The South American fruit fly Anastrepha fraterculus (Wiedemann) is an important pest in many countries. The sterile insect technique is an effective method of controlling Ceratitis capitata (Wiedemann) in Argentina and has been proposed for use against A. fraterculus. Because this technique relies on sterile mass-reared males mating with wild females, it is essential to verify that artificial rearing does not reduce male mating competitiveness. Several morphometric characters were evaluated to detect differences between a wild population and a laboratory strain that was derived from it and reared artificially since 1997. Eight morphometric traits were analysed as indicators of body size, head shape and potential mobility: Thorax Length, Head Width, Face Width, Eye Length, Wing Length, Wing Width, Third Tibia Length and Femur Length. The results were analysed using multivariate analysis of variance, linear multiple regression and logistic multiple regression. In general, laboratory flies were larger than wild ones (possibly because the larval diet was supplied ad libitum). Laboratory males had significantly larger Head Width and Eye Length and a smaller Wing Width than wild males. Laboratory females differed from wild ones only by having narrower wings. These results could be due to environmental and genetic factors, or as a consequence of genetic drift (for the latter) during colony establishment plus gradual adaptation to laboratory conditions, where flight ability is most likely less important (resources are found easily at close distances). Also, short-distance interactions among individuals are more frequent in a colony, possibly favouring increased facial trait sizes by sexual selection. Because long-term morphological changes could represent the beginning of intraspecific differentiation, they should probably be worthy of some consideration if a large mass-rearing colony is established.

Nucleopolyhedrovirus (NPV) was isolated from infected Hyposidra talaca (Walker) caterpillars. This defoliating pest was sampled from the Terai and Dooars tea plantations along the foothills of Darjeeling, India. Phase contrast and transmission electron microscopy revealed polyhedral occlusion bodies (OBs) typical of NPVs. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis showed that the molecular weight of the major protein of the OBs is 32.17 kDa. Dose–mortality bioassays conducted for OBs on the second instar caterpillars of H. talaca resulted in a median lethal concentration (LC50) of 2.8 × 103 OBs/ml. The median lethal time (LT50) was 5.45 days for 1 × 104 OBs/ml, 4.15 days for 1 × 105 OBs/ml and 4.05 days for 1 × 106 OBs/ml concentrations. These results indicate the potential of using this NPV as a microbial pesticide against H. talaca.

Aqueous extracts of Tephrosia vogelii and Hyptis suaveolens, and of oils of Azadirachta indica and Jatropha curcas, as well as the pesticide Furadan 5G were evaluated for their insecticidal activity against the maize cob borer Mussidia nigrivenella Ragonot in laboratory and field experiments. In general, treated plants had a strong deterrent effect on ovipositing M. nigrivenella. The oviposition deterrence index was highest with neem oil at both concentrations, J. curcas at 5% and H. suaveolens at 20%. In addition, neem and Jatropha oils adversely affected egg hatch; it decreased with an increase in concentrations of oil emulsions and varied between 3 and 25.5% for neem and 6 and 16% for J. curcas. The lethal concentration 50 values calculated were 1.3 and 0.8%, respectively, for neem and J. curcas. By contrast, larval survival was not affected by the oil treatments. In the field, Furadan, neem and J. curcas oils significantly reduced the number of M. nigrivenella larvae by 16–49.2%, while aqueous extracts of T. vogelii and H. suaveolens were similar to the emulsified water control. The treatments did not significantly influence cob weight, and only neem oil at both concentrations and Furadan significantly reduced cob damage and consequently grain losses. These results showed that oil emulsions of A. indica and J. curcas oils act not only as an oviposition deterrent but also as ovicides. The prospects for possible inclusion of botanicals into integrated M. nigrivenella control in maize cropping systems are discussed.

Three new species of braconid wasps from Costa Rica are described here: Allorhogas crinitus reared from leaf galls on Protium panamense (Burseraceae), Allorhogas lacuna reared from galls on Melastomataceae and Allorhogas triopsis reared from fruit galls on Psychotria (Rubiaceae). These new species are diagnosed and compared with other species in the genus. These are the first records of an Allorhogas species associated with the plant families Burseraceae and Rubiaceae. It is the third association of Allorhogas with the family Melastomaceae.

