Pest Of Spruce Research Articles

Pest categorisation of Gilpinia hercyniae.

The Panel on Plant Health performed a pest categorisation of the Diprionid sawfly, Gilpinia hercyniae Hartig (Hymenoptera: Diprionidae), for the EU. G. hercyniae is a well‐defined and distinguishable species, native to Europe but also present in North America, Japan, Mongolia, Korea and Pakistan, and recognised as a pest of spruce (Picea spp.). The pest is distributed in 19 Member States (MSs) of the EU. It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC. Protected zones are in place in Greece, Ireland and the United Kingdom (Northern Ireland, Isle of Man and Jersey). Plants for planting of Picea spp. and soil and litter associated with Picea spp. are considered as pathways for this pest, which is also able to disperse by flight. The prepupae overwinter inside cocoons in the litter or in the foliage. In spring, the adults, mostly females emerge and lay 35–60 eggs per female in mature needles. The larvae feed on the mature needles through five instars. There are 1–3 generations per year; some of the prepupae undergo prolonged diapause for more than 1 year. The impact on Picea abies (= excelsa) is minimal, because only the needles of the previous years are attacked; however, outbreaks have occurred on non‐native spruce, Picea glauca and Picea sitchensis. The pest is controlled everywhere by natural enemies, including nuclear polyedrosis viruses. The insects spread on plants for planting of Picea spp., with soil and litter associated with Picea spp., and by flight. The EU protected zones have a similar climate and similar host plants as the MS where G. hercyniae is established. All criteria assessed by EFSA for consideration as potential protected zone quarantine pest and as a potential regulated non‐quarantine pest were met.

Pest categorisation of Ipstypographus.

The Panel on Plant Health performed a pest categorisation of the eight‐toothed spruce bark beetle, Ips typographus L. (Coleoptera: Curculionidae, Scolytinae), for the EU. I. typographus is a well‐defined and distinguishable species, recognised mainly as a pest of spruce (Picea spp.) in Eurasia. It also attacks other conifers such as Abies spp., Larix spp., Pinus spp. and Pseudotsuga menziesii. Native to Eurasia, I. typographus has spread from the native range of spruce to new areas in Eurasia where spruce has been planted, and is now widely distributed throughout the EU (22 Member states). It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC for Ireland and United Kingdom as protected zones. Coniferous wood, bark and wood packaging material are considered as pathways for the pest, which is also able to disperse by flight over tens of kilometres. The insects normally establish on fallen trees but can also mass‐attack healthy trees, killing millions of spruces. The males produce pheromones that attract conspecifics of both sexes. Each male attracts one to four females; each female produces 2–80 offspring. The insects also inoculate pathogenic fungi to their hosts. There are one to three generations per year. The wide current geographic range of I. typographus suggests that it is able to establish anywhere in the EU where its hosts are present. Sanitary thinning or clear‐felling are the major control methods. Pheromone mass trapping is presently judged unreliable because of the large dispersal capacity of the pest. Quarantine measures are implemented to prevent entry in yet uncolonised areas. All criteria assessed by EFSA for consideration as potential protected zone quarantine pest are met. The criteria for considering I. typographus as a potential regulated non‐quarantine pest are not met since plants for planting are not a pathway.

Pest categorisation of Dendroctonus micans.

