This study on predispersal seed predation of the leguminous species Vachellia abyssinica (Hochst. Ex. Benth.) Kyal & Boatwr., Senegalia senegal (L.) Britton, Vachellia seyal (Del.) P.J.H. Hurter, and Vachellia tortilis (Forssk.) Galasso & Banfi was conducted around Lake Langano and Menagesha Forest in Ethiopia to identify the associated seed predators and determine their impact on seed germination. Eight seed beetles Bruchidius albosparsus (Fåhraeus, 1839), B. aurivillii (Blanc, 1889), B. djemensis Decelle 1971, B. discoidalis (Fåhraeus, 1839), B. sinaitus (K. Daniel, 1907), B. silaceus (Fåhraeus, 1839), B. sp 411, B. simulans (Anton and Delobel, 2003), and one unidentified species of Cerambycidae were found associated with seeds of these Acacia species. These predators damaged less than 9% of seeds of these species, which exhibited lower germination. This study provides unrecorded lists of predispersal seed predators associated with seeds of Vachellia and Senegalia species in Ethiopia, and some associations are new. There is need to assess the distribution, abundance and effects of predispersal seed predators on other Vachellia, as well as other tree species.

Spatial dispersion of the nymphs of the jassid, Amrasca biguttula biguttula (Ishida), and the adults of the whitefly, Bemisia tabaci Genn. on F414, a Gossypium hirsutum variety, was systematic in Ludhiana (Punjab). Both the jassid and the whitefly displayed no definite pattern along the height of the plant, though a maximum number of whiteflies were recorded at middle canopy (21–40 cm from bottom). Sample sizes of 10–15 plants, selected in a statistically linear fashion represented populations of jassid nymphs and adult whitefly on all four varieties. Sampling jassid nymphs by visual counting and whitefly by split-cage were the most suitable sampling methods for local cotton growers among the various methods compared.

The flight phenology of the stem borer, Chilo partellus (Swinhoe) at the ICIPE's Mbita Point Field Station (MPFS) and on a nearby farmer's field was monitored using pheromone traps. The relation between pheromone trap catches of males and sorghum plant age, infestation, larval/pupal population density and sorghum cultivars used was examined. At MPFS C. partellus males were caught throughout the year in pheromone traps. Fluctuations of trap catches indicated that the pest completes two main generations on each of the long and short rain sorghum crops. On farmers' fields, males continued to be caught in large numbers after harvest, implying that the pest continues to breed on the sorghum stalks and tillers. Significantly lower observed catches of males occurred only on one (MB-3) of the eight different sorghum cultivars, during the period of 2–6 weeks after plant emergence. In general, positive correlations were observed between the number of males caught in pheromone traps and larval pupal population density, males and percentage plants infested, and males and plant age. However, the pheromone trap appeared to be less effective under high population density, particularly during the flight of the second generation moths, due to competition between pheromone trap and wild females. But the flight phenology as monitored by pheromone traps appeared to reflect major events in population development of C. partellus. Pheromone traps would be useful in detecting C. partellus and for monitoring its flight phenology.

A new aspirator is proposed for the collection of springtails (Collembola) and other small arthropods. It is hand operated, safe and efficient to use.

Recent unusual high damage of finger millet Eleusine coracana (L.) Gaertn. and wheat Triticum spp. by Busseola fusca (Fuller) in Ethiopia prompted the initiation of this study that has involved comparing the host status of these crops with the main host, maize Zea mays. One improved variety and one local land race each of wheat, finger millet and maize were grown with and without fertilizer in a randomized complete block design to evaluate the effect of nitrogen and phosphorous fertilizers and varietal differences on the suitability of these host plants for the development of borer larvae. The results indicated that B. fusca larvae managed to survive up to the adult stage in the stems of finger millet and maize, while wheat failed to support larval development to pupation. The stems of fertilizer-treated crops hosted more larvae than those of untreated ones and these were significantly longer and heavier. Improved varieties tended to be more suitable for B. fusca development. Furthermore, irrespective of the crop species, improved varieties grown with fertilizer were more suitable for the development of B. fusca. An improved finger millet variety, KNE No. 1098, grown with fertilizer was as suitable as the improved maize variety A-511, grown without fertilizer. For wheat, however, immature mortality was 100% irrespective of variety and fertilizer level.

