Veränderung der Krankheitsdisposition von Forstpflanzen durch Herbizide1

Modification in discase-sensibility of forest plants by herbicide treatment. I. Field trials with Lophodermium pinastri. The effect of two herbicides TOP-KH (salt of 2,4,5-T) and Casoron G (Dichlobenil) on incidence of Lophodermium pinastri on Scots pine (Pinus sylvestrií L.) was investigated in field trials with potted plants. Treatment with TOP-KH led to increase in infection with higher herbicide concentrations and to higher numbers of severely infected plants in comparison with controls. Differences were greatest in spring. With Casoron G, however, smaller numbers of sevcrely infected plants were seen in spring and at the end of the growing season the damage was not much greater than in the controls. Possible reasons for changes in degree of infection are discussed as well as effects that could be expected on the epidemiology of pine needle cast.     

Untersuchungen über den Einfluß von Cuticularwachsen auf die Infektionsfähigkeit pathogener Pilze

The effect of cuticular waxes on the infection rate of pathogenic fungi. 1. Lophodermium pinastri and Botrytis cinerea . Spore germination and growth rate of germ-hyphae of Lophodermium pinastri and Botrytis cinerea are influenced by low concentrations of cuticular waxes, added to the germination medium. The stimulating effect increases with decreasing resistance of the species or race used for wax sampling. Generally the separately tested alcohol-, aldehyde-, ester-, fatty acid- and hydrocarbon fractions induce similiar but less pronounced reactions than total waxes. Exceptions occur. They led to suggestions in direction to single chemical components causing resistance. – Finally alcohol and hydrocarbon chromatOgrams of cuticular waxes for Pinus montana, P. nigra and Picea abies are presented for the first time.     

Control of Lophodermium and Phacidium needle cast and Scleroderris canker in Pinus silvestris

Cycloheximide and a mixture of chlorothalonil and cycloheximide gave acceptable control of Lophodermium pinastri as well as of Phacidium infestans and Scleroderris lagerbergii on Pinus silvestris. The recommended number of sprays per year is one and four respectively.     

Untersuchungen zur Variabilität von Lophodermium pinastri

Studies of the variability of Lophodermium pinastri. I. Cultural Variants. Lophodermium pinastri is a variable fungus species. From its behaviour in artificial culture 3 constant, morphological main types are observed. These are described in detail. Observations on sectoring found and on reaction types between various fungus isolates are given.     

Untersuchungen zur Variabilität von Lophodermium pinastri

Studies of the variability of Lophodermium pinastri. II. Differences in physiological behaviour . In culture trials with numerous strains of Lophodermium pinastri of different provenances the influence of temperature, pH and vitamins on growth was studied as well as ability to produce starch hydrolyzing enzymes. On the basis of these tests, the strains investigated could be divided into five groups.     

Pathogenicity of three Lophodermium species on Pinus sylvestris L.

The pathogenicity of Lophodermium pinastri, L. conigenum and L. seditiosum on 14-month old transplants was investigated in Scotland. While L. seditiosum was found to be a serious pathogen, L. conigenum and L. pinastri were not. Under outdoor conditions, L. seditiosum was found to kill needles five months after inoculation.     

Short-term variation in ascospore release by Phacidium infestans on the needles of Pinus sylvestris

Ascospore release by Phacidium infestans was monitored with volumetric-recording spore traps in Finland. Detached branches of Scots pine infected naturally during the previous winter were used as a spore source. Spores were trapped during two autumns with simultaneous recording of weather factors. Free water from rain or thawing of rime or snow on the needles was required to initiate the spore release. After the onset of rain, the number of spores reached its maximum in 4–6 h, while heavy rain decreased the liberation of spores into the air. The number of spores had a higher correlation both with relative humidity and with precipitation delayed 3–7 h than with current precipitation. Temperature did not directly affect the ascospore release. Only a few spores were trapped at temperatures below 0°C. The effect of wind on the release of spores was mainly negative, and indirect through decreasing humidity. No diurnal periodicity was detected in the spore release.     

