bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of treatment with phenylthiosemicarbazide and 4‘‐chlorophenylthiosemicarbazide on Fusarium wilt of pea and tomato plants
Authors: FUCHS A. , HOMANS A. L. , VRIES F. W. de 
Published: February 2008

SUMMARYEffects of treatment with phenylthiosemicarbazide (PTS) and its 4′‐chloro‐derivative (4′‐chloro‐PTS) on Fusarium wilt of pea and tomato plants were investigated. Depending on pH and availability of oxygen, PTS and 4′‐chloro‐PTS are converted to their corresponding phenylazothioformamides and phenylazothioformamide‐S‐oxides, which are the actual fungitoxic compounds. PTS and 4′‐chloro‐PTS were shown to inhibit growth of Fusarium oxysporum f. pisi and F. oxysporum f. lycopersici in liquid media as well as on agar plates at concentrations of 50–100 mg/1. Inhibition was greater at pH 7 than at pH 5. When administered to pea and tomato plants, both compounds caused severe phytotoxic effects, especially at temperatures favouring Fusarium wilt, thus almost entirely obscuring any protective activity against the diseases. All compounds were strongly adsorbed to loam, but readily released from sand. Neither in pea nor in tomato plants were PTS and 4′‐chloro‐PTS converted to any fungitoxic substance, not already present in the aqueous solutions administered.
Water deficit in potato plants infected with Verticillium albo‐atrum
Authors: HARRISON J. A. C. 
Published: February 2008

SUMMARYPotato plants infected with Verticillium albo‐atrum, whether they showed disease symptoms or not, invariably had a lower leaf water content than healthy plants. This water content fell throughout the growing season as the disease progressed and showed greater diurnal fluctuations than in healthy plants. Wilting appeared in diseased plants when a water saturation deficit of c. 20% was attained, but in healthy plants occurred at marginally lower deficits. The acropetal development of wilting symptoms was reflected in the gradient of water deficits along the main axis of the plant.Deficits of 10–28%, which commonly occurred in infected plants grown both in pots and in the field, would suggest that these plants are experiencing internal water stress throughout much of the season, and consequently may have reduced rates of photosynthesis.
3,5‐Dichlorophenoxyacetic acid as a growth retardant
Authors: SMITH MARGARET S. , MOHSIN MOHAMMED 
Published: February 2008

SUMMARYTomato seedlings, grown in the glasshouse, were sprayed with solutions of 3,5‐dichlorophenoxyacetic acid as sodium salt at 2 times 10‐5, 4 times 10‐5 and 10‐4 M. The treated plants became dark‐green, dwarfed, and compact. After 6–7 weeks normal growth was resumed. Measurements and analytical data on treated and control plants are presented.
Saprophytic behaviour of Cephalosporium maydis and C. acremonium
Authors: SABET K. A. , SAMRA A. S. , MANSOUR I. M. 
Published: February 2008

SUMMARYThe competitive saprophytic ability (CSA) of Cephalasporium maydis was smaller at 30 d̀C when measured by the agar‐plate modification than by the original Cambridge method. The agar‐plate method suggested that C. maydis was a less competitive saprophyte than C. acremonium although both were low in CSA. C. acremonium grows and sporulates well on organic and synthetic media. C. maydis grows faster but is more exacting nutritionally and is less able to decompose cellulose or maize straw than C. acremonium. Neither fungus produced pectolytic culture filtrates and both were susceptible to antibiotics produced by soil micro‐organisms. C. maydis survived on maize straw much longer than C. acremonium. In field soils C. maydis colonized and survived in supplemented wheat bran poorly and not below the top 20 cm of soil.
Barley segregates resistant and susceptible to the cereal cyst‐nematode (Heterodera avenae Woll.)
Authors: WILLIAMS T. D. 
Published: February 2008

SUMMARYIn the first year of this experiment both nematode‐resistant and susceptible segregates of spring barley were equally invaded by Heterodera avenae larvae, but few females developed in the roots of the resistant plants and numbers of eggs in the soil were fewer after the resistant crop. In the second year, a commercial, nematode‐susceptible barley crop yielded significantly more grain following the resistant segregate. The resistant segregate, derived from Hordeum pallidum var 191, suppresses the development of Heterodera avenae pathotypes 1 and 2 [British nomenclature] and should be useful in areas where these pathotypes predominate.
Grain yield and incidence of take‐all (Ophiobolus graminis Sacc.) in wheat grown in different crop sequences
Authors: SLOPE D. B. , ETHERIDGE JUDITH 
Published: February 2008

