Ozone increases root respiration but decreases leaf CO2 assimilation in cotton and melon.

It is well established that exposure of plant foliage to tropospheric ozone (O3) inhibits photosynthetic gas exchange in leaves and the translocation of current photosynthate to sink tissues. It is less clear what impact O3-reduced source strength has on the physiological responses of sink tissue such as fine roots. The responses were investigated of carbon acquisition in leaves and carbon utilization in the respiration of fine roots, following chronic (weeks) and acute (hours) exposures to O3 in open top chambers.

Ecological effects of particulate matter.

Atmospheric particulate matter (PM) is a heterogeneous material. Though regulated as un-speciated mass, it exerts most effects on vegetation and ecosystems by virtue of the mass loading of its chemical constituents. As this varies temporally and spatially, prediction of regional impacts remains difficult.

High level methoprene resistance in the mosquito Ochlerotatus nigromaculis (Ludlow) in central California.

In the summer of 1998, failures of methoprene field applications to control the mosquito Ochlerotatus nigromaculis (Ludlow) were noticed in several pastures in the outskirts of Fresno, California, USA. Effective control with methoprene had been achieved for over 20 years prior to this discovery. Susceptibility tests indicated that the Fresno Oc nigromaculis populations had developed several thousand-fold higher LC50 and LC90 tolerance levels to methoprene compared with methoprene-naïve populations.

Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry.

In order to assess and maintain the quality of surface waters, target compound monitoring is often not sufficient. Many unknown micro-contaminants are present in water, originating in municipal, industrial or agricultural effluents. Some of these might pose a risk to drinking water production and consequently to human health.

Effect of Gaseous Ozone Exposure on the Development of Green and Blue Molds on Cold Stored Citrus Fruit.

The effects of gaseous ozone exposure on in vitro growth of Penicillium digitatum and Penicillium italicum and development of postharvest green and blue molds on artificially inoculated citrus fruit were evaluated. Valencia oranges were continuously exposed to 0.3 ± 0.

Ozone impacts on allometry and root hydraulic conductance are not mediated by source limitation nor developmental age.

O(3)could reduce growth and carbohydrate allocation to roots by direct inhibition of photosynthesis and source strength. Alternatively, O(3) could reduce growth indirectly by inhibition of root hydraulic development through a primary lesion in carbohydrate translocation. Another alternative is that O(3) could slow the rate of plant development, only apparently altering carbohydrate allocation at a given plant age.

Survival of Mucor piriformis in Soil of Apple Orchards in California.

Four apple orchards were sampled periodically in 1995 and 1996 to determine the population levels of Mucor piriformis, the causal agent of Mucor rot. The highest population, 119 propagules of M. piriformis per g of dry soil, occurred during winter.

Abscission and Kernel Quality of Almond Fruit Inoculated with the Shot Hole Pathogen Wilsonomyces carpophilus.

Fruit of almond cultivar Mission were aerosol-spray inoculated with aqueous suspensions containing 10, 10, or 10 conidia/ml of Wilsonomyces carpophilus beginning when fruit emerged from the hypanthium and continuing at approximately weekly intervals until they reached full size and embryo development had begun. There was a linear increase in percent fruit abscission (P = 0.001) and average number lesions per fruit (P = 0.

Influence of Fruit-to-Fruit Contact on the Susceptibility of French Prune to Infection by Monilinia fructicola.

In eight commercial prune (Prunus domestica cv. French) orchards, 43 to 69% of brown rot (caused by Monilinia fructicola or M. laxa) infections occurred in clustered fruit as opposed to solitary fruit.

First Report of Mucor Rot in Commercially Sold Cherries Caused by Mucor piriformis.

In August 1996, a commercial retailer of high quality cherries from the Okanagan Valley of British Columbia, Canada, reported severe losses in at least 150 boxes (11.3 kg per box) of packed cherries cv. Stella.

Effect of fenbendazole molasses supplement block treatment on nematode infection and subsequent weight gain of weanling beef calves.

Two trials were conducted to evaluate the effect of fenbendazole molasses supplement block treatment on weight gain of weanling beef calves. An initial (November) oral fenbendazole (5 mg kg-1) treatment was administered to all animals in both trials. In Trials 1 and 2, respectively, two fenbendazole molasses supplement block treatments were administered 6 (6.

X-ray photoelectron spectroscopy surface analysis of aluminum ion stress in barley roots.

X-ray photoelectron spectroscopy (XPS) has been used to analyze root surface changes when Dayton barley (Hordeum vulgare) (Al tolerant) and Kearney barley (Al sensitive) seedlings were grown in nutrient solution in the presence and absence of 37.0 micromolar Al. The electron spectra from root surfaces contained strong lines in order of decreasing intensity from organic forms of carbon, oxygen, and nitrogen and weak lines due to inorganic elements in the form of anions and cations on the surface.

Efficacy of levamisole and netobimin against Haemonchus contortus in lambs in Louisiana.

Efficacy of levamisole was evaluated in a suspected levamisole-resistant population of Haemonchus contortus in the Louisiana State University sheep flock. The efficacy of netobimin also was evaluated against this population of Haemonchus. In trial 1, 5 lambs naturally infected with H contortus were given 8 mg of levamisole/kg of body weight as a drench, and 5 lambs were not treated (controls).

Aerial adulticiding for the suppression of Culex tarsalis in Kern County, California, using low-volume propoxur: 1. Selection and evaluation of the application system.

Propoxur applied aerially at 4.7 liters/ha was an effective adulticide against organophosphate resistant Culex tarsalis. Applications by fixed-wing and helicopter underslung spray systems equipped with hydraulic nozzles provided good coverage of test areas as indicated by the mortality patterns of sentinel mosquitoes.