It is certain that serious loss may and does occur because of falling of the grain due to the cut made by the larva preparatory to hibernation. The extent of this loss will in all probability depend in some degree upon weather conditions during the period of ripening of the grain. A heavy wind or severe storm at this time would cause most of the infested grain stalks to break off and fall so that they would not be picked up by the harvester. In the absence of such a wind or storm, the loss would undoubtedly be much less, but even with favorable conditions a certain percentage of the infested stalks would be broken off by the harvester reel and fall in front of the platform. Kulagin (47) states that losses in Russia due to this species and Cephus pygmaeus are estimated at 14 to 20 per cent, although more severe in some cases. Shtchegolev (49) also reports 15 to 20 per cent injury due to these two pests. Other Russian writers record severe injury without specifying the amount. Unfortunately, in practically every instance these writers treat of the injury by Cephus pygmaeus and Trachelus tabidus collectively, without indicating how much of the damage is chargeable to each. This is no doubt due to the fact that they have been unable to distinguish the larvæ of the two species. Their records, therefore, do not afford a reliable basis for estimating the probable future importance of Trachelus tabidus in this country. PARASITES. In Russia two parasites of Trachelus tabidus have been recorded. Collyria calcitrator (Gravenhorst), an ichneumonid wasp, is apparently a common parasite of this species as well as of Cephus pygmaeus. Borodin (52) records the chalcidid Arthrolysis (Picrocystus) scabricula Nees as having been reared from these two sawfly pests. Neither of these species has, as yet, been found in America. The existence of at least one efficient parasite in America has, however, been established. Numerous specimens of a chalcidoid belonging to the genus Pleurotropis and apparently representing an undescribed species have been reared by Mr. W. R. McConnell at Mount Holly Springs and Carlisle, Pa. So far little is known of the life history of the species. It emerges from the prepupal larva of the Trachelus at about the time of emergence of the host adults and is believed to be a primary parasite, solitary in its habit. Observations to date are too limited in extent to form a very accurate estimate of the efficiency of this parasite, but in some instances at least it appears to exercise a considerable degree of control. SUGGESTIONS FOR CONTROL. In the present state of our knowledge of this species only sugrestions of possible means of control can be given. Measures for control will doubtless be similar to those against Cephus cinctus, the western grass-stem sawfly, and Cephus pygmaeus. It is obviously impracticable to attack the insect in the egg stage or active larva stage, since both stages occur in the growing grain. The adult can not be reached by any known method. It appears, therefore, that control measures to be successful must either aim at destruction of the hibernating larva or pupa while in the stubble, where the insect passes the greater part of its existence, or be confined to cultural methods such as crop rotation. The fact that the larva is located in the part of the stem below the surface of the ground precludes the possibility of accomplishing anything by any ordinary burning of the stubble. Disking the stubble thoroughly as soon after cutting the grain as practicable would possibly be of benefit by turning the infested stubble out and thus exposing the larva to the action of summer heat and winter cold. The larva is quite hardy, however, and only experimentation will prove or disprove the effectiveness of disking. In Russia plowing down of the stubble as deeply