Fumigation of Jute Bags with Ethylene Oxide and Methyl Bromide to Eradicate Potato Ring Rot Bacteria

In a series of full-scale tests, the effectiveness of various fumigant treatments for the eradication of potato ring rot bacteria from bulk lots of contaminated jute bags was evaluated. Survival of these bacteria on infested sample fibers located at various positions within and around a tightly wired bale was determined quantitatively from the growth lag in a liquid medium as indicated by the rate of turbidity development.

Ethylene oxide, though highly toxic to Corynebacterium sepedonicum in laboratory tests, failed to penetrate the jute sufficiently to be effective in the interior of a bale. Methyl bromide showed better penetration, but was not sufficiently toxic at practical dosage levels. A mixture of 5% ethylene oxide and 10% methyl bromide achieved complete eradication throughout a bale in an 18-hr exposure period.

On the basis of these results, eradication of ring rot bacteria from contaminated jute bags by fumigation with a combination of these two gases would appear to be feasible under commercial conditions.

     

Vegetation of the greater Maya Mountains,Belize

This paper describes a new vegetation classification for the Greater Maya Mountains of Belize, focusing primarily on the Chiquibul Forest Reserve. Extensive use is made of GIS, remote sensing, botanical collections and field visits to provide a macro‐ and meso‐scale overview of the vegetation of this region. A total of 32 vegetation classes have been defined, both geographically and structurally, including 11 new classes. Where possible, classes have been compared with earlier classifications. A dominant scaling technique has been used to enable direct comparison between ground truthing data and a supervised Maximum Likelihood Classifier image‐based vegetation classification. The merits of such classifications and the effect of scale are discussed.     

Chemical Deposition of Silver for the Fabrication of Surface Plasmon Microstructured Optical Fibre Sensors

We compare the Tollens reaction, a simple chemical coating method, with the more commonly used RF sputtering technique for use in creating surfaces suitable for sensing applications based on surface plasmon resonance. Experiments show that by optimising the chemical process, these two approaches can produce surfaces that exhibit similar surface plasmon resonance (SPR) performance. Thus, the Tollens method is a viable one for coating the interior surfaces of a microstructured optical fibre. As a demonstration, this technique was applied to a microstructured optical fibre, and a 60-nm silver layer is produced along the entire length of a 1-m-long fibre. This is the first step towards the realisation of a SPR sensing device based on microstructured optical fibres.