The sorghum plant bug, Stenotus rubrovittatus, was reared using wheat seedlings and the spikelets of gramineous weeds. When the spikelets of Poa annua, Digitaria ciliaris, or Eleusine indica were provided as oviposition sites for 10 pairs of S. rubrovittatus along with wheat seedlings as food for 48 h, the average number of nymphs emerging from the spikelets was 88.4, 108.5 and 79.3, respectively; however, only 23.6 nymphs emerged on average when only wheat seedlings were provided. When 10 pairs were reared on wheat seedlings (for food) with spikelets of P. annua (renewed every 3 days) as oviposition sites, more than 70% females survived over 1 month and more than 1,500 nymphs were obtained from the spikelets; however, as the adult density increased, fewer nymphs emerged. The adult eclosion rate was 81.4% when 100 nymphs were reared on wheat seedlings in a rearing cage. Although the eclosion rates decreased as the initial density of nymphs increased, approximately 50% of nymphs reached the adult stage when the initial density in the cage ranged from 500 to 1,500 individuals. These results indicate that wheat seedlings are suitable foods and the spikelets of gramineous plants are suitable oviposition sites for rearing S. rubrovittatus. S. rubrovittatus could be successively reared by using wheat seedlings along with spikelets of gramineous plants (D. ciliaris from summer to fall and P. annua from fall to summer).

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Effects of the prey species Thrips palmi and Tetranychus kanzawai and their stages on the development and reproduction of the anthocorid predator, Wollastoniella rotunda, were investigated under laboratory conditions. When offered first or second instar larvae of T. palmi, first instar nymphs of W. rotunda developed into second instars; however, when offered adult T. palmi females, most predator instars failed to develop into second instars. Conversely, when offered adult females and protonymphs of T. kanzawai, first instars of the predator were capable of developing into second instars. Similar findings were observed in third and fifth instars of the predator when offered either of the two prey species. No difference in predator survival and fecundity was observed when either of the two prey species was offered to females of W. rotunda. These findings indicated that T. kanzawai and T. palmi are both suitable prey species for W. rotunda, and suggest the potential for application of the predator as a biological control agent against both of these pest species.

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Eremothecium coryli has been identified as the causative agent of yeast-spot disease in soybeans. To determine which true bug species might be vectors for yeast-spot disease in Japan, Riptortus clavatus, Nezara antennata, Piezodorus hybneri and Dolycoris baccarum were collected from commercially grown soybean plants in Kyoto and Hiroshima Prefectures, in July to September 2006. The carrying rates of E. coryli were 77.7, 35.7, 20.4 and 43.8% on R. clavatus, N. antennata, P. hybneri and D. baccarum adults, respectively. The carrying rate of E. coryli was 11.5% among R. clavatus nymphs. But E. coryli was not isolated from N. antennata and D. baccarum nymphs. The transmission rates of E. coryli to immature soybean seeds were 81.6, 50.0, 16.7 and 40.0% by R. clavatus, N. antennata, P. hybneri and D. baccarum adults, respectively. The results suggested that these 4 species are capable of carrying and transmitting E. coryli that cause yeast-spot disease in soybeans.

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We assessed several methods for deploying nets over windows and entrances so as to prevent the escape of the adult European bumblebee, Bombus terrestris, from greenhouses. Bumblebees were completely prevented from escaping from glass-based greenhouses by both netting windows and filling gaps around windows with sponge, tape and/or building tamping materials. For windows in greenhouses constructed from plastic-covered steel pipe frames, bumblebees did not escape when nets were set under the plastic film and over steel frames and fixed to the outside of the steel frames, but they did escape when nets were set under the steel frames and fixed to their inside. When an entrance was netted, double netting was imperfect even with a room in front of the entrance; however, a net with a zipper completely prevented bumblebee escape. Bumblebees escaped through ventilation fans irrespective of whether they were operating, and thus netting was required, but they did not escape through fresh-air inlets. Our results indicate that it is possible to completely prevent the escape of bumblebees by netting windows and entrances, but close attention is required.

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In the northern distribution areas of the Asian citrus psyllid, Diaphorina citri in Japan, psyllid population densities in citrus groves were much lower than on Murraya paniculata hedges. We investigated the preference of D. citri adults for M. paniculata and Citrus unshiu to interpret such different occurrences. When D. citri adults were released into a screen house containing potted M. paniculata and C. unshiu, the number of adults on both plants increased until the 4th day after release. Thereafter, the mean densities remained relatively constant for 18 days on each plant species before the start of new adult emergence. On most M. paniculata trees, new shoots were always produced by late December, and adult densities increased after the increase of new shoots and declined one or two months after the peak density. New shoots of C. unshiu available for D. citri reproduction were produced only once on two trees, on which adult densities become abundant after the growth of new shoots and decreased gradually until late December. On the other four C. unshiu trees, adults migrated from other trees and their densities remained relatively constant. When D. citri adults were introduced into a preference test chamber containing buds and leaves of C. unshiu and M. paniculata, the adults were significantly more aggregated on the buds than on the leaves of both plants. No preference between C. unshiu and M. paniculata for either buds or leaves was detected. The present experimental results suggested that the difference in the population levels of D. citri on C. unshiu and M. paniculata in their northern distribution areas was not caused by the preference of the insect, but may be due to continuous production of new shoots and dense planting of M. paniculata hedges favoring the reproduction and survival of D. citri during the typhoon season and winter.

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Ultraviolet (UV) protection of Bacillus thuringiensis (Bt) suspension by addition of iron(III) oxide (Fe₂O₃) was investigated under laboratory conditions using a Bt product (Esmark-DF), a commercial fluorescent lamp (Toshiba-FL20S·E, peak 315 nm: ranges 270–370 nm) and a bioassay with the silkworm, Bombyx mori. Iron oxide was mixed at 0.01–0.1% into one litter of Bt suspension (1 g Bt product weight/1,000 ml water) in a glass beaker and exposed to fluorescent lamps at a distance of 5 cm for 1–4 days. The bioactivity of irradiated Bt suspension with and without iron(III) oxide was compared based on larval weight gains of the 2nd instar of silkworms over 3 days. The bioactivity of Bt suspension without iron oxide fell to 1/224 of the original level during 4 days' irradiation. On the other hand, Bt suspension with 0.1% iron(III) oxide maintained the same bioactivity as that of the original level, indicating good UV protection. UV protection was also observed at lower concentrations of 0.03 and 0.01% of iron(III) oxide, indicating bioactivity as 1/5 and 1/23 of the original, respectively.

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