The salivary glands of the cowpea pod-sucking bugs Anoplocnemis curvipes (Fabricius), Clavigralla tomentosicollis Stål, Clavigralla shadabi Dolling, Riptortus dentipes (Fabricius) and Mirperus jaculus (Thunberg) are described and illustrated. Extracts of the glands were assayed for the presence of proteinases, α-amylase, β-amylase and amyloglucosidase. The salivary glands consist of four-lobed principal glands and a tubular accessory gland, and they differ in shape and size among the different species except for the median lobe, which is more or less spherical. The sickle-shaped nature of the posterior lobe reported before for Riptortus linearis (Linnaeus) was also observed in R. dentipes, suggestive of a probable generic characteristic. Anoplocnemis curvipes has the biggest salivary gland, and it is followed by R. dentipes, M. jaculus, C. tomentosicollis and C. shadabi in descending order. Assays of the gland extracts revealed that the four digestive enzymes tested are present in the five coreoid species. Proteinases were preponderant (1.4–94.9 μg/ml), while amylases were detected in traces [(0.5–11.0) × 10− 3 μg/ml]. Proteinases may be largely responsible for the feeding damage caused by the coreoid species and their concentration in the glands of the different species correlates well with their known capacity to inflict pod damage and yield reduction in cowpea. Fourth instar nymphs of the different species also had higher concentrations of the digestive enzymes compared with their respective adults; and this correlates with the known ability of the nymphs to cause greater pod damage and yield reduction than adults.

In situ field level mass production of Amsacta albistriga nucleopolyhedrovirus (AmalNPV) was achieved at Pavagada (Karnataka, India) during September 2004. The yield of virus mass produced in situ in the field was 5.05 times greater than that when produced in the laboratory. This technique is farmer-friendly, easy to execute and much cheaper than laboratory production, having the potential to be used for the mass production of NPV of gregarious pests that occur in large numbers.

The effects of pH, sunlight and rearing temperature on infectivity of nucleopolyhedrovirus (SpltNPV) were investigated against larvae of Spodoptera litura (Fabricius). The infectivity of virus increased with increased larval rearing temperature. The LT50 values were significantly reduced from 24 to 6 days when rearing temperature was increased from 20 to 35 °C. The pH of the substrate significantly affected the infectivity of the virus. The LT50 values increased to about fourfold when the pH of suspension was raised from 7 to 11. Infectivity of the virus was more adversely affected in alkaline than in acidic suspension. Sunlight also deleteriously affected infectivity of the virus. The LT50 values increased with the increase in the period of sunlight exposure. A complete viral inactivation occurred after 12 h of direct sunlight exposure.

Host-plant resistance is one of the major components of integrated pest management programmes against the noctuid pod borer Helicoverpa armigera (Hübner) in chickpea. Survival and development of H. armigera on nine chickpea genotypes were compared using two food substrates, namely fresh leaves and pods, and artificial diets containing lyophilized leaf or pod powder of the same genotypes. Among the genotypes used, six showed different levels of resistance to H. armigera, while three were used as susceptible checks. Using leaves and pods, five of the resistant genotypes yielded lower larval weights compared to one of the susceptible checks used. Significant differences between four of the resistant and two of the susceptible genotypes were also observed when using artificial diets containing leaf or pod powder, but the rankings were different from that on the fresh leaves and pods. On both substrates, four resistant genotypes resulted in lower larval survival, pupation, adult emergence and fecundity when compared to one of the susceptible checks. A similar trend was also observed for larval survival and development when using F1 hybrids based on four of the resistant genotypes. Survival and development of H. armigera on the two food substrates, fresh leaves and pods and artificial diets with lyophilized leaf or pod powder, were highly correlated, suggesting that incorporation of lyophilized leaves or pods into the artificial diet can be used to assess antibiosis to H. armigera in chickpea.

The effects of methanol extract of Peganum harmala L. seeds were evaluated against Tribolium castaneum (Herbst). Larval growth was inhibited and food intake reduced when the extract was incorporated into the diet at concentrations of 2.5, 5 and 10%. All doses caused an increase in the duration of larval period and completely inhibited F1 progeny production. The main body metabolites were determined in last-instar larvae after feeding for 8 days on the diet treated with different doses. Protein and lipid contents were decreased with concentrations >2.5%. Glycogen content was reduced at a concentration of 10%. Tribolium castaneum larvae possessed two major and one minor α-amylase isoforms as determined by gel assays. Larvae fed the treated diet presented less activity of the major isoforms, while activity of the minor isoform was totally inhibited. The activity of this enzyme is not inhibited in vitro by seed extracts. Histological studies showed that P. harmala extracts caused a severe cytotoxicity on the epithelial cells of the midgut resulting in marked vacuolization of the cytoplasm and a large intercellular space. These findings suggest that seed extracts of P. harmala exert their toxic effect by severely damaging the midgut epithelial cells. This naturally occurring plant extract could be useful for control of T. castaneum.

