Conifers

The Diprionidae and some species of the Pamphiliidae are free feeders on the needles of conifers, the latter being concealed within silken webs. Xyelidae larvae feed within the developing cones of pines.  Within the Tenthredinidae, several nematinae species are also free feeders on the needles of coniferous.

The Siricidae have larvae that tunnel in the timber of conifers and these larvae can be damaging to timber production. 

Coniferous timber has been widely exported around the globe, as have to a lesser extend sapling trees for forestry development. As such the coniferous feeders are of economic interest. 

Coniferous Plants - Family Cupressaceae

Chamaecyparis (Cyprusses)
Xeris spectrum
Juniperus communis (Juniper)
Monoctenus juniperi

Coniferous Plants - Family Pinaceae

Abies (Firs)
Sirex (noctilio, juvencus), Urocerus gigas, Xeris spectrum
Abies alba (European Silver-fir)
Gilpinia hercyniae, Sirex cyaneus, Urocerus augur, Xeris (spectrum, pallicoxae)
Abies cilicica (Cilician Fir)
Xeris pallicoxae
Abies procera (Noble Fir)
Urocerus augur
Larix (Larches)
Cephalcia lariciphila, Sirex (noctilio, cyaneus), Urocerus gigas, Xeris spectrum, Anoplonyx destructor, Euura imperfecta, Pristiphora (bufo, erichsonii, glauca, wesmaeli)
Larix decidua (European Larch)
Xeris (pallicoxae, spectrum), Anoplonyx destructor, Euura imperfecta, Pristiphora (bufo, erichsonii, glauca)
Larix kaempferi (Japanese Larch)
Anoplonyx destructor, Pristiphora (erichsonii, glauca)
Picea (Spruces)
Sirex (cyaneus, juvencus, noctilio), Urocerus gigas, Xeris spectrum, Gilpinia hercyniae, Euura (montana, scutellata), Pristiphora (abietina, amphibola, compressa, decipiens, nigella, pseudodecipiens, saxesenii, subarctica)
Picea abies (Norway Spruce)
Urocerus (augur, gigas), Xeris (pallicoxae, spectrum), Cephalcia arvensis, Gilpinia hercyniae, Euura (montana, scutellata), Pristiphora (abietina, amphibola, compressa, decipiens, nigella, pseudodecipiens, saxesenii, subarctica)
Picea sitchenesis (Sitka Spruce)
Xeris (pallicoxae, spectrum)
Pinus (pines)
Acantholyda (erythrocephala, hieroglyphica, posticalis), Gilpinia (frutetorum, virens), Neodiprion sertifer, Sirex (cyaneus, juvencus, noctilio,), Urocerus gigas, Xeris spectrum
Pinus nigra (Austrian Pine)
Acantholyda posticalis, Diprion pini, Neodiprion sertifer, Xyela (curva, julii)
Pinus strobus (Weymouth Pine)
Acantholyda erythrocephala, Diprion similis, Neodiprion sertifer
Pinus sylvestris (Scots Pine)
Acantholyda (erythrocephala, posticalis, hieroglyphica), Diprion (pini, similis), Gilpinia (frutetorum, pallida, virens), Microdiprion pallipes, Neodiprion sertifer, Urocerus augur, Xyela (julii, longula)
Pseudotsuga (Douglas-Firs)
Sirex (cyaneus, noctilio, juvencus), Xeris spectrum

References

Benson RB. Handbooks for the Identification of British Insects, 6 (2a). Hymenoptera, 2, Symphyta, Section (a). Handbooks Identif Br Insects, 6 (2a) Hymenoptera, 2, Symphyta, Sect (a). 1951.

Benson RB. Handbooks for the Identification of British Insects, 6, 2 (b). Hymenoptera 2, Symphyta, Section (b). London: Royal Entomological Society; 1952.

Benson RB. Handbooks for the identification of British insects 6 (2c). Hymenoptera, 2, Symphyta, Section (c). In London: Royal Entomological Society; 1958.

Cameron P. A Monograph of the British Phytophagous Hymenoptera. (Tenthredo, Sirex and Cynips, Linné.) Vol. 1. London: Ray Society; 1882.

Goulet, H.; Boudreault, C.; Schiff NM. Revision of the World species of Xeris Costa (Hymenoptera: Siricidae). Can J Arthropod Identif. 2015;28.

Lacourt J. Hymenoptera of Europe 2. Sawflies of Europe. NAP Editions; 2020.

Liston AD. Compendium of european sawflies. Dtsch Entomol Zeitschrift [Internet]. 1995;43(2):319. Available from: http://doi.wiley.com/10.1002/mmnd.19960430223

Lorenz, H. & Kraus M. Die Larvalsystematik der Blattwespen (Tenthredinoidea und Megalodontoidea). - Abhandlungen zur Larvalsystematik der Insekten No. 1. Berlin: Akadamie - Verlag; 1957.

Prous, M., Kramp, K., Vikberg, V. and Liston A. North-Western Palaearctic species of Pristiphora (Hymenoptera, Tenthredinidae). J Hymenopt Res. 2017;59.