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Seasonal occurrence and host range of the predatory gall midge Diadiplosis hirticornis (Diptera: Cecidomyiidae), a native natural enemy of Planococcus kraunhiae (Hemiptera: Pseudococcidae)

Fujita, Shohei, Adachi, Shuhei, Elsayed, Ayman K., Shiraishi, Shoko, Tokuda, Makoto
Applied entomology and zoology 2019 v.54 no.2 pp. 197-201
Cecidomyiidae, Icerya purchasi, Phenacoccus solenopsis, adults, bait traps, biological control agents, eggs, host range, hosts, larvae, life history, natural enemies, orchards, pests, pumpkins, surveys, Japan
Diadiplosis hirticornis Felt (Diptera: Cecidomyiidae) larvae feed on the eggs of mealybugs and are potentially useful biological control agents against the Japanese mealybug Planococcus kraunhiae Kuwana (Hemiptera: Pseudococcidae). However, a detailed life history and their wild hosts remain unclear preventing effective use of this gall midge in orchards. We surveyed the seasonal occurrence and natural hosts of D. hirticornis in Saga, Northern Kyushu, Japan. Based on field surveys using pumpkin traps baited with P. kraunhiae, two peaks were detected in the annual adult emergence of D. hirticornis in both 2015 and 2016. Therefore, this gall midge appears to have at least two generations a year. In this study, D. hirticornis was observed to feed on at least three species of Pseudococcidae, including the important pests P. kraunhiae and Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), in the field. However, D. hirticornis was not found on Icerya purchasi Maskell (Hemiptera: Margarodidae) collected from a neighboring site of P. kraunhiae colonies. These results suggest that the host range of D. hirticornis is restricted to only Pseudococcidae.