We summarize the status of the biological control of insect pests in citrus IPM in Japan. Classical biological control against exotic insect pests was used from the 1910s to 1980s. And some species of introduced natural enemies have been maintaining pests at below the economic threshold in the present citrus cultivation. However, the late 1990s, conservation biological control of the citrus red mite Panonychus citri（McGregor）, with severe pesticide resistance was investigated. As a result, acaricide applications were reduced by two or three times by the late 2000s through insecticide selectivity and cover cropping to maintain the habitat for natural enemies. We also discuss the issues of biological control for the establishment of citrus IPM.

In Lepidoptera, the eye and the leg imaginal discs form only in the final larval instar from imaginal primordia that make larval cuticle during the earlier instars but remain diploid. Starvation from the time of ecdysis prevents this formation, which can be restored by feeding in Manduca sexta（L.）larvae. By contrast, these discs form and grow slowly in starved allatectomized（CAX）larvae lacking juvenile hormone（JH）, and this formation is prevented by JH; JH acted directly on the primordia to suppress morphogenesis, but insulin induced by nutrients, which overcomes the inhibitory action of JH, is necessary for the morphogenesis to occur. Thus, disc growth in the final instar larvae is comprised of both morphogenetic growth under the suppressive control of JH and nutrient-dependent growth. Larvae must surpass critical weight before they can enter metamorphosis on a normal schedule that is under the control of JH. Normal larvae respond to starvation by extending their feeding period from 5 to 7 days to ensure that they begin metamorphosis above critical weight. By contrast, CAX larvae start metamorphosis 4 days after feeding regardless of larval size. This constant period between the start of feeding and the onset of metamorphosis suggests that larvae possess a molt timer that establishes a minimal time to metamorphosis.

The aerial dispersal of pink citrus rust mite, Aculops pelekassi（Keifer）, was monitored throughout the 2017 citrus growing season by using silicone grease-coated traps. The seasonal pattern of mite dispersal and of the number of mites on fruit showed marked and coincident peaks in early September. There were significant correlations between trap-catch and population density on both the leaf and fruit. Aculops pelekassi individuals were captured even at 80 m distance from infested citrus trees, and the mean±SD dispersal distance under the prevailing conditions was 18.0±16.3 m. These results suggest that A. pelekassi can move among orchards with different pesticide use histories. Therefore, we recommend not only using pesticides but also planting windbreaks in order to control the spread of A. pelekassi.

In 2010, unidentified necrosis occurred on the stems of tomato plants in a farmer’s greenhouses in Yoichi, Hokkaido, Japan. In 2012, damage to the stems and fruit of tomato was detected in other farmers’ greenhouses near the initial site and Niki, a neighboring town. The damaged stems and fruit contained the larvae and pupae of a cecidomyiid species whose adult and larval morphological features were indicative of Lasioptera. Infestations appeared to originate in plant parts injured by artificial bud trimming. The larvae spun cocoons and overwintered in the residue of stems under the snow. When fully grown, they reached approximately 2 mm long and were yellowish orange in body color. This is the first report of a Lasioptera species infestation of tomato plants in Japan. Further investigation, including genetic analysis, is needed to identify the cecidomyiid to the species level and to confirm if the Japanese species is identical to the Lasioptera sp. that was first found in 2001 infesting tomato and cucumber in Greece.

We developed a new method for collecting eggs of Scepticus uniformis Kono without the use of sand or soil and investigated the development of the collected eggs. Weevils presented with a kidney bean leaflet and a piece of kitchen paper deposited most eggs on the kitchen paper, which proved to be a suitable substrate for oviposition. The developmental period of the eggs differed between 20 and 32°C. We estimated the lower developmental threshold（T₀）as 13.9°C and the effective cumulative temperature of eggs（K）as 104.2 degree-days. It might be possible to set the timing of egg hatch by controlling the rearing temperature in the above range.