Organosoluble extracts from 55 Turkish medicinal plants were tested under standardised conditions for biological activity against third-instar larvae of mosquitoes Aedes aegypti and Anopheles gambiae. Eight extracts demonstrated significant larvicidal activity, with An. gambiae being more susceptible than Ae. aegypti in all cases. The possibility of using indigenous plants for mosquito control is discussed.

The activity of five enzymes – amylase, α-glucosidase, cellulase, proteinase and lipase – present in the foregut, midgut and hindgut of the African variegated grasshopper Zonocerus variegatus (L.) was studied in the post-embryonic stages of the insect. The activities of all the enzymes increased with age of the insect, with the adult stage having significantly higher (P < 0.05) activity than the lower instars. The midgut had the highest activity for all the enzymes except for amylase. Proteinase activity was the highest, and cellulase the lowest in the gut regions. These findings indicate that the adult stage of the polyphagous insect has higher digestive capacity than the immature stages.

During 2007, phytophagous thrips on soybean (Glycine max Merr.) were collected, and differentiated according to sex, genus and species. Scouting for thrips was carried out on leaves and flowers in two consecutive plantings in Adjuntas, Isabela and Juana Diaz, Puerto Rico. A total of nine genera were found, of which eight species were identified. These included Frankliniella cephalica, Frankliniella gossypiana, Frankliniella insularis, Frankliniella schultzei, Caliothrips phaseoli, Neohydatothrips inversus, Rhamphothrips sp., Scirtothrips dorsalis and Thrips palmi. The last species was the most common in the three locations. However, F. schultzei was the most abundant species in Juana Diaz.

Inter simple sequence repeats (ISSR) and random amplified DNA polymorphism (RAPD) markers were used to estimate the genetic diversity among 14 tropical silkworm races (Bombyx mori L.) for identifying potential parents to be used for hybrid preparation for commercial exploitation. High polymorphism (70.91 and 74.70%) was revealed by ISSR and RAPD markers. The dendrograms generated, using unweighted pair group method using arithmetic average from these markers, grouped the 14 silkworm races into two major groups, which corroborates the differences in cocoon characteristics. Discriminant function analysis of ISSR and RAPD markers identified three functions for cocoon weight and two functions for shell weights, respectively. Step-wise multiple regression analysis identified six ISSR markers (834500, 8841700, 8841850, 8271500, 8401500 and 7891250) and seven RAPD markers (834500, 885900, 8101400, 884900, 8361500, 7891250 and 7621700) significantly associated with cocoon and shell weights. The genetically divergent parents, identified through this study, can be used for the preparation of hybrids for commercial utilization. Similarly, the DNA markers identified can be utilized for marker-assisted selection along with those identified through quantitative trait locus mapping by others. Thus the information generated in this study is useful in silkworm breeding programmes in the tropical sericulture industry.

In this study, a liquid larval diet as an artificial rearing medium was successfully tested for the Philippines fruit fly Bactrocera philippinensis Drew & Hancock. The biological parameters studied were pupal weight, adult emergence and fliers, sex ratio, fecundity and fertility. The insects performed most satisfactorily if corn (maize) oil was added to the liquid medium. Compared with the standard sponge ‘Kalle’ cloth, three locally available absorbent materials showed promise as a support matrix for feeding larvae.

Computer programming is ideal for the identification of ticks. This is due to the ability of computers to make rapid, repeated and complete searches of a large database of features in answer to a series of questions which lead to a single species. The program can allow the search to start in any order and to avoid difficult questions. It enables illustrations to be displayed when a question is asked. In contrast, classical dichotomous keys need to be used in a fixed sequence in which it is difficult to avoid questions, and often use vaguely defined characters and obscure language. To program an electronic key a character state matrix is constructed of rows of precisely defined characters with the two or more states in which they may occur and of columns in which the species are placed. Each state is recorded as being positive or negative. This corresponds to the binary system needed for computing and this need enforces a discipline on the identification method that has to define in illustrations and precise standardized language the characters and their states. These concepts are illustrated by the development of ‘Multikey’ program for the identification of ticks of domestic animals in Africa. The advantages of Multikey are its ease of use, its compatibility with comprehensive tick guides on compact discs and the ability to expand it with more information. The disadvantages are the requirement for a computer next to the laboratory microscope and the difficulty in browsing the contents. These disadvantages can be overcome by a printed version and there is use for both the printed and the electronic versions of such guides.

