Application of methyl jasmonate reduces growth but increases chemical defence and resistance against
            Hylobius abietis
            in Scots pine seedlings

Key words: forest regeneration, Conniflex, Trico, mechanical site preparationForest regeneration is crucial stage in commercial forest management because actions during this stage impact future forest productivity and value. Scots pine is one of the main tree species in forestry of the northern part of Europe. Foresters have to overcome different risk factors during regeneration process and two of them are seedling damage by Pine weevil (Hylobius abietis L) and browsing by herbivores of Cervidae family. Pine weevil is one of the main forest pests in Europe that damage regenerated coniferous stands. Damage caused by this pest can produce 70% mortality of planted seedlings. Another significant risk factor is browsing. With increase of deer (Cervidae) population the damaged forest area also increases to the extent that foresters choose other tree species for regeneration. The mitigation of these risks is possible with appliance of forest management practices. &#160;There are used different repelents against Cervidae animals. &#160;Regarding Pine weevil, due to restrictions on insecticide use in EU, different protective coating materials have been developed, and several studies show that soil preparation before planting reduce amount of damaged Pine seedlings and increase possibility of successful regeneration. &#160;We evaluated if and how forest management methods - soil preparation techniques (spot mounding, disc trenching) in combination with different plant protection products (Conniflex, Trico) - affects the degree of damage caused by pine weevil and Cervidae animals to Scots pine seedlings one and two years after outplanting in four forest stands in Latvia. The results from this study shows that application of Conniflex reduce number of damaged trees by 16.8% first and 20.3% second year after outplanting compared to untreated seedlings. Soil preparation has significant impact on reduction of pine weevil damage. The best results have been achieved by planting with Conniflex treated seedlings on spot mounds (2.4% damaged trees compared to 48.9% in unprepared soil without treatment). Repellent Trico do not provide additional protection against Pine weevil and do not have long term protection effect against browsing. Overall conclusion is that combination of soil preparation and use of appropriate coating material (Conniflex) can provide sufficient protection without usage of insecticides, and Trico has to be applied before winter season to achieve effect of protection.

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Induction of Defense Responses in Pinus sylvestris Seedlings by Methyl Jasmonate and Response to Heterobasidion annosum and Lophodermium seditiosum Inoculation

Forests ◽

10.3390/f12050628 ◽

2021 ◽

Vol 12 (5) ◽

pp. 628

Author(s):

Ilze Šņepste ◽

Baiba Krivmane ◽

Vilnis Šķipars ◽

Astra Zaluma ◽

Dainis E. Ruņģis

Keyword(s):

Pinus Sylvestris ◽

Methyl Jasmonate ◽

Scots Pine ◽

Insect Pests ◽

Defense Responses ◽

Heterobasidion Annosum ◽

Protective Mechanism ◽

Seedling Mortality ◽

Pine Seedlings ◽

Seedling Inoculation

The induction of defense responses in Pinus sylvestris L. seedlings by methyl jasmonate (MeJA) was investigated in three experiments. Two different MeJA application methods were tested, and induction of defense responses was assayed by seedling inoculation with Heterobasidion annosum (Fr.) Bref. and Lophodermium seditiosum Minter, Staley and Millar. In the first experiment, five-year-old P. sylvestris ramets of one clone were directly treated with MeJA, followed by inoculation with H. annosum. In the second experiment, open-pollinated Scots pine seedlings were treated with MeJA by direct spraying and vaporization, and inoculation with H. annosum was done using a slightly modified protocol. In the third experiment, open-pollinated Scots pine seedlings were treated with MeJA by vaporization and inoculated with L. seditiosum. Direct application of MeJA induced seedling mortality, and in some cases, decreased resistance to inoculation with H. annosum. Application of MeJA by vaporization was less stressful for seedlings, and resulted in increased resistance to both H. annosum and L. seditiosum. In addition, an unforeseen Neodiprion sertifer (Geoffroy) and Hylobius abietis L. infestation provided anecdotal evidence of the efficacy of MeJA in inducing resistance to insect pests as well. Further studies are required on the induction of resistance to additional diseases and pests. Induced resistance could be used as a possible protective mechanism for Scots pine seedlings prior to planting during reforestation of stands to increase vitality and survival.

