The study reported examined mechanisms of pollen transfer within the genus Lagenaria, including insect vectors in the natural and cropped field environment. The major flower visitors to Lagenaria were observed for 10 months, from June 2001 to April 2002 at five sites, namely the Botanic Garden of the National Museums of Kenya, three farmers' crop fields in Dungicha village in Kilifi District, Katitika and Wayowani villages in Kitui District and the home garden of one of the authors, in Westlands, Nairobi, Kenya. Twenty-two species of insects represented in four orders belonging to 10 families were found to be the major visitors of L. siceraria flowers. From the foraging patterns of the flower visitors, visiting frequencies and development of fruits, four groups of flower visitors comprising hawkmoths (Hippotion celerio, Agrius convolvuli), moths A–D (Noctuidae spp.), skipper butterfly (Gorgyra johnstoni) and honeybee (Apis mellifera) were considered active flower visitors. Hawkmoths were suspected to be the major pollinators of this plant in the locations surveyed.

Pest control strategies against Helicoverpa armigera (Hübner) using protease inhibitors have relied on the gut protease profile of the later larval stages of the insect, with serine proteases being considered predominant. Little is known about the gut protease profile of early larval instars. Therefore, the aim of the present study was to detect the levels of gut protease activities in the third-, fourth-, fifth- and late fifth-instar larvae of H. armigera reared on an artificial diet using specific substrates and inhibitors. The analysis of the gut protease profiles of different instars revealed different levels of protease activities at different instar stages. Significant variations were also observed in the specific activities of trypsin, chymotrypsin, cysteine protease, carboxypeptidase-A and aminopeptidase-N across the instars. In general, the activities of the proteases increased from the third to the fifth instar and then decreased at the onset of pupation in the late fifth instar. Proteolytic activity was optimal at pH 12 for gut extracts from the third-, fourth- and fifth-instar larvae. Bioassays with phenylmethylsulphonyl fluoride (PMSF), a serine–cysteine protease inhibitor, revealed high mortality, and that with sodium ethylenediaminetetraacetic acid (EDTA-Na), a metalloprotease inhibitor, also showed retarded larval growth. The inhibition induced by 0.05% PMSF and 0.05% EDTA-Na in combination was similar to that induced by 0.1% PMSF alone.

An invasive pest, Tuta absoluta (Meyrick) has been observed infesting tomato Solanum lycopersicum L. (Solanales: Solanaceae) in Central Uganda. The affected farmer made the report, and upon visiting the farm, we observed tiny larvae, green to cream in colour with a black head feeding on tomato leaves, fruit, as well as tender stems. Also, we saw several tiny moths resting on screen house linings. Delta traps baited with TUA-Optima® (Russell IPM) were set in and around the affected farm. Dozens of moths were attracted and trapped on the sticky surface of the traps. The team tentatively identified the insect as T. absoluta. Scientists at the International Centre of Insect Physiology and Ecology (icipe) in Nairobi, Kenya identified the insect using morphological features and molecular techniques.

The functional response in terms of prey consumption and numerical response in terms of number of eggs laid by individual female adult predators of Coccinella transversalis Fab. and Cheilomenes (Menochilus) sexmaculatus Fab. (Coccnellidae: Coleoptera) at varied prey (Aphis gossypii Glover) (Aphididae: Homoptera) densities were investigated under laboratory conditions. The feeding rate by individual predators increased at increased prey densities, with both the coccinellids showing the Type II functional response. One hundred percent prey consumption was observed up to an initial prey density of 50 and 20 for Co. transversalis and Ch: sexmaculatus respectively. The fecundity of Co. transversalis increased at higher prey densities, but that of Ch. sexmaculatus remained unchanged.

Female-biased sex ratios in Danaus chrysippus (Linnaeus) (family Nymphalidae, subfamily Danainae, tribe Danaini) populations are attributed to the action of an endosymbiotic ‘male-killer’ bacterium of the genus Spiroplasma. In stark contrast to the extensive geographic range of their host, the Spiroplasma appears to be restricted to East Africa, where four African D. chrysippus subspecies exist sympatrically and form a hybrid zone. In this study, specimens collected at three sample sites within the hybrid zone were screened for Spiroplasma infection. The findings demonstrate that, within the hybrid zone, the frequency of Spiroplasma infection varies both spatially and temporally. Host genotype at three biallelic wing pattern loci, representative of subspecific genetic divergence, is correlated to Spiroplasma infection. Linkage between the frequency of the recessive a allele and Spiroplasma is established, suggesting the presence of a linked allele controlling infection susceptibility. In addition, a negative correlation between D. chrysippus forewing length and Spiroplasma infection is identified, suggesting that infection has a deleterious effect on body size.