The parasitism of Bemisia tabaci (Gennadius) was evaluated on three horticultural crops in the Nicaraguan dry tropic: tomato, Lycopersicon esculentum Mill; squash, Cucurbita argyrosperma (Huber); and sweet pepper, Capsicum annuum L. Parasitoid species were identified and their abundance recorded on the three crops. The study was carried out during both the rainy and dry seasons between 2001 and 2002. The nymphs of B. tabaci were counted weekly and parasitism rates evaluated. During the rainy season, the predominant parasitoids in squash and tomato crops were Encarsia pergandiella Howard and E. nigricephala Dozier. Parasitism rates of 17 and 10% were recorded for squash and tomato, respectively. In sweet pepper, the parasitoid species were E. pergandiella, E. nigricephala, E. desantisi Viggiani and Amitus sp. with a parasitism rate of 12%. During the dry season, the parasitoids in squash were E. pergandiella and E. nigricephala with a parasitism rate of 57%. Encarsia pergandiella was the only species noted in tomato with a parasitism rate of 58%, while in sweet pepper the species noted were E. pergandiella and E. nigricephala, with a 42% rate of parasitism. The abundance of parasitoids remained stable during both sampling seasons. Our results suggest that the parasitism rate is independent of B. tabaci densities. This is the first mention of E. pergandiella, E. nigricephala, E. desantisi and Amitus sp. as parasitoids of B. tabaci in Nicaragua.

In the Ecuadorian cloud forest, males of the parasitoid braconid wasp Napo townsendi Shaw displayed facultative lekking, appearing both singly and in groups of 2–7 on the leaf tops of various plant species. To attract females, they constantly employed a stereotypical, spread-winged calling behaviour, apparently releasing a sex pheromone combed from the lateral metasomal exocrine glands and applied to the wings and hind legs. Aggregated males used the same posture in conspecific agonistic displays, often leading to physical fighting. While female wasps were attracted to and mated with displaying singletons, they also made a choice among aggregated males. When females approached, males vibrated their wings in a brief courtship and mounted. Details of copulation behaviour, which lasted on an average of 3–4 min, are described. Without apparent physical weaponry, the displaying wasps successfully warded off attacks from an assortment of predatory arthropods, particularly salticid spiders. We present case studies of repeated unsuccessful predation attempts by salticids. Here, we postulate that calling and release of sex pheromone may double as both an intrasexual agonistic display and an aposematic advisory to predators that the wasps employ a chemical defence.

In south-eastern Uganda the natural hosts of Glossina pallidipes, G. fuscipes fuscipes and G. brevipalpis appear to influence trypanosome infection rates in these vectors. The transmission index of these vectors also differs. Temperature is yet another factor affecting trypanosome infection rates in these tsetses. Other factors probably also form important components in the transmission cycle. In this region of Uganda and its contiguous lake shore area of Kenya there are extant foci of the infections, and man and his symbiotic livestock are exposed to a high challenge of trypanosomiases. Furthermore, in this high endemic/enzootic ecological zone of tropical Africa, the transmission of trypanosome infections to the adventitious hosts, via the tsetse vectors, depends upon a variety of complex interacting factors.

Cerconota anonella is the most important pest of the Annonaceae in the Neotropical region for larval damage, which can result in 60 to 100% losses in fruit production. However information on the pest's biology is scarce. This research compared different artificial diets for rearing C. anonella under laboratory conditions (25.0 ± 1.0 °C; 60 ± 5.0% RH and 14 h photophase). Five diets were compared: A (bean, soybean meal, wheatgerm, casein and yeast), B (maize flour, wheatgerm and yeast), C (wheatgerm and casein), D (wheatgerm and soybean) and E (wheatgerm and soybean). In diet E, the amount of wheatgerm was higher than that in dietD. The results indicated that diet E was the most suitable one for the development of C. anonella.

The relationship between abundance of the lepidopteran borers Helicoverpa armigera Hubner and Maruca vitrata (Geyer) and damage and yield loss in short-duration pigeonpeas was studied in two multilocation trials in 1995–1996 and 1996–1997 rainy seasons at four locations in India: Patancheru (Andhra Pradesh), Akola (Maharashtra), Sardarkrishi Nagar (Gujarat) and Vamban (Tamil Nadu). Larval populations of Helicoverpa armigera (Hubner) and Maruca vitrata (Geyer) were correlated with pod damage and grain yields. Significant correlation of location, years and genotype on insect population, level of damage and grain yield was obtained. The effect of plant type on lepidopteran pod damage was also observed. The relationships between pod damage, yield and larval population of Helicoverpa and Maruca are discussed.