SUMMARYThe yield of wheat and the incidence of take‐all were measured in crops grown in six different 4‐year sequences, repeated in 3 successive years. The first crop of winter wheat grown after oats or beans yielded 13–23 cwt/acre (1632–2887 kg/ha) more grain than wheat after wheat or barley. Spring wheat after oats yielded 2–5 cwt/acre (250–625 kg/ha) more than spring wheat after wheat. The smaller yields of wheat after wheat or barley were caused mostly by greater prevalence of take‐all. Regression analysis indicates that each 1 % increase in straws with take‐all decreased yield of winter wheat by 0·6%. Take‐all was more prevalent in the second and third successive wheat crops after oats than in the fourth crop.
Perennation of Alternaria longipes and the early stages of its development on tobacco
Authors: NORSE D. , WHEELER B. E. J. 
Published: February 2008

SUMMARY Alternaria longipes (Ell. &Ev.) Mason survived on autoclaved maize stems for 6 months without losing its pathogenicity, but rapidly lost viability on non‐autoclaved stems and could not be re‐isolated 4 months after inoculation. In laboratory tests it infected both living and dead maize leaves. Some Alternaria isolates from non‐solanaceous hosts infected tobacco leaves kept at high humidities for 10 days after inoculation, but not when this incubation period was reduced to 48 h. In the field, perennation on plants other than tobacco is unlikely to be important as a source of inoculum. Pathogenicity of Alternaria isolates was maintained from one season to the next when stored as conidia in sterile soil, or as dried, infected tobacco leaves; some isolates maintained on agar slopes under oil were still pathogenic after 5 years. Alternaria conidia collected from the surface of tobacco seedlings, and isolates from apparently healthy seedling leaves were pathogenic to mature tobacco. In the field conidia were detected on tobacco leaves soon after these emerged, and epiphytic colonies were occasionally found well in advance of symptoms. Many latent infections were also detected up to 5 weeks in advance of symptoms. Visual development of latent infections closely coincided with the end of leaf expansion.
Control of coffee berry disease*
Authors: GRIFFITHS ELLIS , GIBBS J. N. , WALLER J. M. 
Published: February 2008

SUMMARYField experiments comparing six spraying programmes and two fungicides for control of coffee berry disease were carried out at three sites during 1968. These established that protection of the crop by sprays applied throughout the long rains (February–July) gave the best control and increased yields threefold. Early season spray programmes, which reduced the sporulating capacity of the pathogen in coffee twigs, but which ceased before the end of the rainy season, gave no disease control in the late crop (harvested October‐December) and yields were less than in unsprayed controls. All programmes which gave protection at the onset of the rains gave some disease control in the early crop (harvested June‐August). Captafol (‘Ortho‐Difolatan’ 80 WP) was better than a 50% copper formulation (‘Perenox’).Conditions suitable for infection, as determined from meteorological records, occurred frequently during both rainy seasons. Estimates of sporulating capacity and data from spore trappings showed that although inoculum from the bark might initiate an epidemic, subsequent disease progress was more dependent upon spores derived from diseased berries; these accounted for most of the inoculum dispersed during the greater part of the season. Removal of the early crop, which was very small, had no detectable effect on disease in the late crop.Although losses were greatest with early season spray programmes, these did nevertheless delay the onset of the epidemic. However, the subsequent rate of disease increase was greatest and ‘scab’ lesion formation least in these treatments. ‘Scab’ lesions were most abundant in those treatments which caused least delay; in unsprayed coffee, it appeared that early exposure to infection resulted in ‘scab’ lesion formation which subsequently retarded the rate of disease progress. Tree height was positively correlated with disease incidence, but there was little effect of tree aspect. Crop density had a small effect on disease incidence within branches.
Effect of altitude on the distribution of the fungus causing coffee berry disease in Kenya*
Authors: MULINGE S. K. 
Published: February 2008

SUMMARYInvestigations in 1968 and 1969 showed that the relative abundance of the four main strains of Colletotrichum coffeanum (CBD, ccp, cca and cent (Gibbs, 1969)) in the bark of coffee trees varied with altitude. The CBD and ccp strains increased substantially with altitude; the cca strain also increased but to a smaller extent. The cent strain decreased with increasing altitude.It is considered that the greater abundance of the CBD strain at the higher altitudes contributes to the greater severity of coffee berry disease at these locations.
Comparison of fungicides for control of leaf spot (Septoria apiicola) of celery
Authors: RYAN E. W. , KAVANAGH T. 
Published: February 2008

