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The influence of total resin flow in loblolly pine, Pinus taeda L., on initial colonization by the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Scolytidae), was investigated. Resin flow of trees was manipulated mechanically so that it followed the same pattern of decrease and near cessation as seen in trees successfully attacked by southern pine beetle. There were also intermediate treatments where resin flow was allowed to recover after near cessation. Beetles were introduced by means of mesh cages attached to the mid-bole of trees and left until the end of the longest wounding treatment. In trees where resin flow was reduced, significant increases in number of attacks, total gallery length, and length of gallery free of resin occurred.

The influence of total resin flow in loblolly pine, Pinus taeda L., on initial inoculation of the blue stain fungus Ophiostoma minus (Hedgc.) Syd. & P. Syd., a fungal associate of southern pine beetle (Dendroctonus frontalis Zimmermann (Coleoptera:Scolytidae)), was investigated. Resin flow of trees was mechanically manipulated so that it followed the same pattern of decrease and near cessation as seen in trees successfully attacked by southern pine beetle. There were also intermediate treatments where resin flow was allowed to recover. The fungus was inoculated into holes drilled to the xylem surface and allowed to grow for a specified time period. The lesion that formed as a result of the induced reaction was then measured and compared with lesions formed in trees for which resin flow was not manipulated. The experiment was conducted three times in 1993 and 1994 and twice in 1995. It was hypothesized that with decreased resin flow, O. minus would be less inhibited and that growth would be greater before being stopped by the induced reaction. It was found that longer lesions occurred in trees where wounding was prolonged and resin flow was decreased below that of control trees. Mixed results were obtained for trees in intermediate wounding treatments.Key words: oleoresin, blue stain fungus, defenses, bark beetles, induced reaction, Dendroctonus.

The beet armyworm, Spodoptera exigua (Hubner), is a sporadic but devastating secondary pest of cotton. Scouting cotton for egg masses is commonly recommended for identifying potential outbreaks and for proper timing of insecticide applications. However, there is disagreement regarding where to look on the plant for beet armyworm eggs. We investigated and quantified placement of egg masses by laboratory colony females within cotton and pigweed (a preferred wild host plant) canopies of different heights. In cotton, almost all egg masses were deposited on the undersides of leaves, and ≈80% of the egg masses were consistently located in the upper 50% of the cotton canopy, and horizontally within the inner 50% of the canopy around the central axis. Although this trend was consistent among all categories of plant height tested, variation about the means decreased with increasing height. A smaller sample of wild females indicated similar vertical placement, but horizontal placement extending further distally in the canopy. Our results indicate that scouting for egg masses on the underside of leaves in the upper half of the canopy will recover ≈80% of the egg masses present on the plants. In pigweed, egg masses were commonly laid within the inner 50% of the canopy, but along the upper 80% of the vertical axis. As in cotton, variation about the means was less in taller plants. The number of eggs per egg mass was 29% less in cotton than in pigweed. This positional information will aid in further efforts to investigate, predict, and manage beet armyworm populations in cotton and noncotton hosts.

Longevity, duration of the oviposition period, realized fecundity, potential fecundity, and egg fertility of the beet armyworm, Spodoptera exigua (Hubner), were examined in the laboratory under three different adult diet regimes. All parameters were significantly reduced for the water-only diet compared with 10% honey or sucrose diets, except fertility, which could not be measured after 5 d because of high mortality of water-fed females. Oviposition was highest the night after mating and decreased in a logarithmic manner thereafter. In the carbohydrate-fed moths, 92% of lifetime realized fecundity occurred by the fourth night of oviposition. Although our data indicate that carbohydrates in the adult diet can increase realized and potential fecundity, most of the lifetime complement of oocytes (91%) is present at the time of eclosion from the pupa. Pupal weight was significantly correlated with lifetime potential fecundity, explaining 37–66% of the variation among moths depending on adult diet, and this effect was substantial. Taken together, our results suggest that the bulk of variation in realized fecundity is generated in the larval stage, provided suitable oviposition substrate is available for the adults. This information will be important in understanding population dynamics of beet armyworm and to improving our ability to predict population outbreaks from sampling data.