The moth Pareuchaetes pseudoinsulata Rego Barros, whose host plant is the invasive alien plant Chromolaena odorata (L.) King and Robinson, was recently discovered in Uson (6° 14′ 30.77″ N, 6° 04′ 41.37″ E), Evbuabogun (6° 15′ 39.33″ N, 5° 38′ 58.29″ E) and Ekae (6° 15′ 34.90″ N, 5° 37′ 19.75″ E) villages in southern Nigeria after its first release as a biological control agent in that country in 1972. The moth seemed to become more abundant as the rainy season progressed. Studies on some aspects of its biology and behaviour were conducted both in the laboratory and in the field. Females laid eggs on the undersides of C. odorata leaves and on the walls of rearing cages. Female pupae were significantly (P < 0.001) larger than the male ones. Also, adult female wingspan was significantly (P < 0.001) longer compared with that of the males. Adults lived for an average of 4.8 ± 0.01 days and they were active at night, when there was good light intensity. Observations on the behaviour and some aspects of the biology and behaviour are discussed.

The noctuid moth Helicoverpa armigera (Hubner) is the most damaging pest of chickpea worldwide. Plant resistance is an important component for the management of this pest. To develop cultivars with resistance to insects, it is important to understand the role of different components associated with resistance to insects. Therefore, we characterized a diverse array of chickpea genotypes for organic acid profiles in the leaf exudates that are associated with resistance to H. armigera. Chickpea leaf exudates contained five major organic acids that were identified as malic, oxalic, acetic, citric and fumaric acids. High-performance liquid chromatography (HPLC) profiles of the leaf exudates of nine chickpea genotypes showed that amounts of malic acid were negatively correlated with leaf feeding by H. armigera larvae at flowering and maturity, and with pod damage. Oxalic acid showed a negative association with leaf damage in the detached leaf assay. Additionally, the amounts of acetic acid were negatively correlated with larval weights and damage rating at the flowering and maturity stages. Citric acid levels were negatively associated with damage rating at the flowering stage. Implications of using the HPLC profiles of organic acids in the leaf exudates of chickpea to breed for resistance to H. armigera are discussed.

Zygogramma bicolorata Pallister is a potential biocontrol agent of Parthenium hysterophorus L. (Asteraceae). This study was carried out to understand the effect of abiotic (temperature and moisture) and biotic factors (age and reproductive status) on the induction and termination of diapause in Z. bicolorata. We also evaluated the effect of diapause on longevity and fecundity of Z. bicolorata. In Z. bicolorata the induction of diapause occurred between the months of July and December. No diapause was observed in May and June, which coincided with the commencement of the monsoon rains. The percentage of diapause induction in Z. bicolorata was found to increase from one generation to another as well as with the age of adults. Diapause significantly increased the fecundity of females as compared to the fecundity in pre-diapause conditions. Soil moisture (80% RH) played an important role in providing the conditions for initiation and termination of diapause. Similarly, 18.4 and 12.5% of diapause adults resumed their activity in 6 and 5 days when exposed to temperatures of 40° and 45° C for 2 h every day, respectively. Exposure of adults to low temperatures, i.e. 5° and 10° C induced 94.3 and 92.5% diapause, respectively, with no adult mortality. Thus, our findings reveal suitable conditions for preventing and inducing diapause in Z. bicolorata, which is of great importance in the suppression of P. hysterophorus. We discuss the implications of these findings in the control of P. hysterophorus.

Sorghum is one of the most important cereal crops in the semi-arid tropics. Several insect pests damage it. The possibility of identifying genotypes with multiple resistance to these pests and transferring the relevant genes into high-yielding varieties and hybrids has been considered as an attractive approach to reducing yield losses. A set of 12 cytoplasmic male-sterile and maintainer lines, 12 restorer lines and their F1 hybrids were evaluated for resistance to sorghum shoot fly Atherigona soccata Rondani, spotted stemborer Chilo partellus (Swinhoe) and sugarcane aphid Melanaphis sacchari (Zehntner) under field conditions. There were significant differences among the genotypes tested. A total of 50% of male-sterile lines, 41.7% maintainers, 58.3% restorers and 35.4% of the hybrids tested showed moderate to high level of resistance to the three pests. The male-sterile and restorer lines showing resistance to different insects can be exploited for developing hybrids with multiple insect resistance for cultivation by the resource-poor farmers in the semi-arid tropics.

