UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 539 Contribution from the Bureau of Entomology Washington, D. C. L. O. HOWARD, Chief PROFESSIONAL PAPER. September 8, 1917 THE LESSER CORN STALK-BORER.1 By PHILIP LUGINBILL and GEO. G. AINSLIE, Entomological Assistants, Cereal and Forage Insect Investigations. Although the lesser corn stalk-borer (Elasmopalpus lignosellus Zell.) heretofore has occurred in injurious abundance only in sporadic outbreaks, it now has become an insect of considerable economic importance in the Southern States, since crops grown in the poorest types of soils, or in soils lacking humus, are usually the most seriously affected. The injuries to plants by larvæ of this species sometimes resemble closely those of certain beetle larvæ commonly known as "budworms" (Diabrotica 12-punctata Fab.) and it seems probable that injuries frequently attributed to the latter are in reality the work of the lesser corn stalk-borer. While engaged in other investigations early in the season of 1913 near Columbia, S. C., the senior author was informed by the authorities superintending the State farm near that city that the lesser corn stalk-borer was responsible for considerable damage to their field crops almost every year. Investigations begun immediately were continued through 1914 and 1915. The junior author, while engaged in certain investigations in Florida during the winter of 1913-14, encountered this same species in destructive numbers. The following paper, therefore, is a compilation of the results obtained from studies made at Columbia, S. C., during the years 19131915 by the senior author (27)2 and at Lakeland, Fla., in 1913–1914, by the junior author. 1 The authors wish to acknowledge the cooperation of A. H. Beyer and H. L. Dozier in field investigations. * Reference is made by number to "Literature cited," p. 25. 83986-Bull. 539-17-1 ECONOMIC HISTORY. Although the lesser corn stalk-borer was originally described by Zeller (3) in 1848, and was known to scientific workers from several parts of the Western Hemisphere, it was not until 1881 that it began to have other than a purely scientific interest. In July, 1881, C. V. Riley, then entomologist of the United States Department of Agriculture, was notified that an insect (later identified as this species) was injuring corn, both old and young, in the vicinity of Augusta, Ga. Steps were taken at once to learn more of the life history and habits of the pest, and agents of the Division of Entomology spent the remainder of the year conducting investigations at these points in order that they might be able to propose remedial or preventive measures. The studies made at that time showed that this insect had not been known as a pest until about 1878, and that during the period 18781881 it had become of economic importance in Georgia and South Carolina, specimens being taken even as far north as Chapel Hill, N. C. The life history was partly worked out and published by Dr. Riley (8, 9, 10)1; but, as no further complaints were received, the investigation was suspended. In a discussion of the corn insects of Nebraska, Prof. Lawrence Bruner (14) published a brief account of this species and its work, but did not state that it had been found in Nebraska. In 1884 (11) and again in 1893 (16) Riley listed it as injurious to the stalk of corn. Not until nearly twenty years after the first recorded damage did it again become the object of special study by entomologists. In 1899 Dr. F. H. Chittenden, of the Bureau of Entomology, received complaints of injury to beans by the insect in Alabama and South Carolina, and also to peanuts in Georgia (19). Specimens of the insects sent to Washington were identified as Elasmopalpus lignosellus, and further biological studies were begun. All the available information at this time was brought together, and the results published in Bulletin 23 of the Division of Entomology by Dr. Chittenden (18). A brief note by Dr. Chittenden (21) in Bulletin 40 of the Bureau of Entomology, published in 1903, reported damage to cowpeas in Texas and Virginia, and the Yearbook of the United States Department of Agriculture for 1903 (22) records injury to cowpeas, beans, and soy beans in Texas, Alabama, and Virginia, part of these records undoubtedly being repetitions of those given in Bulletin 40. In 1904 Titus and Pratt (23) listed it as injurious to corn, beans, and peas. Dr. S. A. Forbes (24) included this species in his monograph of the insects injurious to corn, drawing largely from Riley's account in describing its habits and methods of attack. He added the information, however, that adults had been taken in Illinois in August 1 See "Literature cited," p. 25. and September, but the account does not indicate that the species caused damage in the State at that time. In 1905, as reported in the Yearbook of the United States Department of Agriculture for that year (25), sorghum, cowpeas, and crabgrass were totally destroyed in some fields near Columbia, S. C., and reports of damage were received from other localities in South Carolina and Georgia. On November 4, 1915, the junior author also found at Nashville, Tenn., a small wheat plant killed by a larva which was nearly full grown and which entirely filled the burrow that it had excavated in the stem. SYSTEMATIC HISTORY AND SYNONYMY. The lesser corn stalk-borer was first described by Zeller (1) from Brazil, Uruguay (Montevideo), and Colombia, South America, and a single female from "Carolina," U. S. A. In this article, aside from the specific description, Zeller describes three unnamed varieties, basing his descriptions almost entirely on color variations. No further notes are given in this account except from the localities listed. Four years later Blanchard (2) redescribed