Despite years of effort, the composition of polar stratospheric clouds (PSCs) is still uncertain. Future studies may be able to use FTIR extinction measurements to determine PSC composition. These studies require accurate optical constants for PSC materials. It has been suggested that accurate infrared (IR) optical constants for aerosols can only be derived from aerosol spectra. We have examined the IR spectra of nitric acid trihydrate (NAT) and nitric acid dihydrate (NAD) films and aerosols formed using a variety of experimental conditions. We conclude that several spectroscopically different types of NAD and NAT may exist. Alternatively, NAT could be birefringent and its spectra depend strongly on crystallographic orientation. The important causes for the different types or orientations seem to be the formation conditions and temperature, rather than whether the material is a film or aerosol.

Laboratory measurements are presented for the freezing kinetics of H 2 O/HNO 3 aerosols over the temperature range of 188-204 K. For 2:1 H 2 O:HNO 3 aerosols crystallizing to NAD we observed a maximum nucleation rate of J= 9.3 x 10 9 cm -3 s -1 at 194 K. This temperature is between the glass point of 161 K [Ji et al., 1993] and the melting point of 235.5 K [Ji et al., 1996]. This can be compared to a previous measurement of J =6.7 x 10 9 cm -3 s -1 at 193 K [Disselkamp et al., 1996] and lower temperature measurements of J 10 10 - 10 12 cm -3 s -1 at 178.8 - 175.8 K [Bertram and Sloan, 1998a]. Measured nucleation rates decrease as the aerosol becomes dilute, but NAD formation is still observable for 2.5:1 H 2 O:HNO 3 at temperatures near 195 K. In contrast, freezing of 3:1 H 2 O:HNO 3 aerosol was not observed for constant temperature experiments throughout this temperature range, yielding an upper limit of J < 1.5 x 10 9 cm -3 s -1 . This is the lowest experimental value determined for 3:1 H 2 O:HNO 3 freezing rates at these temperatures. From the measured freezing rates and knowledge of the free energy of diffusion the average interfacial free energy for NAD in a 2:1 H 2 O:HNO 3 solution was determined to be σ = 25.2 ergs cm -2 . A limit for the interfacial free energy was placed on 3:1 H 2 O:HNO 3 particles, for which freezing was not observed. These data imply that if aerosols reach compositions more concentrated than 3:1 H 2 O:HNO 3 in the atmosphere, NAD may play a role in polar stratospheric cloud formation.

We have determined the infrared optical constants of sulfuric acid solutions at intervals of approximately 5 wt% between 45 and 80 wt% H2SO4 at a temperature near 215 K. The optical constants were determined by first measuring the transmission of infrared light (7000 to 500 cm−1) through sulfuric acid films of varying thickness. An iterative Kramers-Kronig technique was then used to determine the optical constants that yielded the best match between calculated and measured spectra. Finally, a fitting routine was used to create a method for interpolating between the sulfuric acid compositions where optical constants were measured. The optical constants determined here differ considerably from those measured at warmer temperatures using reflection techniques. For some frequencies and compositions, the imaginary refractive index is more than twice as large as was previously measured at 300 K. The change in optical constants has significant implications for retrievals of aerosol mass and composition from satellite measurements.

The crystal structure of [bis(2-diphenylphosphinoethyl)phenylphosphine-P,P',P][bis(diphenylphosphino)-methane-P,P'] carbonylmolybdenum(0), [Mo(dpepp)-(dppm)(CO)] [where dppm = Ph 2 PCH 2 PPh 2 and dpepp = Ph 2 PCH 2 CH 2 P(Ph)CH 2 CH 2 PPh 2 ], is reported. In the distorted octahedral complex, the tridentate ligand adopts a facial arrangement with the monodentate ligand trans to the central P atom. All Mo-P distances are statistically dissimilar.

It has recently been suggested that type Ib polar stratospheric clouds are composed of supercooled ternary-solutions of sulfuric acid (H2SO4), nitric acid (HNO3), and water (H2O). We have studied the low-temperature behavior of ternary-solution aerosols to determine if they will undergo homogeneous freezing nucleation under polar stratospheric conditions. Ternary-solution aerosols were injected into a low-temperature chamber and observed for periods of up to 3 hours. Fourier transform infrared spectroscopy was used to determine the aerosol composition and phase as a function of time. We found that ternary-solution aerosols with compositions similar to those expected in the polar stratosphere remained supercooled for the duration of our experiments. Homogeneous freezing of the particles was never observed, even after warming from 190 to 204 K. However, heterogeneous freezing was occasionally observed for particles adhering to the infrared optics within the chamber.

