Rather than a true adaptive process, laboratory colonization is proposed to depend on the plasticity of the tolerance limits in insect species. Insects will establish successfully in captivity if the magnitude of environmental variables are within the insects' ranges of colonization. Optimum physiological and behavioural responses are obtained when the variables are within the smaller preferred range of colonization. Other concomitant processes at colonization are selection, acclimatization and domestication. Definition of the terms “adaptation”, “acclimatization” and “domestication”, commonly misused in describing processes during laboratory colonization are proposed.

The application of the sterile insect technique to fruit flies involves the mass-production of the pest insects using an artificial diet, irradiation during a narrow time window at the late pupal or early imaginal stage to inhibit reproduction without affecting reproductive capacity, and then release into the target area where the sterile insects compete reproductively with their wild counterparts. The timing of irradiation is important to enable the release of males that are sterile but of good quality and exhibit an acceptable sexual performance. In this study, we examined the pupal development of 12 tephritid (Diptera: Tephritidae) species: Anastrepha fraterculus (Wiedemann), A. ludens (Loew), A. obliqua (Macquart), A. serpentina (Wiedemann), Bactrocera cucurbitae (Coquillett), B. dorsalis (Hendel), B. invadens (Drew, Tsuruta & White), B. oleae (Rossi), B. philippinensis (Drew & Hancock), B. tryoni (Froggatt), B. zonata (Saunders) and Ceratitis capitata (Wiedemann). The insects were reared at various temperatures, in the laboratory (15–28 °C) and under fluctuating natural conditions (20–35 °C). The gradual colour changes of the insect eyes during metamorphosis were observed and photographed, measuring the specific eye colour parameters of each species and matching them with the colour scale of the Munsell Soil Color Charts. The duration of pupal development and the time to emergence in Anastrepha species were longer than those in C. capitata and Bactrocera species at all the holding temperatures. The data obtained can be used by mass-rearing facilities to manage pupal holding conditions and as indicators for optimizing the timing of irradiation.

The fumigant toxicity, ovicidal and oviposition-deterrent potential of the essential oil of Indian dill, Anethum sowa and its three major fractions against the grain beetle Callosobruchus maculatus (Coleoptera: Bruchidae) on chickpea were investigated. Two fractions produced 100% mortality of adult beetles at 3.0 μl/ml dosage, whereas the essential oil was the least effective. Fraction III was 100% ovicidal at a 70 μl/ml concentration. The essential oil and fraction III both completely deterred oviposition at the lowest concentration tested, 10 μl/ml. Neither the essential oil nor its fractions had any significant effect on chickpea seed germination.

The parasitic wasp Anisopteromalus calandrae (Howard) was released at six (5, 10, 20, 30, 40 and 50 pairs) densities to evaluate the effects of different introduction rates in controlling residual populations of the lesser grain borer Rhyzopertha dominica (Fabricius) in wheat grain stored in bulk in 46 m2 rooms. At the 50-pair density, the parasitoid suppressed 83% of R. dominica in June–July and 74% in August–September. At the 5-pair density, the numbers of F1 progeny per female were 44 and 51, during the first and second period, respectively while at the 50-pair release rate, only 6 and 7 individuals were recorded, respectively. In a second test, the effects of different materials used for storing were evaluated on both insects. Five hundred (500) grain-residing 20–22-day-old R. dominica larvae were mixed with 250g fresh wheat stored separately in each of five types of bags, i.e. jute, calico (Americana cloth), polypropylene, polythene, nylon, then exposed to 50 pairs of A. calandrae. The parasitoid suppressed host populations in all types of bags, except in those made of polythene. The highest percentage (69 and 81%) suppression occurred in calico bags during the June–July and August–September periods, respectively. The lowest suppression of 51 and 57% was observed for polypropylene bags during the respective periods. The parasitoid-induced mortality was positively correlated with the parasitoid density.

