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.

The bioefficacy of various plant extracts, namely Azadirachta indica A. Juss, Khaya senegalensis Desrousseaux (A. Jussieu) and Hyptis suavuolens (L.) Poit, either alone or in combination with half the recommended dose of synthetic pesticides, was studied with farmers to find a more sustainable strategy for the management of bollworms in cotton. A number of treatments were farmer innovations. The treatments were compared six times during the season to the application of the fully recommended dose of synthetic pesticides and to a control with no pesticide application. Applications of either the fully recommended dose of the synthetic pesticides or the combinations with a neem seed extract (6 kg/ha) were most effective in reducing bollworm incidence and damage. Both the treatments gave the highest yields of cottonseed, the latter being the most cost-effective. All the pesticides used, except neem alone, had a toxic effect on bollworm predators. This study has increased farmers' confidence in endogenous technology. The researcher's interaction among the local learning group members, who conducted the experiments, facilitated the introduction of a cost-effective alternative to the standard full-dose synthetic pesticide recommendation.

Termite workers, Macrotermes subhyalinus (Rambur), produced two cellulase-free xylanases, namely Xyl A and Xyl B. DEAE-Sepharose CL-6B, Sephacryl S-200 HR, CM-Sepharose CL-6B and Phenyl-Sepharose CL-4B chromatographies purified these enzymes. They exhibited molecular masses of 63–66.1 (Xyl A) and 60.7–62.4 (Xyl B) kDa. Both enzymes appeared to be endo-xylanases, which produced oligomers of xylose from xylan and did not hydrolyse them to xylose. They had different optimum pH (pH 4.6–5.0 for Xyl A and pH 5.0 for Xyl B) and different optimum temperatures (60 °C for Xyl A and 55 °C for Xyl B). However, they had the same pH stability (4.0–5.6). Both enzymes were stable at 50 °C for more than 4 h. At a pH ranging from 4.6–5.0 and 60 °C, Xyl A and Xyl B possessed the half-life of 115 and 60 min, respectively. The xylanase activities were stimulated by Na+, Mn2+ and dithiol-reducing agents and were sensitive to Cu2+ and detergent agents. Their enzymatic activity was slightly reduced by the presence of urea at 1% (w/v) concentration. The two enzymes could be used in the presence of organic solvents such as acetone (up to 10% v/v) without loss of activity.

A water–oil based pheromone trap was used to monitor seasonal population changes of Coniesta ignefusalis Hampson in millet-based cropping systems at Samaru, Zaria, Nigeria for three consecutive seasons (1997, 1998 and 1999). Daily meteorological data were obtained from the Meteorological Unit of the Institute for Agricultural Research, Samaru, Zaria, for the monitoring period. Two population peaks were observed in early August and September in 1997 and 1998. The first population peak in August 1997 was earlier and bigger than the one in 1998. A delayed emergence of the insects was observed in 1999 when only one population peak occurred and this was smaller than those in 1997 and 1998. Using step-wise multiple regression analyses, the relationship between pheromone trap catches of male moths and weather factors was assessed separately for each year to determine which of the weather factors contributed most to the insect population changes. Solar radiation in the preceding 10 days and minimum air temperature in the preceding 40 and 50 days explained 84.9% of the variance in population changes and flight activity of male moths in 1997. Wind direction and speed in the preceding 20 and 60 days respectively accounted for 80.6% of the variance in 1998, while maximum air temperature and relative humidity in the preceding 40 and 20 days respectively explained 99.9% of the variance in 1999. The functional regression equations developed involving these weather factors adequately predicted the changes in each year.

Six companion crops, i.e. Tagetes erecta, Daucus carota L., Coriandrum sativum L., Brassica oleraceae L. var. acephala, Capsicum annuum L. and Zea mays L., were evaluated for their efficacy in suppressing field populations of Frankliniella occidentalis (Pergande) and Megalurothrips sjostedti Trybom on French bean Phaseolus vulgaris L. Each companion crop was interplanted with French beans in a 3×10 m plot and replicated three times in a completely randomized block design. The thrips populations on French bean flowers in experimental plots were compared with those on beans treated with two insecticides: L-cyhalothrin (Karate 1.75% EC) and methiocarb (Mesurol 500 SC) or untreated (control). Coriandrum sativum, Z. mays and T. erecta are recommended as companion crops for intercropping with French beans to reduce populations of thrips and hence minimize the use of chemical insecticides on this crop.

