The effect of cane management techniques on raspberry yellow rust (Phragmidium rubi-idaei)

The effects of various cane removal treatments on the epidemiology of Phragmidium rubi-idaei were studied in four experiments in infected raspberry plantations in Wales and Scotland. In 1981, removal of 15 cm high young canes either by cutting or by spraying dinoseb-in-oil reduced infection of a second flush of canes (replacement canes) compared to that of the first flush of canes on untreated plots of cv. Mailing Delight in Wales and of cv. Glen Clova in Scotland. In 1982, removal of 20 cm high young canes reduced infection of cv. Mailing Delight in Wales but in Scotland only removal of 60 cm high canes by cutting reduced infection of replacement canes. Removal of all fruiting canes and old cane stubs reduced rust infection of young canes, but removal of successive flushes of replacement canes did not reduce infection of lateral shoots on the fruiting canes. Dinoseb-in-oil applied to the bases of fruiting canes before emergence of young canes had no effect on infection of young canes in Wales or Scotland. The production of basidiospores was inhibited in vitro by dinoseb-in-oil at concentrations over 1.0 μg a.i./ml.     

Effects of straddle-harvester design on cane blight (Leptosphaeria coniothyrium) of red raspberry

A new fruit catching device developed for raspberry straddle harvesters to reduce wounding of young canes and their consequent infection by Leptosphaeria coniothyrium was tested. During picking the young canes were contacted only by the foam rubber on a pair of belts which moved backwards along the harvester at the same speed that the machine advanced. The incidence of canes with cane blight lesions in 1981 was 18% following the use of the new device in 1980, and 79% following the use of a conventional commercial harvester equipped with overlapping metal fruit-catching plates. In comparison with the latter plates, the new device avoided wounding the cane surface directly: when the belt marks on these canes were inoculated with mycelium, however, the disease incidence was 77%. The new device caused wounds in 1980 by ripping leaves from nodes. In comparison with the commercial harvester the new device led to smaller lesions in 1981 and a lower percentage of canes dead above the fruit-catching zone. A modified new catching device tested in 1982 made barely detectable pressure marks on the young canes without bruising them. Only 6·6% of these canes developed vascular lesions after inoculation, an incidence similar to that for unwounded control canes (2·5%). The modified new device is advised for regions prone to cane blight where the cropping system has young and fruiting canes growing together.     

Vigour control, an integrated approach to cane, pest and disease management in red raspberry (Rubus idaeus)

The first flush of young canes of red raspberry (Rubus idaeus) was removed at different dates in spring, using the contact herbicide dinoseb. In comparison with untreated plots, cane removal increased fruit yield, controlled excessive cane vigour, and improved the health status of vegetative canes in a plantation infested by raspberry cane midge (Resseliella theobaldi). At the end of the growing season vegetative canes on treated plots were shorter and thinner, and sustained less physical injury than those on untreated plots. Access to the fruit at harvest was also improved. Reduced competition between fruiting and vegetative canes increased yield in the year of treatment by an average of 35%. Yield was not affected by date of cane removal, but growth of replacement cane was reduced below optimum when first flush cane was removed after mid-May. The later the canes were removed, the less was the incidence of pest and diseases. Cankers and lobate vascular lesions (‘patches’) resulting, respectively, from the feeding of first and second generation midge larvae (with associated fungi) affected fewer canes in treated than in untreated plots. Significantly fewer live larvae of R. theobaldi were recovered in the following winter from soil in plots treated on or after 11 May than from untreated plots. The main effect of vigour control on R. theobaldi and midge blight was that replacement canes provided fewer egg-laying sites (natural splits) than did the first flush canes on untreated plots. The incidence of spreading vascular lesions (‘stripes’) attributed to Leptosphaeria coniothyrium infecting either physical wounds (cane blight) or midge feeding wounds (midge blight) was substantially less in treated than untreated plots. Cane botrytis (Botrytis cinerea) and spur blight (Didymella applanata) were also less common in treated plots. Interactions between vigour control and pest and disease incidence are discussed in relation to the efficient management of cv. Glen Clova in eastern Scotland.     

