A new fruit fly species suspected to be from the Bactrocera dorsalis (Hendel) group (originating from Asia), was detected during routine field surveys in the Coast Province of Kenya. Since most species in this group are of tremendous quarantine concern when introduced, and considering the fact that it has never before been detected or reported in continental Africa, surveys were immediately initiated covering a distance of over 3000 km across major fruit-growing and trading localities within Kenya, to determine the extent of spread of the new invasive species. We report on the detection of the flies, preliminary results of the survey, and discuss the potential effects of these flies on the horticulture industry in East Africa.

A one-year longitudinal study was conducted in 92 smallholder diary farms in Kwale district of Kenya, to evaluate the efficacy of Spot-on® (a 10 % deltamethrin pour-on) in the control of East Coast fever, anaplasmosis, babesiosis and trypanosomosis. A comparison of the annual incidence and mortality rates from these diseases was made among four Spot-on® application regimes: biweekly, monthly, bimonthly and untreated control groups. The incidence of East Coast fever, ranging from 2.6 to 6.8% among the treated animals, was significantly lower than in the control group (18.8%). Anaplasmosis incidence ranged from 2.6 to 13.5%, but the differences among the treatments were not statistically significant. There were only seven confirmed cases of babesiosis and therefore no statistical comparisons of the incidence rates were made. The incidence rates of trypanosomosis in the biweekly- (28.2 %) and monthly-treated animals (38.6 %) were statistically lower than in the bimonthly (63.9 %) and control groups (72.6 %). It was concluded that monthly application of Spoton® could significantly reduce the incidence of tick-borne diseases and trypanosomosis in cattle in the coastal lowlands.

The spatial distribution, pupation behaviour and natural enemies of Cirina forda in the soil around its host, the sheanut tree, Vitellaria paradoxa were investigated in the field. Results indicated that final instars pupated within a 6–15 cm depth of soil located within a 90-cm radius around the host tree. Pupal density was significantly higher (P < 0.05) in soils on the north and west axes than on the south and east axes around the host tree. Pupal mortality was significantly higher within the top 5 cm and beyond a 16 cm depth of soil around the host tree. Four fungal pathogens, Trichoderma sp., Aspergillus nigers, A. flaus and Fusarium solarti isolated from diseased larvae were implicated in the significantly high larval and pupal mortality that occurred within a 90-cm radius of the host tree trunk. Percentage field parasitism of the eggs by a parasitic wasp Entedon sp. (Hymenoptera: Eulophiidae) averaged 18%. Investigation on the potential of these microorganisms for biological control of C. forda is ongoing. An integration of effective biocontrol agent(s) with a slow release insecticide with a penetration depth of 15–20 cm could form part of an integrated management plan for the pest.

Studies were conducted into the development of anti-tick vaccines against two tick species, namely Boophilus anniilatus Say, 1821 and Argas persicus (Oken) 1818, which, respectively, are responsible for high economic losses in the cattle and chicken industries in Egypt. Repeated infestation of spring chicken with Argas persicus females stimulated 35.9 % resistance to tick feeding compared to 20.4 % in controls. This resistance was associated with the presence of antibody activity to tick salivary gland antigens. There was increase of both the chicken serum total protein and the number of protein bands separated by SDS-PAGE, which suggested an increase in immunoglobulins. Chicken resistance to tick feeding was also induced by repeated injection (vaccination) with crude Argas persicus salivary gland antigens, with intramascular injection being more efficient at inducing immunity than subcutaneous injection.

Prolonged infestation with Boophilus annulatus ticks induced immunity in cattle. Salivary gland and gut crude extracts of cattle exposed to the ticks contained antigenic proteins, with dominant 66 and 150 KDa glycoproteins. Antibodies against the two extracts or PAGE-separated antigens were detected in cattle that resisted tick feeding. Cell-mediated immunity (CMI) was also detected. The immune response was strong in non-infested Bos indicus and Bos indicus × Bos taurus Linneaeus, 1766 crossbreeds with low infestation, and weak in heavily infested Bos taurus.

M. Knapp and S. S. Kashenge

Effects of different neem formulations on the twospotted spider mite, Tetranychus urticae Koch, on tomato (Lycopersicon esculentum Mill.)

The equation for calculating repellence, shown on page 3 of Insect Science and Its Application, Volume 23 Number 1, under the subheading “Repellence and Oviposition Deterrence” should read: