Antixenosis resistance to Helicoverpa armigera (Lepidoptera: Noctuidae) was studied in 10 tomato accessions selected from a germplasm of 321 at Tamil Nadu, India, using free-choice and no-choice laboratory experiments. The foliage and fruits of two accessions, namely PT 4287 and Varushanadu Local were the least preferred for feeding in both tests. In the no-choice (confinement) test, Seijima Jeisei, Varushanadu Local and PT 4287 were the most preferred for oviposition, but had low egg hatch rates. In the free-choice test, these accessions were the least preferred for oviposition. The first and second instars preferred to feed on the foliage of 30- and 45-day-old plants, respectively than 60- and 75-day-old plants, whereas ovipositional preference was insignificant among the various plant ages.

Soil type selection for oviposition by gravid females of the armoured ground cricket Acanthoplus speiseri Brancsik (Orthoptera: Tettigoniidae), a pest of grain crops in Zambia, was investigated. Twenty randomly collected samples of different types of soil, each replicated five times in an oviposition choice tray, were made available to 20 gravid females maintained in an environmental chamber, and the number of egg pods deposited per soil sample recorded. Physical and chemical characteristics of each soil sample were analysed. Properties of the soil that served as important cues to soil type selection for oviposition by the gravid females were identified and used to develop a best subset regression analysis model, for use by farmers to predict egg pod numbers of the pest in soils collected from their crop fields. There were significant differences (P<0.05) in the mean number of egg pods deposited per soil sample. Acidic, loam, clay loam and sandy loam soils with a pH range of 4.41–6.62, were the preferred soil types for oviposition. The single most important soil quality that accounted for much of the variation observed in mean egg pod number among the soil samples was pH (adjusted r2=0.1152). This was followed by mineral composition, particularly of the elements K (adjusted r2=0.1084) and P (adjusted r2=0.0731). Characteristics of the 20 soil samples tested are presented. Impacts of interactions among the soil characteristics on mean egg pod number are explained and the procedure for using the developed predictive model by farmers in crop protection is discussed.

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.

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 attraction of the melon fly, Bactrocera cucurbitae (Coq.) (Diptera: Tephritidae) to soybean hydrolysate, fishmeal, beef extract, banana/grapes, bread and dog biscuit was evaluated in snakegourd (Trichosanthes anguina L.) gardens during 2000–2001. Vinegar and beer were added as the ‘bait components’ to the above ‘base baits’ to enhance their attractiveness. Edible oils, glycerine and petroleum jelly were tested as the ‘controlled releasers’ to sustain the attractiveness. The results indicated that banana and soybean hydrolysate were 85–95% more attractive to adult B. cucurbitae than fishmeal, beef extract, bread and dog biscuit. Among the fruit pulps, grapes and banana appeared to be more attractive than pineapple. The attractiveness of baits with palm oil lasted longer (up to 5 days) than that of baits without any controlled releaser (2–3 days). Grapes + beer + palm oil was found to be 37% more attractive than the other admixtures. The fruit flies were attracted towards the baits more intensively between 0600 and 0800 h and between 1600 and 1800 h.

The ovipositional response, larval orientation, larval settling, feeding, food assimilation, growth and development of maize stemborer Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) on a susceptible maize (Zea mays L.) genotype (Inbred A) was compared to five wild plant species of the family Poaceae (Gramineae) in the laboratory and greenhouse. The intensity of oviposition differed among the test plants. Pennisetum purpureum Schumach was the most preferred test plant for oviposition when offered in a two-choice situation with maize. Likewise, P. purpureum and Sorghum versicolor Anderss were the most preferred test plant for oviposition when offered in multiple-choice tests. In no-choice tests C. partellus responses to the test plants were not significantly different. The number of first instar larvae that settled on leaf cuts of test plants in Petri dishes was significantly higher on maize and S. versicolor than on the other test plants at 24 h after infestation in a multiple-choice test. No significant differences were observed in larval settling among wild grasses at 4 h and 24 h after infestation in a no-choice test. In a two-choice test there was no significant difference in the number of neonate larvae that settled on maize and S. versicolor at 1 h and 24 h after infestation. Feeding by fourth-instar larvae was significantly higher on maize than on Echinochloa pyramidalis (Lam.) and Hyparrhenia rufa (Nees) Stapf. Larvae fed on maize assimilated significantly more food than those fed on E. pyramidalis, Panicum maximum Jacq. or H. rufa. Larval growth and development was significantly faster on maize and S. versicolor in comparison to other test plants.

