Replanting conifer seedlings after pine weevil emigration in spring decreases feeding damage and seedling mortality

Replanting at appropriate times after harvesting a coniferous forest stand can help efforts to suppress seedling mortality caused by the pine weevil Hylobius abietis, but optimal times are uncertain. We hypothesized that planting in June rather than May in the third season after harvest would reduce feeding damage by the pine weevil and increase seedling survival rates in central Sweden, where new-generation weevils mainly fly away from their development sites in May/early June. An experimental test of the hypothesis in eight clear-cuts confirmed that planting in June instead of May reduced proportions of seedlings attacked by pine weevil, bark removal from seedlings’ stems, and proportions of seedlings killed by feeding damage. These differences between seedlings planted in May and June declined to some extent with time but still remained significant after two growing seasons. The total seedling mortality after two seasons did, however, not differ significantly between seedlings planted in May and June. Overall, 29% of all seedlings were killed by pine weevil, 4.0% by Hylastes bark beetles, and 2.3% by drought. The results indicate that replanting in spring during the third season after harvest can advantageously continue until mid-June with respect to damage and mortality.     

Biochemical responses associated with induced resistance to Colletotrichum acutatum in Pinus radiata seedlings treated with methyl jasmonate and Trichoderma spp.

The effect of Trichoderma (T. atrobrunneumFCC320 and T. atrovirideLU633) and/or methyl jasmonate (MJ) on resistance to terminal crook (Colletotrichum acutatum) and on seedling biochemistry was investigated in radiata pine (Pinus radiata) seedlings. Seedlings were germinated and grown in Trichoderma‐amended or non‐amended media for 3 months and then sprayed with 2.25 mM MJ 1 week before inoculation with C. acutatum. The incidence and severity of terminal crook in the seedlings treated with MJ and Trichoderma+MJ were lower than in Trichoderma‐treated and Trichoderma‐untreated seedlings. The MJ‐induced resistance response was concomitant with an increase in the concentrations of the monoterpenes α‐pinene, β‐pinene, β‐phellandrene, camphene and myrcene in needles, and also α‐pinene, β‐pinene and camphene in stems. The concentrations of α‐pinene, β‐pinene and camphene were elevated from at least 1 week until 4 weeks after MJ application, compared with those in non‐MJ counterparts. Trichoderma alone did not affect monoterpenes, but the concentrations of α‐pinene, β‐pinene and camphene were greater in needles of Trichoderma+MJ than in MJ‐treated seedlings after 28 days. Total phenolic concentration in needles and peroxidase activity in stems were twofold greater in MJ‐treated seedlings than in non‐MJ seedlings over the same period. None of the treatments affected the activity of peroxidase in needles. It is proposed that the accumulation of monoterpene and phenolics and the induction of peroxidases contribute, in part, to MJ‐induced resistance to terminal crook in radiata pine seedlings.     

Effects of planting time on pine weevil (Hylobius abietis) damage to Norway spruce seedlings

Feeding by pine weevil (Hylobius abietis L.) causes severe damage to newly planted conifer seedlings in most parts of Scandinavia. We investigated the effect of planting time and insecticide treatment on pine weevil damage and seedling growth. The main objective was to study if planting in early autumn on fresh clear-cuts would promote seedling establishment and reduce the amount of damage caused by pine weevil the following season. The experiment was conducted in southern Sweden and in south-eastern Norway with an identical experimental design at three sites in each country. On each site, Norway spruce seedlings with or without insecticide treatment were planted at four different planting times: August, September, November and May the following year. In Sweden, the proportion of untreated seedlings that were killed by pine weevils was reduced when seedlings were planted at the earliest time (August/September) compared to late planting in November, or May the following year. This pattern was not found in Norway. The average length of leading shoot, diameter growth and biomass were clearly benefited by planting in August in both countries. Insecticide treatment decreased the number of seedlings killed or severely damaged in both Norway and Sweden.     

