protracted period of chilling depleted rhizome reserves. Chilling also increased the utilization of rhizome carbohydrates during subsequent growth. Node position affected regenerative capacity: buds from the apical end of the rhizomes were found to have the highest regenerative capacity, this being associated with their greater nitrogen content.

Because the name ‘late spring dormancy’ seems to be inappropriate for this phenomena, the term ‘Restricted Regenerative Capacity’ is proposed.
The relative hardening of roots and shoots and the influence of day‐length during hardening in perennial ryegrass
Authors: LAIDLAW A. S. , BERRIE A. M. M.
Published: February 2008

The influence of long and short days during the hardening period on the cold hardiness of perennial ryegrass seedlings was studied as was the relative hardiness of roots and shoots. Hardiness was assessed by the electrolyte release method which was a measure of the amount of damage subsequent to low temperature treatment.

Long days promoted hardiness in shoots of Pax 0tofte plants and in one case under short days the roots were found to be hardy. Generally roots were less hardy than shoots in Pax 0tofte and S23 plants hardened under long days for 2 wk. When hardened at the fourth leaf stage for 2 wk at + 5 oC under long day conditions, Pax 0tofte plants were more hardy than those of S23.

The long day effect on hardiness was arrived at more rapidly, there being no difference in hardiness after 3 wk in Pax 0tofte hardened under long or short days, whereas a significant degree of hardening was observed after 1 wk of hardening under long days at – 4 oC.

The results obtained are discussed in relation to winter kill of grasses in the West of Scotland, and it is considered that root damage is not an important factor in causing winter kill. The promotive effect of long days on hardiness when hardening commences in late autumn is considered an advantage in temperate regions as it may also allow early frosts to be withstood.
A comparison of the effects of a new quaternary ammonium growth retardant with those of other growth retarding chemicals on the pot chrysanthemum (Chrysanthemum morifolium)
Authors: MENHENETT ROGER
Published: February 2008

A new quaternary ammonium growth retardant, i‐allyl‐i‐(3,7‐dimethyl‐octyl)‐piperidinium bromide (ADOPB), was compared with daminozide, ancymidol and chlorphonium chloride for its effectiveness in reducing lateral stem length in the pot chrysanthemum (Chrysanthemum morifolium). Single foliar sprays of ADOPB applied at 100 to 250 ppm active ingredient (a.i.) gave excellent height control without phytotoxicity in cv. Bright Golden Anne throughout the year. Similar results were obtained in two trials with cvs Purple Anne and Regal Anne. As much as 10 to 50 times this concentration of daminozide was required to achieve a similar degree of height control. However, under summer conditions even high concentrations of daminozide did not adequately reduce stem length. Foliar sprays of ancymidol (50–100 ppm a.i.) also gave good control of stem length but this chemical was more effective when applied as a compost drench. Compost drenches of ADOPB reduced stem extension but a greater quantity of a.i. was required compared to a foliar spray. Foliar sprays of dikegulac‐sodium (100 to 5000 ppm a.i.) were very phytotoxic. Reductions in thelength of lateral stems were associated with marked decreases in their fresh and dry weights.

Growth retardants delay the flowering of pot chrysanthemums by inducing a slower rate of flower bud development. Foliar sprays of ADOPB generally delayed flowering by 2–3 days more than did sprays of daminozide, but this was comparable with that associated with the use of compost drenches of chlorphonium chloride. High concentrations of all the retardants reduced the diameter of open flowers. Only daminozide caused a loss of flower colour in cv. Regal Anne.

The results are discussed in relation to the mode of action of growth retardants, with particular reference to the effects of gibberellins on stem extension and flower development in the chrysanthemum.
Economics of forecasting for chemical control of the black bean aphid, Aphis fabae, on the field bean, Vicia faba
Authors: CAMMELL M. E. , WAY M. J.
Published: February 2008

The economics of a forecasting scheme for predicting the need for chemical control of the black bean aphid, Aphis fabae, on spring‐sown field beans, Vicia faba, are compared with alternative control strategies, namely no treatment, eradicant treatment and routine preventive treatment. Two criteria are assessed. First, the ‘risk’ of lost revenue from wrong control decisions and, secondly, the overall profitability of the strategy. A wrong decision is made when a profitable treatment is not applied or when an unprofitable one is applied. These constitute ‘risk’ for the grower. The forecasting scheme involves least risk of monetary loss and the most acceptable alternative strategy is the routine preventive treatment. Relative to the routine treatment, a gain averaging £3.78/ha of bean crop would have been made between the years 1970‐5 by adopting control based on the forecasting scheme.