Studies were conducted for the first time on the gregarious endoparasitoid, Apanteles taragamae Viereck (Hymenoptera: Braconidae) to determine its biology on Diaphania indica (Saunders) (Lepidoptera: Pyralidae). The mean number of eggs laid per host was 24.63 and these eggs increased greatly in size before hatching. Larva passes through three instars as determined by the shape and size of the mandibles. Mean development time from egg to adult was 15.6 days at 24.26°C and 80–85% r.h. The mean number of adults emerging from each host was 14.61 and the sex ratio was 1:1.31 (males:females). The mean number of eggs laid by each female was 242.6. Mean adult longevity on 20% honey was 9.30 days for males and 10.70 for females.

An experiment was undertaken at two locations in Nigeria to identify the major insect pests of cowpea, assess the yield losses caused by them and recommend profitable control packages. Various combinations of insecticidal applications were tested at four crop growth stages, in conjunction with varieties possessing moderate levels of resistance to one or two insect pests. Flower thrips were the most important pests, followed by pod sucking bugs and foliage pests. The resistance levels of the varieties did not contribute much to reducing yield losses. Yield losses of upto 75% were caused by insects attacking cowpea during the flower bud and flowering stages, and of 23% by insects attacking during pod development. Insects attacking during the foliage growth stage had little effect on yields. Profitable spray schedules which increased yields by about 50–200% were: three sprays at flower budding, flowering and podding (the optimum), the sprays at either flower budding and flowering or flower budding and podding depending on the location, and one spray at either flower budding or flowering stage. Other spray combinations were also viable, but less profitable. Appropriate recommendations for various categories of farmers are given.

The behavioural responses of adult female western flower thrips, Frankliniella occidentalis (Pergande) to volatiles from meadow-sweet (Filipendula ulmaria), bay laurel (Laurus nobilis) and sage (Salvia officinalis) were investigated in laboratory bioassays. Volatiles collected by entrainment of a solvent extract of F. ulmaria were more attractive than was the original extract. Frankliniella occidentalis was also significantly attracted to volatiles from L. nobilis and S. officinalis. Analysis by gas chromatography and mass spectrometry identified 1,8-cineole (eucalyptol) as one of the main volatile components of all three plant species. In coupled gas chromatography-electroantennography studies with F. ulmaria, both 1,8-cineole and methyl salicylate elicited responses from F. occidentalis. Eucarvone was identified as the major component of F. ulmaria volatiles, but showed no electrophysiological activity. Behavioural responses of thrips to a range of concentrations of 1,8-cineole and methyl salicylate were tested using a modified Pettersson ‘star’ olfactometer. 1,8-Cineole showed some attractant activity for the thrips at 0.01 mg, but methyl salicylate was repellent at all the concentrations tested.

This paper reviews progress made in the identification of the sex pheromones of lepidop-terous stem-borers and the use of these pheromones in crop protection. These uses include population monitoring with pheromone traps and control by mass trapping and mating disruption, and case histories for Ostrinia nubilalis and Chilo suppressalis are considered in detail to illustrate the problems encountered in applying these techniques. The pheromone blend, trap design, trap siting and pest biology are important factors in any monitoring system, and so far little progress has been made in correlating pheromone trap catches with subsequent larval infestations and crop damage by stem-borers. Control by mass trapping using pheromone traps has been little explored and is thought unlikely to provide a satisfactory control technique for many stem-borers. Control by mating disruption has been more extensively examined with encouraging results. The main potential of this technique would seem to lie in controlling pests of rice, maize and sugar-cane grown under plantation conditions.

