Effects of low temperatures on pupal survival of the stone leek leafminer Liriomyza chinensis (Diptera: Agromyzidae)

Abstract

The cold-hardiness of Liriomyza chinensis pupae was measured in the laboratory by observing pupal mortality at low temperatures. Pupal mortality increased with decreasing temperature and with extended cold exposure time. No recently pupated pupae (6 h) were able to survive after 16 days of chilling at 0, 2.5 and 5°C, but 42.9% survival was observed at 10°C. Pupae at different developmental stages showed significant difference in mortality, with very low levels of mortality observed for older pupae (4 and 7 days) after exposure to 0°C for 16 days. The lethal time for 50% survival (LT₅₀) increased with increasing age of pupae. LT₅₀ for 4-day-old pupae exposed to 0°C was 52.1 days. Analysis of mean temperatures at several localities indicated that L. chinensis is able to overwinter outdoors in southern regions, but is unable to overwinter in open fields in northern regions of Japan, suggesting that overwintering in these regions would only occur in greenhouses.

Keywords:

• Leafminer
• Liriomyza chinensis
• low temperature
• overwintering
• cold survival

Acknowledgement

We thank Mr Hiroyuki Takemoto, Fukuoka Agricultural Research Centre, Japan for providing L. chinensis. We gratefully acknowledge the constructive comments given by Dr Peter Ridland, Victoria, Australia to an early version of the manuscript. This work was supported in part by a Grand-in-Aid from the Japanese Society for the Promotion of Science and Technology (No. 15208007).