There was considerable year‐by‐year and area‐to‐area variation in monetary benefits, with the largest gains in areas where economic damage occurred least frequently and where relatively large areas of beans are grown, as in East Anglia. Other benefits of using the forecasting scheme, e.g. correct timing of chemical application, are discussed but not evaluated.
Chemical control of the cabbage stem flea beetle, Psy Modes chrysocephala, on winter oil‐seed rape
Authors: ALFORD D. V.
Published: February 2008

In East Anglia, from 1974 to 1976, field experiments were carried out on the chemical control of the cabbage stem flea beetle (PsyModes chrysocephala). Carbofuran, 5% granules, proved an outstanding autumn preventive and mid‐winter eradicant treatment under both wet and dry conditions, with 1–5‐2‐24 kg a.i./ha giving virtually 100% control of larvae. Fonofos and phorate granules at 2–24 kg a.i./ha were also effective. AC 92 100 and thiofanox granules were less extensively tested but both gave good control of P. chrysocephala. Several materials showed little or no activity against the pest. The effective preventive granule treatments were all superior to a standard spray of gamma‐HCH.
Extraction of sawfly cocoons from samples of soil and surface litter
Authors: JUKES M. R.
Published: February 2008

A non‐destructive, wet technique to extract sawfly cocoons from a variety of soil and surface litter types is described. The system, involving a pair of tilting, curved sieves was originally developed to extract cocoons of the European spruce sawfly (Gilpinia hercyniae).
The infection of apples by Phytophthora syringae
Authors: EDNEY K. L.
Published: February 2008

Contamination with infected soil has led to high wastage of apples in storage due to rotting by Phytophthora syringae. At 3‐3 oC lesions formed 3–4 wk after inoculation with zoospores; the percentage infection fell if the suspensions dried after 48 h at this temperature and after 22 h at 15 oC. Infected soil rotted fruit only if kept moist; at 3‐3 oC a 3‐day period of wetness resulted in 37‐5% rotting after 8 wk. Fruit dipped in soil slurry remained wet in some parts of a 4361(12 bushel) bin for at least 3 wk. There was a 10‐fold increase in rotting by contact between sound and rotting fruit after 11 wk at 3‐3 oC. Captan gave effective protection against rotting derived from zoospores or infected soil; it had no eradicant action.
The effect of harvest date and duration of wound healing conditions on the susceptibility of damaged potato tubers to infection by Phoma exigua (gangrene)
Authors: ADAMS M. J. , GRIFFITH R. L.
Published: February 2008

In experiments extending over 3 yr, King Edward tubers harvested on various dates from early September until early November were uniformly wounded and kept at 15 oC and c. 95% r.h. for periods of up to 21 days for wounds to cure. When tubers were subsequently inoculated with Phoma exigua var.foveata and incubated at 5 oC for 12 wk, curing for 3 and 7 days decreased gangrene incidence to respectively c. 13 and 4% of the non‐cured controls. When tubers were inoculated before curing and immediately after wounding, curing for 7 days decreased gangrene incidence to only c. 68% of the non‐cured controls. Curing was also progressively less effective the later the date of harvesting, suggesting that there would be advantages in harvesting potato crops early in the autumn.
Investigations on fungicides. XX. The fungitoxicity of analogues of the phy toalexin 2‐(2‘ ‐methoxy‐4’ ‐hydroxyphenyl)‐6‐methoxybenzofuran(vignafuran)
Authors: CARTER G. A. , CHAMBERLAIN K. , WAIN R. L.
Published: February 2008

