The red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier), a concealed tissue borer, is a lethal pest of palms and is reported to attack 17 palm species worldwide. Although the weevil was first reported on coconut Cocos nucifera from South Asia, during the last two decades it has gained a foothold on date palm Phoenix dactylifera in several Middle Eastern countries from where it has moved to Africa and Europe, mainly due to the movement of infested planting material. In the Mediterranean region, RPW also severely damages Phoenix canariensis. Currently, the pest is reported in c. 15% of the coconut-growing countries and in nearly 50% of the date palm-growing countries. Infested palms, if not detected early and treated, often die. However, palms in the early stages of attack respond to chemical treatment with insecticide. RPW has been managed in several countries employing an integrated pest management (IPM) strategy including the use of food-baited pheromone traps. Early detection of infestation in the field is important for the success of any RPW-IPM programme. Ideally, movement of planting material from infested plantations within the country and also from one country to another needs to be stopped. Wherever this is not possible, it is essential to implement strict pre- and post-entry quarantine regimes, wherein only pest-free and certified planting material can be transported. The existing pheromone-based IPM programme can be strengthened by intensifying the search for effective natural enemies, coupled with the introduction of resistance in palms to RPW. This article reviews the work done during the last 100 years on various aspects of RPW viz. life history, damage and symptoms of attack, seasonal activity, spatial distribution, host range, IPM and its main components, including trapping adult weevils and chemical control, besides biological control, host plant resistance and male sterile technique.

A survey of the mite fauna associated with Amaranthus cruentus L. (amaranth), Solanum macrocarpon L. (Gboma) and S. aethiopicum L. (African eggplant), three major indigenous vegetables produced in Benin, was carried out from August to October 2004 both at IITA-Benin station and on a vegetable farm at Togba in Abomey-Calavi area. Thirty-three mite species belonging to 12 families were found on the three vegetables. These species included phytophagous mites, predatory mites of the family Phytoseiidae, and another group whose feeding habits were not clear. The following phytophagous mites were found: Tetranychus urticae Koch and T. ludeni Zacher, in the family Tetranychidae; Polyphagotarsonemus latus (Banks) and another unidentified mite species, in the family Tarsonemidae. The two Tetranychus species were present on all three vegetables whereas tarsonemids were found only on the two solanaceous plants. Polyphagotarsonemus latus was the most dominant pest during the course of the experiments. It is the major mite pest on solanaceous plants, especially on Gboma in vegetable farms, where broad-spectrum pesticides harmful to natural enemies are used. The phytoseiids group was the most diversified with 16 species out of the 33 identified and more predominant in IITA plots where no pesticides were applied, compared to Togba plots where pesticides were regularly applied on nearby plots. They seem to better control P. latus on Gboma than on African eggplant. Other mites identified on the three vegetables belong to the following families: Acaridae, Tydeidae, Erythraeidae, Cunaxidae, Anystidae, Ascidae, Bdellidae, Uropodidae and Oribatidae.

Domestic cockroaches Blattella germanica were trapped from various homes in Gaborone, Botswana using ‘Dyroach’ traps. Isolations of bacteria, yeasts and moulds were done on external body parts and on the faecal pellets using various selective media. Body parts of cockroaches were also fixed with OsO4 vapour for 24 h, sputter coated with gold under special conditions and examined in a Phillips (1) XL30 ESEM in low vacuum mode. A wide spectrum of bacteria including common food spoilage and pathogenic organisms, such as Bacillus spp., Staphylococcus spp., Escherichia coliPseudomonas spp., Enterobacter spp., Klebsiella spp., Erwinia spp. Salmonella sp., Shigella sp. and Serratia spp. were isolated. Yeasts commonly associated with food spoilage, such as Pichia sp., Candida sp. and Torulopsis spp. were found on many cockroaches. In addition, various groups of moulds, some associated with food spoilage and others known to produce mycotoxins, such as Aspergillus flavusAspergillus fumigatus and Aspergillus parasiticus were isolated. Antimicrobial sensitivities of bacterial isolates revealed resistance patterns to various agents. Since cockroaches are prevalent in homes, particularly in food preparation areas and since their body parts and faecal pellets have been found in food storage areas, concern about their impact on food quality and safety is raised and possible control measures including education of communities on proper sanitation are suggested.

Bemisia tabaci (Gennadius) adults from colonies reared on cassava or sweet potato plants were studied to determine their ability to transmit Indian cassava mosaic virus (ICMV) (Geminiviridae: Begomovirus) from cassava to cassava. Virus acquisition access (feeding) periods (AAP) of 48 h on ICMV-infected cassava leaves and 48-h virus inoculation access (feeding) periods on virus-free cassava seedling leaves were investigated. ICMV was successfully transmitted from cassava to cassava by whiteflies reared on cassava, but not whiteflies reared on sweet potato. Virus-specific primers were designed around conserved regions of the coat protein gene (CP) (771 bases) of the Trivandrum (Tri; GenBank accession number AF423180) isolate and used for virus detection in the whitefly vector after different AAP. The activities of the cyanide detoxifying enzymes rhodanese and β-cyanoalanine synthase in B. tabaci were evaluated and shown to be significantly higher in the cassava-reared whitefly population compared with the sweet potato-reared population suggesting a possible reason for higher mortality of the sweet potato strain feeding on cassava. Mating compatibility studies between cassava and sweet potato colony whiteflies resulted in production of fertile offspring with no evidence for reproductive isolation. Results confirm that only B. tabaci whiteflies reared on cassava transmit ICMV from cassava to cassava in India.

