Using the Safe Schools Act in Ontario as an example of a school zero-tolerance policy, I demonstrate that there are more implications for governing students through these policies than the literature tends to suggest. The push to exclude students found in zero-tolerance policies co-exists uneasily with the liberal democratic pull to an inclusive education. Principals negotiate the contradictory positioning of students as simultaneously excludable and includable uniquely. There is also an insertion of ‘choice’ as a strategy to resolve these tensions. Inappropriate conduct conceived as the students’ choice signals a reorientation of the main function of the school, to an institution now interested in managing its own reputation by devolving the responsibility of good behaviour onto the student.

The oviposition behaviour of the cowpea weevils, Callosobruchus rhodesianus (Pic.) and Callosobruchus maculatus (F.) on clean and egg-laden adzuki beans was examined in choice and no-choice experiments. The oviposition rate of C. maculatus was greater than C. rhodesianus in both experiments. Both weevil species were able to distinguish between clean and egg-laden beans. Discrimination by both species was greater against seeds with 12 eggs than with 6, regardless of which species had previously laid eggs. There was a weak indication that the presence of C. maculatus eggs at high densities might reduce the oviposition rate of C. rhodesianus.

Tsetse flies have been eradicated from an area of 48,000 km2 in Zimbabwe since 1981. The main approach has been pesticidal control, involving ground spraying, aerial spraying, cattle dipping and artificial bait techniques, in some circumstances in combination. This represents a change in tactic from the pre-independence period when control relied solely on ground spraying. Factors which have influenced choice of technique are discussed in the paper, including scale of trypanosomiasis problem, technical limitations of the technique, cost-effectiveness and environmental considerations.

Ground spraying, the mainstay of tsetse control operations in Zimbabwe prior to 1980, is becoming increasingly unfavourable because of high logistical requirements and environmental reasons, but remains an effective technique under a wide range of circumstances. Aerial spraying has proved very effective for management of crisis situations but is comparatively expensive, capital intensive in hilly terrain and less effective against Glossina pallidipes than G. morsitans. Vector control by applying insecticide (deltamethrin) to cattle appears technically feasible at a very competitive cost. This is a most promising technique in areas where there are already cattle and few wild hosts.

Control of tsetse using odour-baited and insecticide-treated screens has proven technically feasible in a wide range of terrain, and appears economically competitive with ground spraying. Both technical and financial performance of the technique are still being improved. Bait technology offers scope for the new approaches to the control of the fly and defence of cleared areas from reinvasion.