SUMMARYOf twenty‐one fungicides tested at recommended rates of application for their effectiveness in controlling leaf spot of celery grown in Ireland on peat and on a clay‐loam soil, three formulations containing fentin acetate with maneb and formulations of fentin hydroxide and fentin chloride were most effective. Benomyl was superior to the other non‐tin fungicides tested and, at moderate disease levels, it resulted in marketable yields of celery equal to those recorded after treatment with the organotin compounds. Generally, the organotin compounds and benomyl were followed in descending order of effectiveness by copper oxychloride, captafol, Daconil 2787 and maneb. None of the fungicides tested in the three seasons caused visible symptoms of phytotoxicity and, on disease‐free celery in 1969, none had a significant effect on yield.
A side effect of chlorthiamid and dichlobenil herbicides
Authors: LEACH R. W. A. , BIDDINGTON N. L. , VERLOOP A. , NIMMO W. B. 
Published: February 2008

SUMMARY2,6‐Dichlorobenzamide (BAM) induced leaf margin chlorosis (LMC) on the leaves of kale seedlings and apple trees when applied to the roots. The leaf symptoms were similar to those sometimes seen after use of the herbicides chlorthiamid and dichlobenil. BAM was deposited mainly in the margin of the leaf to which BAM was transported via the transpiration stream. BAM appeared to be the causative agent of chlorosis although hydroxy derivatives of BAM were also present in the leaf. Factors possibly responsible for the variations in the occurrence and in the intensity of LMC are discussed.
Spore discharge in Entomophthora grylli
Authors: PADY S. M. , KRAMER C. L. , LONG D. L. , McBRIDE T. D. 
Published: February 2008

SUMMARY Entomophthora grylli Fres. has been found on larvae of Bradysia (Sciaridae, Diptera) on wood in Kansas State University greenhouses since November 1967. Infected larvae crawled to an exposed site in the night and by morning spores of E. grylli were being discharged. In the greenhouse and under controlled environments spore discharge showed a marked periodicity; spore discharge occurred in the light with peaks in the first 1–4 h; discharge then gradually declined but extended into the dark. On the second and third days peaks occurred in the light but were progressively smaller. In a greenhouse under fluctuating conditions twin peaks occurred at 10·00 and 22·00; in a growth chamber, at constant 21° C. 90% r.h., alternating 12 h light and dark periods, spore discharge was similar, with maximum numbers about 21/2 h after the onset of the photo‐period. In continuous dark and continuous light no endogenous pattern was evident. Temperature range for spore discharge was 2–28·, with optimum at 15·. Decreasing humidities resulted in decreased spore production and cessation of discharge below 40% r.h.
Some factors affecting the relative ability of two strains of Puccinia graminis tritici to survive when mixed
Authors: OGLE HELEN J. , BROWN J. F. 
Published: February 2008

SUMMARYThe process of infection by strains 21 Anz‐2, 7 and 21 Anz‐2, 3, 7 of Puccinia graminis tritici was quantitatively investigated to determine whether differences existed between them at any stage of the infection process and whether any such differences were related to the relative survival ability of the two strains in mixtures. The frequency of urediospore germination, the frequency of formation of appressoria, the period between inoculation and the eruption of uredia, the proportion of infection courts developing into uredia, and the visible characteristics of the uredia, did not differ between the two strains. However, penetration occurred more frequently from appressoria of strain 21 Anz‐2, 3, 7 than from those of strain 21 Anz‐2, 7. Uredia of strain 21 Anz‐2,3, 7 increased more rapidly in size than did those of 21 Anz‐2,7 and were ultimately larger in area. Similarly, more urediospores were produced per uredium by strain 21 Anz‐2, 3, 7 than by 21 Anz‐2, 7. It is suggested that these differences in frequency of penetration and in number of urediospores per uredium could account, at least in part, for the difference in relative survival ability between the two strains.
Influence of weed hosts on the ecology of Verticillium dahliae in newly cultivated areas of the Namoi Valley, New South Wales
Authors: EVANS G. 
Published: February 2008

