In Reunion Island, insect and mite pests are significant limiting factors to the development of market crops. Several studies have been carried out on some families of pests during the last 40 years, but no comprehensive survey has been undertaken on the arthropods of vegetable crops on this island. During 1997/1998, we studied the arthropod complex on eight main families of crops, namely Solanaceae, Cucurbitaceae, Brassicaceae, Fabaceae, Liliaceae, Asteraceae, Apiaceae and Rosaceae. During a complete year of collection, we gathered 123 species of pests, including 114 species of insects and 9 of mites. We also identified a total of 128 species of beneficials, including 51 species of parasitoïds and 77 species of predators and consisting of 101 species of insects, 14 of mites and 13 of arachnids. Our data constitute the first step for the implementation of strategies for pest monitoring and integrated pest management in an important sector for the island's insular economy.

Termites (Isoptera: Termidae), white grubs (Coleoptera: Scarabaeidae) and millipedes (Myriapoda: Odontopygidae) are the major groups of soil pests that are widespread and of economic importance in groundnut production in sub-Saharan Africa. Other Coleopteran pests such as wireworms (Elateridae) and false wireworms (Tenebrionidae) are found to be of occasional importance. Farmers' cultural practices such as improper application of organic manure, leaving crop residues in farms, delay in planting and harvesting, and abiotic factors such as rainfall and soil texture also influence soil pest occurrence and damage. Groundnut farmers in most parts of sub-Saharan Africa seldom apply effective control measures against soil pests. This paper reviews the major soil pests of groundnuts and their damage, and discusses adopted control practices and their applicability in integrated pest management (IPM) modules, with an emphasis on the use of resistant groundnut varieties, cultural practices, botanicals and minimal application of synthetic insecticides.

A survey among 240 resource-poor farmers at the Kenya coast indicated that insect pests were considered to be the main production constraint. Over 70% of respondents mentioned stemborers to be the most important insect pest. Unlike the eggs and adults, stemborer larvae and pupae were frequently seen by farmers. Alternative gramineous host plants for pests were common near maize fields and were often not destroyed until after the first rains. Nearly all farmers left dry stems and stubble in the field after harvest. Farmers knew of many methods for controlling stemborers, but only 32 and 56% of farmers in Kilifi and Kwale Districts, respectively, used any of the methods. Chemical control was the most popular control method, being applied regularly by 19 and 38% of farmers in Kilifi and Kwale Districts, respectively. Traditional methods and cultural control methods were seldom used. Approximately 50% of farmers had heard of beneficial insects, with farmers collectively mentioning 17 predators of stemborers. Cocoons of the parasitoids Cotesia flavipes, released in a biological control programme in the study area in 1993, and the indigenous Cotesia sesamiae had been seen by 33% of respondents, but none knew what these were. The results of the present study stress the need to educate farmers about the biology and ecology of stemborers and the role of natural enemies. Also, after effective control methods suitable for resource-poor farmers have been identified, both groups should be trained in pest management methods, for example through the Farmers Field School approach.

The immature stages of the predaceous mite Typhlodromus talbii Athias-Henriot are described. The mite was reared on different prey species and pollen in the laboratory, and its developmental parameters calculated. Tydeus californicus (Banks) was found to be the most suitable and nourishing diet, giving a shorter life cycle and higher female fecundity (8.8 days and 33.4 eggs respectively), than the scale insect Coccus acuminatum (Gennadius) (10.0 days and 24.8 eggs respectively) at 25 °C. Other associates of Typ. talbii, the eriophyid Cesaberoptus kenyae Keifer, the tetranychid Oligonychus mangiferus (R. & S.) as well as date palm and castor oil pollen, were unsuitable diet. When reared on moving stages of Tyd. californicus (Banks) at 70 ± 5 % RH, 16:8 (L:D) h photoperiod and temperatures of 15,20,25,28,30,32 and 35 °C, the total developmental time of Typ. talbii averaged 21.3, 12.4, 8.8, 7.6, 7.1, 5.8 and 11.6 days respectively. The intrinsic rate of natural increase (rm) and the net reproduction (Ro) reached maximum values of 0.299 individuals per female per day and 28.06 times respectively, at 32 °C.

Conidial suspensions of four isolates each of Beauveria bassiana and Metarhizium anisopliae were evaluated in the laboratory for their virulence to adult Ootheca mutabilis. All the isolates tested were pathogenic to the beetle, but to varying degrees. Three of them, B. bassiana CPD 3 and CPD 10 and M. anisopliae CPD 6 were superior to all other isolates in terms of mortality induced on adult beetle, LT50 and LC50, with B. bassiana CPD 3 having the lowest LC50 value. In feeding assays; consumption by beetles treated with B. bassiana CPD 3 was significantly reduced within 2 days treatment (DAT) and the trend continued until 7 DAT, when all the beetles died. The antifeedant effects of the pathogen on O. mutabilis could partly offset its slow speed of kill, and might play an important role in field control.