the species under the name Elasmopalpus angustellus, erecting for its reception the genus Elasmopalpus, which recently has been accepted as the proper position for the species. Not until two decades later is there a further reference to the species in the literature, when Zeller (3), in an article dealing with some North American moths, adds somewhat to our knowledge of its seasonal and geographical distribution, recording it from Brazil and Colombia, in South America, and "Carolina" and Texas, in the United States. At the latter place three females were taken, one on July 15 and the other two a month later. He also adds the descriptions of two varieties, incautella and tartarella, based on color variations. Each of these varieties was described from a single specimen, and both were taken at the same place and on the same date. The species as a whole is extremely variable and Zeller himself in a later publication (7) placed incautella as a synonym of lignosella though still retaining tartarella as a valid variety. Another variety, designated as "variety B," was described by Zeller (4) from material collected at Valparaiso, Chile. In 1875, Berg (5), using material taken in Patagonia and elsewhere in southern South America, supplemented Blanchard's description of E. angustellus, going into detail, particularly in describing the venation, and two years later, in a further paper on Patagonian insects (6), came to the conclusion that the species he had been considering Blanchard's angustellus was Zeller's lignosella. Since both the species are genotypes, the reduction of angustellus to a synonym of lignosella made Elasmopalpus a synonym of Pempelia, where it remained until revived by Hulst in 1890 (13) for this same species. In 1881 Zeller (7) gave some notes on the amount of variation in the species, basing his remarks on a collection of 25 specimens from Colombia, South America, most of them taken in September and October. Hulst (12) redescribed this species as new, from Texas, under the name Dasypyga carbonella, a mistake which he later rectified in his monograph of the Phycitidae (13), in which he places carbonella as a synonym of Zeller's variety tartarella. In the same publication he redescribes lignosellus, places it in the genus Elasmopalpus for the first time under that name, and gives a bibliography and notes on the distribution and seasonal occurrence. Ragonot (15) covers much the same ground as several of the previous authors, giving the synonyms, bibliography, and a description of the species and calling attention to its great variability. He also uses the name major, the first word of Zeller's description, for the variety B mentioned above and lists it as a variety of the species lignosellus. Smith (17 and 26) records the species from New York, and Dyar (20) lists it with its synonyms in his catalogue of the Lepidoptera of North America, giving the distribution as the Atlantic States and South America. The junior author has gone carefully over all the descriptions given by the various authors mentioned above, examining the specimens in the United States National Museum, and has come to the conclusion that the use of all varietal names in this species may well be discontinued. The varieties that have been described are not constant in any respect either as to size, geographical distribution, or seasonal occurrence, and apparently they indicate merely individual aberrations in color, size, or markings. The synonymy, then, stands as follows: Pempelia lignosella Zeller (1), Elasmopalpus angustellus Blanchard (2), Pempelia lignosella tartarella Zeller (3), Pempelia lignosella incautella Zeller (3), Dasypyga carbonella Hulst (12), Elasmopalpus lignosellus (Zeller) Hulst (13), Elasmopalpus lignosellus incautellus (Zeller) Hulst (13), GEOGRAPHICAL DISTRIBUTION. This species is limited in its occurrence to the Western Hemisphere. It occurs practically throughout South America, having been reported from widely separated localities in all parts of that continent. The list as given by Hulst includes Venezuela, Colombia, Brazil, Argentina (Buenos Aires), Chile, and "Patagonia." In North America (fig. 1), while its range is not so great, it may be said to occur over the entire southern half of the United States. It has been most commonly reported from the States bordering the Gulf of Mexico and the southern Atlantic coast. It has been encountered causing injury in Arizona. Dr. Forbes reports it as having been taken at various points in southern Illinois. There is a specimen in the National Museum rather indefinitely labeled "Iowa." The late Prof. F. M. Webster observed some of the moths years ago at Lafayette, Ind. In addition to the one mentioned above there are specimens in the National Museum bearing locality labels indicating that the moths have been taken at Cohasset, Mass.; Clemson College, S. C.; Miami, Palm Beach, and Lakeland, Fla.; New Orleans, La.; Dallas, Brownsville, Sabinal, Kerrville, Victoria, and Burnet County, Tex.; and San Diego, Cal. John B. Smith, in his List of the Insects of New Jersey, records it from Newark and Montclair and states that it will FIG. 1.-Map showing present known distribution of the lesser corn stalk-borer (Elasmopal pus lignosellus) in the United States. (Original.) be found throughout the State. It undoubtedly occurs throughout Mexico and has been reported from the Bahama Islands. FOOD PLANTS. The following is a list of food plants upon which the larvæ of this species have been found to feed, given here with locality, date, and collector or observer: BEANS: Auburn, Ala., August 16, 1889 (F. S. Earle); Charleston, S. C., September 27, 1889 (H. M. Simmons). CORN (Zea mays): Augusta, Ga., 1881 (C. V. Riley); Illinois, 1905 (S. A. Forbes); Lakeland, Fla., |