The Panel on Plant Health performed a pest categorisation of the great spruce bark beetle, Dendroctonus micans (Kugelann), (Coleoptera: Curculionidae, Scolytinae), for the EU. D. micans is a well‐defined and distinguishable species, recognised mainly as a pest of spruce (Picea spp.) and pine (Pinus spp.) in Eurasia. Attacks on other conifers (Abies spp., Larix decidua, Pseudotsuga menziesii) are also reported. Supposedly originating from north‐eastern Eurasia, D. micans has spread westward and is now distributed throughout the EU (22 Member States). It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC for Greece, Ireland and the United Kingdom (Northern Ireland, Isle of Man and Jersey) as protected zones. Wood, wood products, bark and wood packaging material of the conifers genera listed as hosts are considered as the main pathways for the pest, which is also able to disperse several kilometres by flight. The sib‐mating habits of the species allow each single female to start a new colony on her own. The pest's wide current geographic range suggests that it is able to establish anywhere in the EU where its hosts are present. The beetles attack living trees and usually complete their life cycle without killing their host, except under epidemic conditions at the limits of their distribution range, where hundreds of thousands of trees can be killed. Sitka spruce (Picea sitchensis) is particularly susceptible. Biological control using the very specific predatory beetle, Rhizophagus grandis, is a widespread and efficient option that has been implemented in all areas suffering from outbreaks. It is complemented by sanitary thinning or clear‐felling. All criteria assessed by EFSA for consideration as potential protected zone quarantine pest were met. The criteria for considering D. micans as a potential regulated non‐quarantine pest are not met since plants for planting are not the main pathway.

Pathogens of Ips amitinus: new species and comparison with Ips typographus

AbstractIps amitinus and I. typographus are two serious pests of spruce in Europe, have similar bionomics and are likely to occur and meet on the same host trees. We therefore hypothesized that the two species support similar levels of similar pathogens. To test this hypothesis, we collected mature beetles from three trap trees at each of eight study sites and determined beetle numbers and pathogen infection levels. In total, 938 mature I. amitinus beetles and 3435 of I. typographus were dissected; five pathogens, as well as intestinal nematodes and endoparasitoids, were detected. The neogregarine Mattesia schwenkei is reported here for the first time as a new pathogen in 9.4% of I. amitinus individuals at one site. Average infection levels of most pathogens (Chytridiopsis typographi, Gregarina typographi, Mattesia schwenkei and parasitoids) were significantly higher in I. typographus than in I. amitinus. Metschnikowia typographi was confirmed only in Ips amitinus, while the microsporidium of Nosema typographi occurred only in I. typographus. Within‐season increases in G. typographi infection levels were documented in Ips amitinus.

Interactions between green spruce aphid (Elatobium abietinum (Walker)) and Norway and Sitka spruce under high and low nutrient conditions

Abstract1 Green spruce aphid (Elatobium abietinum) is a serious pest of spruce (Picea spp.) in north‐west Europe, causing defoliation of one‐year‐old and older needles.2 Relationships between population development of E. abietinum, needle loss and tree growth were compared for five pure genotypes of Sitka spruce and mixed‐genotype material of Sitka and Norway spruce, grown under high and low nutrient conditions.3 Despite wide differences in flushing date between spruce genotypes, E. abietinum populations peaked on the same date on each genotype and on the mixed‐genotype material, irrespective of nutrient supply.4 Larger aphid populations developed on trees grown under high nutrient conditions than under low nutrients. However, more needles were lost per aphid in the low nutrient treatment and overall defoliation rates in the two nutrient treatments were similar.5 Total aphid numbers differed significantly between Sitka spruce genotypes within nutrient treatments, but not in relation to bud‐burst or needle terpene content. Reductions in height growth caused by infestation were greater (15–44%), and related to mean aphid densities and defoliation, in the low nutrient treatment, but were smaller (11–27%) and not related to aphid density and defoliation in the high nutrient treatment.6 Development of E. abietinum populations was similar on Norway and Sitka spruce, but Norway spruce lost fewer needles. However, the effects of infestation on tree growth were more closely related to aphid density and were similar for Norway and Sitka spruce.7 Infestation caused a decrease in total root dry weight of Norway and Sitka spruce in proportion to the reductions observed in above‐ground growth.