Five natural compounds possessing antiparasitic activity were isolated from East African plants and tested, together with some semisynthetic derivatives, against micro-organisms and arthropods of agricultural interest. Anonaine (1), from Annona squamosa, canthin-6-one(8) and 5-methoxycanthin-6-one (9), from Fagaropsis angolensis, showed fungicidal activity. E,Z-matricarianol (4), from Hoehnelia vernonioides was fungicidal, Insecticidal and acarlcldal. Caryophyllene oxide (12), isolated from Uvaria sp., turned out to be insecticidal and antifeedant. Canthin-6-one (8) and its dihydroderivative 11 were the most effective antimicrobial compounds tested. The possibility ofusing some of the isolated compounds as leads for new synthetic chemicals is discussed.

Yield losses from insect pests were determined by the insecticide check method in 60 crops in the Philippines from 1976–1986 in three rice environments with traditional and modern cultivars in 10 sites. Plot size of 100 m2 minimized interplot interference from insecticide protection on untreated plots. Low and high crop losses were recorded across sites in drylands (2–39%, = 25%), rainfed wetlands (13–24%, = 21%), and irrigated wetlands (5–40%, = 18%). Weighted crop loss for the Philippines based on production by environment and cultivar type averaged 18.3% or 0.57 t/ha per crop. Consistently greater yield loss occurred in the vegetative (50%) than reproductive (30%) or ripening (20%) stages across environments and cultivars. No epidemics affected the trials therefore crop losses were those from chronic pests. The major chronic pests in the wetlands were stem borers, leaffolders, whorl maggot, and rice bug; and in the drylands were ants, seedling maggots, white grubs, leaffolders, stem borers and rice bug. Yield loss variability was greater between fields than crops or sites, therefore a control strategy based on corrective actions when pest numbers reach threshold levels is more efficient than prophylactic actions. Yield loss was more in early maturing cultivars stressing the importance of compensation in tolerating insect damage. Insect stresses perhaps can be compensated by total crop management to increase the plant's ability to tolerate insect damage.

A study was conducted at Mtwapa in the northern coastal area of Kenya during the long and short rainy seasons of 1999 and 2000 to assess the benefits of agroecosystem diversification—through agroforestry and intercropping—on the activity of natural enemies of maize stemborers. Treatments consisted of maize and cowpea intercrops or maize monocrops planted within hedgerows of Leucaena leucocephala and Gliricidia sepium. The plots were mulched or unmulched and insecticide-treated or not. The maize stemborers encountered, in order of abundance, were Chilo partellus, Chilo orichalcociliellus and Sesamia calamistis. The egg parasitoids Trichogramma spp. and Telenomus spp. were recovered from stemborer eggs. Ants, ladybird beetles, earwigs and crab spiders were found predating on the eggs. The larval parasitoids recovered included Cotesia sesamiae, Cotesia flavipes and Goniozus indicus, and the pupal parasitoid was Pediobius furvus. Mean rates of stemborer egg parasitism were generally high (>70%) while larval and pupal parasitism rates were low (<10%) for all the treatments. The observed rates of parasitism did not support the natural enemies hypothesis, which predicts that natural enemy activity increases with increasing agroecosystem diversity. Predation, larval and pupal mortality rates were generally low in all the treatments (<10%), with no significant differences between treatments.

Little is known about phase polymorphism in the red locust, Nomadacris septemfasciata (Serville) in Madagascar, despite its economic importance. Only solitary and transiens forms have been reported from the island earlier, but not the gregarious form. Important recent outbreaks have allowed for the studying of the phase polymorphism under experimental and field conditions. Morphometric differences (pronotum size and shape, and F/C and E/F ratios) were noted among hoppers and adults caged for several generations and at various densities, in a field laboratory. These criteria were later used to study adults collected in different areas between 1996 and 2002, from populations with various densities (<1000 to >25,000 imagos/ha). Morphometric measurements revealed that gregarious red locust populations have existed naturally in Madagascar and that these were erroneously classified as transiens forms. The upper threshold density for the solitary phase was estimated at 5000 adults/ha; beyond this limit, locusts develop either into transiens or into highly gregarious forms. The southern part of the island, known as a red locust outbreak area, has harboured gregarious phases despite previous reports that prevailing ecological conditions are not suitable for its complete phase transformation. Deforestation in the northern part of the island has probably led to new favourable biotopes for serious outbreaks and gregarious populations development.

