Ecological Studies on Pest Insects which Infest Confectionery in Fukuoka Prefecture

Abstract

he authors have been continuing an ecological investigation of confectionery insects since 1967 in the northern part of Kyushu for the purpose of controlling them and in this paper, the results of 1967 are reported.1. 13 species of insects probably injurious to confectionery were found out in Kurume. Above all, the number of Oryzaephilus surinamensis Linne was largest and that of Plodia interpunctella Hubner was next to it. And Ahasverus advena Walti occurrred in abundance concentrically for a particular short period. And Ephestia cautella Walk, Carpophilus hemipterus Linne and Liposcelis exedra Bodonnel were relatively larger in number than the others.2. The active period of Oryzaephilus surinamensis lasted from the first ten days of May to the middle of November and they became most active in both June and August. On the other hand, Plodia interpunctella have been most active from the last ten days of July to the middle of August, and their highly active period was shorter than that of Oryzaephilus surinamensis. For this species, there was an effective parasite, Bracon hebetor Say, which reduced greatly the outbreak of their hosts after September.3. Each species of these insects varied a little in what kinds of confectionery it preferred. Plodia interpunctella and Ephestia cautella liked the flour of nuts (the mixture of peanuts and almonds), Oryzaephilus surinamensis the flour of nuts and biscuit, and Carpophilus hemipterus the chocolate.4. The population density of each pest insects was highest in the stores where the crumbs of confectionery were scattered around for insufficient cleaning and these crumbs provided the source of succeeding outbreaks for insects. And besides, it was also higher in the stores which sold not only confectionery but other general foods than in the stores which sold confectionery only.5. The possibility of damage by infestation seems to be greatest in the storehouses of wholesale stores where confectionery goods are stored relatively for a long time and the densities of the insects are highest. Thus it can be considered that our efforts to control confectionery insects should be concentrated on control at these storehouses in the process of marketing.