The synthetic sex pheromone, (Z)-3-dodecenyl (E)-2-butenoate, was attractive to male sweet-potato weevils, Cylas formicarius (FABRICIUS), in a sweet-potato field in Okinawa, Japan. A rubber dispenser impregnated with 1mg of synthetic sex pheromone remained attractive for more than one month. The activity of the synthetic sex pheromone was not inhibited by addition of up to 10% of the E, E-isomer of the sex pheromone. Pheromone traps on the ground captured more males than those set above the ground. Most of the males were seen to approach the traps by walking. More males were captured when they were released downwind of the trap than when released from the upwind or other sides. The number of males caught in the pheromone trap increased between 1500 and 1900, and a large peak was observed between 1800 and 2000. The number of trapped males decreased gradually thereafter and decreased rapidly after sunrise.

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In June and July 1990, first-generation larvae of the rice-plant skipper, Parnara guttata guttata, which has never been recorded previously in Miyagi Prefecture, were observed on rice plants mainly in the south part of the prefecture where winter is thought to be too severe for larval hibernation. The date of oviposition estimated from the date of pupation in the paddy fields was mid-May to early June. This is believed to be too early to be the result of oviposition by hibernating population in this prefecture which suggests the possibility of immigration by adults of overwintered-generation from southern Japan.

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The effect of the photoperiod on the induction of diapause in rice stem borer (Chilo suppressalis WALKER) larvae collected from three localities: Hsilo (23.8°N), Tounan (23.7°N) and Pingtong (22.7°N), in Taiwan was studied. The larvae were reared at 25°C under different photoperiods. The period of the mature larval stage (the diapause stage) was prolonged under short day lengths (10L-14D or 8L-16D) which shows that the larvae enter diapause under short day lengths. The critical day lengths for inducing diapause in the Hsilo and Pingtong populations were 9-10h but were around 11h for the Tounan population. Except for the Tounan population, these critical day lengths are much shorter than the natural photoperiod (14.5h max, 11.3h min), indicating that these populations hibernate without diapause. Although some of the Tounan population may enter diapause as a result of the winter day length, the depth of the diapause may be shallow because it was terminated without exposure to low temperatures. Some individuals of all the tested populations did not enter diapause although they were reared under short day lengths such as 8L-16D, showing that there are photoperiod-insensitive individuals in the rice stem borer in Taiwan.

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The spring occurrence of populations of the cotton aphid, Aphis gossypii GLOVER, the seasonal variation in their aliesterase activity, and their susceptibility to organophosphorus insecticides were investigated using eggplants (Solanum melongena L.) and cucumbers (Cucumis sativus L.) cultured without insecticides in a plastic greenhouse (all sides open) and in a field at Higashihiroshima in Hiroshima Prefecture from 1987 to 1990. In the spring, populations of aphids on eggplants increased rapidly and dispersed, but those on cucumbers hardly increased. There were two peaks of 0-5 and 15-25nmol/10min/μg protein in the frequency distribution of aliesterase activity in apterous adults on eggplants and cucumbers. Consequently, individuals could be divided into a low-activity group, and a high-activity group. The majority of individuals on eggplants in the plastic greenhouse had low aliesterase activity but those on cucumbers had high activity. However, some individuals with high aliesterase activity were observed in the populations on eggplants, and the frequency tended to be higher in the autumn and in the field than in the plastic greenhouse. Individuals with low aliesterase activity were also found in the populations on cucumbers, but they did not become predominant. Susceptibility to fenitrothion was higher in the populations on eggplants than those on cucumbers which paralleled the aliesterase activity. The control effect of fenitrothion was also higher for populations on eggplants than on cucumbers.

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The longevity and oviposition of an introduced parasitoid, Torymus sinensis KAMIJO (Ts), and two strains of the endemic parasitoid, T. beneficus YASUMATSU et KAMIJO, one of which is the early-season strain (TbE) and the other is the late-season strain (TbL), were examined under laboratory conditions. Adults survived for about 1 or 2 months on average under the same temperature as in the field. The longevity of TbE was longer than the longevity of Ts and TbL. Under constant temperatures of 10°, 15°, 20°, and 25°C, the survival period of adults was longer at lower temperatures except for TbL males whose longevity was shortest at 10°C. Under outdoor temperature conditions, the mean numbers of eggs laid per female by Ts, TbE, and TbL were 71.0, 25.6, and 18.8, respectively and the pre-oviposition periods were 4.8, 12.5, and 5.5 days, respectively. Ts females oviposited about twice as many eggs as those of TbE irrespective of the temperature conditions. Egg laying activity by Ts females was observed to be highest around 20°C.

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Arylphorins are major serum proteins in larvae of holometabolous insects. We studied cross-reaction of arylphorins from 11 silkworm species with anti-Samia cynthia ricini and anti-Bombyx mori arylphorin sera by Oudin's single immunodiffusion and Ouchterlony's double immunodiffusion analyses. Species used were 1. S.c. ricini, 2. S.c. pryeri, 3. Antheraea yamamai, 4. Antheraea pernyi, 5. Dictyoploca japonica, 6. Actias selene, 7. B. mori, 8. B. mandarina, 9. Prismosticta hyalinata, 10. Pseudandraca gracilis, and 11. Oberthueria falcigera. Species 1-6 belong to Saturniidae, and 7-11 to Bombycidae. Intensity of cross-reaction with anti-S.c. ricini serum was arranged in the order as follows: 1=2>3=4=5=6=9≥10=11>7=8. That with anti-B. mori was as follows: 7=8>1=2=3=4=5=6=9=10=11. These results indicates that similarity of arylphorins is highest between 1 and 2 and between 7 and 8, and that arylphorins of 3, 4, 5, 6, 9, 10 and 11 are more similar to the arylphorin of 1 than that of 7. We discussed the phylogenetic relationship among these species, based on the results.

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A microsporidian infection causing high mortality levels was found in the larvae of the beet armyworm, Spodoptera exigua reared on an artificial diet. Dead larvae contained a large number of microsporidian spores with a similar morphology to that of Nosema bombycis NIS 001. The microsporidian from S. exigua, designated N. sp. Y9101, was transmitted to the next generation of S. exigua via eggs. The rate of spore germination under various stimulated conditions was similar between N. sp. Y9101 and N. bombycis NIS 001. When studied by the latex adhesion test using latex particles sensitized with various species of monoclonal and polyclonal antibodies, spores of N. sp. Y9101 reacted with latex particles sensitized with antibodies against N. bombycis NIS 001 spores. Growth and development of N. sp. Y9101 and N. bombycis NIS 001 in Antheraea eucalypti cell cultures seemed similar. On the basis these data, N. sp. Y9101 was determined to be a strain of N. bombycis.

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