The fumigant toxicity, ovicidal and oviposition-deterrent potential of the essential oil of Indian dill, Anethum sowa and its three major fractions against the grain beetle Callosobruchus maculatus (Coleoptera: Bruchidae) on chickpea were investigated. Two fractions produced 100% mortality of adult beetles at 3.0 μl/ml dosage, whereas the essential oil was the least effective. Fraction III was 100% ovicidal at a 70 μl/ml concentration. The essential oil and fraction III both completely deterred oviposition at the lowest concentration tested, 10 μl/ml. Neither the essential oil nor its fractions had any significant effect on chickpea seed germination.

The behavioural responses of adult female western flower thrips, Frankliniella occidentalis (Pergande) to volatiles from meadow-sweet (Filipendula ulmaria), bay laurel (Laurus nobilis) and sage (Salvia officinalis) were investigated in laboratory bioassays. Volatiles collected by entrainment of a solvent extract of F. ulmaria were more attractive than was the original extract. Frankliniella occidentalis was also significantly attracted to volatiles from L. nobilis and S. officinalis. Analysis by gas chromatography and mass spectrometry identified 1,8-cineole (eucalyptol) as one of the main volatile components of all three plant species. In coupled gas chromatography-electroantennography studies with F. ulmaria, both 1,8-cineole and methyl salicylate elicited responses from F. occidentalis. Eucarvone was identified as the major component of F. ulmaria volatiles, but showed no electrophysiological activity. Behavioural responses of thrips to a range of concentrations of 1,8-cineole and methyl salicylate were tested using a modified Pettersson ‘star’ olfactometer. 1,8-Cineole showed some attractant activity for the thrips at 0.01 mg, but methyl salicylate was repellent at all the concentrations tested.

The levels of lipophorin, the principal insect haemolymph lipoprotein, were estimated during the development of solitary and gregarious phases of Schistocerca gregaria using single radial immunodiffusion. In the gregarious phase, lipophorin titres ranged from 6.69 ± 0.57 mg/ml in the 3rd nymphal instar to 14.42 ± 2.04 mg/ml in mature adults. The titres in the solitary phase were 3.33 ± 0.59 mg/ml in the 3rd nymphal instar and 8.44 ± 0.67 mg/ml in mature adults. Peak lipophorin titres occurred in mature adults (14.42 ± 2.04 mg/ml) and 5th nymphal instar (8.75 ± 0.25 mg/ml) for gregarious and solitary locusts, respectively. Gregarious locusts had significantly (P< 0.05) higher lipophorin titres than their solitary counterparts during the 3rd and 4th nymphal instars as well as in the adult stage (P< 0.01). Estimation of the haemolymph protein levels over the same period showed a general increase from the 3rd nymphal instar to mature adult stage in both phases. It is proposed that the higher lipophorin titre in gregarious locusts is a physiological adaptation that ensures high lipid reserves that are necessary to cope with the high metabolic requirements of this phase.

The objectives of this study were to identify the preimaginal development of instars of Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae: Opiinae), a larvo-pupal parasitoid of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and to define its thermal requirements. Development was followed daily and parasitoid stage and size were noted. Larval samples were observed under a scanning electron microscope. Developmental rate as a function of temperature was studied with the Sharpe-DeMichele 6-parameter biophysical model and thermal requirements (lower developmental threshold and thermal constant) calculated using a linear regression. The duration of parasitoid development at seven temperatures ranged from 16.52 ± 0.96 days at 28 °C to 57.62 ± 1.85 days at 15 °C (males) and from 18.00 ± 0.79 days at 28 °C to 63.60 ± 1.52 days at 15 °C (females). Male development always took shorter than female development. No parasitoids emerged at 29 and 30 °C, which seems to be close to maximal temperature. The development required 322.6 ± 17.6 degree-days above a thermal threshold of 9.19 °C (both sexes cumulated). These data are compared with those of the host fruit fly, and the suitability of D. tryoni in controlling the Mediterranean fruit fly in Reunion Island is discussed.

Aqueous neem seed kernels extracts (NSKE) were used to treat flea-infested goats in Morogoro, Tanzania to determine their efficacy for flea control. Mean population densities of the insects were significantly lower in the treated goats compared to their untreated counterparts (P < 0.05). It was concluded that NSKE has potential in controlling livestock fleas, but further studies are needed to determine the active principals against fleas and their mode of action.