Influence of the population density and feeding behavior of Blattella germanica on the lethal effect of toxic baits containing fipronil was evaluated in laboratory. Firstly, to determine the oral toxicity of fipronil, susceptibility of 2 strains of B. germanica, an insecticide-susceptible strain (Watarida) and a field-collected strain (Osanbashi), was estimated by oral administration. The Osanbashi whose LD₅₀ was 6.99ng/♀, was 1.8 times more tolerant compared with the Watarida whose LD₅₀ was 3.96ng/♀. Secondly, the influence of population density on the lethal efffect of the bait was examined. A hundred percent mortality was obtained by day 11 after placement of 6 or 12 spots of 30mg-bait for ca. 100 cockroaches (1.68 or 3.55mg bait/cockroach, respectively). The mortality due to the bait depended upon the amount of bait treated/cockroach. Furthermore, the lethal effect of 0.05% fipronil bait was compared with that of 0.03% fipronil bait. Both baits for 2 strains of B. germanica exibited >99% mortalities by day 2, except the 0.03% bait for the Osanbashi which gave only 60% mortality. The mortality of the Osanbashi by 0.03% bait was less than that by 0.05% bait. And bait consumption of the Osanbashi obserbed in 0.03% bait was less than a half amount in 0.05% bait. Consequently, an aversion of the Osanbashi to 0.03% bait was considered as a factor which caused the low mortality.

View full abstract

There are many stored product insects infesting cereal foods in processing plants. Some of insects are often required for monitoring. Pheromone traps have been used effectively for monitoring stored product insects, however most of the traps are designed for monitoring one species. If a multiple pheromone is available in one trap, it can be used to monitor several species at the same time. Then capturing efficiencies were tested on a pit-fall type trap with a multiple pheromone mixture and pheromone traps specially designed for each species. The results indicate that pit-fall trap with multiple pheromone showed low efficacy on trapping comparing with pheromone traps designed for each species. However combination trap of book type glueboard and pit-fall trap can trap effectively.

View full abstract

Substantial number of German cockroaches were caught even in a colorless transparent sticky trap (made of a PET plastic sheet) placed side by side with a non-transparent (paper) sticky trap in an experimental arena. When each trap was singly placed in the arena，there was no difference in the trap catches between the two types of traps. Colorless transparent traps caught as many German cockroaches as paper traps of a similar size did in a field sampling trial in a restaurant kitchen. The results indicate that cockroaches do not respond to or choose the traps as their harborages but are caught by chance in their foraging or courtship movements in the night. The trap catches can be counted in the colorless transparent traps even under folded or pressed conditions，so that the collected traps can be carried or sent in a compact container. The colorless transparent PET traps also have other merits such as water-proofing, non-dusting, and non-dioxinemitting characteristics.

View full abstract

The repellency of several insecticides to the final stage nymph, male and female of the Smoky-brown cockroach, Periplaneta fuliginosa was evaluated by counting their feces at the insecticide-treated corner in a test arena (radius 13cm, height 17cm). A nymph, male and female of the cockroach excreted mean number of 8.6, 9.6 and 9.3 spots of feces, respectively per day in the arena when they fed on mouse foods and water. When the arena was divided into four fan-shaped sections, 75%, 71% and 68% of the feces in each group were excreted in the harborage section, while the rest percentages were observed in food, water or blank (harborage-free) sections. When the harborages had been treated with 0.1% a.i. concentration of several kinds of insecticide, they excreted large numbers of feces in the insecticide-free harborage sections than in the insecticide-treated sections. In particular, after use of permethrin EC to the harborage, the number of feces in that section was much smaller and the mortality in 48 hours was very low due to the repellency against the insecticide. After the use of chlorpyrifos-methyl EC, diazinon EC or diazinon MC, the feces numbers were relatively large and the mortalities were high.

View full abstract

When sticky traps were placed at the inside edge of closed windows，a closed door，and in a mail box attached on the door，very small insects with body lengths of about one millimeter or less were caught depending on the operation of a ventilation fan in the room. No insects were caught when the ventilation fan was not operated. This suggests that minute contaminant insects invade structures through small crevices around closed doors，windows，and even incomplete walls and floors，depending on the operation of ventilation fans. Moderate sized insects also invaded another room near by through an incompletely closed window depending on the operation of the same ventilation fan above used. Substantial number of insects even went out during the fan was stopped. The dominant insects were moth flies, chironomid midges, and fungus gnats; this coincides with a trend which is often observed in many industrial facilities.

View full abstract

The German cockroaches, Blattella germanica, invaded into an electric jar and some dead individuals were discharged together with hot water from the jar when pouring. These phenomena were observed either in the working or off of the jar, and the cockroaches seemed to select the electric jar as their hiding places. The results suggest us that the cockroach contamination in foods will occur at the time of pouring water from the jar to foods in the houses.

View full abstract

The tracks of the roof rat, Rattus rattus, were investigated by means of bait containing fluorescent pigments at a residential area and a high-rise building in Tokyo. Their home ranges were less than 7 m horizontally and 4 m vertically in the residential area, and less than 40 m horizontally and 2 m vertically in the building. We found that cables above the road were used by the rats to behave.

View full abstract

Hirosia iyoensis (Shiraki, 1918) is one of the most harmful horse flies for human in Japan because of its sudden outbreak in a short time and its persistent bloodsucking habit. Females of H. iyoensis develop their oocytes in the first gonotrophic cycle without blood intake. Since 1997 we have been studying to control them at some mountainous areas in Toyama Prefecture, central part of Japan, where the great numbers of H. iyoensis occur every year. Eradication of H. iyoensis seems to be unsuccessful by the application of insecticides or the common trapping methods because of autogeny and widespread habitat. On the other hand canopy traps and box traps baited with carbon dioxide (CO₂) were used to mass-capture H. iyoensis. In this study I investigated the anti-bloodsucking measure of H. iyoensis using box trap in camping site and furniture production factory. In the first case two box traps were placed in the camping site in 2001 and 2002, where the great numbers of H. iyoensis were occur every year. Total 8,915 H. iyoensis were captured for 2 seasons. In the second case five box traps were placed in the furniture production factory in 2001, where H. iyoensis and Tabanus rufidens came flying for bloodsucking into the factory. Total 8,967 tabanid-flies were captured for 37 days. In two cases mentioned above, there was no complaint of the bloodsucking from the participants and employees. It was supposed the trap capture was effective to prevent the people from the bloodsucking damage by H. iyoensis.

View full abstract

[in Japanese]

View full abstract

A great number of stink bugs migrated and invaded into the indoor for hibernation, and became a nuisance in houses in Toyama Prefecture every year. We examined the effects of application of concentrated terpene material to the window frames on the control of bugs invasion into the houses. Residual treatment of terpene material to the window frames was effective to prevent the invasion of the bugs.

View full abstract