Fewer insect pests such as aphids, leafminers, thrips and whiteflies, occur in greenhouses covered with UV-absorbing films. This study was conducted to investigate dispersal behavior of the greenhouse whitefly, Trialeurodes vaporariorum between greenhouses covered with UV-absorbing films and open fields. We observed locomotion of female adults of the greenhouse whitefly released in a glass tube in a laboratory. The tube was covered partially with either UV-absorbing or standard (UV-nonabsorbing) film. Whiteflies were less likely to move from no film to UV-absorbing films compared to standard films. The same behavior was observed even when a potted host plant (tobacco) was placed under UV-absorbing film. A much greater number of whiteflies under UV-absorbing film moved to no film than standard film. However, no locomotion was observed when whiteflies were placed directly on host plants. In the experiments with a glass tube covered thoroughly with UV-absorbing or standard films, dispersal behavior of whiteflies was observed. These results suggest that a major effect of UV-absorbing films against greenhouse whiteflies is likely induced by locomotive suppression from open fields into greenhouses.
The attraction of melon thrips, Thrips palmi Karny(Thysanoptera: Thripidae), to reflective-type traps combined with blue sticky board and a blue light emitting diode(LED)array was investigated in July 2011 in an eggplant greenhouse. The peak wavelength of the blue LED array was 470 nm. The LED array was placed close to the plants and directed toward the sticky board. The number of adult thrips caught by the reflective-type trap at a light intensity of 3×1017 photons/(m2·s)was significantly greater than the number caught by the control, a non-illuminated trap. Furthermore, the number of adult thrips caught by the reflective-type trap was significantly greater than that for the control during 18:00–21:00 and 21:00–0:00. Additionally, significantly more female adult thrips were caught by the reflective-type trap than by the non-illuminated trap, especially during the 18:00–21:00 time period.
We investigated the regional structural characteristics of the compound eye of the stinkbug, Plautia crossota stali, in order to elucidate their functional significance for visual orientation. Towards the frontal end of the eye’s equatorial line, we found some special structural features: smaller inter-ommatidial angles, indicating high acuity; and longer rhabdoms, suggesting high sensitivity compared to other regions of the eye. When the bug is flying towards a light source, it orients itself such that the target is always captured by this specialized region. These anatomical and behavioral studies both indicate that the bug exhibits marked regional specialization of the retina. In the dorsal region of the eye, there is another special ommatidial structure: untwisted, orthogonally oriented microvilli, which suggests e-vector discrimination ability. These findings are the first reported examples of regional specializations in the eye of a heteropteran species, and may reflect ecological features of its habitat.
Aphidius gifuensis is an indigenous parasitoid that is promising as a biological control agent against pest aphids in greenhouse crops. However, little is known about its daily activity rhythm. Here, we analyzed the locomotor activity using an infrared monitoring system and revealed its daily distribution pattern under short-day (12L12D) and long-day (16L8D) conditions. Female and male adults began to move after lights-on and settled down within an hour after lights-off in both photoperiods. In contrast, their activity was maintained at quite a low level at night. The fact that A. gifuensis has a strong diurnal activity rhythm should be considered when collecting this parasitoid in the field.
Sex pheromone lures usually attract the target species very specifically; however, non-target species are often also specifically attracted. Non-target species attracted to a sex pheromone lure could lead to technical problems in pest monitoring. In this study, non-target lepidopteran species specifically attracted to the sex pheromone lures for the cotton bollworm, Helicoverpa armigera (Hübner) and the oriental tobacco budworm, H. assulta (Guenée) were examined in four open fields in Tsu City, Mie, Japan. In addition to specific attraction by the target species, ten (Mythimna turca Linnæus, M. hamifera (Walker), Orbona fragariae pallidior Warren, Xylena fumosa (Butler), X. formosa (Butler), Telorta acuminata (Butler), Sufetula sunidesalis Walker, Parapediasia teterella Zincken, Leuroperna sera (Meyrick), and Evippe syrictis (Meyrick)) and one (Lymantria dispar (Linnæus)) lepidopteran species were specifically attracted to the lures for H. armigera and H. assulta, respectively. Among these, M. turca and M. hamifera were considered to be the species susceptible to be erroneous determination when H. armigera are counted mechanically or by inexperienced investigators.
We investigated the occurrence of insect pests and natural enemies on rice plants and weeds around rice fields in Uganda, East Africa, during 2010 and 2013. The following pest arthropods were collected with an insect net: large-sized stalk-eyed fly (Diopsis longicornis), small-sized stalk-eyed fly (D. apicalis), plant bugs (Pentatomidae and Alydidae), planthoppers and leafhoppers (Delphacidae and Cicadellidae), leaf beetles (Chaetocnema spp., Chrysispa viridicyanea and Altica spp.), short-horned grasshoppers (Coryphosima spp. etc.) and long-horned grasshoppers (Tettigoniidae). Small-sized natural enemies, such as parasitic wasps (Hymenoptera: Eulophidae, Cynipoidea, Braconidae and Ichneumonidae), were also captured.