Expression of the two coleopteran-resistant proteins (Bt-Cry3A and oryzacystatin I) was detected in the leaves of field-grown transgenic poplar (BOGA-5) in two or three subsequent years. The BOGA-5 contained &amp;#8764;10&amp;#8201;&amp;#956;g g&amp;#8722;1 of Cry3A over the individual years with no detection in the control, and protein extracts from BOGA-5 displayed a higher reduction in papain activity (&amp;#8764;42%) compared with &amp;#8764;21% in the control. Laboratory feeding experiments showed that the total mortality of the target pest Plagiodera versicolora (Coleoptera, Chrysomelida) larvae fed with BOGA-5 leaves was 76.7%, significantly higher than that of the control (P&amp;#8201;&lt;&amp;#8201;0.05). However, no significant differences were detected in the mortality, exuviation index, pupation rate or adult eclosion rate of the non-target Clostera anachoreta (Lepidoptera, Notodontidae) fed with leaves from transgenic and non-transgenic poplars. Field investigation indicated that the transgenic poplar retained coleopteran insect resistance in the field, suggesting the potential use of the double gene transgenic poplar for pest management in commercial poplar plantations.