Management of needle blight (Lophodermium pinastri) disease in Blue pine trees in Kashmir,India

Evaluation of various fungicides against needle blight disease of pine was carried out at Sheri Kashmir University of Agriculture Sciences and Technology of Kashmir(India) during the year 2008 and 2009. Application of various fungicides were evaluated in vivo at different concentrations. However in both, mist-chamber and poly-chamber, the Blue pine(Pinus wallichiana Jackson)seedlings treated with hexaconazole 5EC(@ 0.03 %) or carbendazim 50WP(@ 0.1 %) depicted significantly less disease incidence and intensity. The seedlings treated with mancozeb 75WP(@ 0.3 %) and chlorothalonil 75WP(@0.3 %) exhibited less disease incidence and intensity.Increase in relative humidity from 60 to 100 % significantly enhanced needle blight disease incidence and intensity. In field trial the fungitoxicants used either as single spray or protectant followed by systemic fungitoxicant spray significantly reduced disease incidence in Blue pine compared to check. The mean disease incidence in fungitoxicant treated plants varied from 11.82 to 25.51 %as compared to 36.03 % in control.     

Lophodermium pinastri and an unknown species of Teratosphaeriaceae are associated with needle cast in a Pinus radiata selection trial

Spring needle cast (SNC) in Tasmania is defined by the early casting of pine needles and appears in 6‐ to 7‐year‐old pine plantations after canopy closure. The severity of SNC can vary significantly among trees growing within the same plantation. Fungal communities were surveyed in a Pinus radiata family trial, using DNA extraction from needles, PCR with fungal‐specific primers and sequencing to detect the presence of fungal species. Samples were taken at the same time as the trees were scored for disease severity. Trees with contrasting levels of SNC disease severity have significantly different needle fungal communities, but family pedigree and different ages of needle are not clearly distinguished by their fungal communities. All common fungal pathogens previously implicated in causing SNC were identified from the study, but of these, only Lophodermium pinastri was correlated with high levels of disease. Several species of Teratosphaeriaceae were detected, and one of these was also strongly associated with needle cast.     

The development of Lophodermium pinastri in conifer nurseries and plantations in North America

The recent outbreak of Lophodermium needlecast in North America first appeared in 1966 in forest nurseries on red pine (Pinus resinosa) and Scotch pine (P. sylvestris). Dispersal of infected nursery stock throughout North America has created a serious needlecast problem in Scotch pine Christmas tree plantations. Two biotypes of L. pinastri are present. The pathogenic strain may be a recent introduction. The fungicides maneb and chlorothalonil are being used for control.     

Physiological studies on variation in resistance of Pinus sylvestris to Lophodermium pinastri

Buffering capacity and pH values of extracts of pine needles varied with age in the course of the ontogeny of needles. Significant differences between a resistant and a susceptible pine clone group in relation to resistance against Lophodermium pinastri could be shown in autumn and winter. Also the variability of the parasite influences the host-parasite interaction as shown by alteration of pH values by 3 L. pinastri strains in cultural trials on needle extract medium.     

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.     

多·硫烟剂防治马尾松落针病试验初报

笔者通过采用13.0%多·硫烟剂、2.5%百菌清烟剂对马尾松落针病进行防治试验,结果表明:13.0%多·硫烟剂防治马尾松落针病的适宜用药量为1600～2000g/666.7m2,且对马尾松生态安全。     

Colonization and decomposition of leaf litter by ligninolytic fungi in Acacia mangium plantations and adjacent secondary forests