as possible is recommended against this species as well as against Cephus pygmaeus. The same treatment is recommended and has proved successful against Cephus cinctus in this country, and it seems the logical treatment for adoption against this species. To be effective the plowing must bury the stub containing the larva so deeply that the maturing adult will be unable to escape. Shallow plowing will not suffice, as the adults undoubtedly will be able to burrow their way out if covered with only 2 or 3 inches of soil. Deep and clean plowing, therefore, will be essential. The plowing may be done at any time between the cutting of the grain and the following spring prior to emergence of the adults in April or May. If, as now seems probable, this insect confines itself, in this country, to the small-grain crops as host plants, there can be little doubt that crop rotation will prove an effective means of reducing damage from it. Wheat, barley, or rye should be followed by some crop which will not serve as a host plant, such as corn or truck crops. The present practice on some farms of growing wheat on the same ground two years in succession is distinctly favorable to the propagation of the pest since the adults upon emerging find themselves surrounded by ideal conditions for oviposition. The practice also of sowing grass or clover with wheat and allowing the wheat stubble containing the larva to stand undisturbed for two seasons could hardly be improved upon as means of increasing the numbers of this insect. Any system of rotation to be effective should insure thorough plowing down of the wheat stubble and the growing of some crop other than a small grain following wheat. (1) FABRICIUS, J. C. (2) LITERATURE CITED. 1775. SYSTEMA ENTOMOLOGIAE . . . Flensburgi et Lipsiae. 832 p. 1781. SPECIES INSECTORUM Hamburgi et Kilonii. Tome 1. Page 420, no. 13: Brief description of Sirex tabidus, with note, "Habitat in Angliae floribus." Page 417, no. 59: Original description of Tenthredo haemorrhoidalis. (3) FOURCROY, A. F. DE. 1785. ENTOMOLOGIA PARISIENSIS . . . Paris. Pars 1. Page 378: Describes species as new under name of Tenthredo longicollis from vicinity of Paris, France. (4) FABRICIUS, J. C. 1787. MANTISSA INSECTORUM Hafniae. Tome 1. Page 259, no. 19: Brief description of Sirex tabidus. (5) VILLERS, C. DE. (6) LINNÉ, C. Page 125, no. 135: Record, as Tenthredo longicollis, from Europe. Page 132, no. 13: Short description of Sirea tabidus, with note, "Habitat in Angliae floribus." 1799. SYSTEMA NATURAE .. Ed. 13 (Gmelin), Lipsiae. Tome 1, pars 5. Page 2674, no. 18: Short description of Sireæ tabidus, with note, "Habitat in Angliae floribus." (7) Rossi, P. 1790. FAUNA ETRUSCA ... Liburni. Tome 2. Page 35, no. 739: Records of Sirex tabidus from Italy. (8) CHRIST, JOHANN LUDWIG. 1791. NATURGESCHICHTE, CLASSIFICATION UND NOMENCLATURE DER INSECTEN. Frankfort-am-Main. 535 p. Tab. 60, col. Page 131 Short description of Sirea tabidus, from England; original description of Sires macilentus. (10) COQUEBERT, A. J. 1801. ILLUSTRATIO ICONOGRAPHICA INSECTORUM. . . Paris. Tome 2. Page 48, Tab. 11, fig. 4: Figure and brief description of Sirez tabidus, from England. (11) WALCKENAER, C. A. 1802. FAUNE PARISIENNE, INSECTES. Paris. Tome 2. Page 46 Record of Sirex tabidus from vicinity of Paris. (12) KLUG, FR. 1803. MONOGRAPHIA SIRICUM GERMANIAE... Berlin. 83 p. Page 56, no. 8: Generic transfer with description and synonymy of Astatus tabidus and note, "Locus in floribus." Page 55, no. 6, Tab. 7, fig. 1: Original description of Cephus analis. (13) FABRICIUS, J. C. 1804. SYSTEMA PIEZATORUM . . . Brunsvigiae. 439 p. Page 252, no. 6: Transferred to Cephus tabidus with references to previous literature. Locality, England. Page 144 Record of Cephus tabidus as common around Paris. (15) PANZER, G. W. F. (16) 1805. FAUNA INSECTORUM GERMANICAE Nürnberg. Heft 85. Tab. XI: Figure of Astatus tabidus, references to previous literature and note, "Habitat in sylvaticis." 