Psacothea hilaris (PASCOE) adults were collected in mulberry fields in Tsukuba City, Japan, in 1990 and 1991. In early summer of both years, overwintered (mainly diapaused) individuals emerged, and the same number of adults were collected as in autumn when non-diapaused individuals emerged. Adults with a broken yellow stripe on the pronotum accounted for about 50% of the males and more than 30% of the females collected in both years. These results indicate that the western ecotype which displays larval diapause and a broken-stripe pattern on the pronotum has invaded Tsukuba City, the dominant area of the eastern ecotype which displays no larval diapause and has a continuous-stripe pattern. The results also confirmed previous hypotheses that: (1) the sex ratio would decrease in early summer and rise in autumn in the hybridizing area between these two ecotypes; and (2) the prime indicator of the adaptive trends of the populations would not be the pronotum pattern but the diapausal response.

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Control of Yellow Tea Thrips, Scirtothrips dorsalis by reflective sheet (RS) was examined in a satsuma mandarin (Citrus unshiu MARC.) orchard in Shizuoka Prefecture, Japan in 1992 and 1993. The diffuse reflectance of RS at 290nm to 800nm was 84%-94%. RS was fully mulched on the ground in three orchards in the growing season. The percentage of ground occupancy by satsuma mandarin trees was 54.4%-60.5% and the mulching period was 4-7 months before harvest. Throughout the mulched period, the number of trapped thrips and the percentage of fruits infested by the thrips were continuously lower than EIL and the fruit damage at the harvest time was low enough for high market quality. Conversely, heavy infestation and fruit damage were observed without RS. This suggests that RS mulching is a practical control measure for Yellow Tea Thrips.

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We investigated the life cycle of the Camphor Tree Weevil, Dyscerus hylobioides (DESBROCHERS) on the Japanese anise-tree, Illicium anisatum L. in Tosayama, Kochi Prefecture, southwestern Japan. Overwintered adults appeared on host trees from April. They mated on the trees and deposited eggs in the bark near the trunk base. Eggs were observed from late spring to autumn with a peak in early summer. Hatched larvae bored into wood and spent five instar stages from summer to the next early summer in the wood. The overwintering larvae were the 2nd to 5th instars. Larvae moved to the lower parts of trees as they aged, and the pupae and adults were mainly found in underground parts of trees. Pupation and adult emergence occurred mainly in the second mid-summer. Newly-emerged adults ate host shoots, and remained on trees until autumn. Therefore, D. hylobioides probably requires 2 years for one generation in the mountain region of Kochi Prefecture.

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An outbreak of the oriental armyworm moth, Pseudaletia separata WALKER, occurred in summer, 1987 in Hokkaido. We surveyed the behavior of the first (outbreak) generation from late July to mid August in Sapporo. Daily emergence from pupae collected from outbreak pastures showed a clear peak in late July. Daily numbers of moths captured by dry grass bait traps, raw sugar bait traps and light traps peaked on 30 July, 30 July and 1 August, respectively. In early August, captured females were virgin and their ovarioles were previtellogenesis stage. By mid August, most females had copulated and their ovarioles had developed. We found and caught many moths in insect collecting nets in and around outbreak pastures in late July, but no moths were found in early August. No females captured in the outbreak pastures had copulated and their ovarioles had not developed to the vitellogenesis stage. We observed moths congregating on Japanese linden trees where they sucked flower nectar during the day in late July to early August. After the flowering finished in early August, the moths disappeared on and around the trees. All females captured sucking nectar were virgin and their ovarioles were at the previtellogenesis stage.

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Ovarian development, oviposition and daily behavior of Cryptalaus berus (CANDÈZE) in Kochi City, Kochi Prefecture were studied to clarify the life cycle. Males emerged and flew from dead pine trees from late April; females flew from mid May, Fertilized females began ovipositing from late May and deposited egg batches under the bark of dead pine trees. Larvae hatched after about 1 month.

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Dendranthema grandiflora (TZVEL.) (84 cultivars) grown under conventional pest control was examined for damage by Liriomyza trifolii (BURGESS) during the flowering period. All cultivars had punctures and mines. SP1332, Pierrot and three other cultivars had only small inconspicuous mines less than 0.5mm in width, and damage was negligible. Sixteen cultivars, including MonBlanc and Waltz had many (>50% of leaf area) large mines (>1mm in width) on all leaves from the bottom to top of the stem. The other 63 cultivars fell into three categories between the above two types. The number of large and medium mines per unit leaf area increased significantly (p<0.01) with the extent of damage. However, the number of punctures per unit leaf area showed no significant difference between categories. The percentage of punctured or mined leaves per stem also showed no significant difference. Flowering occurred earlier in more damaged cultivars than in less damaged ones (p<0.01), but this parameter was no indicator of resistance due to considerable variation.

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Infestation and damage caused by Western Flower Thrips (Frankliniella occidentalis PERGANDE) on satsuma mandarin (Citrus unshiu MARC.) were examined in 1993. The number of thrips infesting flowers was greatest at the end of blossoming. More eggs hatched from the pistil, ovary and calyx than from the petal and stamen. Larva fed inside the calyx, and the damage resulted in young fruit rot as a result of fungal infection in the June rainy season. The economic damage caused by fruit rot can be minimized by fruit thinning. Adults could not survive on young fruits. Feeding on fruit was first observed when the color of peel oil spores changed to yellow and continued throughout the harvest period. Oviposition in the peel increased as the peel color changed from green to orange. Damaged fruit had many small spaces in the epidermis which appeared as whitish irregular dots. The color of frass on the peel was influenced by the color of the food peel. Shoot infestation was not observed.

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The influence of temperature and prey density on development, survival rate and predation of Nabis (Nabis) stenoferus was studied. When eggs and larvae were reared at 20°, 24° and 28°C, the developmental periods were shorter at higher temperatures, but developmental delay was seen at 30°C. The developmental zeros of eggs and larvae were 13.3° and 13.5°C, respectively. The effective accumulative temperature from egg to adult was 321.1 degree-days and the survival rate was the greatest at 24°C. No significant difference was seen in the consumed number of prey at the above temperatures. The larval mortality at 0.5, 1, 3 and 8 prey per day was inversely related to prey density, decreasing as density increased. The total number of consumed prey increased at high prey density.

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Haemolymph and whole-body trehalose contents in overwintering larvae of Enosima leucotaeniella were measured by gasliquid chromatography. The volume of haemolymph (Vμl) was determined by the following relationship: V=(T₂/T₁)×1, 000, where, T₁ is the haemolymph trehalose concentration (mg/ml) and T₂ is the whole-body trehalose content (mg). This estimate was comparable in accuracy with the ¹⁴C-inulin-dilution method. During October to March 1993 and 1994, the trehalose concentration in haemolymph was controlled by ambient temperature. However, the volume of haemolymph barely changed (55% to 65%) during October to February, but decreased markedly in March. Physiological changes such as decreased body glycogen and increased glucose content were also noticed in March. Therefore, the decreased haemolymph volume may be one phenomenon in a series of physiological changes of overwintering larvae in the late post-diapausing stage.

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Transmission of an entomogenous fungus, Beauveria brongniartii, by mating behavior was examined by allowing inoculated Psacothea hilaris adults to mate with non-inoculated ones. There was a significant difference in transmission ability between inoculated males and females. Inoculated adults could transmit the fungus to non-inoculated ones for five successive days, mating once each day after inoculation. The transmission percentage was 100% for adults 2h after inoculation but decreased to 40%-60% 5 days after inoculation.

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