Colonization of leaf litter by ligninolytic fungi and relationships between mass loss and chemical qualities of surface leaf litter were examined in Acacia mangium plantations and adjacent secondary forests in southern Sumatra Island, Indonesia. Leaves were collected from eight A. mangium plantations of different ages and three secondary forests. Partly decomposed leaves beneath the surface leaf litter were used to measure the bleached area which indicated colonization by ligninolytic fungi. Surface leaf litter was used to measure initial chemical content and subjected to the pure culture decomposition test. The bleached area was greater in secondary forests than in A. mangium plantations. Nitrogen content was higher in all the A. mangium plantations than in the secondary forests, and acid unhydrolyzable residue (AUR) content was generally higher in the A. mangium plantations than in the secondary forests. The bleached area of leaf litter was negatively correlated with nitrogen content of surface leaf litter at all sites, indicating an inhibition of the colonization by ligninolytic fungi of leaves with higher nitrogen content. In a pure culture decomposition test inoculating a ligninolytic fungus to surface leaf litter, mass loss of leaves was negatively correlated with AUR content of surface leaf litter. Mass loss of leaves and AUR was not significantly related to nitrogen content. These results suggested that higher nitrogen content in A. mangium leaf litter had a negative effect by colonization of ligninolytic fungi, but the effect of high N in A. mangium leaf litter on the decomposition of leaf litter and AUR remained unsolved.     

Regional variation in rate of mass loss of Pinus sylvestris needle litter in Swedish pine forests as influenced by climate and litter quality

The climatic influence on plant litter decomposition has been successfully correlated on a regional level by using estimated actual evapotranspiration (AET) and annual mass loss. This approach was applied to decomposition studies carried out in a transect along Sweden with litter incubated in four different forest types. A unified needle litter was used and among 14 Scots pine sites about 80% of the mass‐loss rate could be explained. A simple model was made on the influence of both climate and nutrient concentrations (nitrogen and phosphorus) on mass‐loss rate. About 90% of the first‐year mass loss could be explained by this approach. As early decomposition stages were studied (<40%) no influence of lignin was observed.     

Effects of clearfelling on forest floor accumulation and litter decomposition in a radiata pine plantation

The short-term effects of clearfelling a Pinus radiata D. Don. stand in Catalonia (NE Spain) under Mediterranean conditions were assessed. Harvesting had little effect on the surface soil distribution and accumulation. However, after clearfelling the range of soil temperatures increased, the moisture content of the L layer decreased, and the decomposition of brown needles was retarded (mass loss rate for the first year of the incubation 0.47 year⁻¹ vs. 0.29 year⁻¹). Green needles incorporated as a result of harvesting operations showed the same rates of mass loss as brown needles. Brown needles released substantial amounts of all major nutrients, especially at the beginning of the incubation. In both clearfelled and undisturbed stands, this sudden nutrient flush may have important implications in the nutrient economy of the vegetation. In contrast, green needles behaved as a sink of nitrogen and calcium, therefore representing a temporary reservoir after clearfelling.     

Microbial activity,nutrient dynamics and litter decomposition in a Canadian Rocky Mountain pine forest as affected by N and P fertilizers

To study the specific effects of N and P fertilizers on soil microbial processes under field conditions, a pine forest in southern Alberta was fertilized with ammonium nitrate and urea (0 and 188 kg N ha⁻¹, respectively) singly and in combination with triple super phosphate (0 and 94 kg P ha⁻¹, respectively). Microbial respiration (BR), substrate induced respiration (SIR), metabolic quotient (qCO₂) and rates of microbially mediated key processes were monitored in the forest floor FH material during the growing periods of spring 1990 to fall 1992. A transient increase in soil NH₄⁺ availability was detected following N addition but significant increases in PO₄³⁻ availability were detected throughout the study as a result of P enhancement. Microbial variables were unaffected by N addition, whereas soil organic matter and SIR was increased with P fertilization. Microbial BR and qCO₂ were reduced with P fertilization suggesting more efficient utilization of C. Increased net mineralization of P in the P-fertilized plots was found during the second and third summers after fertilization, following immobilization of P during the first year. In contrast, NH₄⁺-N mineralization in the N-fertilized plots was significantly increased only during the first year. Rates of nitrification were unaffected by either N or P addition. Decomposition of pine litter was enhanced with N addition only during the first year and P had no effect on decomposition. Addition of N and P at these rates does not appear to impose a major ecological stress to the soil ecosystem.     