A binary mixture of (Z)-ll-hexadecenal and (Z)-13-octadecenal was first identified as the sex pheromone components of female Chilo suppressalis. Later, an additional component was identified as (Z)-9-hexadecenal, which markedly enhanced the attractiveness to males when it was mixed to the binary mixture. Rubber septa containing ca. 0.3–1.0 mg of a mixture of the above three components in the natural ratio have been shown to keep up significantly higher attractiveness than virgin females for at least one month. It has also been shown that the pheromone trap is much more effective than a light trap, where both traps usually showed similar trap catch patterns. Several factors affecting trap catch, such as trap type, trap placement, etc., have been examined. Feasibility of the population monitoring with the synthetic pheromone was discussed.

Floral characteristics related to pollination were studied in four species of Theobroma and one species of Herrania (Sterculiaceae) in Costa Rica. Anthesis was complete in T. cacao, T. simiarum, T. speciosum, and T. mammosum at 0615 hr following an extended period of floral development throughout the night. Flowers of both T. cacao and Herrania cuatrecusana were fully open by dawn and pollen sacs dehisced throughout the morning hours. Stigma and style receptivity, assessed by hydrogen peroxide tests, were high throughout the morning and early afternoon in T. cacao. Bagged flowers resulted in no fruit-set. When petal ligules were experimentally removed there was no change in rates of flower abortion or total numbers of aborted flowers, tentatively suggesting that these structures play little or no role in attracting pollinators. Both Theobroma and Herrania flowers possess ultraviolet light reflectance'absorbance patterns which may play a role in pollinator attraction. Uptake of neutral red stain in T. cacao and T. simiarum showed scattered glandular activity on petals and sepals, perhaps indicating location of nectaries or other secretory organs. Conspicuous glandular trichomes on the ovary, on the lower third of the style, and in a conspicuous “basal ring” between petals and sepals (most pronounced and colorful in species other than T. cacao) may be sources of both floral attractant and reward.

Differences in floral biology among Theobroma and Herrania species suggest divergence in pollination strategies. The data presented are discussed in terms of plant-pollinator specializations in the New World tropics.

Infectivity of the entomopathogenic fungus Metarhizium anisopliae against workers of the arboreal termite Odontotermes sp. was assayed under laboratory conditions. Test isolates were collected from different sources, including soil from varied locations and insect hosts from the orders Lepidoptera, Coleoptera, Hemiptera and Orthoptera. All the 23 isolates tested and the standard (ARSEF 7413) were pathogenic to the workers of Odontotermes sp. at a concentration of 107 conidia/ml, with mean mortality ranging from 57.5 to 100%. Two of the isolates (Ma2, Ma13) and the standard caused 100% mortality in the termite species. A detailed bioassay was subsequently conducted with the five most promising isolates, namely Ma1, Ma2, Ma13, Ma16 and Ma17, at concentrations ranging from 104 to 107 conidia/ml. The lethal concentrations (LC50) of these isolates ranged from 0.01 to 0.46 × 105 conidia/ml. The average survival time (AST) for the termites treated with the most virulent isolate (Ma2) varied from 4.2 to 5.7 days across the four spore loads, while AST with the standard isolate ranged from 5.3 to 6.3 days. Two of the isolates, Ma2 and Ma13, were found to be significantly more pathogenic to Odontotermes sp. workers than all the others, including the standard.

The sweet potato whitefly Bemisia tabaci (Gennadius) is a pest of diverse agricultural systems worldwide, owing to its capacity to transmit viruses, both intraspecific and host-associated variations. In Ghana, it is the only known arthropod vector for cassava-infecting begomoviruses (Geminiviridae). Two genetic variants of B. tabaci, previously characterized by RAPD–PCR and subsequently reared on cassava and okra, were allowed access to five weed species in order to examine host preference and suitability: Amaranthus retroflexus, Chromolaena odorata, Desmodium tortuosum, Euphorbia heterophylla and Malvastrum coromandelianum. Overall, the duration of the life cycle ranged between 16.5 and 26.3 days and survival rates were 0–27.5%. The population from field-infested okra reproduced and developed to maturity on C. odorata, D. tortuosum and E. heterophylla. Both populations produced male and female progeny. Amaranthus retroflexus and M. coromandelianum were considered poor hosts for both populations, due to the low fecundity and survival of eggs, pupae and adults. The rearing host did not significantly (P>0.05) influence survival on subsequent hosts in either case. The host-restriction of the population collected from cassava was not corroborated here, based on the demonstrated ability of the Ghanaian cassava population to complete its life cycle on D. tortuosum and E. heterophylla. It was estimated that B. tabaci could achieve 13–22 generations per year in Ghana. Removal of C. odorata, D. tortuosum and E. heterophylla from the vicinity of susceptible crops is recommended.