Attempts have been made in recent years to reduce the use of synthetic pesticides and seek alternative and innovative methods for pest control. We conducted a study on the chemical composition of Eucalyptus occidentalis essential oil and investigated the fumigant, contact and repellent effects against Tribolium castaneum (Herbst) (Col: Tenebrionidae) and Rhyzopertha dominica (F.) (Col: Bostrichidae). The major components were τ-cadinol (17.20), 1,8-cineol (15.5%), α-cadinol (14%) and α-pinene (9.21%). The contact toxicity experiment showed that the oil was more toxic to R. dominica (LD50 value 0.82 μL/cm) than to T. castaneum (LD50 value 0.99 μL/cm) and showed the same fumigant toxicity for both insects according to the 95% confidence limit of LC50. The repellency against T. castaneum was more than for R. dominica and increased from 14 to 75% for R. dominica and 22 to 78% for T. castaneum after 2 h. These results suggest that E. occidentalis essential oil is a potential candidate for use as a natural repellent and insecticide for stored-product insect pests.

The effects of sublethal concentrations of the insect growth regulators (IGRs) diflubenzuron and methoprene on some fitness components of an Aedes aegypti (L.) population in south-eastern Brazil were investigated. The fourth instar larvae of the mosquito were exposed to 20 ppb methoprene and 3 ppb diflubenzuron, and adult survivors were evaluated for fitness parameters, including body size and biomass, fecundity, fertility, longevity and symmetry. The sublethal concentrations had negative effects on longevity, but biomass, fecundity and fertility were not affected by either IGR. In separate experiments, A. aegypti individuals' surviving concentrations of 2, 3 and 3.5 ppb diflubenzuron and 5, 10 and 20 ppb methoprene were used for morphological analyses (size and symmetry). Diflubenzuron had negative effects on the mosquito's body symmetry. The observed decreases in longevity and symmetry may have negative impacts on the population dynamics of A. aegypti.

Red palm weevil Rhynchophorus ferrugineus Olivier is a key pest of date palm in the Kingdom of Saudi Arabia. Since 1994, the Ministry of Agriculture has implemented a pheromone-based integrated pest management (IPM) strategy to control R. ferrugineus in the Kingdom. Geographic information system (GIS) technology can serve as a valuable tool to assess insect activity and in addition the impact of the control strategy. We used GIS-based techniques to ascertain the spatial and temporal spread of R. ferrugineus in 234 ha of date plantation in Al-Sohemia-1 in the Al-Ahsa region of Saudi Arabia. One hundred and fifty six pheromone (Ferrolure™) traps in Al-Sohemia-1 were logged using the Trimble global positioning system to determine the east longitude and north latitude of each pheromone trap and transformed to the GIS as a shape file. The spatial and temporal variations for R. ferrugineus activity based on captures in pheromone traps were studied for each of the four seasons of the year and also year-wise during 2009 and 2010. Results revealed that during both 2009 and 2010, maximum weevil activity was recorded during late spring and early summer, with captures declining during autumn and winter. Spatial variations in the activity of R. ferrugineus indicated that in general 2009 registered lower weevil activity compared with 2010. Furthermore, most of the area exhibited medium to very high weevil activity in spring and summer during both 2009 and 2010, while most of the area recorded very low to low weevil activity during the autumn and winter seasons of both the years. The ongoing R. ferrugineus-IPM programme in Al-Ahsa needs to be strengthened in areas showing high to very high weevil activity.