The combination of a trapping system of insecticide impregnated screens and biconical traps followed by the release of sterile males led to the complete control of Glossina palpalis gambiensis and Glossina tachinoides in the agro-pastoral zone of Sideradougou. This area, situated south of Bobo Dioulasso, Upper Volta, in the Guinea savannah, covers an area of approx. 3000 km2. Along more than 650 km of rivers, bordered by gallery forests and infested by riverine tsetse, 6500 impregnated screens were placed during 4 months of the dry season, followed by the release of sterile males in the rainy season. For release purposes, colonies of 150,000 producing females of G.p. gambiensis and 85,000 females of G. tachinoides were maintained in industrial colonies on artificial membranes. Reinvasion of the project area was prevented by two barriers consisting of biconical traps impregnated with synthetic pyrethroid in one and simple biconical capture traps in the other. The screens reduced the initial fly population by 94% and permitted the release of only 35 sterile males per km of river to attain the planned ratio of seven sterile males to one wild male. Regular surveys showed that, after 4 months of release of sterile males, the relic fly population was constantly decreasing and tending towards disappearance.

An economic evaluation based on the production costs of the sterile males together with the costs of field operations showed that this combination of two non-pollutant methods was competitive with other methods of tsetse control.

The composition and preparation of an artificial diet for the coffee berry borer, Hypothenemus hampei is described. Ten generations were obtained without any significant change in fecundity. Development at 25°C on this diet was similar to previously reported work using coffee berries. One female reared on this diet lived for 380 days. This diet will permit investigations into the genetics of insecticide resistance, potential biopesticides and other research, requiring a convenient laboratory rearing system.

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.

Seven species of stored grain pests were found infesting underground storage pits “bakars” in the Bay Region of Somalia. These species and their relative abundance (%) in “bakars” are as follows: Alphitobius laevigatus (Fabricius) (Coleoptera, Tenebrionidae) (3.7%), Palorus subdepressus (Wollaston) (6.1%), Tribolium castaneum (Herbst) (29.2%); Rhizopertha dominica (Fabricius) (Bostrichidae) (23.9%); Sitophilus oryzae (Linneaeus) (Curculionidae) (4.7%); Cryptolestes ferrugineus (Stephens) (Cucujidae) (32.4%); Sitotroga cerealella Oliver (Lepidoptera, Gelechiidae) (unsampled). The mean percentage damage by insects for the region was 10.4 and by rats was 8.4 for sorghum grain stored as heads in 100 “bakars”. Actellic, K-Othrine and Malathion, applied as a 2% dust to threshed durra sorghum grain stored in sacks above ground, provided 99.2, 99.5 and 94.5% control, respectively.

Volatile oils of Citrus sinensis, Ageratum conyzoides, Cymbopogon citratus, Callistemon rigidus and Ocimum gratissimum were tested as repellents against blackfly, Simulium damnosum s.l., the vector of human onchocerciaisis. Topical applications of 10 and 20% v/v concentrations of the oils with liquid paraffin as the carrier, were made on the forearms and legs of four volunteers, with ordinary paraffin oil used as the control. At 10% v/v concentration the protection time was between 30min and 1h with the Citrus, Ageratum, Cymbopogon and Callistemon oils. At 20% Citrus, Ageratum and Cymbopogon oils repelled the blackflies for up to 2h while Callistemon and Ocimum oils were effective for 3h. Application of these volatile oils, especially at the peak biting periods, would serve to reduce human–vector contact and thereby limit disease transmission.

