European red mite (Panonychus ulmi (Koch)) and its adaptation to the Stanthorpe district, Queensland

Abstract

European red mite was first recorded from Queensland in 1957 and has since become a serious pest of deciduous fruit orchards in the Stanthorpe district. Field observations over three seasons have shown that the hatching of overwintering eggs is broadly synchronized with green-tip of apples (mid September). The first deuteronymphs appear in early October and the resulting females produce summer eggs. Overwintering eggs may be laid as early as January on mite-damaged trees, but on healthy trees they are not produced until mid March. The critical photoperiod of Stanthorpe material (latitude 28°S.) has been determined as 13 hr at 15°C, and this is evidence that strains differing in photoperiodic adaptation exist in this species. Temperatures in the range -1° to 13°C have proved effective in terminating diapause over periods of 126 and 154 days. The seasonal history is discussed in the light of these data. The species appears well adapted to environmental conditions prevailing in the Stanthorpe district.