Field Response of Green Ash (Fraxinus pennsylvanica) and Honey Locust (Gleditsia triacanthos) to Aminocyclopyrachlor1

Field trials were conducted to assess the impact of aminocyclopyrachlor on green ash (Fraxinus pennsylvanica Marshall) and honey locust (Gleditsia triacanthos L.) trees in an urban environment. Aminocyclopyrachlor is a relatively new, selective, plant-growth-regulator herbicide in the pyrimidine carboxylic acid family. Treatments were applied to Kentucky bluegrass (Poa pratensis L.) sod growing with and without trees present. Evaluations included determination of a safe spraying distance from target trees and the effect of application timing on tree response. This multi-year study showed that green ash was highly tolerant to aminocyclopyrachlor while honey locust developed severe injury in trees closest to applications. Honey locust trees up to 7 m (23 ft) from the tree trunk to the edge of the application displayed moderate to severe injury symptoms and fall treatment in October and November had the lowest tree injury compared to all other application timings. Honey locust trees exhibiting moderate to severe cosmetic injury would not be acceptable to landowners; recovery over time was minimal. Trees located 13 m (43 ft) away displayed no injury for any treatment timing. Soil analysis demonstrated that aminocyclopyrachlor dissipation was the same underneath green ash and honey locust trees, and that dissipation was faster in the presence of growing trees. Taken together, these results provide a basic groundwork necessary for improving aminocyclopyrachlor labels, and a better understanding of this herbicide's effect on certain woody species. Index words: Herbicide injury, aminocyclopyrachlor, herbicide fate, tree safety. Species used in this study: Green ash, Fraxinus pennsylvanica Marshall, honey locust, Gleditsia triacanthos L. Chemicals used in this study: Aminocyclopyrachlor.

Parameters of biliary hydrodynamic injection during endoscopic retrograde cholangio-pancreatography in pigs for applications in gene delivery

The biliary system is routinely accessed for clinical purposes via endoscopic retrograde cholangiopancreatography (ERCP). We previously pioneered ERCP-mediated hydrodynamic injection in large animal models as an innovative gene delivery approach for monogenic liver diseases. However, the procedure poses potential safety concerns related mainly to liver or biliary tree injury. Here, we sought to further define biliary hydrodynamic injection parameters that are well-tolerated in a human-sized animal model. ERCP was performed in pigs, and hydrodynamic injection carried out using a novel protocol to reduce duct wall stress. Each pig was subjected to multiple repeated injections to expedite testing and judge tolerability. Different injection parameters (volume, flow rate) and injection port diameters were tested. Vital signs were monitored throughout the procedure, and liver enzyme panels were collected pre- and post-procedure. Pigs tolerated repeated biliary hydrodynamic injections with only occasional, mild, isolated elevation in aspartate aminotransferase (AST), which returned to normal levels within one day post-injection. All other liver tests remained unchanged. No upper limit of volume tolerance was reached, which suggests the biliary tree can readily transmit fluid into the vascular space. Flow rates up to 10 mL/sec were also tolerated with minimal disturbance to vital signs and no anatomic rupture of bile ducts. Measured intrabiliary pressure was up to 150 mmHg, and fluid-filled vesicles were induced in liver histology at high flow rates, mimicking the changes in histology observed in mouse liver after hydrodynamic tail vein injection. Overall, our investigations in a human-sized pig liver using standard clinical equipment suggest that ERCP-guided hydrodynamic injection will be safely tolerated in patients. Future investigations will interrogate if higher flow rates and pressure mediate higher DNA delivery efficiencies.

Evaluation of the Efficacy of Sex Pheromones and Food Attractants Used to Monitor and Control Synanthedon Myopaeformis (Lepidoptera: Sesiidae)

Synanthedon myopaeformis (Borkhausen, 1789) (Lepidoptera: Sesiidae) is a prominent pest of commercial apple orchards in Europe. the sex pheromones of S. myopaeformis and food attractants based on apple juice, beer and red wine were evaluated as tools for monitoring and control the populations of S. myopaeformis in apple orchards in the Czech Republic. For monitoring S. myopaeformis flight activity, trap designs were also evaluated, and the results indicated that wing traps were more suitable than delta traps because of their high efficacy even at low population densities of S. myopaeformis. The flight activity patterns of S. myopaeformis showed high intrapopulation variability and variability between years. The use of pheromones as a mating disruption technique led to a decrease of tree injury in comparison to untreated controls during the three years of the experiment. The reduction of the number of S. myopaeformis larvae per tree on a 14-ha plot treated subjected to the mating disruption technique reached 56 % in the third year of the experiment. In the three-year experiment using food attractants for the mass trapping of S. myopaeformis, catches of S. myopaeformis in traps using a combination of beer and apple juice (50:50) at a density of 4 traps/ha on a 4-ha plot increased more than 4-fold.