Cutaneous leishmaniasis (CL) has become an important health problem in Sri Lanka. Dickwella Divisional Secretariat Division (DSD) located in southern Sri Lanka has been identified as a highly endemic focus for CL. However, to date, the potential sandfly vectors of the Leishmania parasite causing CL have not been elucidated in this focus. This study aimed to determine the species composition and population dynamics of sandflies prevalent at three sampling stations representing different ecological conditions in two high-risk areas in Dickwella DSD, over a period of 27 consecutive weeks. Resting sandflies (i.e. indoor collection) were collected from the lavatories of human households using Castro aspirators at weekly intervals. In addition, cattle-baited traps were deployed at bi-weekly intervals to capture foraging sandflies (outdoor collection). Sergentomyia zeylanica Annandale was found to be the only sandfly species and hence was considered as the potential vector of the Leishmania parasite that causes CL. As a whole, 84 and 96% of the sampling occasions were positive for resting and foraging sandflies, respectively. Seventy-six per cent of the lavatories sampled contained sandflies regardless of the sampling station. Altogether, 34,481 sandflies were captured from lavatories, whereas 691 were collected in cattle-baited traps. The ecological habitat, which comprised dense vegetation and a stagnant water body, seemed to be highly productive for this sandfly species. However, dryness and heavy rains negatively affected its population density. The sex ratio of the sandflies was male-biased at 1:2 (females:males). The findings of this study suggested that the management strategies of S. zeylanica could be targeted on lavatories especially after moderate rains.

The influence of solitary versus group rearing on the development and survival of the three-striped ladybird beetle Brumoides suturalis (Fabricius) was studied using two aphid species, Acyrthosiphon pisum (Harris) and Aphis gossypii Glover, as diet. Rearing pattern (solitary or group) had no significant influence on the success of rearing, but prey species did. While immature stages developed faster on A. pisum, the survival of early instars was higher on A. gossypii. Diet had no effect on pupal survival.

The growing recognition of problems associated with chemical pesticide use has led to increased attention on integrated pest management (IPM). This paper describes how Tunisian potato farmers have learned to manage an important field and postharvest insect pest, the potato tuber moth, Phthorimaea operculella (Zeller), and how interdisciplinary research on integrated pest management has contributed to this process. During the 1980s, new pest control technology and better farmer awareness led to changes in how farmers manage the potato tuber moth in their fields and stores. Farmers reduced insecticide treatments in potato fields and made more use of agronomic practices to avoid crop losses from the insect pest. New government regulations and agricultural extension efforts have caused farmers to discontinue use of environmentally harmful chemicals such as DDT. Research is continuing on biological insecticides that are not toxic to mammals and some farmer adoption of these products has occurred.

Neem oil (NO), and different formulations of neem oil in a solution of Tetrapleura tetraptera as emulsifier, including neem oil emulsifiable concentrate (NOEC), neem oil slurry emulsifiable concentrate (NOSEC) and 5% NOEC obtained from the seeds of the neem plant, were tested for their efficacy in the control of Maruca testulalis Geyer, under laboratory conditions using flowers of Ife Brown, cowpea variety.

The different concentrations of NOEC (5, 10 and 20%) exhibited a high degree of insecticidal activity on M. testulalis larvae. All the treated flowers were protected from larval damage 2 days after treatment as compared to the 100% damage recorded on untreated flowers and on the flowers treated with T. tetraptera solution alone.

The NOSEC and the 5% NOEC prepared using different volumes of the emulsifier also exhibited some insecticidal activity which decreased with a decrease in concentration. NO/NOEC were superior to NOSEC and the 5% NOEC prepared in different volumes of the emulsifier.

The objective of the present study was to evaluate the larvicidal potential of the α-amylase inhibitor from the seeds of Macrotyloma uniflorum (Lam.) Verdc. against Aedes aegypti (L.) larvae. Macrotyloma uniflorum α-amylase inhibitor (MUAI) was partially purified using ion exchange chromatography on a carboxymethyl cellulose column. MUAI at concentrations of 20, 60, 100 and 200 ppm was tested against different instar larvae, pupae and adults of A. aegypti to establish its bioefficacy. MUAI showed a strong larvicidal and a moderate adulticidal effect at a concentration of 200 ppm but did not exhibit pupicidal and ovicidal activities. MUAI-treated larvae showed lower α-amylase activity. MUAI also exhibited ovipositional deterrence activity. Dose-dependent mortality was observed, being highest in the first and second instar larvae. The results thus obtained provide a safe and eco-friendly means in the biological control of A. aegypti larvae.