Experiments were performed to evaluate the effectiveness of a semi-synthetic diet developed from locally available ingredients in Saudi Arabia for the laboratory rearing of the red palm weevil Rhynchophorus ferrugineus Oliv. The diet was developed based on existing literature, in addition to screening for a number of ingredients from locally available materials. Maize flour, wheat flour, shredded date palm frond tissue and distilled water were chosen as the final ingredients for the diet. Red palm weevils were successfully reared on this semi-synthetic diet and these ingredients were found capable of supporting larval development. However, larval weight decreased on this diet. The larval growth rate on the semi-synthetic diet was comparable to the standard growth rate achieved on date palm. One additional larval instar was observed on the diet. No significant differences were observed in the tested behavioural parameters between females fed the semi-synthetic diet versus those fed the natural diet. In conclusion, red palm weevils can be successfully reared on this semi-synthetic diet, and further optimization of it is warranted.

We studied the behaviour of three Anastrepha spp. (Diptera: Tephritidae) that were attracted to protein hydrolysate in glass McPhail traps, hung on an 8 m tall wild mango tree, Mangifera indica at three different heights. Out of 665 flies that landed on the exterior of the trap only 31 % were caught. Females represented 60.2 % of all flies trapped. The intermediate trap hung at 5m caught the most flies (57.5%). We observed a great deal of feeding activity (on trap, leaves, branches and fruit) including régurgitation and reingestion of liquid food droplets. When not on the trap surface, flies were more commonly seen on leaves than on branches and fruits. Inter- and intraspecific encounters between all Anastrepha spp. and both sexes were commonly recorded. Males were observed calling alone or in leks. All leks were formed on leaves and on two occasions included individuals of two species. Our observations suggested that the McPhail traps attracted different Anastrepha spp. with varying degrees of intensity.

The survival of female Anopheles gambiae s.s. mosquitoes inside two village house types (grass-thatched and iron-roofed) was studied in relation to diet and ambient indoor microclimatic conditions. Two batches of 20–30, 1-day-old laboratory-bred mosquitoes were maintained inside cages in the grass-thatched (n=2) and iron-roofed (n=2) houses and fed daily, one group on 10% glucose and the other on human blood. Throughout the experiments, indoor temperature and relative humidity of the houses were recorded, and mortality of mosquitoes monitored daily until all had died. The experiments were replicated thrice. There was no significant variation in the overall mean temperature (P=0.93) or relative humidity profiles (P=0.099) between the two house types, although the iron-roofed houses recorded higher temperature peaks. A Kaplan–Meier survival analysis showed that the mean survival times of mosquitoes were 8 and 10 days in the two grass-thatched huts and 7 and 10 days in the two iron-roof houses for mosquitoes feeding on blood and sugar meals, respectively. The mean survival times of mosquitoes maintained inside similar house types differed only due to diet. In the proportionality of hazards model (Cox regression), the dietary regimes significantly influenced the probability of survival (P=0.0001), with mosquitoes surviving longer on sugar meals than on blood. Microclimatic factors inside houses also significantly influenced mosquito survival. Although higher peak temperatures were recorded in corrugated iron-roofed houses, the survival of the mosquitoes resting in them did not differ significantly from that in grass-thatched houses. However, the impact of these temperatures on the development of malaria parasites inside the vector needs to be investigated.