This selected bibliography on the whitebacked planthopper, Sogatella furcifera (Horváth), contains 506 published and unpublished references for the period 1899 to February 1984. References are arranged alphabetically by the name of the author and also classified by subjects. A distribution map, two tables of the varietal resistance to the pest and its natural enemies, and a brief description of the current status of the pest are also provided.

The effects on the reproductive responses and the offspring fitness in monogamous and promiscuous females of the seven-spotted ladybird Coccinella septempunctata Linnaeus were studied. Reproductive responses were higher in monogamous and promiscuous females with unlimited mating than those subjected to limited mating. Monogamous females with unlimited mating recorded longer oviposition period and higher fecundity than those subjected to limited mating. Promiscuous females with multiple mating recorded the longest oviposition period, the highest fecundity and percentage egg viability (short-term benefits), and the shortest developmental period, maximum larval survival and adult emergence (long-term benefits).

In this study, the effects of relaxed mass-rearing conditions on Anastrepha obliqua (Macquart) production and quality were determined. Relaxed rearing conditions were defined by a reduction in the density of adult flies, from 80,000 to 60,000 flies per mass-rearing cage, and a reduction in the density of larvae, from 6.18 to 3.70 eggs/g of diet. In the parental generation, flies reared under relaxed conditions exhibited significant and a few non-significant changes – increased daily fecundity from 37 to 42 eggs per female, larval recovery from 80 to 91%, larval weight from 18.5 to 19.5 mg, pupation at 24 h from 92 to 96%, pupal weight from 13.5 to 14.3 mg, adult emergence from 92 to 94% and percentage of fliers from 89 to 90%. During the following 12 generations, non-significant differences were observed, but comparisons between relaxed and non-relaxed colonies were significant. The sexual competitiveness of males produced under relaxed conditions was similar to that of wild males.

Cowpea Vigna unguiculata (L.) Walp. is an important component in mixed cropping systems that are appropriate to the agro-ecological characteristics of the West African savannah. However, the contribution of cowpea to overall productivity of the systems is reduced by a number of insect pest species. Compared with the humid zone, important features of insect pests in the savannah region include: (i) a tendency towards higher pest incidence during the limited growing period, (ii) a more advantageous situation for generalist and migratory pests in the scanty and unstable vegetation and (iii) lower mortality inflicted by parasitoids on the pest populations. The key pests of cowpea of importance in the West African savannah are the legume flower thrips Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), the legume pod borer Maruca vitrata (Fabricius) (Lepidoptera: Crambidae) and the pod-sucking bug Clavigralla tomentosicollis Stål (Hemiptera: Coreidae). To control these insects in a sustainable manner, pest management practices such as the use of resistant cowpea varieties, mixed cropping systems, botanical and reduced risk insecticides, and biological control assisted by pest monitoring have been developed. Nevertheless, no single component is effective when used alone, but specific combinations can work synergistically. This paper highlights recent progress in integrated pest management strategies for cowpea in cereal-based cropping systems in the West African savannah.

A study to determine the species richness and spatial distribution of five meliponine bee species in three different habitats in the Kakamega forest was undertaken for the first time. Two forest (indigenous and mixed indigenous) and two grassland (with Eucalyptus spp. trees and indigenous trees) types, along with homesteads (in the vicinity of mixed indigenous forest and indigenous forest, respectively), were surveyed. Line transect methods were used in the nest survey in each habitat. The highest number of species was recorded in the indigenous forest, while no nest was discovered in the grassland with Eucalyptus spp. trees. The mean number of nests per transect was higher in homesteads followed by the indigenous forest. The nesting pattern of almost all species nesting in the indigenous forest, mixed indigenous forest (Meliponula bocandei [Spinola]) and grassland with indigenous tree species (Meliponula ferruginea [Lepeletier] reddish brown) was dispersed. The nesting pattern of M. ferruginea (reddish brown) and Hypotrigona gribodoi (Magretti) changed from a dispersed and random pattern, respectively, to a clumped nesting pattern when nesting in homesteads. The degree of nest clustering was low for M. ferruginea (reddish brown) and high for H. gribodoi. Differences in average nearest-neighbour distance were observed within species nesting in a dispersed or clumped pattern. This study reveals that habitat type in the Kakamega forest influences the species richness and nesting pattern of the five stingless bee species.