A survey on the geographical distribution of Chnootriba similis (Thunberg), formerly known as Epilachna similis, was undertaken from 2001 to 2003 in the main cereal-growing areas of Ethiopia. The population density of the insect was estimated by sweep netting (100 sweeps/farm). In addition, more detailed studies on seasonal and annual fluctuations in population density of C. similis were carried out in southern Ethiopia between 2002 and 2003 by sampling 10 quadrants of 0.25 m2 per farmer's field. The damage levels were determined using scores of 0–9. The survey revealed that C. similis is widely distributed in different parts of the cereal-growing regions of Ethiopia. It was observed that the beetles had spread to altitudes ranging from 1217 to around 3000 m asl. However, the variations in population densities of C. similis cannot be directly attributed to altitude, as highly differing population densities in similar altitudes of different locations were recorded. Annual and seasonal variations in population density were observed in different areas of the southern part of Ethiopia. These results suggest that C. similis has a sporadic nature and can occasionally build up to outbreak levels. Beetles fed on both cereals (barley, wheat, tef, maize, sorghum and finger millet) and wild grasses (Leersia hexandra (Sw.), Avena abyssinica (Hoechst) and Lolium temulentum (L.)). Population densities and damage levels on the cereal crops varied considerably with the highest densities and damage levels on barley.

Euproctis latifascia Walker is an important pest attacking old leaves of tea bushes and mother leaves of nursery cuttings in Darjeeling foothills, Terai and Northeast India. Laboratory experiments were designed to assess the effect of an artificial diet and a natural diet, i.e. tea leaves, Camellia sinensis, on life history traits like development time, survival and fecundity of E. latifascia. In addition, the maintenance cost as well as the nutritional and production indices were estimated for each substrate (diet) using the gravimetric (dry mass) methods. On the natural (tea leaves) and artificial diets, the total development periods were 78.4 and 68.6 days, fecundity 248.8 and 230.3 eggs/female; in the final caterpillar stage (VI), the relative consumption rates were 0.8 and 0.6, relative growth rates 0.05 and 0.07, maintenance costs 5.1 and 2.9 and production index 0.1 and 0.2, respectively. The fifth instar larvae also showed similar differences in their nutritional indices. Based on these parameters it appears that the artificial diet is more suitable for laboratory rearing of E. latifascia than the natural tea-leaf diet.

To characterize the population dynamics of Erionota thrax Linnaeus and its major parasitoids, biweekly samplings were carried out in a commercial Cavendish banana plantation and a subsistence farm of local varieties, from April 2004 to November 2005. Five primary endoparasitoids were recorded: Ooencyrtus erionotae Ferriere, Cotesia erionotae Wilkinson, Brachymeria albotibialis Hoffmann, Elasmus sp. and Melaloncha sp. Ooencyrtus erionotaeC. erionotae, and B. albotibialis were, respectively, the major egg, larval and pupal parasitoids. In 2004, there was no significant difference in the E. thrax population densities and parasitism of immature life stages in both farms. In 2005, the pest population densities were significantly different, while only egg and larvae parasitism rates were significantly different. In the commercial plantation, peaks of E. thrax population densities per banana mat were recorded in April, June, July, and October–December and highest values for eggs, larvae and pupae were 4.66, 2.76 and 1.7, respectively. Percentage parasitism peaked in August, October, and February with peak values ranging from 60 to 100%. In the subsistence farm, peak E. thrax population densities were observed between May–July and September–December. Percentage parasitism peaked in January, February, July, August, October and November, with peak values ranging from 24 to 100%. Correlations between population densities of E. thrax and the numbers of parasitized insects showed strong positive relationships. There was evidence of a delayed density dependence of the parasitoids as most peaks of parasitism appeared 1 or 2 months after those of the host stages. Parasitism rates in the commercial plantation were substantial in spite of the frequent use of insecticides, and activities of the parasitoids were more favoured in the subsistence farm compared with the commercial plantation.

Six distinct biotypes of the Asian rice gall midge, Orseolia oryzae (Wood-Mason), have been characterized so far from different parts of India and their geographical distribution has been well mapped and monitored annually through the national gall midge biotype studies. These studies have been showing minor changes in the virulence pattern of the pest population at Warangal in Andhra Pradesh state since 2000. Hence, a sample of the pest population from the site was collected during 2003 and selected subsequently in a greenhouse through 13 successive generations for virulence against diverse sources of plant resistance. This Warangal-derived population (WDP) was tested to record reactions of two sets of differential rice varieties used for biotype detection and known to carry one of the 10 known gall midge-resistance genes. The results revealed that WDP has acquired virulence against CR-MR1523, one of the biotype differential rice varieties, which derived resistance from the source Ptb21 cultivar. Since the virulence pattern noted for WDP was different from that noted for the six characterized biotypes, it is proposed to designate this new biotype, tentatively, as biotype 4M. Only three of the resistance genes, viz. Gm3Gm4 and Gm8 confer resistance against this biotype.