SUMMARYThe evidence suggests that Verticillium dahliae is not indigenous to the Namoi Valley, but was introduced, probably in weed seed, and then increased on the natural dicotylendonous weeds, from which it spread to introduced crops such as cotton. V. dahliae could have been introduced and disseminated as microsclerotia, which are plentiful in the woody fruits of noogoora burr (Xanthium pungens) and Bathurst burr (Xanthium spinosuni) and in achenes of saffron thistle (Carthamus lanatus). V. dahliae was isolated from the stem and tap root of twenty‐six of fifty‐four species of weeds growing in naturally infested soils. It was not isolated from four species recorded as hosts elsewhere. Fifteen native or introduced weed species are newly recorded hosts. V. dahliae also colonized the roots of many wilt‐immune species, but died on the roots of most plants without producing microsclerotia. The only wilt‐immune plants in which microsclerotia formed in the roots were fat hen (Chenopodium album), red root (Amaranihus macrocarpus) and Canadian flea‐bane (Erigeron canadensis) but these are reported as hosts elsewhere.
Effect of an organo ‐ mercurial fungicide, chlormequat and decenylsuccinic acid on frost hardiness and seedling diseases of oats
Authors: RAWLINSON C. J. 
Published: February 2008

SUMMARYTreating oat seeds of ten cultivars with an organo‐mercurial fungicide (Ceresan) and a dust formulation of the growth regulator chlormequat (2% a.i.) increased survival of seedlings growing under natural and simulated winter conditions. Treatment increased frost hardiness in less‐hardy cultivars, increased soluble sugars in stem base tissues and protected them from attack by soil fungi. It also increased root length in some cultivars but did not affect leaf area. Foliar applications of 10‐3m decenylsuccinic acid did not increase frost hardiness and also increased disease on stem base tissues. The possibility that sugar concentration may influence frost‐ and disease‐resistance of seedlings is discussed.
Quantitative studies of the post‐penetration phase of infection by Puccinia graminis tritici
Authors: OGLE HELEN J. , BROWN J. F. 
Published: February 2008

SUMMARYData obtained during the first 120 h after several resistant and susceptible varieties of wheat and some non‐host species were inoculated with uredio‐spores of Puccinia graminis tritici provided further evidence in support of the suggestion that hypersensitive necrosis is a consequence, and not the cause, of resistance. No evidence was obtained that individual genes for stem‐rust resistance specifically influenced colony growth or the histological changes that occurred during infection. However, combinations of major resistance genes or the presence of minor genes for resistance apparently did affect colony growth and hypersensitive cell collapse. Three groups of varieties – resistant, intermediate and susceptible – were distinguished on the basis of colony growth and the amount and proportion of necrotic tissue associated with colony development. The boundary between the intermediate and susceptible groups was not as distinct as that between the intermediate and resistant groups.
A survey of Ribes species for aphid resistance
Authors: KEEP ELIZABETH , BRIGGS J. B. 
Published: February 2008

SUMMARYField surveys from 1967 to 1970 of a Ribes species collection comprising ninety‐five plants representing fifty‐six species and fourteen sections of the genus, revealed moderate or severe aphid infestations as follows: Hyperomyzus lactucae (L.) on ten species included in five sections; H. pallidus H.R.L. ten species, two sections; Nasonovia ribisnigri (Mosley) twenty‐eight species, seven sections; Aphis grossulariae Kltb. twenty‐two species, ten sections; Cryptomyzus ribis (L.) four species, two sections; C. korschelti Börner three species, two sections.Cut shoot tests suggested that c. 50% of sixty‐three field‐resistant accessions were tissue‐susceptible to H. lactucae, and about 70% of fifteen field‐resistant types were tissue‐susceptible to N. ribisnigri. Possible field escape mechanisms are discussed.In breeding black‐currants resistant to H. lactucae and gooseberries resistant to N. ribisnigri, the donors R. sanguineum and R. cereum, and R. roezlii, respectively, were chosen for their high field and tissue resistance and for the known, or expected, fertility of their F1 hybrids with black‐currant and gooseberry.
Seasonal changes in aphid populations on Brussels sprouts
Authors: DUNN J. A. , KEMPTON D. P. H. 
Published: February 2008

