Showing papers by "Mississippi State University published in 1969"

Sex Pheromones Produced by Male Boll Weevil: Isolation, Identification, and Synthesis

Abstract: The response of female boll weevils to males, Anthonomus grandis Boheman, in laboratory bioassays can be reproduced by exposure to a mixture of compounds I, II, and either III or IV, all isolated from male weevils and their fecal material. The same response was elicited by mixtures of tile synthesized coimpounds. Compound I is (+)-cis-2-isopropenyl-l-methylcyclobtutaneethanol; II, cis-3,3-dimethiyl->(1,beta)cyclohexaneethanol; III, cis-3,3-dimethlyl->(1,alpha)-cyclohexaneacetaldehyde; and IV, trans-3,3-dimethyl->(1,alpha)-cyclohexanecetaldehyde.

Electromagnetic pulse scattering in time-varying inhomogeneous media

Abstract: A finite difference solution technique is used to solve Maxwell's equations directly in the treatment of electromagnetic pulse scattering in a time-varying inhomogeneous medium. In particular the scattering from a cylindrical rod inside a cylindrical waveguide is considered where axial symmetry is obtained.

Systematic desensitization of snake-avoidance under two conditions of suggestion.

Abstract: Two groups of Ss received systematic desensitization for “snakephobia.” 9 Ss were led to expect anxiety reduction from desensitization; another 9 were not. Changes in snake-avoidance for these two groups were compared with changes displayed by 9 Ss who received no treatment.

Sources of error in the use of fish-brain acetylcholestrinase activity as a monitor for pollution.

Abstract: Recurring pollution of natural waters from the manufacture s~ud use of pesticides has accentuated the need for suitable monitoring methods. The determination of fish-brain acetylcholinesterase (ACHE) activity has been proposed as a means of detecting organophosphorous pollution (4) and has been used for monitoring purposes (5, 6). Weiss (1, 2, 3) demonstrated that a 40-7~ inhibition of fish-brain AChE is usually lethal. He detected inhibition from concentrations of phosphate insecticides as low as 1 ppb over a 15 day exposure period and Ool ppb over a 30 day exposure period. Williams and Sova (5) detected inhibition in brains of two SPecies of fishes collected downstream from suspected sources of organophosphorous pollution. Holland et al. (6) evaluated this monitoring method and reported AChE inhibition in fish from polluted waters. AChE inhibition data have been used as evidence implicating agricultural chemical plants in

Adaptive sampling technique

Abstract: An adaptive sampling technique utilizing the first three terms of a Taylor series expansion about the n th sampling instant for the error signal in an error-sampled feedback control system is presented. The necessary rules for determining the sign convention used in applying the technique are given along with an example illustrating the method. The procedure basically depends on the determination of a preselected constant difference between successive sampling instants.

Low-pressure arc discharge motion between concentric cylindrical electrodes in a transverse magnetic field.

Abstract: A theoretical and experimental investigation of the Lorentz, stationary, and retrograde modes of motion of a low-pressure arc discharge is presented. It was found that an increase in the applied magnetic field strength will cause either an increase or a decrease in the arc's rotational speed, depending on the pressure. Experimental information obtained by highspeed photography reveals the nature of the low-pressure arc kinematics for the aforementioned three modes of motion. The films show the cyclic structure by which these modes progress under the action of an applied transverse magnetic field. The effects of temperature nonequiiibrium on the electrical conduction current density in the arc discharge are discussed. It is shown that in arc regions of high nonequiiibrium with large spatial gradients in the electron temperature, electrical currents can occur in a direction opposite to that produced by the electromagnetic field alone. The various characteristics of the arc discharge are discussed as the results of temperature nonequiiibrium.

Shrinkage properties of second-growth southern yellow pine

Abstract: Several factors which may affect the shrinkage of wood had been studied using loblolly pine (Pinus taeda L.). It was observed that volumetric, tangential and radial shrinkages decreased as the height increased. Longitudinal shrinkage increased with height. Only tangential shrinkage was significantly affected by the distance from the pith factor. All shrinkages were found to vary significantly according to cardinal directions. For the trees studied, lower volumetric, tangential and radial shrinkages were observed for specimens from the south side of the pith. Longitudinal shrinkage was noticeably higher in this direction.

Factors contributing to resistance and susceptibility of cotton and other hosts to the boll weevil, anthonomus grandis

