Tanaka, M. 1981a [Utilization of a parasite, Aphytis lingnanensis (Hymenoptera, Aphelinidae) to control arrowhead scale insect, Unapsis yanonensis.].. Bulletin of the Fruit Tree Research Station Series D (Kuchinotsu) (3): 81-92.

Notes: Arrowhead scale insects, U. yanonensis and citrus red mites are the most serious citrus pests in Japan. Scale insects are ordinarily controlled with phosphorus compounds, which destroy natural enemies of the citrus red mite causing severe outbreaks. They have become resistant to acaricides. For this reason, selective insecticides are necessary. In 1972, parasites of white snow scale, U. citri were introduced to Japan from Hong Kong. The wasps parasitized on arrowhead scale, U. yanonensis. Utilization of the parasite to control arrowhead scale insects was studied. The parasite could not hibernate in Japan. Wasps were then investigated to control the scale insects as a biotic insecticide. It is called HK-J A. lingnanensis. The parasites were mass produced on the Diaspidae scale insects. Hemiberlesia lataniae infested Japanese pumpkins. Aiguri, Kurokawa and Hiuga No. 14. A. lingnanensis oviposits on the female young adult stage of the scale insect. Mass releasing of the parasites should be done at the young female adult stage. Releasing time can be predicted by the monitoring of the male adults of the scale insects captured on sticky suction traps. In 1978 and 1979, releasing tests were conducted in 20 yr old Satsuma orange orchards. In 1978, 500 wasps/tree were released in the middle of July and Aug. In the next year, 1500 wasps were released from the end of June to the middle of July, and in the middle of August. In 1978, the numbers of released parasites were too small and the 1st releasing time was too late. In 1979, the rate of damaged fruits in the released plot was regulated under 5%. The utilization of A. lingnanensis HK-J is a practical control technique. Two kinds of natural enemies of the arrowhead scale insects, Aphytis sp. and Physcus sp. were collected in China and introduced to the laboratory.