The crystallization of binary HNO3/H2O aerosols may be an important step in the formation of type Ia polar stratospheric clouds (PSCs). We have used Fourier transform infrared (FTIR) spectroscopy to probe the crystallization kinetics of supercooled 2:1 and 3:1 H2O:HNO3 films to nitric acid dihydrate (NAD) and trihydrate (NAT), respectively. Nitric acid/ice films were grown on a silicon substrate at temperatures near the glass point. The substrate was then warmed to a temperature above the glass point, and the crystallization of the film was measured using FTIR absorption spectroscopy. The temperature dependence of the crystallization rate was used to determine the activation energy for a nitrate ion to cross the liquid−solid phase boundary. The activation energies ranged from 22 to 41 kcal mol-1 for NAD crystallization at temperatures between 177 and 168 K and from 22 to 35 kcal mol-1 for α-NAT crystallization at temperatures between 171 and 161 K. In addition, activation energies at higher temperatures w...

Sub-micrometer sized sulfuric acid H2SO4 particles were generated using a constant output atomizer source. The particles were then exposed to water vapor before being injected into a low temperature cell. Multipass transmission Fourier Transformation Infrared (FTIR) spectroscopy was used to determine the phase and composition of the aerosols as a function of time for periods of up to five hours. Binary H2SO4H2O aerosols with compositions from 35 to 95 wt % H2SO4 remained liquid for over 3 hours at room temperatures ranging from 189-240 K. These results suggest that it is very difficut to freeze SSAs via homogeneous nucleation. Attempts to form aerosols more dilute than 35 wt % H2SO4 resulted in ice formation.

Basic information on oviposition behavior of Neodiprion fulvicepsis presented. We present evidence which suggests that adults possess circadian rhythms for emergence and female oviposition activity. A behavioral catalog was developed and it was found that females, while inactive, spend 54% of their time oriented basally on needles and, while active, 18% of their time walking up and down needles. A description of the oviposition sequence and time spent in each step is presented. It was determined that females spend a significantly longer time cutting the first egg pocket than successive egg pockets. We also present evidence of an oviposition deterrent factor.

1 The effect of ponderosa pine (Pinus ponderosa Doug]. ex Laws) water stress, measured by xylem water potential, on oviposition preference and egg development of Neodiprion fulviceps was determined by two laboratory experiments in 1987 and 1988. 2 In the first experiment, adult females were allowed to choose between foliage from water-stressed, watered, and untreated control trees. 3 Significant differences were found between treatments in xylem water potential in 1987 but not in 1988. 4 Females chose water-stressed trees and a positive correlation was found between female preference and xylem water potential in 1987 but not in 1988. 5 In the second experiment, females were placed in globe cages with a single branch from each treatment and allowed to oviposit. 6 Significant differences were found among treatments in egg survival in 1987 but not in 1988. 7 These results indicate that sawflies can distinguish between stressed and non-stressed trees and that this behaviour is adaptive in that egg survival was greatest on the preferred treatment.

The reactions of a series of mono(dinitrogen) complexes of molybdenum Mo(N 2 )(dpepp)(L 2 ) [where dpepp=PhP(CH 2 CH 2 PPh 2 ) 2 and L 2 =PMe 2 Ph, Me 2 PCH 2 PMe 2 (dmpm), 1,2-(Me 2 As) 2 C 6 H 4 (diars), Ph 2 PCH 2 PPh 2 (dppm), Ph 2 PCH 2 CH 2 PPh 2 (dppe)] with acids are reported. Reactions with excess HX (X=Br, Cl) in the solid state or HX in toluene led to the isolation of the hydrazido(2-) complexes [MoX(NNH 2 )(η 2 -dpepp)(PMe 2 Ph) 2 ]X [(X=Cl) and (X=Br)] in which dpepp is bidentate

The reactions of anhydrous HX (X = Br, Cl) with trans-Mo(N2)2(triphos) (PPh3) (1) where triphos = PhP(CH2CH2PPh2)2, yield [MoX(NNH2)(triphos)(PPh3)]X as a mixture of isomers: 1A(X) and 1B(X). In solution, PPh3 dissociates rapidly from the B isomer. Addition of PPh3 to a mixture of 1A(X) and 1B(X) enabled the separation of the isomers by fractional crystallization. Addition of PPh2Me to a mixture of 1A(X) and 1B(X) led to the isolation of 1A(X) and [MoX(NNH2)(triphos)(PPh2Me)]X [2B(X)]. Amber 1A(Cl) crystallizes with one molecule of toluene in the monoclinic space group P21 with a = 13.714(2), b = 13.924(2), c = 14.279(3) A, β = 102.44(1)°, and Z = 2. Olive-green 2B(Cl) crystallizes with two molecules of salvation; one each of pentane and toluene, in the triclinic space group P 1 with a = 12.922(2), b = 13.552(3), c = 18.067(4) A, α = 106.04(1), β = 107.65(1), γ = 97.22(1)°, and Z = 2. Loss of PPh3 from 1B(X) is proposed to be due to steric factors. Yields of ammonia and hydrazine formed from all the nitrogen hydride complexes are summarized.

