Dust derived from food processing can accumulate in places difficult to reach, where stored-product pests could thrive. The purpose of this work was to verify the development of Plodia interpunctella, Ephestia kuehniella, and Tribolium castaneum in dust collected on pipes and beams (15 m and 7.5 m) in a silo area of a pasta industry. Proximate analyses showed a higher metal content in the dust collected at the two different heights than semolina, including the presence of chrome, cobalt, arsenic, and lead. Particle size distribution analysis showed that in the two samples of dust the highest percentage was constituted by particle sizes smaller than 106 μm. The tests were carried out by using two quantities 4 g or 0.15 g of dust (corresponding to 3 mm and 0.1 mm), at controlled conditions. Fifty larvae, 0-24 hours old, of each species, were used for each dust, semolina, and thickness test. The number of emerged adults was assessed daily. T. castaneum developed on all the tested substrates, despite the high content of metals and the small particle size in the environmental dust. A significant interaction between diet and thickness of the layer was observed, but thickness had a stronger influence than diet. Moreover, light filth analysis detected a large number of fragments of Tribolium sp. in dust collected at a different height. Dust was unsuitable for the development of moths; only two E. kuehniella adults emerged from 3-mm-deep dust collected at 15 m, and development lasted more than 90 d.

Test arenas and corrugated cardboard traps were used to test attractive properties of synthetic pheromone, (4S,5R)‐sitophinone, and various foods to rice weevils, Sitophilus oryzae (L.), in laboratory and in storage room. Cracked corn, rice kernels and corn germ oil trapped significantly more insects than 1 mg of (4S,5R)‐sitophinone. A strong synergistic effect between the pheromone added with cracked corn or rice kernels or corn germ oil was demonstrated. Rice weevils were successfully lured out of a food source when cracked corn and (4S‐5R)‐sitophinone were present in the traps. A new design of corrugated cardboard trap was reported. Zusammenfassung Untersuchungen zum Einfluß von Pheromonen und Fraßlockstoffen beim Fang von Sitophilus oryzae (L.) (Col., Curculionidae) Mit Untersuchungsgefäßen und Fallen aus Wellpappe wurde im Labor und in einem Lagerhaus getestet, welche Pheromonmenge [(4S,5R)‐sitophinone] und welche verschiedenen Nahrungsmittel attraktiv für Sitophilus oryzae waren. Mit zerdrückten Getreidekörnern, Reiskörnern oder Getreide‐samenöl konnten signifikant mehr Käfer gefangen werden als mit 1 mg (4S,5R)‐sitophinone. Ein deutlicher synergistischer Effekt konnte nachgewiesen werden, wenn das Pheromon und zerdrückte Getreidekörner, Reiskörner oder Getreidesamenöl gemeinsam angeboten wurden. Wurden das Pheromon und zerdrückte Getreidekörner gleichzeitig angeboten, konnte S. oryzae damit erfolgreich aus anderen Nahrungsmitteln angelockt werden. Des weiteren wird über einen neuen Fallentyp berichtet.

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In this paper, the effect of a highly purified N2 (98.5%) controlled atmosphere-generated in situ by a membrane nitrogen separator on mixed age eggs of Sitophilus oryzae and Tribolium confusum was evaluated. Trials were carried out in an airtight stainless silo filled with wheat, in which a nitrogen atmosphere was maintained for durations lasting from one to several days. The mean temperature recorded during the treatment varied from 22 to 24°C. After the treatment, the eggs were transferred to a jar with rearing medium and kept at 27±1°C and 70±5% R.H. The jars were checked every two days to record adult emergence. Eighty percent mortality was observed in T. confusum and S. oryzae with two and four days of treatment, respectively. One hundred percent mortality was obtained after five days of treatment in the case of T. confusum and six days for S. oryzae.

Cholesterol content of Bombyx mori larvae was measured in two different silkworm groups, normally spinning and nonspinning, respectively. Cholesterol content in the spinning group showed very high values immediately after the moults, following which the concentration decreased and reached a minimum before the next moult. Alternatively, cholesterol content in the nonspinning group during the fifth instar increased up to the death of the larvae. Comparable behaviour was observed in a small percentage (about 20%) of nonspinning larvae of the second group. The reason for the nonspinning behaviour is not clear.