The effects of four different neem formulations (Neemros®, Neemroc EC®, Neemroc Combi and Saroneem) and a combination of Neemros® with a synthetic acaricide (Mitac®) on the twospotted spider mite (Tetranychus urticae Koch) were compared with Mitac® on tomato (Lycopersicon esculentum Mill.) leaf discs in the laboratory, The following LC50 were determined: Neemroc EC® 12.9 ml/1, Saroneem 5.8 ml/1, Neemroc Combi 1.0 ml/1 and Mitac® + Neemros® 1 ml/1 + 17.6 g/1. No LC50 was determined for Neemros® since the highest mortality observed was 11.4 %. The combination of Mitac® and Neemros® resulted in the highest mortality after 24 hours (83.3 %), followed by Neemroc EC® (78.3 %), Saroneem (53.4 %), Mitac® (50.8 %), Neemroc Combi (38.9 %), the control (4.5 %) and Neemros® (0.0 %). All neem formulations also caused repellence and oviposition deterrence in T. urticae.

We studied the mite complex—consisting of Tetranychus cinnabarinus (Boisduval), T. urticae (Koch) and Aculops spp.—on three varieties of carnation (Finesse, Optima and White Barbara) in a flower farm in Kenya. Over a period of 24 months, those carnations established in a soilless substrate (pumice in gunny bags) harboured on average less than five mites per leaf as compared to over 20 per leaf on plants established on bare soils. This was the case whether the crop was judiciously or prolifically sprayed with acaricides. The study further established that the economic gain was the same when lower volumes of pesticides were used, whether sprayed judiciously or prolifically. The variety White Barbara generally harboured higher mite numbers than Finesse or Optima. Furthermore, there were fewer rejections, and higher market value when plants were established on pumice substrate compared to bare soils. The study further showed that planting in pumice holds promise for mite control in flower farms. Furthermore, predatory natural enemies of the pest mites, including phytoseiid mites and Orius spp., were conserved in plots where pumice was used with minimum spray.

The resistance of 63 tomato (Lycopersicon esculentum Mill.) accessions to the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), was investigated in screen house experiments and compared to Money Maker, a T. urticae-susceptible variety widely grown in Kenya. The number of motile mite stages 12 days after inoculation with 5 adult female mites was significantly lower than in the control variety (Money Maker) in seven accessions (Marglobe, Roma-VF, 94 RT 330, Continental Michel, Early Pearson, ARP 366–4 and 94 RT 316). Egg numbers were significantly lower than in the control in 14 accessions (Marglobe, Cal-J-VF, Roma-VF, Beauty, 95 RT 315, 93 KT 20, EC.3504,94 RT 313, EC-1193, Continental Michel, Early Pearson, ARP 366–4,94 RT 316 and Malawi Local 3). This study reveals the existence of resistance to T. urticae in the tomato accessions.

Kampimodromus aberrans is a predatory mite species present in vineyards of South of France and also in uncultivated areas, from where great densities disperse into the neighbouring vine fields, mainly by aerial means. In order to determine the origin of migrants in an experimental vine plot, a molecular study using RAPD markers was performed. It was found that there exists genetic differentiation of populations collected in the experimental vineyard, and those collected, both from surrounding cultivated and uncultivated areas. No correlation between genetic and geographic distances was found. Thus, despite the dispersal of great densities of mites into the plot, selection pressures may affect their settlement. To determine the impact of pesticide application on mite settlement, we studied the insecticide resistance of K. aberrans populations collected in the vine field and on an oak located in a neighbouring uncultivated area. The insecticide tested, quinalphos, is the most frequently applied pesticide in the plot. High resistance levels were observed in both populations. However, at the recommended concentration, mortality rates (80 and 87 %) were quite the same for the two populations. Thus, the application of this pesticide seems not to be the major explanation of the poor settlement of migrants coming from woody areas into the plot, and other studies have to be conducted to determine other factors involved.

Laboratory experiments were conducted to investigate the effect of diet on the biology and prédation capacity of the phytoseiid mite Amblyseius zaheri Yousef & El-Brolossy. The predatory mite was able to develop and reproduce when fed on nymphs of the twospotted spider mite Tetranychus urticae Koch, nymphs of the citrus brown mite Eutetranychus orientalis Klein, motile stages of the eriophyid mite Eriophyes dioscoridis Soliman & Abou-Awad, eggs of the scale insect Parlatorio ziziphus Lucas, nymphs of the whitefly Bemisia tabaci (Genn.) and pollen grains of date palm, Phoenix dactylifera. The predatory mite's development was fastest on a diet of nymphs of Er. dioscoridis. All of the diets led to a female-biased progeny, which was most pronounced in predators fed on date palm pollen. The results are discussed in light of the biological control capacity of the phytoseiid mite.

In order to study factors affecting phytoseiid mite occurrence in uncultivated areas, we sampled phytoseiid mites (densities, diversity and age structure) on several plants located in 4 uncultivated areas surrounding European vineyards over 3 years to determine how plants, and mainly their leaf structure, affect mite communities. The plant composition of these areas greatly influenced phytoseiids density and diversity. The relationships between leaf structure (trichomes, pollen densities, number and structure of domatia, leaf surface) and Kampimodromus aberrans (Oudemans) densities were also studied. The frequency of occurrence and the abundance of K. aberrans per cm2 were correlated to high trichome densities. A complex phylloplane (many hairs and shelters or domatia) can benefit K. aberrans more than other phytoseiid mite species. The number and the rating of domatia were important for the development of K. aberrans; high proportions of immatures were observed only on plants with these structures. Pollen densities were significantly correlated to trichome densities; domatia structure had only a somewhat lesser effect. Furthermore, we demonstrated that K. aberrans does take up plant fluids. Our study shows how dense trichome and pollen levels can affect the development of K. aberrans populations and adds perspective to the influence of domatia on these important predaceous mite populations.

A simple, rapid and low-cost method for the isolation of high molecular weight DNA from small amounts of cells or tissue is described. The method does not require liquid nitrogen, proteinase K or costly buffers. This method was successfully applied in the isolation and purification of DNA from eggs of Hyalomma excavatum, H. dromedarii, Argas persicus, A. hermanii and Boophilus annulatus, in addition to Escherichia coli, actinomycetes (Nocardia sp.) and leaves of soybean (Glycine max L.). The DNA concentration was calculated from the optical density (OD) value at wavelength 260 nm and the ratios OD260/OD280 and OD260/OD280 determined. The quality and amount of DNA obtained by this method were comparable to those of DNA isolated from equal amounts of material using a commercial genomie DNA purification kit.

Ticks, and the diseases they transmit, are of great economic and medical importance worldwide, and especially in Africa, where they are considered to be the greatest animal disease problem. The four major genera of ticks are Amblyomma, Rhipicephalus, Hyalomma and Boophilus. Ticks harm their animal hosts by sucking their blood thus reducing growth rate and milk yield, cause mechanical damage to hides and skins causing tick worry, introduce toxins and predispose the animals to myasis. Theileriosis, cowdriosis and dermatophilosis are the major tick-borne and tick-associated diseases of grazing cattle in Africa. The conventional method of tick control is the application of chemical acaricides, but it is associated with a number of problems including environmental pollution, chemical residues in meat and milk products as well as in wool, development of tick resistance and high cost. Some of the alternatives to chemical control of ticks that are available in Africa are discussed in this paper.

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.

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.