Abstract: A large portion of the world's germ plasm of cotton has been screened at the USDA Boll Weevil Research Laboratory, State College, Mississippi during the period 1962–68 utilizing developed techniques. An oviposition suppression factor causing 25–40% reduction in number of eggs laid by the weevil has been found in Gossypium barbadense and successfully moved into upland cotton, G. hirsutum. Two years field data with frego cottons indicate that the frego character contributes a significant degree of non-preference for egg laying by the boll weevil under field conditions. The frego character is currently being combined with selected lines of G. hirsutum carrying the oviposition suppression factor. A seedling screening technique utilizing field cages and greenhouse sand flats has been shown to have significant value in screening for individual resistant plants within a commercial variety. A number of selections with 25% or more resistance to oviposition are under extensive investigation. A number of biologically active materials have been detected in the cotton plant and other hosts of the boll weevil which significantly influences feeding stimulation, feeding deterrency, repellency and attractancy of the weevil to its hosts. A highly active square abscission factor has been detected and extracted successfully from 2nd and 3rd instar larvae. The material injected into cotton squares causes 95% abscission of squares within 48–60 hours. ZUSAMMENFASSUNG RESISTENZ- UND ANFALLIGKEITSFAKTOREN DER BAUMWOLLE UND ANDERER WIRTSPFLANZEN GEGENUBER DEM BAUMWOLLKAPSELKAFER, ANTHONOMUS GRANDIS Ein groser Teil des Weltsortiments der Baumwolle wurde in den Jahren 1962–68 im USA-Baumwollkafer-Institut der Staatshochschule von Mississippi mit modernen Methoden getestet. Ein die Eiablage unterdruckender Faktor, der die Anzahl der abgelegten Eier um 25–40% herabsetzt, wurde bei Gossypium barbadense gefunden und erfolgreich in Hochland-Baumwolle, G. hirsutum, eingekreuzt. Zweijahrige Erfahrungen mit “frego”-Baumwolle weisen darauf hin, das das “frego”-Merkmal unter Feldbedingungen in einem signifikanten Ausmase zur Nonpraferenz fur die eierablegenden Kafer beitragt. Das “frego”-Merkmal wird laufend mit selektierten Linien von G. hirsutum kombiniert, die den Faktor fur Eiablage-Unterdruckung tragen. Eine Samlings-Prufungstechnik, die Feldkafige und Gewachshaus-Sandbeete benutzt, hatte nachweislich signifikanten Wert fur die Auslese resistenter Einzelpflanzen innerhalb einer Handelssorte. Eine Anzahl Selektionslinien mit 25 oder mehr Prozent Eiablage-Resistenz wird intensiv gepruft. Eine Anzahl biologisch aktiven Materials wurde bei Baumwolle und anderen Wirtspflanzen entdeckt, das Frasstimulation, Frasabschreckung, Repellenz und Attraktanz der Kafer in bezug auf ihre Wirte signifikant beeinflust. Ein hochaktiver Kapsel-Abwurf-Faktor wurde entdeckt und erfolgreich aus Larven des 2. und 3. Stadiums extrahiert. In Baumwollkapseln injiziert, verursachte dieses Material innerhalb 48–60 Stunden Abwurf von 95% der Kapseln.

Electromagnetic scattering from arbitrary configurations of wires

Abstract: A general formulation is presented for the treatment of electromagnetic scattering from an arbitrary configuration of thin wires. A system of integral equations is derived for obtaining the currents in the wires.

Effect of gamma radiation on tissues of the tobacco budworm, Heliothis virescens.

Abstract: Fifth stage larvae and 6-day-old pupae of H. virescens (F.) were irradiated with a cobalt-60 source. Damage to various organs was studied. Testes and wing pads appeared to be the most sensitive tissue in both larvae and pupae. Radiation caused some of the epidermal cells of the developing wing pads to enlarge causing an irregular adult cuticle to be produced. Radiation also caused the production of bridges of cuticle between the upper and lower lamellae of the wing pads which prevented the expansion of the adult wing. Death in the pupal stage was often due to failure of the adult to free its wings from the pupal case. Larvae stopped feeding following irradiation, the midgut cells enlarged and later disintegrated. Midgutcell replacement was curtailed. The peritrophic membrane was reduced or absent possibly because of damage to the secretory cells. Fat body cells appeared to be depleted of their stored nutrients. The cuticle failed to separate from the epidermal cells. This failure may have been due to radiation affecting the production of hormones in the endocrine system or enzymes involved indigestion of the old cuticle. Death of larvae following irradiation appeared to be due to failure to molt at higher doses and to energy depletion which may also account for the reduced adult life span. Irradiation effects on testes were noted, and chromosomal bridging was observed in the germ cells.

Greenhouse Studies of Host Plant Suitability to Graminella nigrifrons, a Vector of Corn Stunt Virus

Abstract: The suitability of 34 plant selections, representing 28 species, for feeding, survival, oviposition or nymphet development of the black-faced leafhopper, Graminella nigrifrons (Forbes), was tested in the greenhouse. Of the test leafhoppers, 20% or more survived 10 days on 14 of 30 test plants. Percent survival of females was significantly higher than that of males. Twelve of 30 test plants had 20 or more eggs laid in them within a 10-day period. Millet, oats, rice, and sorghum with 67, 56, 54, and 51 eggs, respectively, were the preferred hosts for oviposition. Incubation of eggs varied from 13 to 19 days on 12 test plants, being shortest on barley, oats, and rye and longest on common Bermuda grass. Development of nymphs to adulthood required from 17 to 18 clays on 9 plant species. Nymphs were observed on 29 of 33 test plants. However development to adulthood occurred on only 15 of these. Barley and rye appeared to be good hosts for colony development, while millet, oats, tall fescue, orchard grass, wheat, and perennial ryegrass were considered fair to poor host plants.

