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A modification to a vacuum direct reading optical emission spectrometer is described. The light reflected from the grating is focussed onto the entrance slit of a secondary monochromator to extend the range of wavelengths available. Results for the analysis of sodium in mineral, rock, and ash samples by a fusion briquette method are given. The application to the analysis of other alkalis and to background correction is discussed.

Male beetles of the larger grain borer,Prostephanus truncatus Horn (Coleoptera: Bostrichidae) were shown to produce material causing an electroantennographic (EAG) response from both male and female beetles. Volatiles from mixed sex cultures were collected on Porapak Q and fractionated by liquid chromatography (LC) with gradient elution. The total volatiles and the fractions were analyzed by gas chromatography (GC) linked to EAG, and two compounds eluting in the same LC fraction elicited EAG responses from male and female beetles. These were assumed to be components of the male-produced aggregation pheromone. Amounts of these compounds obtained were very low and less than 10-3 times the amounts of the aggregation pheromone components produced by the related species,Rhyzopertha dominica, under similar conditions. The most abundant of these EAG-active compounds was identified as 1-methyiethyl (2E)-2-methyl-2-pentenoate by comparison of its GC retention times and mass spectrum with those of synthetic analogs. The synthetic compound elicited electrophysiological and behavioral responses in both male and female beetles significantly greater than those to structural analogs. This compound is attractive toP. truncatus beetles in the field, and has been given the trivial name of “trunc-call 1”.

A quartz optical fiber flexible light conductor conveys light from the analytical gap of a vacuum optical emission spectrometer to a secondary monochromator, to extend the range of wavelengths available and enhance the versatility of operation. A simple modification to the spark stand is described. Results are given for the determination of alkali elements in mineral and ash samples. Examples of use of the enhanced versatility are discussed.

After the fumigation of stock, grain stores may be resprayed regularly with a residual insecticide to lower the rate of insect reinfestation. For financial justification, respraying must result in a substantial delay in the need for refumigation. The costefficiency of respraying, for the protection of bagged milled rice, was investigated in six stores in East Java, Indonesia. All six stores were sprayed immediately after fumigation and then four were resprayed, at monthly intervals, with fenitrothion e.c. or w.p. Store reinfestation was monitored using bait-bag traps and spear sampling, and the performance of the treatments assessed in the light of the calculated minimum delay to refumigation required for costeffective pest control. The major pest in all stores was T. castaneum although other insects were present, especially Psocoptera. No substantial slowing of insect reinfestation was observed in the resprayed stores; the possible reasons for this are discussed. Thus neither of the respray treatments could be regarded as cost effective. Abandoning respraying of bagged milled rice stores might, at worst, result in a small increase in the frequency of fumigation but reliance on fumigation together with a single non-residual spray treatment is likely to be a cheaper and more efficient option.

A high purity iron—26% chromium—1% molybdenum alloy which has recently been made available in commercial quantities has outstanding resistance to attack in a wide variety of chloride-ion-containing environments and organic acids. The material is resistant to stress-corrosion cracking in boiling magnesium chloride, and its low carbon and nitrogen content makes it highly resistant to intergranular attack.