1806. KRITISCHE REVISION DER INSEKTENFAUNE DEUTSCHLANDS Page 145: References to previous literature on Cephus tabidus. (17) JURINE, LOUIS. 1807. NOUVELLE MÉTHODE DE CLASSER LES HYMENOPTÈRES ET LES DIPTÈRES. Page 72: Description of Trachelus haemorroidalis; short description of 1807. FAUNA ETRUSCA Helmstadii (Ed. Illiger)., Tome 2. Page 53 Brief description of Sirex tabidus with notes, "In Gallia (20) LEPELETIER DE ST. FARGEAU, AM. 1823. MONOGRAPHIA TENTHREDINETARUM . . . Paris. 176 p. Page 19, no. 54: Species described as new under name of Cephus mandibularis, with note, "In agro Parisiensi." Page 20, no. 55: Species described as new under name of Cephus nigritus, with note, "An mas Cephi mandibularis?" Page 20, no. 57: Description of Cephus tabidus with references to previous literature. (21) AUDINET-SERVILLE, J. G. In: VIEILLOT, LEPELETIER, ETC. 1823. FAUNE FRANÇAISE... Paris. Hyménoptères. (22) CURTIS, JOHN. 1830. BRITISH ENTOMOLOGY. . . London. V. 7. Plate 301 (accompanying text): Trachelus tabidus recorded on flowers and grass in fields of Dover and Southgate, England. Page 106, no. 9: Description of Cephus tabidus; found in Hertford, (24) HARTIG, THEODOR. 1837. DIE FAMILIEN DER BLATTWESPEN UND HOLZWESPEN Page 363: Description of Cephus tabidus. (25) BLANCHARD, C. E. ... Berlin. 1840. HISTOIRE NATURELLE DES INSECTES . . . (26) HERRICH-SCHÄFFER, G. A. W. 1840. NOMENCLATOR ENTOMOLOGICUS. Regensburg. Heft 2. (27) LUCAS, H. 1849. HISTOIRE NATURELLE DES ANIMAUX ARTICULÉS. Pars 3. Insectes Paris. In Exploration Sci. de l'Algérie . . . 1840, 1841, 1842. Page 342 Records Cephus tabidus taken in May in Constantine. ... Page 980: Note that larvæ of Sirex tabidus live in stems of grain. (30) DAMIANITSCH, RUDOLPH. 1866. HYMENOPTEROLOGISCHE BEITRÄGE. In Verh. Zool.-Bot. Ges. Wien, Bd. 16, p. 993-996. Pages 993-995: Original description of Cephus erberi, taken at edge of barley field in Syria. (31) TASCHENBERG, E. L. 1871. EINIGE NEUE SÜDEUROPÄISCHE HYMENOPTERA. (32) COSTA, A. Ges. Naturw., Bd. 4 (n. s.). In Zeitschr. f. d. Page 306: Description of Cephus tabidus; found in Island Lesina. 1878. RELAZIONE DI UN VIAGGIO PER L'EGITTO, LA PALESTINA, E LE COSTE DELLA TURCHIA ASIATICA PER RICERCHE ZOOLOGICHE. In Atti Acc. Sci. Napoli, v. 7, no. 2. Page 14 (footnote): Species described as new under name of Cephus vittatus; from Egypt. (33) ANDRÉ, ED. 1881. SPECIES DES HYMENOPTÈRES D'EUROPE ET D'ALGÉRIE . . . Beaune, Page 535, no. 31: Description of Cephus tabidus; found in England, (34) CAMERON, P. (35) 1886. A SYNOPSIS OF THE BRITISH SPECIES OF CEPHINA. In Ent. Mo. Mag., v. 22, p. 175–177. 1890. A Page 177: Brief description of Cephus tabidus; synonymy; table. MONOGRAPH OF THE BRITISH PHYTOPHAGOUS London. v. 3. HYMENOPTERA. Page 120, no. 6, Pl. 3, fig. 9: Description, previous references in literature, and synonymy of Cephus tabidus. Found in England, Sweden, Germany, Spain, Italy, N. Africa, Syria. (36) MAGRETTI, P. . 1890. IMENOTTERI DI SIRIA In Ann. Mus. Civ. Stor. Nat. Genova, (2) v. 9, p. 522-548. (37) COSTA, A. Page 528 Cephus tabidus recorded from Europe, Algeria, Syria. 1894. PROSPETTO SISTEMATICO DEGLI IMENOTTERI ITALIANI. Napoli. Pars 3. Page 253: Cephus tabidus recorded from Italy and Sicily. (38) DALLA TORRE, C. G. DE. 1894. CATALOGUS HYMENOPTERORUM... Lipsiae. v. 1. (39) [ASHMEAD, W. H.] In SMITH, J. B. 1900. INSECTS OF NEW JERSEY. In Ann. Rept. Sta. Bd. Agr., Suppl., 1899. p. 501-615. Page 600: Species listed as Calamenta [Calameuta] johnsoni. (40) ASHMEAD, W. H. 1903. Two NEW PHYTOPHAGOUS HYMENOPTERA, In Can. Ent., v. 35, p. 233. Page 600 Species described as new under name of Calmeuta johnsoni, from Riverton, New Jersey. |