Cosmic-ray heavy-nucleus enders at various atmospheric depths.

Abstract: The increased ionization of a heavy cosmic-ray nucleus near the end of the range can cause the deposit of radiation dosage as high as several thousand rads along its trajectory. Although the biological significance of such radiation is still not well understood, it is of interest to know the intensity of stopping heavy nuclei at altitudes where supersonic trasports are expected to operate. The flux of enders of chargesZ ⩾ 6 in nuclear emulsions has been obtained for three balloon flights during 1965–1966 at atmospheric depths 3, 38 and 58 g/cm2. It has been found that the flux of enders incident from a particular zenith angle is a function of the path length from the top of the atmosphere. The number of heavy-nucleus enders encountered at the supersonic transport flight level of (60 000 ÷ 70 000) feet is calculated to be only a few percent of the number that would be encountered on top of the atmosphere for the same duration.

Applications of Microwave Energy in Preparation of Poultry Convenience Foods

Abstract: An economic analysis of three systems for the commercial cooking of chicken is presented based on actual costs of batch steam and theoretical (but believed realistic) costs of conveyorized steam and conveyorized microwave in steam atmosphere systems. Microwave cooking shows certain advantages in operation over batch systems and over steam or water continuous systems of cooking. Advantages are of such magnitude that they would pay out the increased capital investment in about 1.27 years. Other advantages in microwave cooking are discussed.

Corn Stunt Vector Leafhopper Attractancy to and Oviposition Preference for Hybrid Dent Corn. I. Dalbulus maidis

Abstract: Results from a series of attractancy and oviposition preference tests conducted in a field cage in which Dalbulus maidis (DeLong & Wolcott) (Homoptera: Cicadellidae) was given a free choice of corn hybrids indicated that this vector of corn stunt virus apparently does not prefer corn-stunt-susceptible hybrids over hybrids exhibiting resistance. Large but insignificant differences were obtained in the number of eggs laid in some corn hybrids. Egg-laying tests in the greenhouse where leafhoppers were confined to individual hybrids were not consistent with field-cage results.

Preference Studies with Hosts and Nonhosts of the Boll Weevil, Anthonomus grandis

Abstract: Tests were made to determine the presence of feeding stimulants and attractants for Anthonomus grandis Boheman in aqueous extracts of host and nonhost species of the family Malvaceae including cotton, Gossypium hirsutum L. The host plants found infested most frequently in nature generally contained the highest concentrations of feeding stimulant and attractant. Also, all known plants except Hibiscus syriacus L. attacked in nature by the boll weevil contained gossypol. Thus, plants containing gossypol seem preferred, but its presence does not appear to be an absolute requirement for host acceptability. Of the species tested, Cienfuegosia sulphurea (St. Hill.) Garki and Thespesia populnea (L.) Soland ex Carrea seemed the most suitable wild hosts next to cotton. H. syriacus again was not preferred. However, late in the season when it is near cotton it is sometimes attacked. For this reason, and because of its wide geographical distribution and general abundance as an ornamental throughout the Cotton Belt, it is the most important of the alternative hosts to consider in any future eradication programs against the boll weevil.

Amino Acids in Hosts and Nonhosts of the Boll Weevil, Anthonomus grandis

Abstract: Protein and nonprotein amino acids were detected in the buds of several hosts and nonhosts of Anthonomus grandis Boheman by ion exchange chromatography, and identifications were confirmed by thin-layer chromatography. Twenty-three amino acids plus ammonia were identified in the cotton samples, including 5 that had not been previously reported in cotton buds. These 5 were: beta-alanine, cysteic acid, ethanolamine, glucosamine, and taurine. Concentrations were always greater in the protein samples. All plant buds analyzed contained 9 of the 10 amino acids essential for the weevil. A microbiological assay detected tryptophan in cotton bud tissue. Amino acid profiles of these hosts and nonhosts were established. There were not sufficient qualitative and quantitative differences in the amino acids to explain the host and nonhost status.

Hampea sp., Host of the Boll Weevil. II. Laboratory Antibiosis Studies ,

Abstract: Anthonomus grandis Boheman developmental studies were conducted on diets of freeze-dried cotton buds, Gossypunn hirsutum L., and buds and capsules of Hampea sp., a dioecious host, using the laboratory strain of weevils and a wild strain collected from Hampea. A high degree of larval antibiosis was found in Hampea . It was more pronounced in female buds and capsules than in male buds. On diets from male buds and female buds and capsules, smaller adults and a longer developmental time were observed. However, the percent adult emergence of the laboratory, but not the Hampea strain of weevils, from male bud diets was about equal to cotton diets. In the female buds and capsules the antibiosis was also expressed as high larval mortality. The 2 strains of weevils were physiologically different in their growth and development on all diets. Quantitative chemical analysis of gossypol, ascorbic acid, total sugars, and reducing sugars in the male and female buds and capsules failed to show that any of these materials except possibly gossypol was related to the expressed resistance. Thus, some unknown toxic factor rather than nutrition is suspected as the cause of antibiosis.