Fate of a water-soluble herbicide spray on foliage: Part I. Spray efficiency: Measurement of initial deposition and absorption

MSMA (monosodium methylarsonate) is non-volatile and degrades in the environment to arsenic species which can be determined at the nanogram level. It is thus an excellent tracer for the study of the efficiency of deposition (defined as the fraction of material sprayed that deposits on target foliage) and subsequent fate of a water-soluble pesticide applied to foliage. MSMA was applied to rice (Oryza sativa L. cv. Labelle) foliage at two rates and at various stages of growth. After spraying the foliage was sampled and analysed for surface (removable by water-washing) and absorbed MSMA. Absorption of MSMA was so rapid that within the two hours between application and washing nearly one-half of the recovered MSMA became unavailable for wash-off. The total amounts of MSMA recovered were approximately proportional to plant size and application rate. When the rice foliage reached approximately 80 cm in height, the canopy closure (ground cover) was complete; nevertheless, only about 50% of the sprayed MSMA was found on and in the plants. As the rice canopy approached maturity, or approximately 130 cm high, complete interception of the spray occurred. These results indicate that canopy volume rather than ground cover was more important in determining the efficiency of spray deposition in this case, and that deposition efficiency may approach 100% with non-volatile active ingredients.     

Bacterial isolates from equine infections in western Canada (1998-2003)

All bacterial samples of equine origin submitted to the diagnostic laboratory at the Western College of Veterinary Medicine from January 1998 to December 2003 from either "in-clinic" or Field Service cases were accessed (1323 submissions). The most common bacterial isolates from specific presenting signs were identified, along with their in vitro antimicrobial susceptibility patterns. The most common site from which significant bacterial isolates were recovered was the respiratory tract, followed by wounds. Streptococcus zooepidemicus was the most common isolate from most infections, followed by Escherichia coli. Antimicrobial resistance was not common in the isolates and acquired antimicrobial resistance to multiple drugs was rare. The results are compared with previous published studies from other institutions and used to suggest appropriate antimicrobial treatments for equine infections in western Canada.     

Facing Rose rosette virus: A risk to European rose cultivation

Roses (Rosa) are one of the most valuable ornamental flowering shrubs around the globe. They are susceptible to numerous pathogens that require management, increasing the cost of cultivation. Rose rosette virus (RRV; genus Emaravirus) is a devastating virus that has been spreading since the 1940s in the United States and Canada. It is an emerging risk to European and worldwide rose cultivation, causing symptoms such as witches' broom, malformations, excessive thorn production, and eventually plant death. RRV is transmitted by the eriophyid mite Phyllocoptes fructiphilus and by grafting. Research is being undertaken to understand RRV and to find control measures and resistant cultivars, as they are not currently available. Early detection of the disease is the key to prevent the establishment and spread of RRV and its vector. Different molecular and serological diagnostic methods have been designed and implemented, including ELISA, RT-PCR, RT-qPCR, LAMP, and high-throughput sequencing. RRV infected plants can remain symptomless for long periods, so these diagnostic assays are necessary in conjunction with visual assessment to facilitate early detection. Significant social, economic, and environmental impacts are expected if RRV and its vector establish and spread in Europe. Rose trade between countries is the most likely pathway of introduction of RRV into Europe. In this review we describe current knowledge about RRV, the molecular and serological methods available for the detection of this virus, pathways to entry, and the possible impact if it establishes and spreads in Europe.     

饲料原料及加工技术对猪饲料质量的影响(下)

当今养猪生产中,生产者和营养师对日粮能量水平、氨基酸浓度和比例、最佳维生素和微量元素供给等方面都给予了极大的关注。选择价格合适、品质优良的饲料原料,采用适当的原料加工方式来配制饲料,对猪场获益非常重要,但良好饲料加工规范常被大家忽视。本文将讨论加工技术对饲料原料和配合饲料营养价值最大化的影响。     

CONSUMPTION OF FROZEN AND LIVE Artemia BY PROTOZOEA OF Penaeus setiferus

The role of an animal component in the diet of protozoeal penaeid shrimp larvae is not known. Short-term experiments were performed on the larvae of Penaeus setiferus (L.) to determine the ability of each protozoeal substage to consume frozen and live Artemia nauplii. Significant consumption of frozen Artemia took place during the protozoea 2 and 3 substages at rates of 1.0 and 1.6 Artemia nauplii/penaeid larva/hour respectively. Consumption of live Artemia occurred in the protozoea 3 substage, at a rate of 0.7 Artemia nauplii/penaeid larva/hour. Data suggesting that there is a beneficial role of an animal component in the diet of protozoeal penaeid shrimp larvae are discussed.     

Dye-sensitized photoinactivation of the lactic dehydrogenase and acetylcholinesterase from the boll weevil,Anthonomous grandis

The lactic dehydrogenase and acetylcholinesterase enzymes of the boll weevil, Anthonomous grandis, have been shown to be inactivated by dye-sensitized photooxidation mediated by substituted xanthenes. The efficiency of the photooxidation reaction was correlated with the degree of halogenation of the dye molecule, the efficiency of the dye in singlet oxygen formation, and the strength of binding to lactic dehydrogenase. Changes in the in vivo levels of these enzymes due to ingestion of rose bengal by adult weevils are not further modified in the presence of light.