Effect of Reforestation Methods on Pine Weevil (Hylobius abietis) Damage and Seedling Survival

Örlander, G.1 and Nilsson, U. (Swedish University of Agricultural Sciences, The Southern Swedish Forest Research Centre, Asa Forest Research Station, S-360 30 Lammhult, Sweden and Swedish University of Agricultural Sciences, The Southern Swedish Forest Research Centre, Box 49, S-230 53 Alnarp, Sweden). Effect of reforestation methods on pine weevil (Hylobius abietis) damage and seedling survival. Received Feb. 16, 1998. Accepted Sept. 15, 1998. Scand. J. For. Res. 00: 000-000, 199X. Damage to Norway spruce (Picea abies (L.) Karst.) seedlings by the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), was monitored in relation to clear - cutting age and silvicultural treatments in southern Sweden. New clear - cuttings were established on four sites during five consecutive years, and seedlings were planted on them from 1989 through 1993. In total, 31 774 seedlings were planted on 20 clear - cuttings. The measures evaluated were seedling insecticide treatment, application of herbicide to ground vegetation, scarification (mound) and planting late in the season. In addition, the effects of slash removal and seedling type were studied. The pine weevil was, by far, the dominant damaging agent. Planting without insecticide or soil treatment on fresh, one- or two - year - old clear - cuttings resulted in a mean level of weevil - caused mortality exceeding 60%. The results indicate that the risk of serious damage by pine weevils remains high until the clear - cuttings reach four or five years of age. Killing the vegetation with herbicide had no effect on pine weevil damage. Slash removal decreased damage on older clear - cuttings, but the effect was small. Scarification (mounding) strongly reduced damage. On fresh clear - cuttings the mean mortality caused by pine weevils in mounded plots was 13%, whereas it was 77% in the controls. The mounding effect varied between sites and clear - cuttings of different ages. Late planting (10 June instead of 1 May) reduced damage on two- and three - year - old clear - cuttings. Three - year - old, bare - rooted seedlings were not damaged as seriously as two - year - old, containerized ones, but the effect was probably due to the larger size of the bare - rooted seedlings. Non - lethal injury resulted in reduced seedling growth. Damage by pine weevils varied between years and within growing seasons. However, on fresh, one- and two - year - old clear - cuttings, damage was severe enough to cause high mortality during all studied years.     

松褐天牛引诱剂Mat-1号的研究

以单萜烯类化合物为主要成份配制的松褐天牛ＭｏｎｏｃｈａｍｕｓａｌｔｅｒｎａｔｕｓＨｏｐｅ引诱剂Ｍａｔ—１号，主要对产卵期的松褐天牛起引诱作用。每个诱捕器在成虫出现期的诱捕量最高可达７４．３头，初诱日在５月２０日前后，终诱日在９月上旬。在离林缘３０ｍ、５０ｍ、１００ｍ、１５０ｍ、２００ｍ距离引诱到的松褐天牛百分比分别为５０％、２０．０％～２２．７％、１２．５％～１３．７％、９．１％～１０％、４．５％～７．５％，引诱的最远距离为２００ｍ     

Assessment of pine weevil numbers on clear-cut and forest sites with shelter boards and pitfall traps

Field experiments were conducted in 1991 and 1992 on clear-cut and forest sites in four forest areas in southern Sweden with the aim to test possibilities for estimating pine weevil (Coleoptera: Curculionidae) population sizes. More pine weevils (Hylobius abietis andH. pinastri) were caught in baited pitfall traps than under shelter boards. The proportions ofH. pinastri in the totalHylobius catch were higher under shelter boards than in pitfall traps, indicating a difference between the species in behaviour towards the trap types. Numbers ofH. abietis found on forest sites were lower than those on fresh clear-cut sites, but not those on one year old or older clear cut sites. In mark-recapture experiments the recapture rates ofH. abietis ranged from zero to 73%; they were zero on fresh clear-cut sites. Recapture rate was not correlated to dispersal distance. Estimates of population size (Schnabel method) were in magnitudes of 150 to 5000H. abietis per hectare. The estimates did not reveal consistent differences between forest and one-year old or older clear cuttings. Dispersal distances were on average 6.0 m in 1991 and 5.4 m in 1992. Only in one area in 1992 the dispersal distances were significantly different between forest and clear-cut site.     

