Connecticut western news., 1880-06-23
THE ARMY-WORM PEST.
Prof Comstoclk's Plans for Protect-
 ing Crops from it's Ravages.

J. denTy OOmSGOcK, the enIOmO40g1SG, addressed letter to the Hon. William e. Le Due, Commissioner of Agriculture, in which he gives the result of his inves- tigation of the irruption of the army worm in Kent county, Del. He states that Tn every instance the pest first ap- peared in wheat, but the greatest injury was done to the corn, which, being young and tender, was eaten to the ground wherever it was encountered. The dan ger in Kent county is now nearly over, but in localities further north, where the worm appeared later, much remains to be done. Prof. Comstock gives con- densed account of the natural history of the army worm, and the methods of pro- tecting crops from its ravages, of which the following is synopsis:
 The adult insectis night-fying moth, of dull brown color, marked in the centre of each fore wing with distinct white spot, and with an expanse of wing of little over F inches. The egg is white and almost perfectly spherical, its average diameter is 23-1OOO of an inch.
 The moth deposits her eggs in the folds of grass or grain, nearly always. conceal ing them from sight by pushing them
 down in the enfolded portion of the leaf,
 or by cementing the edges of the leaf to- gether over them. Eggs may be laid singly or in rows, which sometimes con- tain as many as fifteen or twenty. The | fo,,,o o,,5 r,1Ir,,. <>f 41,o =1o,.r,o ;o 4o o11
 known to require description here. The duration of its life in this stage varies from fifteen to thirty days or more.
 When full grown the worms burrow for
 an inch or more in the ground, and there
 transform to pupe. The pupa is dark
 brown in color, and about three fourths
 of an inch in length. The number of generations in @ season varies greatly
 with the climate. In the Northern States
 it has always been supposed to have but
 one generation. Further south, during
 winters of unusual mildness, succession
 of broods is kept up through the entire
 year, ess ssgzsssss
 | E Assoon ass the weather becomes warm
 in the spring, the moths emerge from
 their pupal cases or their hibernating
 quarters; and=lay their eggs as before de-
 scribed. The duration of the egg state
 is from eight to ten days. In 1879, eggs
 deposited on clover in Washington
 matched about May 10. The natural
 habitat of the army worm was stated by
 Dr. Fitch to be Gin the wild grass of
 wet spots, in swamps, and on the border
 of marshes, /" and in this statement he
 has been followed by nearly all succeed
 ing writers. The question, then, natu-
 rally arises, what is the cause of these
 sudden and extensive periodical visita-
 tions to cultivated crops? Dr. Fitch
 observed that the year 1861 was very
 wet, while that.of 1860 had been extreme
 ly dry. On examining the records he
 found that in previous worm years the
 season in which the worms appeared was
 wet, while the preceding year was dry.
 He therefore proposed the theory that in
 a dry season this insect, having an un-
 limited extent of feeding range, becomes
 greatly multiplied, ssand, when it is thus
 multiplied. wet season and. oyerfowed
 swamps drives it out from its lurking
 place in focks, alighting here and there
 over the country. But on being thus
 rusticated it finds our arabic lands toe
 dry for it, and immediately on maturing
 and getting it's wings again it flies back to the swamps, whereby it happens thai ) we see no more of it. Prof Riley adop ted this theory, and showed that the con ditions in 1869 and 1875 (two marked army worm years) coincided with those mentioned by Fitch.
 : If the theory just quoted be true, the best means of preventing the occurrence
 of this pest in cultivated fields will be to
 keep watch of any extensive tracts O. } low land which may be in the neighbor 3 hood, and, if army-worms are discovered [ destroy them, either by burning over tht :, land, if possible, or by poisoning witt f arsenic, Paris green, or London purple l or by any other means of which the loca r conditions will admit. It would be vel :! to burn over all the low lands in the vi ! cinity each winter, thus destroying tn, . hibernating insects. In case the worm ' do appear in cultivated lands, the bes n plan of action to follow is to prevent tn d spreading of the insect. This may b. done by destroying them or by confnin| | ! them to the fields in which they appear s The best method of destroying them r by crushing with rollers or by poisoning : with arsenic. Paris green, or Londo1 s purple. Either of these substances ca V be applied rapidly by mixing with wate o y and using a fountain pump or garde V syringe. The second line of defense e by means of ditches and pits dug aroun
 the infested field or that to be protected
 The ditches can be made quite rapidly n First blow, furrow with the clan st side next to the field to be protected e and then with spade make this side ( l. the furrow vertical, or if the soil be con W 1 pact enough to admit of it, overhangine ,e When the ditchis completed, holes shoul
 be dug in it from one foot to eightee ," inches deep, and from twenty to thirt .e feet apart: The sides of these hole le ls rshould also be vertical, or, if possible ts ts overhanging. The worms, unable ,e climb up the vertical side of the ,ditcl 90 will crawl along the bottom of it and ia le into the holes, where they will soon pc se se ish. Where the soil is sandy, so tn se the ditch cannot be made with vertic lg side, it should be dug deeper than d, other cases, and the side made as near y perpendicular as possible, so that whe if ----. u