The damage potential of the spider mite Tetranychus ludeni Zacher was studied on 20–65-day-old seedlings of four eggplant Solanum melongena varieties: Madurai (MDU1), Coimbatore (CO1), Annamalai and Panruti at introduction levels of 2, 5, 10 and 15 mites/leaf. The average seedling mortality among varieties was lowest at the introduction level of two mites and maximum at the introduction level of 15 mites/leaf. The overall seedling mortality was 23% when the four levels of mite population were introduced on 20-day-old seedlings, and only 14% on 30-day-old seedlings. Among the different varieties, the MDU1 seedlings recorded higher mortality (1.6%) and Panruti the lowest (0.3%). The percentage losses in total plant height, number of leaves, number of flowers and fruits and fruit weight due to mite attack were highest (37–50%) in MDU1 and lowest (7–11%) in the variety Panruti. The other two varieties CO1 and Annamalai were found to be intermediate between Panruti and MDU1. The inoculated mites at different levels multiplied greatly on the variety MDU1 followed by CO1, Annamalai and Panruti. The extent of damage was higher in 35-day-old plants, when mites were introduced on 35- and 65-day-old seedlings. Therefore, the variety Panruti is recommended for cultivation in the study area in view of its resistance to T. ludeni.

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.

A morphological diversity study was conducted on African rice gall midge Orseolia oryzivora Harris & Gagné and two other African species, Orseolia bonzii Harris and Orseolia nwanzei Harris & Nwilene, sp. n. Morphological differences between adult and immature stages of the three species are slight and mainly evident in pupal characters. Due to limited differences in morphological characters, genomic DNA fingerprinting of these three insect species was carried out using random amplified polymorphic DNA (RAPD) and sequence-characterized amplified region (SCAR) methods. Out of 90 operon primers, 15 showed polymorphism among the three species tested, generating 86 bands, 60 (70%) of which were polymorphic. Primer OPV6 produced three RAPD markers that distinguished the three Orseolia species. These markers were cloned and sequenced. Their sequence was then used to design six SCAR primer pairs. Each SCAR primer pair amplified and distinguished the three Orseolia species at genomic DNA level. Both SCAR and RAPD genomic DNA fingerprinting revealed that O. oryzivora and O. bonzii are most closely related and O. nwanzei is distinct. Each of the six SCAR primer pairs produced a specific DNA fragment size specific for O. nwanzei, O. oryzivora and O. bonzii. The DNA fingerprints will be useful for entomological survey, identification of new species and differentiating aggressive from non-aggressive species, aimed at the effective development of rice cultivars with durable resistance to African rice gall midge.

The African root and tuber scale Stictococcus vayssierei Richard is the only known hypogeal species of the family Stictococcidae. Its wide range of host plants together with concurrently field observed differences in host preference provided evidence of polyphagy or the involvement of more than a single-scale species. To establish the baseline information for future taxonomic studies, newly emerged larvae were collected from infested cassava from three sites in the humid forest zone of southern Cameroon. A glass binocular magnifier was used to observe morphological changes of live individuals and slide-mounted individuals of all developmental stages were examined with a compound microscope. Stictococcus vayssierei females went through three developmental stages—two larval instars and an adult stage. The first and second instars were purple-red, while the adult was brown. Body size and the degree of sclerotization of the dorsal line increased in each developmental stage. White waxy secretions on the basal periphery of the second instar, and both dorsum and periphery of the adults, distinguished them from the first instar, which lacks the white waxy secretions. On slide-mounted specimens, certain aspects of the anal complex (i.e. number of opercular plates and -setae) were found to be the most discriminating features of S. vayssierei life stages. These results are useful for further studies on the diversity of subterranean stictoccocid scales.