The effect of sprays of thiophanate–methyl on cane diseases and yield in red raspberry, with particular reference to cane blight (Leptosphaeria coniothyrium)

Spur blight (Didymella applanata), cane botrytis (Botrytis cinerea) and cane blight (Leptosphaeria coniothyrium) were studied in two consecutive seasons in unsprayed raspberries and in plots sprayed with thiophanate-methyl in the first season alone, (a) twice pre-harvest, (b) twice post-harvest, or (c) twice pre- plus twice post-harvest. Pre-harvest, but not post-harvest sprays, gave moderate control of both spur blight and cane botrytis; both diseases occurred mainly on the lower halves of canes, the latter being the less common. Cane blight occurred at the base of canes where they were wounded by old cane stubs. In the first year it was severe; 37% of canes died before harvest in the unsprayed plots. The three spray programmes all decreased cane death due to cane blight and they all increased yield by c. 45% even in those plots sprayed post-harvest where spur blight was severe and not controlled. Clearly this last disease, despite its high incidence, had no effect on potential yield in this experiment. In the second year cane blight was common but less severe and the incidence of its lesions was reduced similarly by all programmes, but only 4% of canes died in control plots. Analysis of the potential yield and the sizes of lesions caused by L. coniothyrium in canes inoculated at fortnightly intervals in the previous year showed that potential yield loss occurred only when lesions girdled canes. A bimodal distribution in the lesion sizes, measured by length or girdling, indicated some endogenous control of lesion development which might explain the marked differences in the effect of cane blight on potential yield in two seasons.     

Effects of Didymella applanata and Botrytis cinerea on axillary buds, lateral shoots and yield of red raspberry

The viability of axillary buds and the growth and potential yield of lateral shoots at nodes of red raspberry (Rubus idaeus) infected naturally by Didymella applanata or Botrytis cinerea were measured on excised nodes, decapitated nursery canes or on canes from fruiting plantations. In comparison with lesion-free nodes, buds at infected nodes were smaller and fewer of them were capable of growth when excised and ‘forced’, although the difference in growth between infected and uninfected nodes decreased during late winter. After February, those buds at infected nodes which were capable of forced growth did so as early and with a similar growth rate as those at lesion-free nodes. In April, 70% of buds at infected nodes were capable of growth compared with 94% of those at lesion-free nodes. When nursery canes of cv. Mailing Delight were decapitated above infected nodes the emergence of lateral shoots from the terminal infected node did not differ significantly from that at lesion-free nodes. On a range of farm sites in Scotland the emergence of shoots at infected nodes in the cropping region of canes was significantly poorer than from uninfected nodes but substantially better at infected nodes of cv. Glen Clova than at those of cvs Mailing Jewel and Mailing Orion. It is suggested that cv. Glen Clova is relatively tolerant of spur blight and cane botrytis. The length and potential yield of laterals which developed at infected nodes in the cropping region of canes in these three cultivars did not differ significantly from those at lesion-free nodes. In all tests there was no significant difference in growth at nodes infected by D. applanata and B. cinerea which may indicate a common mechanism for suppression of buds.     

Effect of coconut (<Emphasis Type="Italic">Cocos nucifera</Emphasis> L.) water extracts on adventitious root development in vegetative propagation of <Emphasis Type="Italic">Dracaena purplecompacta</Emphasis> L.