Some nutrient dynamics associated with litterfall and litter decomposition in hoop pine plantations of southeast Queensland, Australia

Litterfall was collected over a 12-month period with littertraps in hoop pine (Araucaria cunninghamii) plantations aged 10, 14 and 62 years in southeast Queensland, Australia. The bulk of litterfall occurred during spring, mainly as hoop pine foliage with the annual litterfall ranging between 6.0 and 10.9 t ha⁻¹, respectively, for the younger stands (10 and 14 years) and the mature 62-year old stand. The amount of nitrogen (N) and phosphorous (P) recycled annually through litterfall was lower in the younger stands (28–37 kg N ha⁻¹ and 4.4–5.3 kg P ha⁻¹) compared with that of the mature stand (85 N ha⁻¹ and 6.2 kg P ha⁻¹). The N and P retranslocated during senescence varied across the three stands studied with a trend for N and P retranslocation to increase as availability of soil mineral-N decreased.

Decomposition of the hoop pine foliage component of litter was also studied in the same stands using a litterbag technique and mass-balance analysis. The estimated half-life of hoop pine foliage mass ranged between 1.5 and 1.8 years. Litter-mass loss was strongly correlated with litter substrate quality indicators of N, C, P, C/N ratio, lignin, lignin/N ratio and polyphenols. During the course of the study, there was no difference in litter-mass loss between the stands of different ages. During the 15-month period, the order of element release from the hoop pine litter was K>Na>C>Mg>P, with N, Ca and Mn generally demonstrating varying degrees of net accumulation. During the course of the study, the lignin/C ratio of the hoop pine litter increased from 0.61 to 0.96. This suggested that the litter-C was predominantly in a recalcitrant form and, therefore, the associated N was unlikely to be rapidly released in the hoop pine litter layer.     

Effects of clear-cutting on decomposition processes in leaf litter and the nitrogen and lignin dynamics in a temperate secondary forest

The effects of clear-cutting on the decomposition rate of leaf litter and on nitrogen (N) and lignin dynamics were investigated in a temperate secondary forest. Decomposition processes were examined over an 18-month period by the litterbag method and compared between a clear-cut site and an adjacent uncut control site using leaf litter from five dominant tree species (Clethra barvinervis, Quercus serrata, Camellia japonica, Ilex pedunculosa and Pinus densiflora). The decomposition rate for litter from C. barvinervis, Q. serrata and I. pedunculosa was significantly greater in the clear-cut plot than in the control plot, and there was no significant difference between plots for C. japonica and P. densiflora. Water content of litter was consistently lower in the clear-cut plot than in the control plot. Nitrogen mass increased after 6 months in the control plot, whereas no net increase of N was observed in the clear-cut plot. Nitrogen concentration increased with respect to accumulated mass loss of litter and was consistently lower in the clear-cut plot for all five species. The mass of lignin remaining in decomposing litter was generally lower in the clear-cut plot, but lignin concentration in decomposing litter was not significantly different between the clear-cut and control plots.     

The influence of experimental acidification on needle litter decomposition in a Picea abies L. forest

The effect on litter decomposition rates was studied after annual additions for four years to the forest floor of sulfuric acid (64 kg S.ha^?1), sulfur powder (64 kg S.ha^?1), and in the first year limestone (dolomite) powder (412 kg Ca+230 kg Mg.ha^?1). The litter was Norway spruce needles which were incubated in the field in litter‐bags. Drastic reductions in decomposition rates were observed and the addition of diluted acid caused a rate reduction to 66% of that in control and the additions of sulfur powder a reduction to 80%. The effect of the sulfur powder on litter mass‐loss rate appeared to be delayed and could not be noted until one year after the first addition. No effect could be seen of the limestone powder.     

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.     

The chemical composition of needle and leaf litter from Scots pine, Norway spruce and white birch in Scandinavian forests