The literature on African pollination biology is reviewed. It is found that relatively little work has been done on pollination biology in Africa, and a very small proportion of pollination relationships has so far been studied. Much of the research which has been done is of an evolutionary nature. Very little work has been conducted at the community level and comparatively little applied work, either to agriculture or conservation, was encountered. Most research has been conducted in South Africa, in particular, from the Cape region, which is the only part of Africa for which a reasonably comprehensive body of work on pollination biology exists. In a number of instances results of African studies challenge conventional understanding of pollination biology. It is argued that as more work on pollination is done in Africa, more differences between African systems and the rest of the world, particularly the North temperate regions will be found and changes to the overall conceptualization of pollination systems in different ecosystems are likely to ensue. A more thorough understanding of pollination biology would also make an important contribution to food security and conservation of biodiversity on the continent. Scientists working in fields other than pollination biology, and amateurs, should be encouraged to contribute to the groundwork of African pollination biology by the documentation of pollination relationships.

Rearing temperature has an important influence on the efficiency of food utilization by larvae of the silkworm Bombyx mori L. To assess food intake and utilization efficiency in B. mori reared at different temperature combinations, larvae of Pure Mysore race were fed ad libitum on M5 mulberry leaves and reared at four different constant temperatures, viz. 26, 28, 30 and 32°C during instars I to III and combinations of these temperatures during later instars (IV and V). The larvae reared at 28°C (T2) when young and combinations of temperatures 26–26, 28–26, 30–26 and 32–26°C later were taken as controls. The amount of dry food consumed was significantly higher, but a significant decrease in conversion efficiencies (K1 and K2) was noticed in silkworms reared young at 28°C than at the other temperatures. However, the dry food consumed, food converted, assimilation rate and assimilation efficiency increased with the increasing temperature, and larval duration and conversion efficiency decreased significantly with the rise in temperature during both young- and late-instar rearing. Comparisons between these two ages with regard to food utilization parameters were carried out and the factors responsible for these changes are discussed.

Trioza erytreae Del Guercio (Hemiptera: Triozidae) has been reported to be a major vector of the African huanglongbing, a form of citrus greening disease. In the tropical regions of Africa, factors regulating population changes of the pest within citrus orchards and plantations are almost unknown. This study carried out in an experimental plot of citrus orchard in Yaoundé, Cameroon, aimed at monitoring some climate and edaphic factors, which regulate the population changes of the pest. From January 1992 to December 1993, psyllids were counted weekly on flushing shoots and buds from 65 ten-year-old citrus trees. In 1992, the psyllid population changes revealed eight generations with three main peaks (January–March, April–September and September–December), and only three generations with one peak in 1993 (October–December). Among climate factors studied, higher maximum temperatures and saturation deficit index were negatively correlated with psyllid population. The shoot flushing rhythm within citrus trees was also highly correlated with psyllid population. In 1993, citrus trees were not weeded and no fertilizer was applied, and this led to disappearance of the pest from the plot and to a decreased number of annual generations from eight recorded in 1992 to three in 1993. Results from this study represent an important step towards the citrus psyllid ecology and the development of an integrated pest management programme for its control, with regard to weather conditions, cultural practices and host plant relationships.

