Wireworms and their Control

Wireworms (Elateridae) may be recognized because of their resemblance to a short piece of shiny copper or bronze wire. In color, most wireworms vary from light yellow to a light; or even dark brown. The body is long and worm-like, cylindrical or flattened, and covered by a comparatively hard skin. Three pairs of short legs are present on that part of the body immediately back of the head. Most of the native wireworms when fullgrown, measure from ½ to 1 ¼ of an inch in length. An occasional species measures more than 1 ½ inches. Wireworms are classed as destructive because they feed on living plants. Usually the portions of the plants that are attacked are in the soil, such as planted seed, germinating seed, roots, crowns, tubers, bulbs, corms, stems, etc., but sometimes the wireworms may work their way up inside the stems of plants a short distance above the surface of the ground. Unsprouted seed, germinating seed, and young plants suffer more damage than do older plants. In completing their life cycle, wireworms (Elateridae) pass through four radically different stages, namely, egg, larva or wireworm, pupa, and beetle. The beetles are the adult insects, commonly known as elater-beetles, click beetles, snapping beetles, or skip-jacks, from their habit of making a clicking noise when they throw themselves in the air after falling, or being placed on their backs. The duration of the life cycle of the various species is by no means identical. Some species complete their entire life cycle in one year, while others require as much as five years. The eggs of most of the wireworms are laid in the spring by beetles that hibernated over the winter, but there are some that lay their eggs in the fall of the year. In the latter case, the eggs hatch later in the fall, and the young wireworms hibernate. Pupation takes place usually late in the summer or early fall, and the pupal stage extends over a period of three or four weeks. Nearly 7000 species of Elateridae have been recorded in the world, and of these, about 700 are found in America, north of Mexico. Sixty species and varieties have been found in South Dakota

New amorphous magnetic materials of Fe-B-Be and Fe-B-Au

Substitution of Be for B in the amorphous binary alloy Fe(,82)B(,18) caused an initial increase in saturation magnetization (M(,s)) to a maximum of 200 emu/g at 4.2K, followed by a decrease for alloys with more than 4 at.% Be. Concurrently, the Curie temperature (T(,C)) of the Fe(,82)B(,18-x)Be(,x) alloy decreased progressively with Be content. These changes in M(,s) and T(,C) differ from those observed in Fe-B-M\u27 metallic glasses, where M\u27 is another metalloid (P, C, Si or Ge). Results from Auger electron and Mossbauer spectroscopies also detected the reversal trend established by the magnetization measurements. The Auger results indicated that there is a charge transfer from Be in the alloys with x (LESSTHEQ) 4, but no such transfer for x \u3e 4. (\u2757)Fe Mossbauer spectra obtained at 77K and 300K on this series of alloys indicated an initial increase in effective hyperfine field for x (LESSTHEQ) 4, but a decrease for x \u3e 4. The isomer shift was -0.032 mm/sec for x (LESSTHEQ) 4, but changed to -0.050 mm/sec for x \u3e 4. The annealing behavior of Fe(,82)B(,18-x)Be(,x) was also studied by X-rays and Mossbauer spectroscopy and a two-step crystallization process was observed. For x \u3e 0, a solid solution of (alpha)-Fe-Be was formed in the first stage and then Fe(,2)B was precipitated at higher temperatures;Additions of Au to Fe-B tended to increase the average Fe^moment, (mu)(,Fe), resulting in values for (mu)(,Fe) at 2.20 (mu)(,B) in(\u27 )^Fe(,82)B(,16.5)Au(,1.5) and 2.46 (mu)(,B) in Fe(,87)B(,11)Au(,2). The ternary alloys^containing Au up to 1.0 at.% displayed two crystallization stages^(with products of an (alpha)-Fe-Au solid solution followed by Fe(,2)B) while^those with higher Au content displayed a third stage with an Au-^rich solid solution as the crystallization product. Annealing of^Fe(,87)B(,11)Au(,2) resulted in lower M(,s) values, unlike the annealing effect usually observed in Fe-base metallic glasses;Radial distribution function (RDF) analyses were conducted on Fe(,87)B(,13), Fe(,82)B(,12)C(,6), Fe(,82)B(,12)Si(,6), Fe(,82)B(,14)Be(,4), and Fe(,82)B(,13)Be(,5). When compared to Fe(,87)B(,13), the results for the alloys containing C and Si indicated a reduction in the intensity on the lower r-side of the first peak in the RDF. The results were explained in terms of an increase in the spin-wave stiffness constant. An important result of the RDF analyses is the determination of the Fe-Fe interatomic distance (r(,Fe-Fe)) at 2.51(ANGSTROM) and 2.47(ANGSTROM) for Fe(,82)B(,14)Be(,4) and Fe(,82)B(,13)Be(,5), respectively. This decrease in r(,Fe-Fe) corresponds to a change in the number of nearest neighbors from 10.5 to 9.1. The RDF results for these two alloys containing Be were correlated with the changes observed in T(,C) and the average Fe moment;(\u271)This work was done at the Ames Laboratory, Iowa State University, Ames, IA, operated for the U.S. Department of Energy by I.S.U. under contract No. W-7405-eng-82. The research was supported by the Director of Energy Research, Office of Basic Energy Sciences, WPAS-KC-02-01