The dry and largely deciduous forests in Santa Rosa National Park in northwestern lowland Guanacaste Province, Costa Rica, Central America, have a moth fauna of about 2800 species. These moths pass the six month rain-free dry season, and some other portions of the year, by: (a) remaining dormant in the egg stage (1 species only), (b) remaining dormant in the pupal or prepupal stage (many species), (c) undergoing larval development (a few species of particular life forms) (d) remaining in the Park as a potentially active but non-reproductive adult (many species), and (e) migrating out of the Park after one to two generations and then returning at the beginning of the following rainy season (a few species of particular life forms). The migrating moths constitute a strong link between the dry forest and the rainforests to the east of the dry forest. The seasonal patterns of dormancy of immatures, reproductively dormant adults, and migration are not well correlated with the simple presence or absence of foliage on host plants, or with climate changes (except that the temperature drop that occurs at the beginning of the rainy season appears to be a widely used cue for pupal eclosion). The pattern of habitat use by leaf-eating caterpillars is probably determined more by the seasonal abundance of carnivores (parasitoids and predators) than by the mere presence of leaves; this process is very strongly evident in the failure of many moths to have more than one generation per year, even when their host plants are leafy throughout the six month rainy season or are even evergreen.

Resistant rice varieties have proved to be highly effective against the brown planthopper Nilaparvata lugens (Stål), but their long-term stability is threatened because of the evolution of prolific biotypes. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to pest in greenhouse screenings and in field plantings of test nurseries at many locations. So far, three N. lugens biotypes that attack different rice varieties have been identified in the Philippines. Biotype 1 can survive on and damage only those varieties that do not carry any genes for resistance. Biotype 2 can thrive on varieties carrying Bph 1 resistance gene and on those susceptible to biotype 1. Biotype 3 can infest and destroy varieties having bph 2 resistance gene and those susceptible to biotype 1. However, none of these biotypes is capable of damaging varieties with Bph 3 and bph 4 genes for resistance, and the variety Ptb 33 carrying two unidentified genes is resistant to almost all known biotypes. Recently, a population of N. lugens was found thriving on the common weed grass Leersia hexandra Swartz on the IRRI farm and in some locations in Luzon, Philippines. This biotype does not survive on rice.

Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka because the South Asian biotypes of N. lugens are more virulent than the Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Rice Brown Planthopper Nursery (IRBPHN) has been established in many cooperating Asian countries.

Biotypes can also be differentiated by studying their behavioural and physiological responses to plants of known genotypes. Distinctive differences can be observed in insect feeding, growth, longevity, fecundity, oviposition and population increase on differential varieties and relative susceptibility or tolerance for hosts' allelochemics. Recent investigations of the existence of subtle morphological, cytological, and electrophoretic differences among N. lugens biotypes and results of hybridization experiments strongly complement other methods of biotype identification.

The evolution of biotypes is a complex process that is governed by the interactions of the genetic and other biological characteristics of the pest populations and the genetic makeup of cultivated varieties. While the strategy of sequential release of varieties with major resistance genes has been fairly successful, the monogenic nature of those varieties makes them vulnerable to the development of virulent pest biotypes. Therefore, present breeding endeavors envisage use of both major and minor resistance genes for effective pest suppression.