The stored grain weevil, Sitophilus oryzae (Linnaeus), causes significant losses to maize grains in tropical countries. Despite the nutritional superiority of the quality protein maize (QPM), an important concern is the possible vulnerability of QPM genotypes to stored grain weevil infestation. In the present study, the responses of 24 QPM inbred lines, along with several non-QPM inbred lines and hybrids, were evaluated against S. oryzae under laboratory conditions. Two attributes, namely (i) % weight loss in the grains after a fixed period of incubation with the insect and (ii) the number of progeny insects (insect multiplication) generated from six pairs of adult insects, were considered. A cumulative resistance index was computed for each genotype giving equal weight to both attributes. The study revealed DMRQPM-60 and CML167 as the most resistant entries. Shaktiman-1, the released QPM hybrid in India, showed moderate resistance against the grain weevil. However, most of the elite QPM inbred lines as well as some non-QPM inbred lines and hybrids were found to be highly susceptible to the weevil infestation. To explore the possible relationship between enhanced protein quality and varying degree of kernel vitreousness and vulnerability to the grain weevil infestation, both the QPM and the non-QPM genotypes were analysed. The correlations between kernel quality traits and kernel texture with % kernel weight loss due to weevil infestation and insect multiplication were found to be non-significant, indicating possible influence of other factors, including pericarp thickness and endosperm composition, in determining the susceptibility of the QPM genotypes to S. oryzae. The study indicates that QPM genotypes are not necessarily susceptible to the stored grain weevil and identifies promising QPM genotypes with resistance to S. oryzae.

A survey to establish the distribution of tsetse flies (Diptera: Glossinidae) in southern Sudan was conducted using biconical traps. Only Glossina fuscipes fuscipes was caught. The results obtained revealed a further northern advance of G. f. fuscipes of c. 29 km along River Bahr el Jebel and 48 km along River Luri, and a southern contraction of Glossina morsitans submorsitans belt from Lewis' distribution limit. Glossina f. fuscipes was encountered in gallery forest along water courses with no significant differences in sex ratios and proportions of tenerals and non-tenerals between trap catches (P>0.1). Flies were absent from villages and open savanna woodland forests away from water courses. Trap catches were significantly higher during wet than dry season (t = 2.681; P < 0.025), although flies could be caught in any one location during both seasons. These results are discussed in relation to the current epidemic of human African trypanosomosis (HAT) in southern Sudan.

The antibiotic effects of 12 different cotton genotypes on Bemisia tabaci (Gennadius) were studied during June–July and August–September 2003, with the objective to determine the biological parameters which are important to study the mechanism of antibiosis and to identify the genotypes in which antibiosis is operating. The detailed biology of whitefly, i.e. developmental period, survival, fecundity, longevity and sex ratio were studied under ‘no choice’ conditions, by confining the whiteflies in leaf cages. The study revealed that incubation period, nymphal developmental time, total developmental time, nymphal survival, total survival, fecundity and female longevity are the most important biological parameters for detecting the presence of antibiosis in resistant cotton genotypes against whiteflies. On the other hand, pupal period and survival, male longevity and sex ratio do not seem to play important roles in antibiosis. The combined effect of these parameters indicated that Gossypium arboreum genotype PA 183 was the most resistant while Bt 6304, TX Maroon 2–78 and F846 were the most susceptible ones. Other genotypes with moderate resistance include Supriya and LD 694.

Three transgenic maize hybrids, viz. Prabal YG, Hishell YG and Double YG, producing Bacillus thuringiensis (Bt) Cry1Ab protein (event Mon 810), were evaluated under field and laboratory conditions for their resistance to spotted stemborer Chilo partellus (Swinhoe). The Bt maize hybrids suffered less damage than their non-Bt iso-hybrids with respect to per cent plant infestation (0.0–0.6), leaf injury rating (1.0–1.1) and per cent stem tunnelling. These hybrids also resulted in significantly higher larval mortality (79.4–100.0%) in laboratory bioassays. The toxin protein produced in leaves was equally effective against neonates and 15-day-old larvae. Neonate larvae consumed less leaf area (5.0–13.8%) in case of Bt hybrids than their non-Bt iso-hybrids.

Neem products are often perceived as harmless to natural enemies, pollinators and other non-target organisms. For this reason, several integrated pest management (IPM) programmes have adopted neem as one of the prime components. This study revealed toxic effects of neem on soil-inhabiting and aerial natural enemies in chickpea to an extent of 41 and 29% population reduction, respectively, compared with 63 and 51% when using a conventional insecticide (endosulfan). Neem also affected the parasitization of Helicoverpa armigera (Hübner) larvae by Campoletis chlorideae Uchida up to 20%. The natural enemy population started building up from the vegetative phase and reached their peak during the reproductive phase, and there was a gradual decline from pod formation to pre-harvest phases of the crop. Adapting the currently used IPM system in chickpea using neem during the vegetative phase, followed by an application of Helicoverpa nuclear polyhedrosis virus (HNPV) at flowering and need-based application(s) of chitin inhibitors like novaluron or flufenoxuron instead of endosulfan during pod formation would strongly augment natural enemy populations. This paper discusses the relative toxicity of neem and other IPM components on soil-inhabiting and aerial natural enemies in the chickpea ecosystem.

A new aspirator is proposed for the collection of springtails (Collembola) and other small arthropods. It is hand operated, safe and efficient to use.