Antifungal properties of terpenoids in Picea abies against Heterobasidion parviporum

The antifungal properties of 14 major oleoresin‐constitutive terpenoids of Norway spruce (Picea abies) against Heterobasidion parviporum were evaluated in vitro at three gradient concentrations, 0.1, 0.2 and 0.4 μmol/cm², on potato dextrose agar medium. Eight monoterpene hydrocarbons (+)‐ and (?)‐α‐pinene, (?)‐β‐pinene, (+)‐3‐carene, myrcene, (+)‐ and (?)‐limonene, terpinolene; four oxygenated monoterpenes α‐terpineol, terpinen‐4‐ol, 1,8‐cineole, bornyl acetate; and two resin acids abietic acid and dehydroabietic acid were selected. Abietic and dehydroabietic acids showed the highest antifungal activities at all concentrations. Among oxygenated monoterpenes, bornyl acetate and α‐terpineol showed antifungal activity at the highest concentration. Among monoterpene hydrocarbons, (+)‐α‐pinene showed similar activity to terpinen‐4‐ol and 1,8‐cineole at the highest concentration; however, it was lower than α‐terpineol and bornyl acetate. Other monoterpene hydrocarbons inhibited mycelial growth by <10%. Re‐extraction of medium surfaces after the test period revealed that most α‐terpineol and terpinen‐4‐ol remained unchanged on the surface but monoterpene hydrocarbons completely disappeared. However, notable fungal transformed products were observed on surfaces applied with 1,8‐cineole and bornyl acetate. Thus, mycelial growth inhibition of monoterpenoids might be caused by complex functions such as biodegradation and/or detoxification by interaction between mycelium and compound. These results provide a basis for future studies considering the role of chemodiversity in the comprehensive chemical defence of P. abies.     

Monitoring spruce bark beetle (Ips typographus (L.)) populations under non‐epidemic conditions

Population levels of Ips typographus in 8 Danish forest districts were monitored by pheromone traps and baited trees in 1988 and 1989. The number of trees with spontaneous colonization was also registered. All monitoring results were below earlier defined “risk thresholds”;, and accordingly no serious damage was found. Mean catch ranged from 3406 to 12043 beetles per trap group, and induced colonization averaged 1.08 trees per tree‐baiting site. Trie number of colonized trees (total infestation) ranged from 3.5 to 63.2 trees per 100 ha forest. Correlation was found between mean catch and induced colonization (r=0.56), and between induced colonization and total infestation (r=0.65). Accumulated data from 1988–89 and 1984–86 showed good correlation between catch size and number of infested standing trees (r=0.91). From 1988 to 1989 no significant changes occurred, apart from a shift in host material from standing trees to windfalls and timber. I. Typographus monitoring on regional levels is possible also under non‐epidemic conditions. With a limited number of monitoring units, trapping, tree‐baiting and registrations of infestation in exposed edges can give estimates sufficiently accurate to be of practical use to local foresters.     

Role of monoterpenes in Hylobius abietis damage levels between cuttings and seedlings of Picea sitchensis

Abstract

This study investigated the role of monoterpenes, a group of chemicals known to be involved in plant defence, in the susceptibility of Sitka spruce [Picea sitchensis (Bong.) Carr.] plants derived from both cuttings and seedlings to attack by the large pine weevil Hylobius abietis (L.). Results showed that, given the choice, weevils prefer to feed on the shoots of seedlings than of cuttings and that this preference continued over a period of 6 days, although the overall level of feeding declined. This observation was associated with a higher level of monoterpenes in the shoots from cuttings than in those from seedlings. When the weevils were restricted to the stems and given no choice, levels of damage to the bark were similar in both plant types.     

Blowfly (Diptera,Calliphoridae) damage on stockfish in northern Norway: pest species,damage assessment and the potential of mass trapping

Production of high quality stockfish in northern Norway takes place from February to May. The dominant blowfly species (Diptera: Calliphoridae) with adults present during stockfish production were Calliphora vicina and Protophormia terraenovae. Larval collections identified the damage-causing species to be C. vicina. Other saprophagous blowfly species were only found after the production period. Fish dried in sun-exposed locations experienced more damage than fish in shaded locations, and the risk of damage was higher in fish dried later in the production period. Yellow sticky traps and funnel traps baited with dimethyl trisulphide were tested for their potential in mass trapping. Sticky traps caught flies during early spring, while funnel traps increased in efficiency closer to summer. Attraction to dimethyl trisulphide was found to be significantly higher for C. vicina compared to P. terraenovae, and the catch of C. vicina consisted of 92% females. The catch of female flies during the critical drying period consisted of 5–30% of the estimated number of flies having caused damage. The target specificity with high female catches and the cost efficiency of these traps indicate that mass trapping can be used as an integrated part of a management program to reduce damage from blowflies in stockfish producing areas.     