Density Effects on the Conifer Mortality in Declining Spruce-fir Forest in Northern Japan: Implication of Bark Beetle Attack to, Cause Spruce Decline

We examined mortality patterns of two conifer species in relation to tree abundance and species composition in a declining spruce-fir forest in Akan National park, Hokkaido, northern Japan. The data taken from eleven 58 m × 58 m square study plots showed that percentage basal area (BA) of dead trees of canopy trees during the last decade was 49% forPicea jezoensis (Sieb. et Zucc.) Carr and 30% forAbies sachalinensis (Fr. Schm.) Masters. InP. jezoensis, percentage basal area (BA) of dead trees was positively related to both BA of its own species and proportion of it to BA of all species, whereas it was not significantly related to both of these variables inA. sachalinensis. Multiple logistic regression with dbh as a confounding factor also indicated that, inP. jezoensis, the proportion of dead stems was positively affected by the stem density of conspecific trees, whereas it was negatively affected by the stem density of the other species in each study plot. However, inA. sachalinensis, the proportion of dead stems was significantly related to neither of these factors. The different mortality pattern between two conifer species suggests that the spruce bark beetle,Ips typographus (L.), which is a serious pest of spruce, may have caused theP. jezoensis decline. Instead of wind-throw or thinning that usually initiate this bark beetle attack, some unknown factors seemed to predispose the trees to insect attack. These unknown factors may also explain the high mortality ofA. sachalinensis in this forest.

The white pine weevil in British Columbia: Basis for an integrated pest management system

Research programs to date in British Columbia on the biology, damage and control of the white pine weevil, Pissodes strobi (Peck), a pest of spruce, Picea spp. and pine, Pinus spp., are reviewed. Significant progress has been made in the areas of genetic resistance, silvicultural and chemical control. An integrated pest management (IPM) system is formulated which combines silviculture-driven and resistance-driven tactics. The system relies on accurate hazard rating of plantation sites and requires continuous monitoring of attack levels and the forecasting of plantation productivity under various IPM tactics through the use of a decision support system. Research needs which would increase effectiveness of the IPM system are reviewed and organized in the context of the plantation productivity cycle. Key words: insect control, Pissodes strobi, IPM, genetic resistance, silvicultural control, chemical control, decision support system

Mixed integer programming improves spray operation planning

The spruce budworm is the most destructive pest of spruce and fir forests in the northern United States and Canada. To counter the insect, the Maine Forest Service has, for the last decade (1975–1985), conducted a large-scale spray operation in Maine's northern and eastern forests. The operation involves the use of several types of aircraft flying from several airfields to spray hundreds of target areas. A minimum cost mixed integer programming model was developed to determine the airfield locations, the number of types of aircraft, and the flight plans to best conduct the spray operation. The model extends and complements a microcomputer linear programming model previously developed for and used by the Maine Forest Service. The savings obtained by the mixed integer programming model can be seen by the included comparison of their results.

Biology and Control of the Spruce Needleminer12

Taniva albolineana (Kearfott), considered to be a relatively minor pest of spruce, was a serious pest of young Black Hills spruce, Picea glauca var. densata Bailey, in nurseries during 1970–72. Foliar sprays of several insecticides applied during July were effective in controlling this insect. The compounds and rates of AI/100 gal water were carbaryl at 0.5 and 1.0 lb, diazinon at 0.25 and 0.5 lb, dimethoate at 0.15 and 0.3 lb, trichlorfon at 1.0 lb, and Gardona® (2-chloro-l-[2,4,5-trichlorophenyl]vinyl dimethyl phosphate) at 1.0 lb.

Notes on the Life History and Seasonal Development of the Pine Needle Scale, Phenacaspis pinifoliae (Fitch) (Diaspididae: Homoptera)

The pine needle scale is a serious pest of spruce and pine in shelter-belt and ornamental plantings in the agricultural region of the Prairie Provinces of Canada. The present study was made to provide accurate data on the life cycle, habits, and seasonal development of the pine needle scale in this region. This information is essential for investigations of artificial control.Observations were made at Indian Head, Sask., in 1947. The populations sampled were on Scotch pine in a shelter belt and white spruce in an ornamental planting. Other populations were sampled when further information was required.