Sustainable pest management requires the use of ecosystem-friendly control options (e.g. entomopathogens) coupled with target-specific application methods. Here we investigate the susceptibility of the sorghum chafer (Pachnoda interrupta, Olivier) to Metarhizium sp., isolated from dead P. interrupta under field conditions over several years. Target-specific trapping was achieved using Japanese beetle traps or locally made autoinoculation devices, with methyl salicylate or banana as an attractant. Of the attracted and infected beetles, 49% mortality was achieved during October 2005 and 71% during July 2006, while the corresponding mortality in control treatments was 13 and 5%, respectively. We further confirmed that the mortality of the beetles was due to the fungal treatment as 50 and 80% of the dead beetles showed mycosis, respectively. The performance of the pathogen was also investigated in an autodissemination device in 2008 and 2009, where the beetles that were attracted passed through an inoculation chamber. Of the attracted and infected beetles in the autodissemination device, 58.5% (October) and 90.9% (July) were dead within 15 days after treatment. Control mortality was only 3 and 2%, respectively. The potential for horizontal transmission was investigated, where 47% (October) and 59% (July) of the beetles exposed to the pathogen through horizontal transmission were killed. The pathogen was found to be viable for more than 3 days in the field. Our results show that Metarhizium sp. has potential as a biological control agent, and for achieving autodissemination using the target pest as the vector.

We assessed the host stage preference and performance of the aphid parasitoid Diaeretiella rapae (McIntosh) on two aphid species, Brevicoryne brassicae (L.) and Lipaphis pseudobrassicae (Davis). Although the parasitoid parasitized all nymphal instars of both aphid species, it showed a higher oviposition preference for 2nd (48.2 ± 7.74%) and 3rd (41.0 ± 7.82%) instars of L. pseudobrassicae, and for the 3rd (40.0 ± 4.59%) instar of B. brassicae. Across the host species, there was no significant difference in parasitoid preference between the 3rd and 4th instars, while 1st and 2nd instars of L. pseudobrassicae were significantly more preferred than their counterparts (B. brassicae). Days to mummification among different instars of the same host was not significantly different when the parasitoid was reared on B. brassicae, whereas this was highest on the 2nd, 3rd and 4th instars of L. pseudobrassicae. Number of mummies was also significantly different among the nymphal instars of both host species and between the two host species for the 1st and 2nd instars. In terms of body size, female D. rapae reared on L. pseudobrassicae were significantly larger than those reared on B. brassicae. We discuss the findings in the context of laboratory mass rearing of D. rapae and its potential as a biological control agent for both aphid pest species.

Annual losses of cocoa in Ghana from mirids are significant; therefore, accurate timing of insecticide application is critical to enhance yields. However, cocoa farmers often lack information on the expected mirid population for each season to enable them to optimize pesticide use. This study assessed farmers' knowledge and perceptions of mirid control and their willingness to use forecasting systems informing them of the expected mirid peaks and the time of pesticide application. A total of 280 farmers were interviewed in the Eastern and Ashanti regions of Ghana with a structured open- and closed-ended questionnaire. Most farmers (87%) considered mirids the most important insect pest on cocoa, with 47% of them attributing 30–40% of annual crop losses to mirid damage. There was a wide variation in the timing of insecticide application as a result of farmers using different sources of information to guide the start of application. The majority of farmers (56%) did not have access to information about the type, frequency and timing of insecticide use. However, respondents who were members of farmer groups had better access to such information. Extension officers were the preferred channel for information transfer to farmers, with 72% of farmers preferring them to other available methods of communication. Almost all the respondents (99%) saw the need for a comprehensive forecasting system to help farmers manage cocoa mirids. The importance of the accurate timing of mirid control based on forecasted information to farmer groups and extension officers is discussed.

Glossina pallidipes, a widely but discontinuously distributed African savanna species, is one of the economically important tsetse flies because it is a vector of trypanosomiasis, a lethal disease of cattle and other domestic animals. DNA sequences of ribosomal (r16S2, 249 bp) and cytochrome oxidase I (COI, 421 bp) concatenated mitochondrial genes were analysed in 23 geographically diverse samples of G. pallidipes from Ethiopia, Kenya, Tanzania, Zambia and Zimbabwe. Among 873 flies, we detected 181 composite haplotypes and found that their spatial diversities and frequency distributions were heterogeneous. Haplotype and nucleotide diversities were greatest in Ethiopia and least in southern Africa. We observed little haplotype and nucleotide diversity among regions, and detected severely limited maternal gene flow among the sampled populations (ΦST= 0.42). Tests for demographic stability and analysis of mismatch distributions revealed regionally contrasting demographic histories. The Ethiopian populations were phylogenetically the oldest and genetically the most diverse, and exhibited successive waves of contraction and expansion. The southern African populations were phylogenetically the youngest and genetically the least diverse, and showed only a single, recent expansion. Likely ecological correlates of historical tsetse fly demography include population suppression trials in East Africa and recurring rinderpest epizootics in southern Africa, beginning in the late nineteenth century that reduced host mammalian populations.

A total of 39 strains of Anopheles stephensi, an important urban malaria vector, were collected from various parts of India and maintained in the insectary for this study. Based on the egg-float ridge number, 19 strains were classified into ecological variants and 32 strains were exposed to chlorpyrifos and propoxur to investigate their resistance status. Filter paper containing freshly laid eggs was taken, the ridge numbers on the floats were counted under the microscope, and strains were classified into ecological variants. Of the 19 strains, 18 were of ‘type form’, with ridge numbers ranging from 15 to 21. The Papareddipalya (PRP) strain belonged to the ‘intermediate form’, with 14 to 17 ridge numbers. Larval bioassays were carried out according to the procedure of the WHO. For chlorpyrifos, the lowest LC50 value was 0.00107 mg/l (Padmanabhanagar strain) and the highest value was 0.0403 mg/l (GOA-A strain). Furthermore, the lowest LC90 value was 0.00368 mg/l (Delhi strain) and the highest was 0.1746 mg/l (GOA-A strain). For propoxur, the lowest LC50 value was 0.00029 mg/l (Goraguntepalya strain) and the highest value was 0.0037 mg/l (JP Nagar strain). Moreover, the lowest LC90 value was 0.00094 mg/l (Goraguntepalya strain) and the highest value was 0.0115 mg/l (JP Nagar strain). The tolerance values ranged from 1.26 to 37.68 for chlorpyrifos and from 1.34 to 12.77 for propoxur. All the type forms were from urban and semi-urban locations, and the intermediate strain was from a semi-urban location. The bioassay results indicated that the strains of An. stephensi were more susceptible to propoxur than to chlorpyrifos.