Propagation by softwood canes and cuttings is preferred as a practical system for vegetative reproduction of many ornamental plant species, despite the advances in tissue culture techniques. Dracaena purplecompacta L. is a species that has a high demand for exports. Conversely, coconut water (CW) is a rich supplement that naturally contains plant growth regulators such as indole acetic acid (IAA). The objective of this work was to evaluate the potential of CW extracts containing natural IAA, on adventitious root development in vegetative propagation of ornamental plant canes of D. purplecompacta L. Five different concentrations (28, 57, 143, 286, 571 μM of natural IAA) of CW extracts were tested. Another set of treatment was carried out with the same concentrations of authentic IAA hormone for comparison purpose. The 143-μM IAA CW extract recorded the best root induction and development. It was found that the root expression was faster (5 weeks) with the use of the novel method. In the conventional method, the canes are propagated by quick dip application of commercial product containing artificial hormone IAA and placing them on coir fiber dust beds. It takes up to 6 weeks for the canes to develop adventitious roots to the desired level. Steeping canes in 143-μM IAA CW extract improved rooting in D. purplecompacta L., and it was comparable to the application of 143-μM authentic IAA. The study indicates that adventitious root development, shoot development, and leaf emergence of D. purplecompacta L. is promoted by IAA CW extracts.     

Der mit der Versuchsdauer anwachsende Resistenzfaktor

Abstract

Pseudomonas spp. strains capable of inducing systemic resistance were applied to sugarcane by sett treatment followed by soil applications in the field. Later the fungal pathogen Colletotrichum falcatum causing red rot disease of sugarcane was inoculated in the treated canes and its colonization was assessed by ELISA at different nodal positions above the point of inoculation. Studies with three cvs showed a significant variation in pathogen colonization only in disease susceptible cv CoC 671 and not with cvs Co 8021 and BO 91, moderately susceptible and moderately resistant to the disease, respectively. In further studies when pathogen colonization was assessed on the entire stalks of cv CoC 671, the pathogen titre was significantly reduced from three nodes upwards in the treated canes. In the upper nodes no pathogen colonization was noticed in bacteria-treated canes, whereas in the control all the nodes recorded higher titre for pathogen infection. Incorporation of chitin in the talc formulation caused further reduction in fungal colonization in the stalks.     

Effects of spur blight (Didymella applanata) and premature defoliation on axillary buds and lateral shoots of red raspberry

Nodal lesions typical of natural infections of Didymella applanata were produced on young raspberry canes when wounded petioles were inoculated with mycelium. The buds which developed in the axils of these inoculated petioles were smaller and less likely to produce lateral shoots than those in the axils of delaminated or undamaged petioles, but only when the petioles were inoculated in the field before the end of July. This effect was more pronounced in cv. Mailing Jewel than in cv. Glen Clova which suggests that the latter is more tolerant of D. applanata. Sprays to control D. applanata in the cropping region of canes will probably be effective in Scotland only if applied before the end of July.     

Common resistance in red raspberry to Botrytis cinerea and Didymella applanata, two pathogens occupying the same ecological niche

Comparisons were made between Botrytis cinerea and Didymella applanata, which occupy the same ecological niche on canes of red raspberry. Isolates of B. cinerea from diverse localities within the British Isles were pathogenic to the SCRI selection M30 when internodal wounds on young canes were inoculated. A single inoculation frequently caused the buds at several nodes to fail the following spring. Differences in the lengths of the stem lesions that formed indicated differences in isolate pathogenicity, but these were not related to isolate origin. Bud suppression and lateral shoot failure also occurred when petioles of cvs Mailing Orion, Mailing Jewel and Glen Clova were wound inoculated with B. cinerea up to late August. The relative resistance of seven cultivars to three isolates of each pathogen was determined. Principal components analysis of data from five estimates of resistance to each pathogen showed that 40% of the variation described a common resistance to the two diseases. Further analysis showed that cvs Chilcotin and Meeker had the strongest common resistance and that cvs Glen Prosen and Mailing Jewel had the weakest. The remaining variation described cultivar differences in relative bud length after petiole inoculation with either pathogen, and differences in the relative importance of spring and autumn symptoms. Only 7% of the variation indicated independent resistance to the two pathogens and this was not influenced by cultivar differences.     

An evaluation of canes as a management technique to reduce predation by gulls of ground‐nesting seabirds

The best documented method to decrease predation of breeding seabirds by gulls are culling regimes; however, studies on the effectiveness of this method show ambiguous results. Here we tested an alternative method, using bamboo canes erected in four breeding sites of Arctic Tern Sterna paradisaea as a gull‐deterrent. Although we found fewer predation attempts in the caned areas than in the control areas, canes did not reduce the probability of predation success per attempt. This pilot study documents that the use of canes as a conservation strategy to reduce gull predation is promising, economic and simple, and is thus probably a versatile tool for conservation managers.     