A series of hydroxy‐and methoxy‐2‐phenyl benzofurans, structurally related to the phytoalexin vignafuran, have been synthesised and their antifungal activity assessed both as inhibitors of spore germination in vitro and as protective foliar sprays against three pathogens. All fungitoxic compounds have a hydroxy group in the molecule although most di‐ and tri‐hydroxy compounds were inactive. Methoxy compounds were inactive but substituting methoxy groups into the molecule of monohydroxy compounds sometimes enhanced their fungitoxicity. No close correlation was established between antifungal activity and either Hansen n values or the n.m.r. chemical shift of the phenolic protons.
Tomato pith necrosis caused by Pseudomonas corrugata n. sp.
Authors: SCARLETT CAROLINE M. , FLETCHER J. T. , ROBERTS PAULINE , LELLIOTT R. A.
Published: February 2008

A disease of mature tomato plants is described, the symptoms of which include brown discoloration and/or necrosis and collapse of the pith. These are sometimes accompanied by vascular browning, external dark brown to black stem lesions, bacterial flux from stem wounds and adventitious root formation. The disease, which appears to be favoured by high humidity and/or free water on the plant surfaces and by high N fertiliser, has been widespread on many glasshouse holdings in England since 1971 but has caused severe loss on only a few. It is thought to be caused by a new species of the genus Pseudomonas for which the name P. corrugata Roberts and Scarlett is proposed.
Early warning of egg hatching in pea moth (Cydia nigricana)
Authors: LEWIS T. , STURGEON DOLORES M.
Published: February 2008

Female pea moths (Cydia nigricana) kept at 23 oC began to lay eggs 2–3 days after emergence, lived for 16–21 days and laid on average 71 eggs. Individuals kept in field cages lived for slightly longer and laid on average 91 eggs. About 85% of eggs were laid during the first 11 days of the oviposition period, usually in the late afternoon and early evening.

The relationship between the rate of egg development and temperature was defined. The estimated developmental zero was 9‐4 oC at constant temperatures and 8‐5 oC at fluctuating temperatures. Above 28 oC mortality increased and above 31 oC development was apparently retarded. Development at constant temperatures took 6–16% longer than at fluctuating temperatures with the same mean.

Estimates of hatching dates in the field made from temperature data recorded at several sites in and near a pea crop, and 8 km distant, were usually within a day of the observed date. In warm weather, estimated and observed dates usually coincided; in cooler weather hatching was 2–3 days later than expected. Hatching dates predicted from temperature data after only 80% of development had occurred were correct on 28 out of 36 occasions.

An example is given to show how the method could be used eventually with a sex attractant trapping system to provide early warning of first hatching and spraying dates.
Occurrence of Phialophora radicicola var. graminicola and Gaeumannomyces graminis var. tritici on roots of wheat in field crops
Authors: SLOPE D. B. , SALT G. A. , BROOM E. W. , GUTTERIDGE R. J.
Published: February 2008

Assessments of Phialophora radicicola var. graminicola (PRG) and Gaeumannomyces graminis var. tritici (GGT) were made by culturing and by direct microscopic examination of pieces of seminal roots from 16 winter wheat crops grown in different cropping sequences and with different phosphate manuring. PRG occurred on all wheat crops, but was abundant only on wheat after grass, where it seemed to delay the onset of damaging take‐all by 1 yr. Delayed occurrence of take‐all by phosphate fertiliser was not related to differences in populations of PRG. Wheat grown in ‘take‐all decline’ soils had only small amounts of PRG, indicating that the development and the decline of take‐all epidemics may be influenced by different biological control mechanisms; breaking sequences of wheat crops by 1 yr grass leys might harness the advantages of both mechanisms.
Thermal inactivation of cherry leaf roll virus in tissue cultures of Nicotiana rustica raised from seeds and meristem‐tips
Authors: COOPER VALERIE C. , WALKEY D. G. A.
Published: February 2008

Nicotiana rustica tissue cultures derived from seeds or embryos infected with cherry leaf roll virus (CLRV), remained infected after culture at 22 oC. No infectivity was found in cultures held at 32 oC for 5 days but it was readily detected after such cultures were transferred to 25 oC for 8 days. Virus was permanently eradicated from most plants after 20 days incubation at 32 oC and from all plants after 7 days incubation at 40 oC.

Partially purified preparations of CLRV lost infectivity after 9–12 days at 22oC, 5 days at 32oC and 3 days at 40oC.