Resin flow was measured at four heights along the bole of loblolly pine, Pinus taeda L., using two, four, and eight wounds per height in May, June, July, and August of 1990. Consistent differences in resin flow between heights were observed with the eight per height treatment. The greatest amount of flow was found to be from the midbole and below. The differences in flow for the two and four samples per height treatments followed the same pattern as the eight per height treatment; however, no statistical differences were detected. Total flow for the entire tree was found to increase from May to August. Key words: oleoresin secretory system, Pinus taeda, southern pine beetle, insect – host interaction, induced response.

Publisher Summary This chapter examines the crystallization of binary 2:1 and 3:1 H20:HNO3 aerosols under stratospheric temperature conditions using Fourier transform infrared (FTIR) spectroscopy. The main advantage of measuring the crystallization rate of an aerosol, rather than a bulk sample is the avoidance of the possibility for heterogeneous crystallization on a supporting substrate. Another difference between aerosol and bulk studies stems from differences in sample volume. The homogeneous crystallization rate of a sample is proportional to its volume. Previous studies on bulk samples have used volumes of >10-2 cm3, whereas a 1 micrometer diameter particle has a volume of ∼10-12 cm3. Therefore, the homogeneous crystallization rate of the aerosol sample is reduced by a factor of at least 1010 relative to bulk studies. The interfacial surface energy for nitric acid dihydrate (NAD) nucleation from a 2:1 H2O:HNO3 solution is much lower than the corresponding surface energy for nitric acid trihydrate (NAT), suggesting a possible role for NAD in type Ia polar stratospheric cloud (PSC) formation.

Preparation de MoBr(NNCH(CH 3 )(C 6 H 13 )(S,S)-chiraphos) 2 . Spectres RMN de 1 H par reaction de trans-Mo(N 2 ) 2 ((S,S)-chiraphos) 2 avec le bromo-2 octane

The synthesis is reported of a mono-dinitrogen complex of molybdenum, Mo(N2)(triphos)(PMe2Ph)2, where triphos = PhP(CH2CH2PPh2)2, that yields significant yields of ammonia and hydrazine when treated with HCl or HBr in organic solvents. Generally, increasing the temperature increases the combined yield of ammonia and hydrazine.

It has been suggested that the biological reduction of N2 involves, after N2 binding, a series of six electron-proton transfer steps (Thorneiey, Lowe, 1984). No nitrogen-hydride intermediates have been identified in any biological system. However, indirect evidence has led to the following proposed intermediates: (1) diazene-level(N2H2) intermediate (HD formation; Burgess, Newton 1981), (ii) mo2tygdenum-hydride-N2 [Mo(H) (N2)] complex (HD formation and pre-steady state kingtic data; 2Thorneley, Lowe, 1984), and (iii) hydraz ido (2-) (NNH2) species (quenching to form hydrazine; Thorneley, Lowe, 1984).

Yates Petroleum has developed successful drilling and completion practices through experience with 200 wells in the Pecos Slope Abo gas field. Several methods have been used for estimating ultimate reserves from the wells in this low permeability reservoir. The most promising is a drawdown analysis that matches computerized type curves with data on daily flow rates and tubing pressure.

The mono-N2 complex fac-Mo(N2)(triphos)(L2) (1), where triphos = PhP(CH2CH2PPh2)2 and L = PMe2Ph, reacts with HX (X = Br, Cl) to give the hydrazido(2—) complex, [Mo(NNH2)(η2-triphos)(PMe2Ph)2]X (2), in which triphos is bidentate. Complex 1 reacts with HBr (1 mol) to give an almost quantitative yield of MoHBr(triphos)(PMe2Ph) (3). With HBr (1 mol), 3 produces MoH2Br(triphos)(PMe2Ph).