Cutworms, semiloopers, budworms and armyworms in the genera Agrotis, Chrysodeixis, Heliothis, Mythimna, Persectania and Spodoptera are important pasture and crop pests in Australia. They comprise both cosmopolitan species, such as A. ipsilon, H. armigera, M. separata and S. exempta and endemic species such as A. infusa, H. punctigera, M. convecta, P. ewingii and P. dyscrita. Although the cosmopolitan species are major pests of parts of Asia and Africa, they are, with the exception of H. armigera, less important agricultural pests in Australia than their endemic counterparts. The latter are widely distributed outside cropping areas, because they breed on a wide range of native host plants as well as on introduced crops and pastures and also have the potential to invade cropping areas from native habitats. The cosmopolitan species are largely confined to tropical and subtropical summer crops and improved pastures of north and east Australia where chronic infestations often develop although major outbreaks and migration out of cropping areas are rare. Periodic outbreaks of endemic species result from an unusually favourable growth of vegetation in early autumn, following drought-breaking rains in the inland. Moths arrive in the rain-affected areas as a result of migration and concentration by rain-bearing troughs and depressions. Southward migration of their progeny occurs in spring on warm northerly airflows produced ahead of eastward-moving cold fronts and results in invasions of temperate crops and pastures. Migration also occurs in anticyclonic conditions, resulting in an extensive redistribution of populations and is adapted to the erratic distribution of rainfall in inland Australia. Among cosmopolitan species, only Spodoptera spp. cause outbreaks which are infrequent and occur with the onset of summer rains in coastal and sub-coastal areas. Most movements of cosmopolitan species are confined within cropping areas although migration from coastal to inland crops, under the influence of prevailing SE winds, and in frontal systems, troughs and storm outflows, is also suspected.

This paper reviews and analyses literature on the effect of plant species diversity on crop pests. It is observed that populations of several crop insect pest species are depressed under conditions of plant species diversity. The factors responsible for this depression are: parasites, predators, masking, camouflage, repellency, less colonization, resource concentration, unfavourable microclimate, physical obstraction and trap cropping. Natural enemies account for more than half of the cases where the pest population was claimed to be regulated in the weed-diversity systems. However, under conditions of crop–crop diversity, natural enemy action accounted for less than a third of the cases reviewed. It is further observed that most of the reviewed crop–crop diversity systems were of annual crops. It is therefore concluded that under conditions of annual cropping natural enemies are probably of lesser importance than other regulating factors.

l-menthol isolated from the essential oil of Mentha arvensis and seven of its acyl derivatives were tested for contact and vapour toxicity, and ovicidal and repellent activity against the storage pests Callosobruchus maculatus F., Rhyzopertha dominica F., Sitophilus oryzae L. and Tribolium castaneum Herbst. Menthyl propionate and l-menthol were highly toxic in contact assays and vapour toxicity assays respectively. l-menthol was also found to be strongly repellent (82–100% at 0.353 μg/cm2 dose) against all the insects, while menthyl acetate was highly ovicidal against T. castaneum.

In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increase in cabbage production. Little is known about the spatial and temporal distribution of cabbage pests, which makes the design of management recommendations to small-scale farmers challenging. The objectives of this study were to: (i) evaluate the status of insect pests observed in cabbage farmers’ fields; (ii) give information on the spatial and temporal distribution of key pests and (iii) assess the effect of temperature, insecticide applications, and host crop abundance on their incidence. A total of 116 cabbage fields were monitored for insect pests and related damage over four crop cycles, from October 2012 to May 2014, in the main vegetable producing area of Senegal (Niayes). The diamondback moth Plutella xylostella (L.) was by far the most important pest present in all the fields and with high levels of incidence (37.1% infested plants), particularly in the latter part of the dry season in the South of Niayes (50% infested plants). The cabbage webworm Hellula undalis (F.) was mainly observed in the early dry season in the south of Niayes, with an incidence of up to 12.5% infested plants. More surprising was the detection of the tomato fruit worm Helicoverpa armigera (Hübner), with damage of up to 9.4% of cabbage heads. The incidence of sucking pests such as whiteflies Bemisia tabaci (Gennadius), or aphids (including Lipaphis pseudobrassicae (Davis, 1914), Myzus persicae (Sulzer) or Brevicoryne brassicae (L.)) was generally low. The incidence of P. xylostella increased significantly with the number of insecticide applications, indicating that control deployed by growers was ineffective. The incidence of H. undalis did not depend on the number of insecticide applications, but significantly increased with host crop abundance and decreased with temperature. This study is a first step towards developing alternative pest management strategies in the framework of sustainable vegetable production systems.