The historical account of the rise and fall of Nosema locustae as a biological control agent of grasshoppers has substantial implications for the successful development and implementation of biological control of migratory locusts in Africa. The potential of N. locustae was ultimately not sufficient to overcome a set of impediments, including: efficacy (the rate and extent of mortality were relatively low), target specificity (not all pest species were susceptible), formulation (wheat bran bait excluded feeding by some pests), cost (the price of the formulated product was excessive), storage (the organism lacked long-term stability), complex application (the pathogen and its carrier had to be applied during a narrow set of environmental and logistical parameters) and production (the use of an in vivo production system made high-volume production difficult). Some of the most significant limitations that led to the failure of N. locustae have been overcome by work on other pathogens, including the problems of formulation, storage, efficacy and production. However, at least four relevant lessons can be derived from the N. locustae story and applied to ongoing work with biological control of migratory locusts. First, the erratic population dynamics of acridids necessitates that the production, storage and distribution of an augmentative biological control agent will be driven by a boom-and-bust cycle. Second, the immense spatial scale and low unit value of the resources (rangelands) being protected create a unique set of logistical challenges. Third, the control of acridids involves the management of a native insect pest embedded within complex, native ecosystems, which suggests that our interventions should be undertaken with a great deal of caution, monitoring and, ultimately, humility. Fourth, although pathogens can be used as ‘bio-insecticides’, biological control requires education of end-users regarding a more sophisticated approach to pest management.

1,8-cineole, one of the components of the essential oil of Artemisia annwa, was evaluated for repellency and toxicity against three stored product coleopterans—Callosobruchiis maculatus F. (Coleoptera: Bruchidae), Rhyzopertha dominica F. (Coleoptera: Bostrychidae) and Sitopliilus oryzae L. (Coleoptera: Curculionidae). It was found to be moderately repellent to all three species, with a mean repellency in the range of 65–74% at the highest dose tested (4.0 μl/ml) within 1h. A contact toxicity assay revealed that direct topical application was more effective than using impregnated filter paper. The compound was more effective as a fumigant and gave 93–100% mortality against all the three pest species at the dose of 1.0 μl/l air under empty jar conditions as compared to treatment of jars filled with grain (11–26% mortality). The lethal dose and lethal concentration required to kill 50% of the beetles (LD50 and LC50) respectively varied.with the toxicity assay method. LD50 values of 0.03, 0.04 and 0.04 μl/insect against C. maculatus, R. dominica and S. oryzae respectively were found in the topical application assay while the LC50 in the fumigant assay was 0.28, 0.33 and 0.46 μl/l against C. maculatus, R. dominica and S. oryzae respectively.

Résumé: —L'un des composés de l'huile essentielle d'Artemisia annua, le 1,8-cineole, a été évalué pour sa répulsion et sa toxicité vis à vis de trois coléoptères des denrées stockées, Callosobrnchus maculatus F. (Coleoptera: Bruchidae), Rhyzoperta dominica F. (Coleoptera: Bostrychidae) et Sitopliilus orizae L. (Coleoptera: Curculionidae). Il s'est avéré être modérément répulsif pour les 3 espèces, avec une répulsion moyenne de 65–74% à la plus forte dose testée (4.0 ml/ml) pendant 1 heure. Un essai de toxicité de contact indique qu'une application locale directe est plus efficace que l'utilisation d'un papier filtre imprégné. Le composé est plus efficace en fumigation et provoque 93–100% de mortalité chez les trois espèces de ravageurs à la dose de 1.0 ml/l d'air dans un pot vide par rapport à un pot rempli de grains (11–26% de mortalité). La dose létale et la concentration létale requises pour tuer 50% des scarabées (LD50 et LC50 respectivement) varient avec le type d'essai de toxicité. Des valeurs de LD50 de 0.03, 0.04 et 0.04 ml/insecte pour C. maculatus, R. dominica et S. oryzae respectivement ont été trouvées dans l'essai avec une application locale alors que la LC50 dans l'essai de fumigation était respectivement de 0.28, 0.33 et 0.46ml/l pour C. maculatus, R. dominica et S. oryzae.