The effect of temperature on the response of canes of red raspberry cv. Mailing Jewel to infection by Didymella applanata

A single population of container-grown red raspberry plants cv. Mailing Jewel was divided and grown in two environments prior to wound inoculating young canes with Didymella applanata in late July. The plants were then sub-divided and held in one of three contrasting post-inoculation environments. Various assessments were made to examine the effect on spur blight of the different environmental treatments. Inoculation of internodes showed that D. applanta produced longer lesions and more pseudothecia on canes grown in spring in an unheated glasshouse than on canes grown outside, but post-inoculation conditions had little effect on these aspects of disease. Petiole inoculations showed that dwarfing of axillary buds in the first season and lateral shoot failure in the year after infection were most serious on canes grown outside in spring but held at relatively high temperatures in August and September after inoculation. The results indicate that spur blight may have the potential to cause higher yield losses in areas with warmer spring and autumn conditions than those usually experienced in north-east Scotland.     

Small-scale spatial pattern and size structure of Rubus hirtus in a canopy gap

Abstract. The response of a Rubus hirtus population to the creation of a new forest gap was analysed. All individuals in two 30-m² plots – one in a gap and one with full canopy cover – were mapped and the length of Rubus shoots measured. This was done 1, 2, 3, 4, and 7 yr after creation of the gap. Spatial patterns were analysed using Ripley's K-method. Although the density of Rubus in the gap increased from 3 to 24 rooting points/m², the change in spatial pattern of individuals over 7 yr was very limited. During the first four years a clumped pattern appeared at distances of > 0.5 m. After seven years the pattern was random at all distances. Young shoots spread in all directions with equal probability. The expansion was achieved by establishment of new ramets, increase in the number of shoots per rooting point playing a minor role. Individual plants contributed to gap filling very unequally; few of them produced many rooting points. The average size of canes and the proportion of tip-rooting canes were highest in the second year after the gap formation.     

Cane blight (Leptosphaeria coniothyrium) in mechanically harvested red raspberry (Rubus idaeus)

Leptosphaeria coniothyrium, the cane blight pathogen, was the fungus most commonly isolated from vascular lesions developing from mechanical harvester wounds on first-year red raspberry canes. When inoculated to scalpel wounds, it induced similar lesions which were later associated with bud failure and cane death as were infected wounds on machine damaged canes. Cane resistance increased from May until August, inoculations later than July inducing only small lesions and rarely causing bud failure.     

A comparison of fungicides for the control of raspberry spur blight

Effective control of raspberry spur blight (Didymella applanata) and increased crop yields in the following season were obtained in a plantation of cv. Mailing Jewel with a programme of four or five sprays commencing when the new canes first appeared. Treatments were applied at 14-day intervals and continued until c. 2 wk before harvest. Thiram (0.16% a.i), benomyl (0.025% a.i.), dichlofluanid (0.10% a.i.) and captan (0.10% a.i.) gave good control of the disease but as benomyl and dichlofluanid were also effective in controlling powdery mildew (Sphaero-theca macularis) and Botrytis cinerea on the berries these fungicides appear to be the most suitable.     

Epidemiology of stamen blight of raspberry

Stamen blight, caused by Hapalosphaeria deformans Syd., is a disease of a number of Rubus species. It is widespread on commercial raspberries in Angus and east Perthshire. Evidence indicates that spread is from diseased flowers to the axillary buds of young canes during the summer and entry into these buds is complete by autumn, after which it is unlikely that the pathogen can be reached even by an eradicant fungicide. Attempts to infect young canes artificially, however, have failed. Rain splash appears to be of considerable importance in dispersal, but some spread by wind and pollinating insects could occur. Possible control measures are discussed and the importance of planting canes from spawn beds, where no flowering canes are kept, is emphasized.     

