The potential of irradiation as a postharvest disinfestation treatment against Phlyctinus callosus (Coleoptera: Curculionidae).

Phlyctinus callosus (Boheman) (Coleoptera: Curculionidae) is a pest of major phytosanitary concern for some of South Africa's biggest export markets such as the United States and Europe because this pest does not occur there. At present, fumigation with methyl bromide is the only postharvest disinfestation treatment against this pest; therefore, sustainable alternatives are needed. One such alternative is irradiation treatment of whole pallets of packed fruit to sterilize insects that may be present within the cartons. Wild adult P. callosus weevils were treated with 5, 10, 20, 40, and 80 Gy of gamma-irradiation and then cross mated to breed with either treated or nontreated adults of the opposite sex. Fecundity and fertility were monitored and recorded. Trials were conducted during the 2009-2010 and 2010-2011 fruit harvesting seasons. The results from both seasons indicated that irradiation did not affect fecundity but fertility was significantly affected, decreasing as irradiation doses increased. Egg hatch was zero for mating crosses that involved females weevils treated with a dose of 80 Gy gamma-irradiation. Probit analysis indicated that in the first season, the estimated LD95 for crosses involving treated males and treated females was 30 Gy, while in the second season it was 49.5 Gy. Respective estimated LD99S were 47.9 and 169.4 Gy. Ultimately, a dose lower than the current generic dose of 400 Gy, approved for irradiation disinfestation treatments, would control P. callosus should they occur in packed export fruit.

Dental caries in South African black and white high school pupils in relation to sugar intake and snack habits.

DMFT scores, total sugar intakes and snacks habits were determined in 1918 South African Black pupils (923 rural, 995 urban) and 724 White pupils (English and Afrikaans speaking) aged 16-18 years inclusive. Mean DMFT scores of school groups of Black pupils (both sexes) ranged from 0.9 and 2.0 in rural areas, to 4.2-6.7 in urban areas (where data were far higher than such obtained 7 years ago), and were 9.2 and 10.2 for White pupils. Corresponding mean daily sugar intake were - rural Blacks, 69 g and 97 g, urban Blacks 118-141 g, respectively (all slightly higher than previously); and Whites 102 g and 123 g. Mean DMFT scores of girls were higher than those of boys; yet while mean sugar intakes of Blacks girls and boys were somewhat similar, White girls' intakes were much lower than those of White boys. In the ethnic-sex groups studied, mean DMFT scores for pupils in upper, compared with lower, third of sugar intake, were higher in nine of the 14 sub-groups. Mean DMFT scores in upper, compared with lower, third of exposure to snack practices were higher in 11 of the 14 groups. However, most of the differences were slight. In further research, more intensive enquiries should be pursued on roles of ethnic and familial factors, as well as on roles of inter-acting dietary components additional to sugar and sugar-containing foods.

Tonsillectomy prevalences in South African schoolchildren.

Tonsillectomy prevalences, using questionnaires, were determined on series of school pupils (total number 10,271), aged 16-18 years, in four South African ethnic groups. Prevalence were, approximately: rural Blacks 2%, urban Blacks 3%, Indians 8%, Coloureds (Eur-African-Malay) 9% and Whites 44%. The inter-ethnic profile of differences is similar to the inter-ethnic profiles of other differences (e.g. in appendicectomy prevalences).

Knowledge of nutrition among housewives in three South African ethnic groups.

Studies on housewives and other groups in Western populations have revealed: (i) a generally high level of claimed or "perceived' knowledge of nutrition; (ii) a much lower level of accurate knowledge; and (iii) an often unsatisfactory application of correct knowledge. Since little is known of knowledge of nutrition in South African populations. White, Indian and Coloured housewives were questioned by use of a questionnaire similar to that used overseas. While the local populations had a fair knowledge of the identity of most nutritional components, their knowledge about good sources of these components and of foods commendable for body building, energy, and slimming, or of those which promote fattening, was only moderately satisfactory. Misconceptions were similar to those reported elsewhere. Factors having a bearing on inadequate or incorrect information are discussed, as is the extent to which this may affect health and disease patterns in Third World and Western populations. Factors detrimental to progress are differences of opinion among nutrition experts and insufficient knowledge on the health/ill-health patterns of those who are knowledgeable of nutrition compared with those who are less knowledgeable.

Appendicectomy prevalences in South African adolescents.

From questioning 16,939 South African pupils of 16-18 years, in 56 high schools, mean prevalences of appendicectomies in representative segments of ethnic groups were found to be: rural Blacks 0.6%; urban Blacks 0.7%; Indians, 2.9%; Coloureds (Eur-African-Malay), 1.7%; Whites, 10.5%. Percentages in the sexes were similar. Only those of Indian and Coloured pupils appear to be increasing. Blacks and Whites, respectively, have high and low intakes of fibre-containing foods, which are negatively correlated with appendicectomy prevalences. However, although intakes of fibre-containing foods are slightly higher in Indians and Coloureds than in Whites, the former's appendicectomy prevalences are lower than would be dietarily expected.