3个中国沙棘优良品种扦插技术研究

针对辽西地区沙棘资源发展现状,以3个中国沙棘优良类型中红果、中黄果、中无刺为研究材料,对其苗木繁育技术进行了深入系统的研究。结果表明,采用炉渣灰扦插基质、ABT生根粉1号、插穗长度10cm左右、扦插时间为6月21日左右,这种处理效果最佳,但从经济角度考虑,最宜采用鲜河沙作为基质。中国沙棘苗木繁育采用裸地沙盘全光喷雾嫩枝扦插快繁技术效果较好。沙棘硬枝扦插的成苗率受多种因素的制约,硬枝扦插时间为4月下旬至5月初,采用20cm长的插穗,2~3年生的插穗成苗率较高,生产中采用2年生的插穗。     

Pine Weevil Population Density and Damage to Coniferous Seedlings in a Regeneration Area With and Without Shelterwood

Damage to planted conifer seedlings by the pine weevil, Hylobius abietis (L.), is considered to be less severe in shelterwoods than in clear-cuttings. To evaluate possible reasons for this reduction, this study investigated the relationship between seedling damage and pine weevil population density in the presence and absence of shelter trees. Assessments of seedling damage throughout a full growth season and absolute population density estimates were made at a fresh clear-cutting and an adjacent shelterwood (1 ha each). A grid of 100 pitfall traps was placed over each area, and population estimates were made using the mark–recapture technique. Pine weevil damage to seedlings was about twice as high in the clear-cutting, whereas pine weevil density was estimated to be higher in the shelterwood or about the same in the two treatments (～14?000 weevils ha^?1). Existing differences in microclimate between the shelterwood and clear-cutting did not seem to be the cause of the differences in damage levels. Thus, the hypothesis that seedling damage is reduced in shelterwoods because of increased availability of alternative food remains a candidate for further testing.     

Estimating risks for spruce bark beetle (Ips typographus (L.)) damage using pheromone‐baited traps and trees

The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 12 forest districts in the Nordic countries during three years. Pheromone‐baited traps and trees were used. Five groups of three traps were deployed annually on fresh spruce clear‐fellings in each district. The mean catches within districts and years ranged from 950 to 46000 beetles per trap group. The standard error averaged 15 % of the mean catch. One tree was baited annually at each of five other sites in each district. The mean number of trees colonized by Ips typographus in each district and year ranged from 0 to 5 per site. The standard error was high, averaging 44% of the mean. Inventories of tree mortality within the districts yielded values ranging from 0 to 150 killed trees per km of spruce forest edge. There was a strong linear correlation between mean catches in traps and log‐transformed tree mortality (r=0.82). The correlation between colonization success at tree‐baiting sites and tree mortality was weaker (r=0.59), owing to one deviant observation. The results indicate that pheromone traps and baited trees may be used to assess the risk for damage caused by Ips typographus.     

红皮云杉S_(3-0)苗龄型苗高年生长规律的研究

以红皮云杉S3-0苗龄型的苗木为对象,连续3 a观测年生长规律,结果表明:红皮云杉S3-0整个生长期可划分为4个阶段,分别为:生长初期,5月中下旬至6月上旬;生长速生期,6月上旬至7月上旬;生长未期,7月上旬至7月下旬或8月上旬;停止生长期,7月下旬或8月上旬。     

Resistance of picea abies to ips typographus: tree response to monthly inoculations with ophiostoma polonicum,a beetle transmitted blue‐stain fungus

Fifty pole stage trees were inoculated with O. polonicum at monthly intervals between May and September. Most infection, measured as the area of sapwood blue‐stained, occurred in July and least in May and September. The difference between July, August and September might be explained by the effect of temperature on fungal growth, but in May and June the trees had a higher resistance than expected. Tree resistance was correlated with resinosis. Tree variables not correlated with resistance were DBH, annual ring width, periodic growth, vigor index, or phloem carbohydrate concentration.     