Difficulties of identification of natural enemies of cereal stemborers for ‘redistribution’ in Africa are discussed. Tritrophic level studies on wild and cultivated habitats of borers and beneficial species are needed to judge the impact of a natural enemy species in the cropping system. Areas with low pest pressure which are climatically favorable for pest development may be selected for study. Based on the results of various countrywide surveys to map the relative importance of Sesamia calamistis Hampson, Eldana saccharina (Walker) and Busseola frisca (Fuller) in western Africa, recommendations are given for sites for tritrophic level studies. It is hypothesised that because maize is not always present in the field and because of its high susceptibility, natural biological control has to come from wild habitats. This emphasises the importance of the knowledge on the wild host-plant range. Survey results complemented with oviposition and life-table studies in the laboratory showed that, rather than being reservoirs for pests, most wild grass species act as trap plants causing mortalities of 100%. A comparison of light trap catches with pupae found on wild hosts and the scarcity of known wild hosts in areas with high pest pressure suggest gaps in our knowledge of the range of host plant species. Based on comparison of known natural enemy complexes in East and West Africa, the scelionid egg parasitoid Telenomus isis and an East African strain of the braconid larval parasitoid Cotesia sesamiae (Cameron) are proposed for redistribution against B. fusca and S. calamistis, respectively. Telenomus isis has never been reported from East Africa whereas G sesamiae is common in East and southern Africa and scarce in western Africa, suggesting that G sesamiae is probably not adapted to S. calamistis and B. fusca in this region.

Dengue vector control programmes are mainly focused on insecticide fogging/space spraying to control adult Aedes mosquito vector populations. Due to the diurnal habit of the vectors, spraying is routinely conducted during the day when many other insect species are also active. This study reports the simultaneous effect of fogging on non-target insects by direct counting of knockdown in the insect population. Eight fogging treatments were conducted in two sites in Kurunegala District of Sri Lanka. Pesguard insecticide was sprayed in each treatment for 8 minutes according to the standard methodology and the ‘knockdown insects’ were collected on randomly spread polyethythene sheets (10 m2). A total of 3884 insects (24.3 insects per treatment per m2) belonging to 12 orders were collected and 12.44% of them recovered during a 24-hr recovery period. Diptera was the most affected insect order (36%) followed by Collembola (30%) and Thysanoptera (17%). Out of the 31 mosquitoes (<1%) collected, only two (<0.1%) belonged to the genus Aedes. Body length of 93% of the affected insects ranged from 0.35 mm to 1.8 mm. Positive controls using the WHO standard cage bioassays with the mosquito Ae. albopictus (n = 417) and the stingless bee Trigona iridipennis (n = 122) showed 100% initial knockdown, and 83.5% mosquito and 93.5% bee mortalities after the recovery period. The study shows that insecticide fogging does have a severe effect on non-target insects such as pollinators; therefore, fogging operations should be done in a controlled manner and indiscriminate fogging should be avoided.

A comprehensive review of the acquisition of resistance in bovine and laboratory hosts as a result of natural infestation with various species of ticks is undertaken. In this review I discuss the biological aspects of the expression of resistance, deal with acquisition of resistance to ticks by bovine and laboratory animals, give details on the environmental and physiological factors which affect the resistance and explain the mechanisms of resistance in both bovine and laboratory animals. I also deal with the relationships between ticks and their bovine hosts and emphasize the difference in the acquired resistance of individuals in the breed as well as the negative correlation between the decrease in mean weight of the ticks and the increase in the levels of globulins in the serum of the different hosts.

Aspects of cross resistance by hosts to different species of ticks are also discussed in this review.

The tea mosquito bug Helopeltis theivora (Waterhouse) is an important economic pest of tea in India. The development of resistance in H. theivora populations obtained from a conventional plantation and an organic plantation was studied in the laboratory for five generations, and associated changes in life cycle traits were assessed. Selection using sub-lethal concentrations of endosulphan resulted in a 4.4-fold increase in insecticide resistance ratio from the F1 to the F5 generation in the H. theivora population from the conventional plantation. By the F5 generation, nymphal duration was higher and fecundity was lower in the endosulphan-selected strain than in the non-selected strain from a conventional plantation and the susceptible strain from an organic plantation. These findings have practical implications for insecticide resistance management of this important sucking pest of tea.