Fire-injured ponderosa pine provide a pulsed resource for bark beetles

Bark beetles can cause substantial mortality of trees that would otherwise survive fire injuries. Resin response of fire-injured northern Rocky Mountain ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson) and specific injuries that contribute to increased bark beetle attack susceptibility and brood production are unknown. We monitored ponderosa pine mortality and resin flow and bark beetle colonization and reproduction following a prescribed fire in Idaho and a wildfire in Montana. The level of fire-caused tree injury differed between the two sites, and the level of tree injury most susceptible to bark beetle attack and colonization also differed. Strip-attacked trees alive 3 years post-fire had lower levels of bole and crown injury than trees mass attacked and killed by bark beetles, suggesting that fire-injured trees were less well defended. Brood production of western pine beetle ( Dendroctonus brevicomis LeConte) did not differ between fire-injured and uninjured trees, although mountain pine beetle ( Dendroctonus ponderosae Hopkins) brood production was low in both tree types, potentially due to competition with faster developing bark beetle species that also colonized trees. Despite a large number of live trees remaining at both sites, bark beetle response to fire-injured trees pulsed and receded within 2 years post-fire, potentially due to a limited number of trees that could be easily colonized.

White Oak and Northern Red Oak Leaf Injury from Exposure to Chloroacetanilide Herbicides

Previous research by the authors found simulated acetochlor (with atrazine) and s-metolachlor drift to white oak at the leaf unfolding stage caused loss of interveinal tissues (leaf tatters). Reports of leaf tatters in the landscape and nursery settings are more common on white oak (Quercus alba L.) than on northern red oak (Quercus rubra L.). Our objectives were to determine if white and northern red oak differed in susceptibility to chloroacetanilide herbicides, if injury varied between chloroacetanilide herbicides, and if adding atrazine increased leaf injury. Two-year-old seedlings at the leaf unfolding stage were treated with acetochlor, s-metolachlor, and dimethenamid-P alone or combined with atrazine at 1%, 10%, and 25% of the standard field use rate. Within 6 days, all chloroacetanilides at 10% and 25% field use rates, alone or combined with atrazine, caused leaf tatter injury in both species. Acetochlor, s-metolachlor, and dimethenamid-P caused a similar type of leaf injury. Atrazine did not cause loss of leaf tissues or increase injury from chloroacetanilides. At 1% field use rate, only acetochlor, acetochlor + atrazine, and dimethenamid-P caused leaf injury to northern red oaks. The white oaks were not injured by all of the chloroacetanilide treatments at 1% field use rate. The northern red oaks were slightly more susceptible to chloroacetanilides compared with the white oaks. A second study found acetochlor only injured northern red oak when applied at the leaf unfolding stage and only at 25% of field use rate. Acetochlor at 1% field use rate did not injure red oak. Research is needed to explain the greater frequency of leaf tatters on white oaks than on northern red oaks in the landscape and to develop strategies to avoid tree injury.

Weed Control in Christmas Trees with Flumioxazin and Other Residual Herbicides Applied Alone or in Tank Mixtures