The present study was undertaken to determine the occurrence of virus particles in male accessory reproductive glands and to describe the changes in the affected tissues. Using electron microscopy techniques, it was possible to identify rod-shaped virus-like particles in accessory reproductive glands of male tsetse, Glossina morsitans morsitans Westwood. The viruses occurred intracellularly within the epithelial cells and in the lumen of the glands. Cell degeneration characterized by abundant clear vacuoles, membrane-bound vesicles, disorganization and elimination of cell organelles typified the infection. The inference, therefore, is that virus infection may be primarily responsible for the necrotic changes identified in the gland cells. It is suggested that the lesions caused in the gland epithelium by the infection would disturb the glandular cells and disrupt synthesis of the secretion. This may eventually destroy the male accessory reproductive glands leading to inability of the male flies to form spermatophores for transferring spermatozoa to the female tsetse. Lack of sperm transfer would consequently result in no egg fertilization.

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.

The parasitism of Bemisia tabaci (Gennadius) was evaluated on three horticultural crops in the Nicaraguan dry tropic: tomato, Lycopersicon esculentum Mill; squash, Cucurbita argyrosperma (Huber); and sweet pepper, Capsicum annuum L. Parasitoid species were identified and their abundance recorded on the three crops. The study was carried out during both the rainy and dry seasons between 2001 and 2002. The nymphs of B. tabaci were counted weekly and parasitism rates evaluated. During the rainy season, the predominant parasitoids in squash and tomato crops were Encarsia pergandiella Howard and E. nigricephala Dozier. Parasitism rates of 17 and 10% were recorded for squash and tomato, respectively. In sweet pepper, the parasitoid species were E. pergandiella, E. nigricephala, E. desantisi Viggiani and Amitus sp. with a parasitism rate of 12%. During the dry season, the parasitoids in squash were E. pergandiella and E. nigricephala with a parasitism rate of 57%. Encarsia pergandiella was the only species noted in tomato with a parasitism rate of 58%, while in sweet pepper the species noted were E. pergandiella and E. nigricephala, with a 42% rate of parasitism. The abundance of parasitoids remained stable during both sampling seasons. Our results suggest that the parasitism rate is independent of B. tabaci densities. This is the first mention of E. pergandiella, E. nigricephala, E. desantisi and Amitus sp. as parasitoids of B. tabaci in Nicaragua.

Effect of heating on Callosobruchus maculatus (Fabricius) in Vigna angularis (Willd.), Ohwi & Ohashi, seed was assessed using an 118° obtuse base angle solar box heater. The box heater was constructed with 1.2 mm thick sheet metal, glued inside with aluminium foil and insulated on the outside by fixing 1 cm thick polystyrene and glazed with 0.15 mm thick clear plastic sheet. Electric energy from a solar simulator panel adjusted to simulate heat trapped from natural solar energy was used. Exposure of the various developmental stages of C. maculatus infesting adzuki bean seed to heat for 45 min and more raised the temperature between and within the seeds well in excess of the lethal level (>60 °C) and resulted in complete control. Heating at 60°C of up to 3 cm adzuki bean seed (seven to eight seed layers) took about 1 h and resulted in complete control of the pest. This would enable this heater to treat large amounts of seed at a time compared with solar heaters demonstrated so far in which only a single layer of seed can be treated. Therefore, solar heating of infested adzuki bean seeds using the aforementioned box heater around noon, for 1 h, gives effective control of C. maculatus. Results of the effect of heat treatment on seed viability and moisture content showed that adzuki bean seed germination is affected by heating; hence seed meant for planting should not be heat treated to control storage insect pests. Heat treatment also did not affect seed moisture content.

Citrus orchards in the Nile Delta and middle Egypt were surveyed for predacious soil mites and parasitic nematodes. There were 16 species of predacious mites and the citrus parasitic nematode, Tylenchulus semipenetrans Cobb. was recorded everywhere. In the medium-heavy soil of the Nile Delta orchards, the general predators or decomposer mites like uropodids were most common. In the light-medium soil of El-Fayoum in middle Egypt, the specialized predator mites like gamasids were most common. In localities where gamasids were common, negligible infestations of citrus parasitic nematodes were reported. Regarding Egypt as a whole, the uropodid mites Uroobovella krantzi (Zaher & Afifi) and Nenteria hypotrichus (El-Borolossy & El-Banhawy) represented about 50% of the sampled mites. The remaining mites were represented by 14 mesostigmatid species, the most common being Gamasiphis pulchellus (Berlese). At least 6% of orchards suffered injurious nematode infestations, 13% critical infestations and 22% moderate infestations, and the remaining 59% were free or with negligible infestations.