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Emissions of biogenic volatile organic compounds (BVOCs) from the rhizosphere of Scots pine (Pinus sylvestris) seedlings exposed to warming, moderate N addition and bark herbivory by large pine weevil (Hylobius abietis)

Plant and Soil ◽

10.1007/s11104-021-04888-y ◽

2021 ◽

Author(s):

Muhammad Usman Rasheed ◽

M. Kivimäenpää ◽

A. Kasurinen

Keyword(s):

Scots Pine ◽

Growth Conditions ◽

Hylobius Abietis ◽

N Addition ◽

Single Exposure ◽

Oxygenated Monoterpenes ◽

Growing Seasons ◽

Pine Seedlings ◽

Volatile Organic ◽

Pine Weevils

Abstract Aims Biogenic volatile organic compound (BVOC) research has been mostly focused on foliar emissions. In this experiment, the main focus was on rhizosphere BVOC emissions of Scots pine seedlings under changing growth conditions. Methods Soil-growing Scots pines were exposed to increased air (0.5°C) and soil (4.0°C) temperature and N addition (30 kg N ha− 1 yr− 1) for three growing seasons in a field experiment. In addition to these factors, seedlings were exposed to bark herbivory by large pine weevils in two last seasons. Gas-chromatography and mass-spectrometry was used for analyzing the BVOC samples collected from pine rhizosphere. Results Almost 98 % of BVOCs were non-oxygenated monoterpenes (nMTs), 1 % oxygenated monoterpenes (oMTs), 0.5 % sesquiterpenes (SQTs), and 1 % other BVOCs. In both years, there was an interaction of warming, N addition and bark herbivory on rhizosphere BVOC emissions. In 2015, warming and N addition in single exposures decreased oMT emissions, while herbivory in single exposure increased oMT emissions. In 2016, the three-way interaction showed that the effects of warming, N addition and herbivory on BVOCs were mainly detected in single exposures. In 2016, warming decreased nMT, oMT, SQT and other BVOC emissions; N addition decreased oMT and SQT emissions; and herbivory decreased SQT and other BVOC emissions. Conclusions Warming and N addition in single exposures decreased the rhizosphere BVOC emissions. The effect of bark herbivory on BVOC emissions varied between the years from increase to decrease. It seems that under altered growth conditions Scots pine seedlings may reduce carbon investment to rhizosphere BVOCs.

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Effect of buds manually removal and their damage by large pine weevil (Hylobius abietis L.) on Scots pine seedlings in Siversky Donets river valley

Наукові праці Лісівничої академії наук України ◽

10.15421/411826 ◽

2018 ◽

pp. 113-120

Author(s):

Valentyna L. Meshkova ◽

Iryna M. Sokolova ◽

Serhii O. Yeroshenko ◽

Lesya M. Koval

Keyword(s):

Scots Pine ◽

Stem Bark ◽

Hylobius Abietis ◽

Height Increment ◽

Pine Weevil ◽

Apical Bud ◽

Apical Buds ◽

Lateral Buds ◽

Pine Seedlings ◽

Quantitative Influence

Large pine weevil (Hylobius abietis L.) damages different organs of Scots pine (Pinus sylvestris L.) seedlings in unclosed plantations, including foliage, buds, stem bark and roots. Simulated damage of respective organs, particularly debudding is one of the ways to evaluate qualitative and quantitative influence of such damage on tree condition. The aim of research was to evaluate the dependence of Scots pine seedlings mortality and height increment on artificial and large pine weevil caused bud damage. The growth of apical shoots of Scots pine seedlings was registered since the beginning of May to the end of June. Development of new shoots in seedlings with manually bud removal or large pine weevil damage started in beginning of May and continued in July. Mortality of Scots pine seedlings with 20% of lateral buds damaged did not differ from that in undamaged plants. The seedlings with apical and lateral buds manually removed as well as with apical and over 70% lateral buds damaged by large pine weevil have died in the year of treatment or damage. The seedlings with apical buds damaged as well as with apical and over 50% lateral buds damaged died in the 4th year after damage. Removal or damage up to 50% lateral buds did not affect the growth of Scots pine seedlings. Height increment of seedlings with apical buds manually removed or damaged by large pine weevil did not differ significantly in May and June of the year of treatment or damage. In July the height increment was statistically greater in the variant with manually removal of apical bud. Previously suggested scale of Scots pine seedlings bud damage satisfactory reflects the score of large pine weevil injuriousness. We can suggest that height increment in the next years after bud damage does not depend on damage way and intensity but mainly on ecological conditions.

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