Notes on Forest Pests in the Government of Vladimir.
AbstractThis paper deals with the principal pests of pine and spruce observed in 1927 and 1928 in the Vladimir Government, where the forests became very susceptible to infestation after serious fires that occurred in 1920-22.
The adults of Spondylis buprestoides, L., were on the wing in the second half of June and oviposited at the base of the trunks of burnt pines or sometimes of less severely damaged ones, especially when part of the roots was exposed. Most of the larvae occurred in the roots and up to about 20 ins. above the ground. There was one generation a year, pupation taking place in May. The infested trees should be felled and the stumps uprooted and removed at once. The goatsucker (Caprimulgus europaeus) was found feeding on the adult beetles.
The mass flight of Monochamus sutor, L., and M. galloprovincialis, Ol., occurred in mid-June in 1927 and mid-May in 1928. The beetles chiefly infested recently felled pines exposed to the sun, but also attacked standing trees weakened by fires or by Myelophilus (Blastophagus) piniperda, L., and M. (B.) minor, Htg. In fallen trees the eggs were deposited in the upper part. Felled trees left in the forest should be barked, and all weakened and dying trees removed. Monochamus quadrimaculatus, Motsch., was abundant on logs and fallen trees of spruce in uncleared mixed stands of pine and spruce where the latter was the predominant tree. The adults were on the wing about the middle of June, their flight coinciding with that of Sirex gigas[Urocerus gigas], L. The larvae occurred chiefly in the butt-end of the trees and logs, mining deep into the wood. There is probably one generation a year. Barking logs and removing fallen trees is essential.
Hylobius abietis, L., is a very common pest of young pines between 5 and 10 years old, growing in uncleared areas with sandy soil. Owing to the injuries caused, the trees exude a large amount of resin and dry up. The stumps of felled trees should be barked in spring and blocks lying in shady and damp places, in which the weevil often breeds, should be removed. In a heavy infestation, the best method of control is the use of trap ditches [R.A.E., A, iv, 499; xvii, 146]; 500-600 weevils may be caught weekly in each ditch. Four weevils per sq. yd. of ground indicates a serious infestation. Pissodes harcyniae, Hbst., was very abundant on young spruces in old and healthy stands adjacent to burnt areas, infesting 60 per cent. of trees measuring 30.5-ins. in diameter from top to bottom. Oviposition probably took place at the end of July, as young larvae occurred in the beginning of August, together with fully mature ones, pupae and young adults resting in their chambers. A number of the young adults and about 70 per cent. of the pupae were killed by a fungous disease, moisture having penetrated through the bark and bast into the pupal chambers during heavy and frequent rains. P. piniphilus, Hbst., was abundant in some localities on pines weakened by Myelophilus. Oviposition was protracted, occurring chiefly in June and July. The weevils also readily infested recently felled trees with fresh bast.
Myelophilus minor and M. piniperda [cf. xvii, 145, 399] caused very serious damage. Abundant rain or extreme heat compel the larvae of the former species to penetrate into the wood deeper and sooner than usual so that 50-60 per cent. of them die. Ips acuminatus, Gyll. [cf. xvii, 399] was abundant in healthy stands of pine of middle age thinned out by felling. I. typographus, L., infested fallen spruce; in 1927 the mass flight occurred at the end of May. Laying out trap trees from spring till July is recommended as a control measure. I. (Orthotomicus) starki, Spess., infested the branches and leading shoots of fallen spruce. Cryphalus saltuarius, Wse., occurred in small numbers on spruce drying up owing to the plantation being too dense. It was accompanied by Xylechinus pilosus, Knoch, which has not been previously recorded from the Vladimir Government.