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Show Worms destroy Large Acreage tSW- C. J- Sorenson, Associate Sinologist Utah Agricultural Si Experiment Station ."..JAN As a result of work done 'May 15, 1936, by entomologists . utah Agricultural experiment i it Is estimated that approx- y 7500 acres of dry-farm wheat "'liar valley and on the foothill invest of Lehl have been most-"Voyed most-"Voyed by this insect, iftirt 500 acres of wheat, on the n ridge were seriously damaged. 1 infestltations were also found ' Serai farms in the latter dis-So; dis-So; infestations of varying in-""S in-""S Were found in a few irrigated on Mapleton bench, near Lehi, "'"it Bluff dale In Salt Lake vki cutworms were also found l dry-farm area north of Lehl, lining east nearly to Alpine. 'Wtrms of north Sanpete coun-'Ojrtliwest coun-'Ojrtliwest Cache valley, and in 2ler county, north of Fielding -viverside were found uninfest-this uninfest-this pest. l(ie spring of 1934, an outbreak Aj pale western cutworm oc- in Cedar valley, Utah coun- 'proximately 1000 acres of fall .ring planted wheat were com- pletely destroyed. More than 9000 acres of other wheat in this valley were more or less infested with the worms. The area Infested and the damage done was greatly increased in 1935. Control Measures ' The pale western cutworm differs from other cutworms in that it does not come to the surface of the ground at night to feed. It burrows bur-rows through the ground following drill rows and cutting off the wheat below the surface. Because of this (feeding, habit, Ipoison (brow Ibaitey used in the control of other cutworms, cut-worms, are not effective against the pale western cutworm. No thoroughly satisfactory methods meth-ods known for its control. However, How-ever, it has been observed that the moths prefer loose, mellow soil In which to lay their eggs. Advantage has been taken of this preference of the moths and the cultivation of the summer-fallow managed and timed in such a manner as to leave the surface well crusted during- August Au-gust and early September when the moths lay their eggs. The crusted soil surface prevents or hinders egg-laying. egg-laying. This method has given a considerable consid-erable degree of control in other infested areas. In order to obtain a surface crust, land to be summer sum-mer f allowed should be plowed as early in spring as it is possible to work the ground. It should be plowed deeply with a mold board plow. The summer-fallow should be kept absolutely clean by necessary summer cultivation until about July 1st, after which cultivation should cease. Showers and rains will crust the soil surface which should remain entirely undisturbed) until) after the moths have laid their eggs. Seeding may then be done. If this time is not known, it would be advisable to delay seeding until after October 1. It has been found that the use of press drills are advantageous, since they firm the soil along wheat rows. These cutworms avoid packed soil. In areas known to be infested by pale western cutworms it would seem desirable to discontinue the use, at least for a few. years, of Wheatland plows, using instead mold-board mold-board plows. The former plow does not cover the stubble sufficiently but leaves portions of it exposed- on the surface where it prevents crusting crust-ing and is otherwise especially attractive at-tractive to the egg-laying moths. There is a possibility that deep plowing, followed by heavy rolling or cultivating of infested fields after af-ter the cutworms have finished their feeding will bury these dormant worms to a sufficient depth and pack the soil to prevent the moths from reaching the surface. There is no experimental evidence at present pres-ent to support this theory, such as there is for the other methods already al-ready suggested. Irrigation, where possible, has been found to give a considerable degree of control for infestitations of pale western cutworms. Life History Pale western cutworms hatch from eggs very early in spring and some may even hatch late during the preceding fall. The hungry young worms feed and grow actively active-ly until they attain a length of 1 to 1 inches. They are plain greenish-gray in color. Their favorite food plant is wheat, grasses, corn, other smalj grains, Russian thistle, tumbling mustard and dandelion. Feeding takes place underground, at or near the moisture line. When these worms become fun they discontinue feeding; burrow into the ground three or four inches where they construct an earthen cell, and pass into a resting period and transformation stage which lasts for approximately two months. At the end of this period they emerge as mottled-gray moths, usually usu-ally appearing In August or early September. A few days after their emergence, the moths lay their small, whitish eggs in loose, mellow soil, from VA toiy2 Inches below the surface. Stubble, weedy and summer-fallowed ground is chosen in which to lay the eggs. ' |