Susceptibility of Healthy and Ozone-injured Needles of Pinus strobus to Invasion by Lophodermium pinastri and Aureobasidium pullulans1

Lophodermium pinastri and Aureobasidium pullulans were the fungi most often associated with foliar symptoms, including those caused by ozone, on Pinus strobus in the field. Following artificial inoculation of ozone-fumigated and untreated foliage on pine seedlings, L. pinastri was Isolated without relation to visible symptoms of ozone injury. A, pullulans was isolated only from tissues killed by ozone. No evidence of additive or interacting effects of ozone and the fungi was found.     

Veränderung der Krankheitsdisposition von Forstpflanzen durch Herbizide

Modification in disease-sensibility of forest plants by herbicide treatment. III. Damping off. A study was made of the effect of the two herbicides, Simazin and TOP-KH (salt of 2,4,5-T) on attack on seedlings of two provenances of Norway spruce by different damping off fungi.In addition, the effect of the two herbicides on the growth of these fungi in arlificial culture was investigated. Different levels of attack on the seedlings were related to the herbicide applied, its concentration and the origin of the spruce. The results gave evidence for a change in susceptibility of the host due to the herbicide.     

Fungi dangerous at Pinus contorta with special reference to pathogens from North Europe

Examples are given of North American fungi potentially dangerous to Pinus contorta plantations in northern Europe. The pathogenicity of North European fungi is discussed. P. contorta was found to be immune or nearly immune to all European rust fungi, more resistant than P. sylvestris to Phacidium infestans and Lophodermium pinastri, but less resistant to Crumenulopsis sororia and Discella strobilina. For other fungi no such clearcut conclusions could be drawn.     

Beobachtungen über Wechselwirkungen dreier Nadelpilze der Kiefer in vitro

Interactions in vitro among three pine needle fungi . Interactions in vitro among Lophodermium pinastri, Naemacyclus niveus and Dothistroma pini, all fungi on conifers, were related to their various host spectra. The results were remarkably conformable, with those species which were mutually tolerant in vitro being joint colonisers of many host species and vice versa.     

Züchtung von Reinkulturen des Pilzes Lophodermium pinastri (Schrad.) Chev. zur Entstehung von sexuellen Fruchtkörpern (Hysterothecien)

Production of hysterothecia from pure cultures of Lophodermium pinastri (Schrad.) Chev. A method is described for the production of hysterothecia from pure cultures of L. pinastri. Previously sterilized needles of Finns sylvestris, after being overgrown on the culture dish are removed and put on living moss under natural conditions. In 2–2,5 months hysterothecia appear.     

Two biotypes of Lophodermiul11 pinastri in Scotland

Two biotypes of Lophodermium pinastri, perhaps differing in their pathogenicity, were recognised on Pinus sylvestris in NE Scotland. These biotypes are described in artificial culture and are shown to be associated with definite habitats on pines, both in the plantation and in the nursery. In the discussion it is suggested that the present results might help to explain the difficulty many workers have experienced in trying to infect artificially young pine needles with L. pinastri.     

Effects of Stump-treatment Substances for Root-rot Control on Ground Vegetation and Soil Properties in a Picea abies forest in Sweden

There is increasing commercial interest in treating stumps to restrict the spread of root rot [Heterobasidion annosum (Fr.) Bref.] when thinning Swedish coniferous forests during the summer. Both chemical and biological substances are used for this purpose. During the treatment, however, a large proportion of the substance applied is spilled beside the stumps. A field study was conducted on the effects of stump-treatment substances on various ground-vegetation species in a Picea abies (L.) Karst. forest in Sweden. Three different substances commonly used in forestry were studied: urea solution (0.23 kg N m^-2), borate solution (10 g B m^-2) and a fungal preparation of Phlebiopsis gigantea (Fr.) Jül. spores (1 g spores m^-2). The principal objectives were to assess whether any of the substances were harmful to plants and whether plant species differed in their sensitivity. Both borate and urea solution caused severe damage to most ground-vegetation species tested. Bryophytes were affected more strongly than vascular plants and urea was slightly more toxic than borate. Treatments with P. gigantea caused no obvious damage. The size and persistence of chemical changes in the soil induced by the treatments were also analysed. Transient changes were apparent in topsoil where borate or urea had been added. Very high concentrations of B were initially observed where borate had been applied, and even after 1 yr they were slightly higher than the threshold concentration at which plant injuries are expected. Urea treatment initially resulted in a pH increase of 2 units and a substantial increase in soil ammonium content. After 1 yr these effects had largely disappeared, although some increase in ammonium was still detectable.     