Needle litter from 14 stands of Scots pine (Pinus silvestris,L.), 13 stands of Norway spruce (Picea abies (L.) Karst.) andleaf litter from three stands of white birch (Betula pubescensEhrh.) were analysed for chemical composition. The concentrationsof the elements N, P, K, Ca, Mg and Mn as well as solid organiccomponents (lignin, cellulose and hemicelluloses) and solubleswere determined. When the average chemical compositions werecompared the Scots pine needle litter was clearly the most nutrient-poorlitter type. Of the solid organic-chemical components the ligninfraction dominated in the spruce and birch litter whereas thecellulose dominated in the pine needle litter. When Norway spruce and Scots pine were growing in adjacent standson soils with the same bedrock origin the spruce litter hadsignificantly higher concentrations of nutrients (N, P, K, Ca,Mg, Mn) than the pine needle litter. At sites where Norway spruceand white birch were growing in adjacent stands, the birch leaflitter had generally higher concentrations of nutrients. However, significant or nearly significant differences were onlyobtained for Mg (P = 0.002), K (P = 0.056) and N (P = 0.087),probably due to the few replicates of stands compared. Concerningorganic chemical components, the spruce needle litter had significantlyhigher concentrations of lignin and mannan than all the otherlitters and lower levels of ethanol-soluble substances, celluloseand galactan than the pine needle litter. Further, it had lowerconcentrations of water solubles, rhamnan and xylan than thebirch litter. No relationships were established between the nutrient statusof the conifer litters and the site index H100 (the dominantheight of the trees at a reference age of 100 years) of thestands. Concentrations of solid carbohydrates in the litterswere, however, positively correlated with site index (P <0.001). Further, the concentration of nitrogen in the pine needlelitter was negatively correlated with the latitude of the sites(P < 0.01). The influence of litter chemistry on the decompositionof litter and nutrient cycling of forests is discussed.     

松针的综合利用

松针是重要的森林资源,富含多种有机成分和生物活性物质,经过适当的加工可以生产多种重要的林产品。     

The influence of experimental acidification on nutrient release and decomposition rates of needle and root litter in the forest floor

The influence of experimental acidification (diluted H₂SO₄) on mass-loss rates of needle and root litters was investigated in forests of Scots pine, lodgepole pine, Norway spruce and white birch located in a climatic transect through Sweden. Of the two dosages given (32 and 96 kg S ha⁻¹), significant effects on mass-loss rates were observed mainly with the higher dose. When comparing the effect of acid on mass-loss rate of needle litter on all sites together for the whole 3-year period, no effect was seen. By distinguishing the different types of forest and understorey we found a significant general decrease in rate for needle litter of about 8% for the pine forest sites (n = 10). For the spruce sites (n = 8) and the birch sites (n = 2) no significant effects were seen. When considering single sites after 1 year of decomposition, significant effects (rate decrease) were also found for the birch forests. At some spruce sites significant differences in mass-loss rate were seen (both rate increase and rate decrease). When a significant effect was seen its magnitude was found to be dependent on the decomposition rate (soil biological activity) of that site.For root litter the results were less clear. No significance was seen when comparing all sites together or sites of one type of forest. Significant decreases in mass-loss rate after acid treatment were, however, noted for some of the sites after different incubation periods. The patterns of dynamics of the nutrients N, P, S, K and Ca were not affected whereas those of Mg and Mn were and significantly higher release rates were found for these nutrients after acid treatment. The release rates of the nutrients N, P, S, K and Ca from litter were proportional to litter mass-loss and for the Scots pine stands this meant a decreased release rate for these nutrients.     

Lophodermium needle cast,insect defoliation and growth responses of young Scots pines in Estonia

Using a retrospective approach, based on historical needle cast disease and insect pest records, data series of needle losses (reconstructed by the use of the needle trace method), tree growth parameters and meteorological data were studied to determine the impact of the appropriate pointer (epidemic or calamity) years on the annual radial and height increment of 46 sample trees in six Scots pine (Pinus sylvestris) stands in Estonia from 1887 to 2006. First, the needle cast epidemics during the last 120 years were retrospectively determined, with resulting 4.6 epidemics per decade as a mean frequency. If the sum of precipitation from May to August reached 300 mm (the mean of 12 epidemic years studied: 361 ± 15 mm), an epidemic of needle cast caused by Lophodermium seditiosum might follow the next year in young plantations. For insect defoliators, similarly clear triggering threshold values of precipitation or temperature could not be determined, although dry and warm summers and mild winters supported the calamities. We separately detected that both larger needle losses and growth reductions in trees related to Lophodermium needle cast epidemic years lasted until the same age of pines, 22–24 years, but for insect pest (diprinoid sawflies) calamity years the growth reduction lasted longer. The relevance of these findings for the prediction of Lophodermium needle cast epidemics is briefly discussed.