The insecticidal and repellent properties of Lantana camara and Tephrosia vogelii were evaluated against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) in stored maize grain. Five treatment rates (1.0, 2.5, 5.0, 7.5 and 10.0% w/w) of each powdered plant material, an untreated control and a synthetic insecticide (Actellic Super™ 2% dust) were used to investigate treatment efficacy on mortality of the adult insect (five to eight days old), F1 progeny emergence and repellency against S. zeamais adults. After 21 days, L. camara and T. vogelii caused 82.7–90.0% and 85.0–93.7% insect mortality, respectively. The mean lethal exposure times (LT50) to achieve 50% mortality varied from five to six days (7.5–10.0% w/w) to seven to eight days (2.5–5.0% w/w) for both plants. Probit regression analysis showed a significant relationship between plant powder concentration and insect mortality. The plant powders and synthetic insecticide reduced adult F1 insects by more than 75% compared to the untreated control. Tephrosia vogelii was most repellent to S. zeamais at 7.5–10.0% (w/ w), repelling 87.5% of the insects, followed by T. vogelii at 2.5% w/w and L. camara at 10% w/w which repelled 65.0 and 62.5% of insects respectively. The implications of these results are discussed in the context of smallscale farmer usage of these plants for stored product protection.

Hyposidra talaca (Walk.) is a major pest of tea (Camellia sinensis L.) in Northeastern (NE) India. The present study examined (1) the likely causes of expansion of H. talaca to tea from its ancestral home of sal forests, and (2) the anti-predatory mechanisms that helped it to build up in tea plantations. Studies were made on the role of the regulating agents of the eggs and caterpillars of the pest and responses of caterpillars to different predator-like stimuli (predatory wasps, ants and birds) and mechanical vibrations. Eggs collected from the fields were reared in the laboratory to study egg parasitization and monitored in the field to study the role of natural predators. Prolonged drought and inconsistent rainfall influenced the range expansion of H. talaca. In tea plantations, female moths preferred to conceal the eggs in the scaly bark of shade trees. Excluding woodpeckers, H. talaca eggs were scarcely attacked by other natural enemies. The caterpillars dropped off the plant in response to potential predators and assumed a deimatic ‘U’ or ‘S’ shape, and remained motionless when stimulated by mechanical vibration. This study suggests that the lack of specialized natural enemies helped H. talaca to build up in the tea plantations of NE India in a short period of time.

The present study was undertaken to determine the nutritional value of the fifth instar larva of Bombyx mori, locally referred to as ‘Niang ryndai’, which is a popular edible silkworm among the local inhabitants of East and West Khasi Hills and Ri-Bhoi district. Larvae were collected from the Iewduh market of Shillong in the months of October and November as these larvae are available during these months. The composition of lipids, amino acids and the fat-soluble vitamins A and E in the frozen and oven-dried samples of B. mori was estimated and compared with that of conventional food items. The detection of the fatty acids eicosapentaenoic acid and docosahexaenoic acid in the larva indicates its potential to support a healthy cardiovascular function. Because of their use for the production of silk yarn, silkworms have economic potential for the people of the State and north-eastern region of India. Increased appreciation of this insect as an alternative and cheap source of nutrition would contribute to the socio-economic development of the indigenous people.

Mutualistic bacterial endosymbionts provide many benefits to their insect hosts, but their role in mating has not been studied in the past. In this study, we examined copulatory success and mating latency as two parameters of mating success to assess the influence of Candidatus Erwinia dacicola on mating between a laboratory population of olive flies (Bactrocera oleae Rossi) of Israel origin and a wild population of olive flies from Israel. Previous studies have shown that in many species of tephritid flies, laboratory-reared males have lower fitness and achieve fewer matings than wild males. Our research has shown that this Israeli population of olive flies reared in the laboratory on an artificial diet lacked an endosymbiont, Ca. E. dacicola, found in wild-caught insects from Israel. We hypothesized that decreased fitness and mating ability in laboratory-reared flies could be due to the absence of this endosymbiont. Mating assays between both sexes of these two Israeli populations revealed matings to occur primarily between laboratory-reared females and wild males. Laboratory-reared males achieved only 22% of the total matings. Candidatus Erwinia dacicola was found in significantly fewer insects from the laboratory population than in the wild population; within populations, male and female olive flies were equally likely to have the endosymbiont. However, differences in readiness to mate between the two populations, and not the presence of the endosymbiont, explained mating latency.