The Effect of Chitinase on Didymella applanata, the Causal Agent of Raspberry Cane Spur light

In vitro and in vivo studies were conducted to assess the efficacy of the two microbial chitinases Chi I (from Streptomyces sp.) and Chi II (from Serratia marcescens) on Didymella applanata (Niessl.) Sacc., the fungus which causes spur blight of raspberry (Rubus idaeus L.). D. applanata was isolated from canes of diseased raspberries in a plantation in Novosibirsk, Russia. In vitro, the effective concentration of Chi I that reduced the growth of D. applanata was 0.4 U/ml (p = 0.05), but Chi II had no influence on the growth of the fungus in medium. In inoculation experiments on raspberry canes, both chitinases at the rate 0.5 U/ml reduced fungal development. In plantation where canes were inoculated after spraying with chitinase, fruiting bodies of fungus failed to form in all enzyme treatments, whereas a significant number of these fungal fruiting bodies (12.8 per cm²) developed in control treatments lacking chitinases spraying. The chitinases reduced the size of lesions and limited the infection of internal tissues of canes. Field testing of Chi I under natural conditions showed a significant suppression of the independent spur blight. These studies form the basis for further evaluation of ecologically benign control measures for raspberry spur blight.     

Resistance to Botrytis cinerea in canes of Rubus idaeus and some related species

Mycelial inoculation of canes with Botrytis cinerea proved a useful method for assessing Rubus material for resistance. When canes were inoculated in summer resistant genotypes developed relatively small lesions which produced few small sclerotia in the following spring. The size of lesions in autumn generally provided the best discrimination between genotypes. Very strong resistance was found in several species, of which Rubus pileatus and R. occidentalis are the most useful for breeding; hybrids of raspberry with these species or with R. crataegifolius also had strong resistance. The resistance shown by a derivative of red raspberry cv. Chief was less strong, as was the resistance conferred by gene H, which determines cane pubescence.     

Disease measurement in a study of apple scab epidemics

The growth and yield increases in red raspberry which followed the repeated application of benomyl were not due to the suppression of pests. Benomyl had little effect on numbers of aphids and nematodes which, anyway, were insufficiently abundant to cause damage. Benomyl did, however, decrease the earthworm population. In the following years, when benomyl was no longer applied, significantly more canes died from midge blight in the plots treated most frequently with benomyl than in the untreated. This was probably a consequence of increased infestation by larvae of the raspberry cane midge (Resseliella theobaldi) in the benomyl-treated plots because benomyl increased the extent of cane splitting and hence the number of egg-laying sites for cane midge.     

Differential occurrence of suberized sheaths in canes of grapevines suffering from black dead arm, esca or Eutypa dieback

Compared to healthy canes of Ugni-Blanc grapevines, structural modifications were observed in August in wood of growing canes showing foliar symptoms induced by esca and Eutypa Dieback. The observed changes appeared attenuated in canes of the current season sampled in December. In contrast, Black Dead Arm (BDA) did not induce significant modifications compared to healthy canes. A seasonal pattern in suberization was observed in control canes since a first suberized sheath occurred in mid-July at the interface xylem ring/pith and a second sheath was built up in August till December at the interface primary phloem/cortex. The same pattern was observed in BDA-attacked vines. In contrast, these continuous structural barriers were not formed in July and August in canes of the current season in grapevines attacked by esca or Eutypa dieback, but restored in the canes observed in December. These structural modifications were quantified and these events were discussed in the scope of plant physiology and pathogenicity of the implied fungi.     

The profitability of smallholder rattan cultivation in Southern Borneo,Indonesia

Fieldwork in the village of Dadahup along the Lower Barito basin in Central Kalimantan (Southern Borneo, Indonesia) shows that smallholder rattan cultivation is financially profitable to smallholders and economically profitable to the nation. The financial net present value (NPV) for green and processed canes is Rp 828,000 and Rp 946,000;the economic rate of return is about 22% for both green and processed canes. The article contains a discussion of the methodology for evaluating the shadow price of a nontimber forest good.