The tea (Camellia sinensis (L.) Kuntze) industry is the backbone of the agroeconomy of the North Bengal region located at the foothills of the Himalayas in North-East (NE) India. This region accounts for about 25% of the total tea production in India. The tea mosquito bug, Helopeltis theivora Waterhouse, is one of the most devastating sucking pests of tea in this region. Various kinds of synthetic insecticides are continuously sprayed to control this bug. The lynx spider Oxyopes javanus Thorell has been found to remain associated with tea plants and feed on H. theivora. The present study investigated the predation potential and efficacy of the O. javanus spider against one of its most common prey species, H. theivora. In the laboratory, with an increase in H. theivora density, the predation rate of both male and female O. javanus increased. Per capita predation rates exhibited by male and female O. javanus per day against adult H. theivora were 3.67 ± 1.52 and 11.67 ± 1.53 (mean ± standard deviation), respectively. At a reasonably small prey density, the prey consumption rate was highest, reaching up to 100%, indicating that the spider predator has the potential to eliminate smaller populations of the pest. The predation effectiveness calculated using Holling's disc equation was 6.08 and 356.58 for male and female O. javanus, respectively. The prey handling time was 0.138 day for male O. javanus and 0.012 day for female O. javanus. Female O. javanus exhibited about fivefold higher searching efficacy than male O. javanus. It appears that the conservation or augmentation of O. javanus in the tea ecosystem can provide effective biological management of the major tea pest, H. theivora, in sub-Himalayan foothills and plains of NE India.

Comparisons of numbers of Heliothis armigera moths, caught in a light trap at ICRISAT Center (17°N 78°E), with wind direction has provided circumstantial evidence for windborne migration in India. The evidence is less convincing than that from northern Europe, possibly because flying populations are present around the trap throughout the year, although varying greatly in numbers between seasons. Comparisons were made for occasions when trap catch rose or fell over four successive nights with a correlation coefficient ≥0.9 and rate of catch change > 1 moth/night. Catch rises were used from only those parts of the lunar cycle when falls would be expected, and catch falls from those parts when rises would be expected. During the period May 1977 to December 1983 there were 23 rises and 16 falls. Rises occurred mostly during the seasons of maximum catch. All seven rises in February–April occurred with southeasterly winds, even though such winds blow on average only half the time in those months. These rises sometimes coincided with onset of southeasterlies; at other times there was a lag, consistent with flight from distant sources. Similar migrations seem possible in October–December, sometimes in the presence of cyclones over the Arabian Sea. The evidence for migration in August at ICRISAT, and in all seasons at ICRISAT Sub-Center, Hisar (29°N 76°E), is inconclusive.

Seven species of mosquitoes oviposited in open and bored bamboo traps at a site in Peradeniya, Sri Lanka, the most prevalent being Aedes albopictus, Aedes novalbopictus and Armigeres subalbatus. These three species preferred to lay in open than in bored traps. Aedes albopictus and Ar. subalbatus preferred to lay at ground level but Ae. novalbopictus showed no preference between ground level, 3.5 and 7.0 m height. A comparison of two collection series, one with traps in fixed positions and the other with traps interchanged randomly with respect to the positions, showed that individual trap attractiveness is a factor that can have a marked influence on the overall oviposition trends in Ae. albopictus and Ar. subalbatus.

A study of oviposition with respect to height above the water level showed that in Ae. albopictus and Ar. subalbatus, more than 75% of the eggs were laid within about 16 mm of the waterline. However, there was a markedly greater dispersion of eggs in Ae. albopictus, indicating more vertical movement during oviposition in this species than in Ar. subalbatus.