Herbivory affects ovarian development in the zoophytophagous predator <Emphasis Type="Italic">Brontocoris tabidus</Emphasis> (Heteroptera,Pentatomidae)

The effect of prey-based and combination prey and plant-based diets [Tenebrio molitor pupae alone; T. molitor pupae and Eucalyptus cloeziana plants; T. molitor pupae and Eucalyptus urophylla plants; and T. molitor pupae and Psidium guajava (guava) plants] on the morphometry of the ovary of Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) was analyzed in the field. Females fed on T. molitor pupae without plants presented with smaller ovarioles. The number of oocytes per ovary was higher for B. tabidus females fed on a combination diet of E. urophylla and T. molitor pupae when compared to females fed only on prey. In addition to diet, the number of oocytes in the ovariole was shown to vary with the age of B. tabidus. The 21-day-old B. tabidus females were found to have a higher number of oocytes per ovariole than the 15-day-old females in all diet conditions. The 15-day-old females exhibited more developed oocytes when fed on diets containing both prey and eucalypts plants and less developed oocytes when fed with a combination diet containing guava plants or T. molitor pupae alone. The 21-one-day-old B. tabidus females which were fed with a diet without plants had smaller oocytes than those fed with plants. Herbivory improves the morphology of the ovary of B. tabidus, affecting the size of the reproductive structures and the oogenesis of this natural enemy in the field.     

Life cycle of Lophodermium piceae in Norway spruce needles

The spruce needle inhabiting ascomycete Lophodermium piceae can live symptomless for several years, before it completes its life cycle within less than one year as detailed studies have shown.     

黄山松上的散斑壳

对安徽省岳西县妙道山国家森林公园黄山松上的散斑壳进行了调查研究，共发现６个种，其中岳西散斑壳系一新种；南方散斑壳，扰乱散斑壳为黄山松上的新记录；针叶树散斑壳，库曼散斑壳，松针散斑壳为国内已记载的种。对新种作了汉文和拉丁文描述，记载了已知种的戽性。     

Sources of inoculum of Lophodermium seditiosum on Pinus sylvestris1

A survey of the incidence of Lophodermium seditiosum, L. pinastri and L. conigenum in plantations of Pinus sylvestris in north-east Scotland showed that L. seditiosum predominated on fallen cones and on young needles which tell prematurely in early summer. L. pinastri predominated on old senescent needles which fell in autumn. The incidence of L. conigenum was low on fallen cones and needles and it is not thought that tins species could effectively replace L. seditiosum. It is concluded that the main source of L. seditiosum inoculum for infections in plantations and nearby nurseries is young infected fallen needles on which ascocarps form in late summer and autumn.     

Identification of Lophodermium seditiosum and L. pinastri in Swedish forest nurseries using species‐specific PCR primers from the ribosomal ITS region

Lophodermium seditiosum is a serious needle pathogen on pine, particularly in nurseries, and there is a need to detect the pathogen during its latent phase. The internal transcribed spacer (ITS) regions of the rDNA of L. seditiosum and L. pinastri were amplified with universal primers and sequenced. Sequence comparisons of the two species allowed the design of species‐specific primers for the ITS regions. The primers were between 18 and 24 bp long with a minimum of 3 bp differences between the species. These primer pairs did not give any amplification of DNA from any other of the examined fungal species or from healthy Pinus sylvestris needles. It was also possible to identify either L. seditiosum or L. pinastri in infected needles with and without signs of infection using these primer pairs. The method was found to be very useful for detection of latent infections of L. seditiosum in P. sylvestris needles in nurseries.     

Phacidium infestans on dwarf plants of Pinus sylvestris

A review of the literature is presented and an infection experiment described. Dwarf plants of Pinus sylvestris are seldom infected and destroyed by the snow mould fungus Phacidium infestans. The reasons are: The amount of infection material is usually small, the ecological conditions do not favour infection and subsequent development of the disease, the plants are small targets for spores and infective needles, the dwarf plants are fairly resistant.