SUMMARYPopulations of Brevicoryne brassicae (L.) and Myzus persicae (Sulz.) were assessed weekly on Brussels sprouts at Wellesbourne, from July onwards in each of 3 years. A peak of B. brassicae numbers occurred every year about the end of July, and in 1968 and 1970 this was larger than the September peak. Some alates were produced in the generation born to the June immigrants and the dispersal of those produced at the end of July consistently brought a decline in B. brassicae populations in early August. In 1968 and 1970, however, outbreaks of entomogenous fungi which followed rain, added considerably to this decline. Records of predators and parasites indicated that these natural enemies had only a minor effect on aphid numbers. M. persicae colonized sprouts slightly earlier than B. brassicae; in 1969 and 1970 its numbers in July were low and some persisted after the first week of August in 1968 only. In each year the first eggs of B. brassicae were laid at the beginning of October, but viviparae were still numerous for a further 7 to 10 weeks.
The infection of apples, cv. Bramley's Seedling, by Nectria galligena Bres
Authors: SWINBURNE T. R. 
Published: February 2008

SUMMARYIn laborator experiments germinating conidia penetrated leticels and wounds but not the intact surfaces of apples. Date of harvest had no significant effect on the numbers of apples infected with Nectria galligena but the earliest picks rotted first in barn store. Inoculations of unpicked apples resulted in small arrested lesions which only developed into progressive rots after a considerable period in store. Rots developed mosy quickly from inoculations made between mid‐August and mid‐September. The size of rot increased with spore number and many inoculations with 10–100 conidia remained as arrested lesions.Arrested lesions developed 10–15 days after unripe apples were inoculated and consisted of a zone of fungal colonization surrounded by suberized, necrotic cells in which compounds toxic to both N. galligena and Penicillium expansum were detected. No antifungal compounds were found in progressive rots to mature apples or in healthy apples of any age. Antifungal activity, measured by inhibition of P. expansum, was greatest 15–20 days from inoculation of unripe apples with N. galligena but decreased after a total of 35 days incubation at 20 d̀ C. Much less antifungal activity was produced in ripe or desert apples.
The resistance of spores of resistant strains of Botrytis cinerea to quintozene, tecnazene and dicloran
Authors: ESURUOSO O. F. , WOOD R. K. S. 
Published: February 2008

SUMMARYSpores formed by strains of Botrytis cinerea resistant to quintozene, tecnazene, or dicloran did not always produce resistant colonies when grown on agar in the presence of these fungicides.Only about one half of spores produced by fungicide‐vapour‐resistant strains in the absence of fungicides gave resistant colonies whereas all spores produced by the same strains in the presence of fungicides formed resistant colonies on agar.Some spores produced by resistant strains that had developed on agar containing the fungicides were not viable, but those that were always gave resistant colonies on agar.
Factors affecting the development of spraing in potato tubers infected with potato mop‐top virus
Authors: HARRISON B. D. , JONES R. A. C. 
Published: February 2008

SUMMARYA larger proportion of tubers of Arran Pilot potato growing at the surface of soil infested with potato mop‐top virus (PMTV) showed spraing symptoms (brown rings) at harvest than of tubers from below the surface. Infected tubers with or without spraing developed a spraing ring when stored in darkness, first for 1–2 wk at 18 d̀C and then for 1–2 wk at any constant temperature between 5 and 13 d̀C. Only a faint surface ring developed when either of these periods was decreased to 1 day; 4‐day periods were needed to induce distinct symptoms. Internal tuber symptoms developed more slowly than surface symptoms, and their formation was favoured by cutting the tubers in half. Additional pigmented surface rings were produced outside the first ring by successive cycles of treatment at 18 and 9d̀. Spraing did not develop when the first stage of treatment was at 22–25d̀, when the tubers were kept first at 10d̀ and then at 5d̀, when the treatment at 5–13d̀ preceded that at 18d̀, or when the tubers were kept at constant temperatures ranging from 5 to 25d̀.When tubers of six potato varieties were grown in PMTV‐infested soil and then stored at temperatures designed to induce symptoms, the varieties known to be the most susceptible in the field were those which had the greatest tendency to develop spraing during storage. When infected tubers were exposed to light, typical spraing symptoms were not induced, but greening of the tuber surface was much delayed in localized ring‐shaped areas, so that pale weals appeared.Spraing symptoms were produced, in favourable conditions, by the reaction of cells at the periphery of the PMTV‐invaded zone. Internal spraing did not prevent PMTV invading tissue outside the brown arcs; its rate of spread was about 10 μm/h at 14–18d̀.