The age-specific mating incidence and mating behaviour of an aphidophagous ladybird beetle Coelophora saucia Mulsant were studied. Males started mating at the age of 4 days. Newly emerged females mated with older males albeit forcibly. The incidence of mating was 100% at the age of 10 days. Courtship involved five steps, viz. approach, watch, examine, mount and attempt, and was male dominated under laboratory conditions. Results indicate that physical cues probably play a role in the initiation of courtship, while chemical signals are probably involved in the continuation of courtship, culminating in intromission. The mating duration, latent period and number of bouts gradually decreased with increase in the number of matings; however, the interval between bouts slightly increased. Pseudo-mating with dead mates was observed in C. saucia. The oviposition period, fecundity and % egg viability were highest in females mated multiple times, while lowest in those that mated once.

The willingness of a species to leave a forest fragment is a prerequisite for subsequent dispersal across the intervening non-forested landscape. Species with stringent fidelity to the forest patch will be isolated from populations in other fragments and predisposed to factors that promote extinction of local populations. Here, we document which fruit-feeding, forest-dwelling butterflies occur in the farm bush savannah outside an afrotropical forest reserve in order to gain a first approximation of those potentially dispersing across it. Standard fruit-baited traps hung at 80 m inside the forest, the forest edge and 12 and 50 m into the savannah matrix were used to characterize communities in the different habitats. A total of 1616 specimens were collected from the 19 traps, representing 90 species. Rarefied species richness was generally comparable across habitats. Multivariate ordination analyses, which integrate species composition and relative abundance in addition to richness, uncovered two broad community types, i.e. forest (edge plus 80 m inside) and matrix. Relative fidelity to forest habitat was investigated for the 45 species that were represented by at least five individuals. More than half of the forest-associated species showed relaxed fidelity to forest habitat and were commonly trapped in the matrix. Although forest generalists and dry forest species were expected to be more commonly trapped outside the forest relative to wet or moist forest species, there was no relationship between the relative occurrence of species in matrix versus forest habitat and their habitat association category.

The egg parasitoid Telenomus busseolae Gahan is the most important parasitoid of sugarcane pink borers and plays an important role in the suppression of their populations in Iran. To understand the efficiency of T. busseolae parasitizing Sesamia cretica Lederer, in this study, the functional response of the parasitoid was investigated at different temperatures (20, 25, 30 and 35 °C). The results of logistic regression indicated a type III functional response at all the temperatures. Roger's random parasite equation fitted the observed data at 30 and 35 °C, but Holling's disc equation fitted the data better at 20 and 25 °C. The attack rate of T. busseolae ranged from 0.0036 to 0.2148, 0.00017 to 0.1031, 0.0049 to 0.2952 and 0.0006 to 0.0382 per h, and the estimated handling time was 0.80, 0.48, 0.32 and 0.13 h at 20, 25, 30 and 35 °C, respectively.

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.

In this study, laboratory and field cage experiments were conducted to assess the performance of sterile mass-reared Mexican fruit fly Anastrepha ludens (Loew) irradiated at various doses. In small laboratory cages, the radiation dose was found to have no effect on adult emergence, flying adults or survival at 25 days. In field cages, non-irradiated males and males irradiated at 20 and 40 Gy were found to exhibit greater mating propensity than males irradiated at 60 and 80 Gy. In large field cages in competition with wild males, cohorts of flies (male and female) irradiated at the low dose of 40 Gy and wild non-irradiated flies mated randomly, while flies irradiated at the high standard dose of 80 Gy mated assortatively. Irrespective of the radiation dose, laboratory flies courted and attempted copulation significantly earlier in the day than wild flies. In large field cages, cohorts of flies irradiated at low doses, e.g. 40 Gy, tended to induce greater sterility into a cohort of wild flies than those irradiated at 80 Gy, but the difference was not significant. Our results suggest that lowering the radiation dose currently applied to mass-reared flies in the Mexican fruit fly eradication campaign would substantially improve male mating performance. This could result in greater sterility induction without posing a risk in areas where target pest populations naturally prevail and are under suppression during the early stages of eradication programmes.