Grass pea Lathyrus sativus L. plays a major role in the nutrition of many poor people in Ethiopia. However, the crop suffers heavy damage by pea aphids Acyrthosiphon pisum (Hemiptera: Aphididae). To test potentially more sustainable and harmless alternatives to the commonly used insecticides, some botanicals (neem, garlic and hot pepper), soap, kerosene and the aphicide pirimicarb, were tested for their efficacy against A. pisum at Wondata village, close to the town of Bahir Dar, in northwestern Ethiopia, from 1999 to 2002. After pirimicarb, hot pepper was consistently the most effective botanical in controlling the pea aphid in terms of both pea aphid population as well as grain yield. Compared to the untreated control, there was up to 83 and 55% lower aphid population on pirimicarb- and hot pepper-treated plots in the 2000/2001 cropping season, respectively. There was also up to 93 and 54% higher grain yield on plots treated with pirimicarb and hot pepper extract, respectively. Soap was less effective, while kerosene caused phytotoxicity. Infestation levels increased with advancing maturity of the crop, rising exceptionally suddenly and dramatically near crop maturity. Combined ANOVA over years and crop growth stages indicated that aphid populations varied with years and growth stages. In 2001/2002, aphid populations were higher and grain yields were lower compared with the other years. Percentage parasitism of aphids was significantly higher on pirimicarb-treated plots (∼40%) than other treatments (<20%). Parasitism was essentially a late-season occurrence. Predator population, especially of ladybird beetles (Adonia spp.), was especially higher on hot pepper- and garlic-treated plots, and lowest on pirimicarb treated plots. Grain yield was positively correlated with level of aphid parasitism, ladybird beetle population and number of pods per plant, and strongly negatively correlated with aphid population. In conclusion, a fresh extract of hot pepper sprayed at the rate of 70 ml/4 m2 was selected for further research on rate, frequency and cost of application.

Phytoplasmas are insect-vectored pathogens that cause characteristic and destructive diseases in carrots and other vegetables. A phytoplasma disease was first observed in Israeli carrot fields in 1995. Analysis of infected carrots showed the presence of aster yellows and western-X phytoplasmas. In this study, commercial and experimental fields in the western Negev region of Israel were monitored for three years using yellow sticky traps and vacuum sampling. Potential vectors of leafhoppers and planthoppers were analysed by PCR for the presence of phytoplasma DNA. Infected plants were also assayed for phytoplasma DNA. Extracted phytoplasma DNA was subjected to RFLP analysis to determine groups to which the phytoplasmas belonged. It was determined that carrots and leafhoppers from the experimental station were infected with a phytoplasma belonging to the Elm Yellows (EY) group; this is the first report of EY infecting carrots. Based on our findings, the two most probable insect vectors are Circulifer haematoceps complex (Mulsant & Rey) and Neoaliturus fenestratus (Herrich-Schäffer).

Two shaving methods, one by using a sharp razor blade and the other a small pair of dissecting scissors, were tested on pods of Vigna vexillata accessions to investigate the effect of trichomes on feeding and development of the pod-bug Clavigralla tomentosicollis Stål (Hemiptera: Coreidae). Electron micrographs of unshaved (control) pods showed that all trichome types (glandular, long non-glandular and short non-glandular) were present on the pod surface. Shaving with a pair of scissors shortened long non-glandular trichomes, with little or no damage to the glandular types. Percentages of seed damage and nymphs surviving to the adult stage were similar (P>0.05) between unshaved and scissors-shaved pods. These pods showed significantly lower (P<0.05) percent seed damage than razor-shaved and solvent-washed pods, whose glandular trichomes were all completely scraped or washed off. The opposite trend was observed for the insect's growth index, indicating that glandular trichomes had a greater influence than non-glandular trichomes on feeding and development of C. tomentosicollis. The present study suggests that the scissor-shaving method would be more appropriate if the effect of trichome length is being investigated, and the more abrasive razor-shaving method if the effect of glandular trichomes is of interest

There is now considerable evidence for disruption of plant–pollinator mutualisms in fragmented landscapes. The causes can be myriad, and vary from lack of nesting sites for key insect pollinators, to a decline in pollinator visits when plant population sizes are reduced by fragmentation. One important and well-documented consequence of disruption in pollination systems is reduced seed production in plant populations in fragments as a result of pollen-limitation. When reduced seed production, in turn, has a negative effect on seedling recruitment, populations may enter a spiral towards extinction. Some pollination systems, on the other hand, are surprisingly resilient to anthropogenic changes, and pollen flow between trees in fragments separated by several kilometres has been reported recently. Understanding how reproductive attributes of plants, such as breeding systems and specificity of pollination systems, affect the outcome of habitat fragmentation remains a key challenge.