应用聚集信息素监测与防治纵坑切梢小蠹效果初报

为了防控纵坑切梢小蠹对红松的危害,在抚松县林业局红松母树林利用人工合成信息化学物质———聚集信息素对纵坑切梢小蠹进行监测与防治,结果表明:利用聚集信息素诱捕器对纵坑切梢小蠹的诱捕数量比人工调查查获数量提高50倍以上,监测准确率可达到100%,持续防治4 a后的林间诱集量下降率为81.6%。纵坑切梢小蠹在抚松县的扬飞期从5月中旬开始,高峰期出现在6月中旬,至7月中旬扬飞量明显减少,至9月上旬扬飞期基本结束。     

F2型引诱剂对辽宁云杉花墨天牛诱捕效果试验

为探究辽宁省松材线虫病发生区林间云杉花墨天牛Monochamus saltuarius Gebler种群发生规律,验证F2型引诱剂对云杉花墨天牛诱捕效果,2018年5—8月在辽宁省抚顺市和丹东市开展了诱捕天牛试验.结果显示:F2型引诱剂对云杉花墨天牛具有较好引诱效果,在抚顺、丹东试验松林内,F2型引诱剂共诱捕到天牛14...     

Rejuvenation of juvenile growth characters in picea abies

Cuttings were made from six‐year‐old seedlings of Picea abies L. (Karst.) that had been studied in the Stockholm phytotron. The seedlings belonged to four full‐sib families, one being of French origin, one of North‐Swedish origin and two being hybrids between parents of North‐Swedish and French origin. Nine clones from each family were included. After the rooting phase, the cuttings were exposed to the same cultivation regimes as the seedling ortets. Characteristics of growth rhythm, percentage free growth and leader length were recorded during the 2nd to the 5th growth period (GP). Plagiotropic growth habit was recorded in the 3rd to the 5th growth period, and, characteristics of the rooting phase were studied. A juvenile behaviour very similar to that characterizing growth periods 2–3 of the seedlings was observed for growth rhythm characteristics and for free growth capacity during GP2 of the cuttings. The absolute value of the differences between each observation of the seedling ortets in GP6 and the means of the cuttings in GP2 produced a new variable that quantified the degree of rejuvenation. This new variable was meaningfully calculated only for growth rhythm and growth pattern variables. A gradual reversion of the growth rhythm occurred for the cuttings, which corresponded to the change with increasing age for the seedlings. The capacity for free growth, on the contrary, disappeared already in GP3 for the cuttings, except for the French family. A large variation in the rejuvenation ability between families was observed. Furthermore, the rejuvenation ability was negatively correlated with the ability to grow plagiotropically.     

Field performance of Salix clones propagated via shoot cultures in vitro

Survival, growth, plant structure and insect damage of in vitro‐derived cuttings from two Salix clones (5. schwerinii and 5. viminalis) were compared in a field trial with performance of conventional cuttings of the same clones. No obvious morphological abnormalities were induced by in vitro treatment. The survival rate of in vitro‐derived cuttings of the S. schwerinii clone was much higher than that of conventional cuttings. In the 5. viminalis clone, height growth was slightly but significantly reduced for in vitro‐derived cuttings compared with conventional cuttings although stem basal area and estimated plant dry weight were unaffected. The number of stems per cutting, the number of side shoots per stem and gall midge damage did not appear to be affected by the type of cutting. Electrophoretic analysis of 12 enzyme systems revealed identical isozyme patterns for m vitro‐derived and conventionally propagated plants.     

梁山慈竹播种育苗技术

通过对梁山慈竹种子贮藏时间、播种覆盖方式及实生苗移植时间、合理密度的研究,其结果表明,采种后在自然条件下贮藏10 d是比较理想的贮藏期(即5月下旬至6月上旬播种);遮阴是获得较多和较好幼苗的关键技术措施,用地膜+遮阴网覆盖的方法,是理想的覆盖方法;梁山慈竹幼苗移植应在8月20日前进行;苗圃生产中以采用30cm×35cm的移植密度较好.