A Migration Study of \u3ci\u3eStelidota Geminata\u3c/i\u3e (Coleoptera: Nitidulidae)

The strawberry sap beetle, Stelidota geminata (Say), is a major pest of strawberries in the northeastern United States. Further knowledge of the migratory habits of this insect pest can enhance the effectiveness of pest management strategies. This nitidulid was shown to migrate from its overwintering sites to one of its primary reproductive sites, strawberry fields, in late May. The beetle population peaked in the third week in July, 1993 in the strawberry field and then gradually declined. In 1994, the peak, as well as the total population, was much greater than in 1993. Furthermore, S. geminata was concentrated in the transition areas surrounding the strawberry fields prior to the ripening of the fruit

Reaction of Isocyanates with Southern Pine Wood to Improve Dimensional Stability and Decay Resistance

Ethyl, n-propyl, and n-butyl isocyanates reacted with wood without catalyst to yield modified southern pine that was 30 to 50% more dimensionally stable than unmodified specimens and that had improved decay resistance. Phenyl and p-tolyl isocyanates and 1,6-diisocyanatohexane, isophorone diisocyanate, and tolylene-2,4-diisocyanate formed nonbonded polymers in wood voids and did not increase dimensional stability. In the presence of 35% dimethylformamide, however, n-butyl and phenyl isocyanates, 1,6-diisocyanatohexane and tolylene-2,4-diisocyanate reacted with wood, resulting in increased dimensional stability. The best dimensional stability and decay resistance of all specimens tested were shown by those modified with n-butyl isocyanate in the presence of 35% dimethylformamide. The dimensional stability was 70% better than that of unmodified specimens and the weight lost in the decay test was 2%, indicating a high resistance to decay

Determination of Dimensional Stabilization of Wood Using the Water-Soak Method

Erroneous results can be obtained by the water-soak method in determination of dimensional stability that Chemically treated wood. Leaching of bulking chemicals results in a loss of dimensional Stability that can be determined only after an initial soaking cycle. After a first soaking cycle, values for percet dimensional stabilization are more realistic for those treatments where the bulking chemical has reacted with cell-wall components. Where the bulking chemical is not bound to cell-wall components, leaching during the first soaking cycle removes most of the chemical, so that in the second soaking cycle, values for percent of dimensional stability are very low. It is important that the test method used be tailored to fit the end use of the product. For products stabilized only against changes in humidity, a second soaking cycle should not be used to determine dimensional stability. Treatments that only fill cell lumens and do not bulk the cell wall result in a low degree of dimensional stability

Effects of Moisture on the Chemical Modification of Wood With Epoxides and Isocyanates

The effects of moisture on the reaction of epoxides and isocyanates with wood were investigated. Ponderosa pine at 0%, 5%, and 10% equilibrium moisture contents was reacted separately with either propylene oxide or butylene oxide catalyzed with triethylamine, or with butyl isocyanate catalyzed with dimethylformamide. Five successive treatments were performed while recycling the treatment solutions on specimens with 5% and 10% equilibrium moisture contents. Grinding and extracting the treated wood showed significant losses of nonbonded chemical at these original moisture levels. When antishrink efficiency was determined on propylene oxide treated wood using the double water-soak method, a high resistance to dimensional changes was observed on the first water-soak cycle. Most of this dimensional stability was lost based on the second water-soak cycle, showing that nonbonded polymer had been extracted. Somewhat higher antishrink efficiency values were obtained for butylene oxide and butyl isocyanate treatments. Gas chromatographic determination of products from the propylene and butylene oxide/triethylamine treating solutions showed little water buildup. Total accountable volatile products decreased with successive treatments on specimens originally containing 5% and 10% moisture, indicating the formation of nonvolatile polyglycols in the wood cell wall. Determination of butyl isocyanate solutions following each treatment showed that one quarter or less of the active isocyanate was lost due to reaction with the water in the wood

The oxygen-II luminosity density of the Universe

Equivalent widths of [OII] 3727 A lines are measured in 375 faint galaxy spectra taken as part of the Caltech Faint Galaxy Redshift Survey centered on the Hubble Deep Field. The sensitivity of the survey spectra to the [OII] line is computed as a function of magnitude, color and redshift. The luminosity function of galaxies in the [OII] line and the integrated luminosity density of the Universe in the [OII] line are computed as a function of redshift. It is found that the luminosity density in the [OII] line was a factor of ~10 higher at redshifts z~1 than it is at the present day. The simplest interpretation is that the star formation rate density of the Universe has declined dramatically since z~1.Comment: accepted for publication in Ap

Insects in the Killbuck Marsh Wildlife Area: 1993 Survey

Author Institution: Ohio Agricultural Research and Development Center, Ohio State UniversityThe Killbuck Marsh Wildlife Area was the focus of a seven month survey performed in 1993 to determine the diversity of selected insects. Primary emphasis was focused on three families of Coleoptera: ground beetles, including tiger beetles (Carabidae); sap beetles (Nitidulidae); and carrion beetles (Silphidae). Rare or endangered species within these families were of particular interest and constant vigilance was made to detect them. Five collection methods were used at five sites within the Killbuck Marsh. These included: ultraviolet (black light) traps, flight interception (window) traps, bait traps, carrion bait sampling, and aerial and aquatic sweep netting. In all, 68 ground beetle, 30 sap beetle, and seven carrion beetle species were identified. In addition to these families, beetles from 47 other families (372 species) of Coleoptera were collected and identified. Aside from Coleoptera, several dragonflies and damselflies (Odonata), caddisflies (Trichoptera), butterflies and moths (Lepidoptera), and mosquitoes and midges (Diptera) were also taken. Six ground beetle species considered uncommon were encountered: Agonum cupripenne (Say), Agonum galvestonicum Casey, Chlaenius niger Randall, Oo'des americanum Dejean, Blemus discus (F.), and Stenocrepis cuprea (Chaudoir). One hister beetle (Histeridae), Anapleus marginatus LeConte, was also very uncommon for this area