The reproductive activity and the offspring development of the bruchid Callosobruchus maculatus (Coleoptera: Bruchidae) were monitored in the seeds of seven cultivars of Cicer arietinum and three cultivars of Vigna unguiculata. The number of eggs laid by the C. maculatus was higher on the V. unguiculata cultivars than on those of C. arietinum. The survival rate during the embryonic development was higher than 90% regardless of the plant species and cultivars while the post-embryonic development rates did not differ significantly between the cultivars. However, the duration of the embryonic and post-embryonic development and the weight of the emerging females varied with seed species. V. unguiculata seeds allow a higher reproduction and a better development than C. arietinum. In this study, no cultivar had been found to be resistant. In Algeria, C. maculatus can develop in stored grains of both chickpea and cowpea, and it is a major stored grain insect pest.

A particularly rich array of pollination systems is represented in the flora of southern Africa. Hopliine beetles, long-proboscid flies, satyrine butterflies, hawk moths, birds and rodents appear to assume greater importance as pollinators than they do in other temperate regions. These ‘alternative’ pollination systems may have developed because the bee-fauna of southern Africa is not particularly rich relative to the flora. Pollination by moths, for example, is relatively frequent in the eastern half of southern Africa where bee diversity is lowest. Pollination systems in southern Africa are relatively specialized and shifts between pollinators have been shown to be an important driving force in plant diversification and speciation. Changes in land-use, particularly afforestation and ploughing of grasslands, invasion of alien plants, overgrazing and urban developments have disrupted these mutualisms with mostly unknown consequences for ecosystem functioning. Future research will be directed at expanding our knowledge of pollination systems, with a strong focus on the conservation of mutualistic ecological interactions.

Toxicity and antifeedant activity of crude seed extracts of Annona squamosa (Magnoliales: Annonaceae) from Maluku, Indonesia, against the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) and the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) were determined using different bioassays. Aqueous seed extracts and an aqueous emulsion of ethanolic seed extracts were toxic to both species. Crude aqueous extract also deterred feeding of fourth-instar P. xylostella in a leaf disc choice bioassay. Toxicities of crude aqueous extracts to natural enemies, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Orius insidiosus (Say) (Hemiptera: Anthocoridae) were investigated using direct spray and residual contact tests. Chrysoperla carnea larvae were less susceptible to the extracts than were O. insidiosus adults.

Lipids were extracted from the plasma and gonads of fourth and fifth instars and adults of Dysdercus koenigii (Heteroptera: Pyrrhocoridae). Thin layer chromatography of the extracts revealed fractions of free fatty acids (FFA), monoglycerides (MG), diglycerides (DG), triglycerides (TG), phospholipids (PL), free cholesterol (FC) and esterified cholesterol (EC). There were distinct differences in the lipid profiles within sexes for both tissues during development. Phospholipid from female plasma showed significant fluctuation during development, while that from males remained constant. In female gonads, PL levels increased significantly from the fouth instar to the fifth instar. Monoglycerides were detected only in adult male plasma and adult female gonads, at very low levels. Plasma DG in males was found to increase significantly during development. Maximum gonadal DG was recorded in male fourth instars and female fifth instars. Triglycerides in female plasma declined from the fourth instar to the adult stage. In contrast, TG in gonads increased significantly in the fifth instar of both sexes. Plasma FFA of both sexes fluctuated during development. Free cholesterol was detected only in adult male plasma. Plasma EC increased from the fourth instar to the adult stage in males, and it was highest in gonads of fifth instars of both sexes.