Four studies were conducted from 2001 to 2004 in Michigan to determine Christmas tree tolerance and weed control with flumioxazin and other herbicide treatments. In Study 1, fraser fir (Abies fraseri) leader length was greater with fall-applied flumioxazin (0.38 lb/acre) than with halosulfuron (0.21 lb/acre), isoxaben (1 lb/acre), oxyfluorfen (1 lb/acre), simazine (2 lb/acre), or sulfentrazone (0.5 lb/acre). Flumioxazin applied in the fall provided preemergent control of common ragweed (Ambrosia artemisiifolia), field violet (Viola arvensis), and hoary alyssum (Berteroa incana) 79% to 98% the following summer. Preemergence weed control with the other herbicides was more variable. In Study 2, fraser fir treated in the spring with oxyfluorfen had the shortest leader length (terminal stem growth of the current growing season) at 4.3 inches. Trees treated in the spring with flumioxazin, isoxaben, simazine, and sulfentrazone had leader lengths of 6.7 to 8.7 inches. Flumioxazin applied preemergence in the spring controlled common ragweed 80%, but controlled field violet, hoary alyssum, and white campion (Silene alba) only 43% to 64%. In Study 3, fall-applied flumioxazin alone did not injure colorado blue spruce (Picea pungens). However, mixtures of flumioxazin plus pendimethalin (3 lb/acre) caused 5% and 6% tree injury at 6 months after treatment (MAT) and sulfentrazone plus pendimethalin caused 9% and 23% injury at 6 MAT in 2003 and 2004, and 52% injury at 9 MAT in 2004. There was no significant injury to the trees treated with isoxaben plus pendimethalin, oxyfluorfen plus pendimethalin, or simazine plus pendimethalin in 2003 and 2004. Leader length was reduced by sulfentrazone plus pendimethalin compared with flumioxazin plus pendimethalin and oxyfluorfen plus pendimethalin. Flumioxazin plus pendimethalin provided 84% to 88% preemergence control of annual grasses, common catsear (Hypochoeris radicata), horseweed (Conyza canadensis), and virginia pepperweed (Lepidium virginicum). In Study 4, spring-applied mixtures of flumioxazin plus pendimethalin resulted in minor (2%–10%) visual injury to colorado blue spruce, although leader length at the end of the season did not differ significantly from the control. In summary, flumioxazin controlled several weed species with acceptable selectivity in colorado blue spruce and fraser fir Christmas trees.

Ecological Relationships Between Fungi and Woodpecker Cavity Sites

The presence of rotted wood is often noted in descriptions of woodpecker nest and roost sites, and ornithologists have found that certain fungi and species of woodpeckers, such as the red heart fungus (Phellinus pini) and Red-cockaded Woodpeckers (Picoides borealis) are intimately linked. The relationship assumed is usually one of woodpecker dependence or preference for partially decayed wood in which to excavate cavities, but the woodpecker is also sometimes suggested as a vector for the fungus. In this paper we review such associations and describe patterns evident among woodpecker nest sites that suggest microclimatic and microhabitat characteristics favoring fungal colonization of trees, woodpecker-favorable responses of trees to fungi, and ultimate use of the trees for woodpecker cavity excavation. Factors that favor fungal invasion and tree use by woodpeckers include tree species, growth history, site characteristics such as proximity to water and exposure to sun or shade, nature and position of tree injury, local climate, forest age and species composition, fire frequency, and human management activities. Woodpecker cavity height and entrance orientation may be related to the dispersal dynamics of fungi, which in turn may be related to forest vegetation, thermal, and hydric characteristics. Relaciones Ecológicas entre Hongos y Cavidades de Pájaros Carpinteros Resumen. En las descripciones de los nidos y dormideros de los carpinteros, muchas veces se menciona la presencia de madera podrida. Los ornitólogos han encontrado que ciertos hongos y especies de carpinteros, como el hongo Phellinus pini y el carpintero Picoides borealis, están íntimamente ligados. Usualmente se supone que el carpintero depende de o prefiere la madera en cierto estado de descomposición para excavar las cavidades, pero a veces también se sugiere que el carpintero es el vector del hongo. En este trabajo revisamos estas asociaciones y describimos patrones evidentes entre los sitios de nidificación de los carpinteros que sugieren (1) que existen características micro-climáticas y micro-ambientales que favorecen la colonización de los árboles por parte de los hongos, (2) que los árboles responden a los hongos de modo favorable para los carpinteros y (3) que los carpinteros usan luego los árboles para excavar las cavidades. Los factores que favorecen la invasión de los hongos y el uso de los árboles por parte de los carpinteros incluyen la especie de árbol, la historia de crecimiento, las características del sitio tales como la proximidad al agua y la exposición al sol o a la sombra, el tipo y posición del daño que presenta el árbol, el clima local, la edad y composición de especies del bosque, la frecuencia de fuego y las actividades antrópicas de manejo. La altura y orientación de la entrada de las cavidades de los carpinteros pueden estar relacionadas con la dinámica de dispersión del hongo, la cual a su vez puede estar relacionada con las características térmicas, hídricas y de la vegetación del bosque.