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Predators as well as parasitoids native to Europe accept the exotic horse chestnut leafminer, Cameraria ohridella Deschka and Dimić 1986 (Lepidoptera: Gracillariidae), either as prey or as host. However, the influence of these antagonists on the populations of the pest insect is so far very low. Therefore, efforts to develop an integrated pest management system against C. ohridella should include methods which foster the natural enemy complex. In the present study we developed a laboratory rearing method and investigated several biological parameters of Pnigalio agraules (Walker 1839) (Hymenoptera: Eulophidae), a dominant species in the horse chestnut leafminer’s parasitoid complex in many European regions. This native parasitoid satisfies three basic requirements for successful use as a biocontrol agent with regard to C. ohridella. The parasitoid’s fecundity, longevity and the speed of juvenile development by far exceeds that of the leafminer, enabling the parasitoid population to increase faster than that of the host. Furthermore, our results show that the impact of this species on C. ohridella populations has been previously underestimated, because non-reproductive killing (i.e. host-feeding and host-stinging) of the hosts, resulting in considerable larval mortality of the leafminer, has not been quantitatively assessed. However, naturally occurring parasitoid populations have negligible impact on C. ohridella populations. Further studies, including experimental releases of P. agraules, are necessary to understand the constraints limiting the parasitoid’s performance in the field and to assess the potential benefits of releases for the control of C. ohridella. [ABSTRACT FROM AUTHOR]

The continuous epidemic infestation of horse chestnuts by C. ohridella is a serious aesthetic and economic problem in urban environments. The aim of the presented studies was therefore to develop control measures which meet the special needs of urban plant protection. Removal of infested leaves in autumn and appropriate disposal of the leaflitter is the only practicable measure to reduce infestation levels so far. Another two methods, which are currently in an experimental stage, had an impact on the leafminer populations. A gelformulated combination of the C. ohridella-pheromone with a contact insecticide as attract-and-kill-system proved to be efficient at low population levels. Easily applicable and safe banks of systemic insecticides turned out to be effective in killing preimaginal stages of the leafminer on young trees. The complex of parasitoids attacking C. ohridella is comparable to that of other leafminers. Nevertheless, parasitism rates are very low at present and far away from having any controlling effect on the pest insect.

Epidemiological studies have suggested that dietary factors may differently affect p53-dependent and p53-independent pathways to colon cancer. Results of such studies may depend on the method used to assess p53 status. This case-control study of 185 colon-cancer cases and 259 controls examines this relation, using both immunohistochemistry and SSCP(exons 5-8)/sequencing to detect p53 abnormalities. Of 185 carcinomas analyzed using immunohistochemistry, 81 (44%) were categorized as p53 over-expression. p53 mutations were detected in 59 tumors (32%). A slight increase in risk observed for intake of saturated fat was largely due to an increased risk in cases without p53 over-expression (OR per 16.1 g/day, 1.46; 95% CI, 1.08-1.97), and no association in cases with p53 over-expression (OR, 1.07, 95% CI, 0.78-1.47). However, findings were less pronounced when cases were classified by mutation analysis (wild-type OR, 1.33; 95% CI, 1.01-1.75; mutated OR, 1.16; 95% CI, 0.81-1.65). Similar results were observed for total fat intake. For other nutrients and for vegetable and meat food groups no differences in risk for either p53 pathway were observed, independent of the laboratory technique used. Interestingly, in cases with transversion mutations in the p53 gene, an increased risk was observed for saturated fat (OR, 2.00; 95% CI, 0.97-4.14), in contrast to those with mutations at CpG sites (OR, 0.93; 95% CI, 0.55-1.57). An increase in colon-cancer risk for the p53-independent pathway due to fat intake, is more pronounced when using immunohistochemistry. However, mutation analysis is needed to study the possible association with a small group of tumors with transversion mutations.