A comprehensive review of the major investigations on the biology of African ixodid ticks is made with a view to identifying weaknesses in the life systems which may be employed as control components in an integrated package. The possibility of breeding ticks with low oviposition capacities needs to be confirmed and further studied with respect to the economically important ticks in Africa. Studies on the membrane or artificial feeding of ixodid ticks must be conclusive and more importantly the disease transmission abilities of these membrane fed ticks is worthy of being looked into. Additionally, the hybrid status of both Genus Rhipicephalus and Genus Amblyomma ticks should be studied. Efforts must also be made to intensify research on selecting resistant host breeds to multihost ticks, R. appendiculatus and A. variegatum, among the very many cattle breeds present in Africa.

Acanthoplus speiseri Brancsik, a pest of grain crops in Zambia, was reared in the laboratory at different temperatures. Mean development times of the eggs, nymphs and adults were determined at the different temperatures and used to develop a thermal unit model for use by farmers to predict the appearance dates of the different nymphal instars and the adults in the field in a given season. The predictions generated by the developed model for the 1990/1991 season, were compared to the actual dates on which the first specimen of each developmental stage was collected in the field during the season. The predicted dates of appearance all fell within 1 week of the observed dates of collection. Reasons for the slight deviations between the predicted and observed dates and the significance of the developed thermal unit model to the future control of A. speiseri in Zambia, are discussed.

A method of formulating granules from an acetone extract fraction of the fruit of Melia volkensii, a Kenyan tree known to possess insecticidal properties, was developed. The granules were tested for toxicity to third and fourth instars of Aedes aegypti L. Some acute physiological effects were observed within 24 hours of adding the granules to water as larval food. A mortality of 95% was achieved on various developmental stages of the mosquito after 12 days, with only 5% adult emergence being recorded.

Biconical traps were studied for their efficiency in sampling for Glossina morsitans morsitans Westw., G. pallidipes Aust., G. austeni Newst. and G. brevipalpis Newst. in three localities in Mozambique where these species occur sympatrically or singly. Studies were also carried out to determine whether acetone vapour was effective in enhancing the efficiency of the biconical trap. Various comparisons were also made between biconical traps and Langridge traps, and with fly-round patrols, with and without bait oxen.

It was demonstrated initially that the blue biconical trap (BBT) was more efficient for G. morsitans and G. pallidipes than red or white models or Langridge traps. In all subsequent studies, therefore, the BBT was used. It was concluded that: the BBT was ineffective for sampling G. morsitans, with or without acetone; the BBT was markedly more effective than fly rounds for sampling G. pallidipes, and its efficiency was significantly enhanced by acetone; and G. austeni was attracted to the BBT, but not all flies would enter the non-return cage—G. brevipalpis was readily caught in the BBT. Acetone with the BBT gave inconclusive results for these species.

Recent entomological surveys in the Bouaflé sleeping sickness focus of the Ivory Coast have revealed that Glossina tachinoides is considerably more widely distributed than hitherto. Some flies were found in the fringing riverine forests of tributaries of the River Marahoué. However, the greatest concentrations were found in villages and settlements where domestic pigs were kept. The southern limit of G. tachinoides now appears to lie one half degree of latitude further south than that reported by earlier investigators. The authors think there is good evidence that G. tachinoides is extending its range eastwards and southwards through and beyond the Bouaflé area, and the epidemiological significance of this is briefly discussed.

Screening of leishmanial parasites from domestic and wild animals was carried out in Kacheliba, West Pokot District. Spleens and livers of the animals were cultured in NNN diphasic medium. Thin smears of the same tissues were also made and stained with Giemsa stain and examined under microscope. Positive slide smears were obtained from goats and positive cultures obtained in four goats, one rat and two lizards.

The major alkanone constituents of the resin of Commiphora rostrata, 2-decanone and 2-undecanone, and a series of structural analogues were bioassayed for their repellency against the maize weevil, Sitophilus zeamais in olfactometric assays. All the aliphatic ketones and aldehydes showed comparable or greater activity than the synthetic commercial insect repellent N, N-diethyl toluamide (DEET). In the 2-alkanone series the C-8 and C-9 compounds demonstrated significantly higher activity than their shorter- and longer-chained congeners. Analogues differing in the relative positions of the carbonyl group, including aldehydes, showed a variable pattern of repellency. Alkanols appeared to be mildly attractive to the weevil. The results support our previous suggestion that the resin constituents may play an allomonal role in the ecosystem where the plant thrives.

Green marine algae (Codium sp.) was extracted sequentially with different organic solvents on cold. Lima bean leaf discs treated with the different extracts were offered to adult female T. urticae for 96 hr and the corrected percentage mortality of the females was calculated. The toxicity of the different extracts to the eggs was also recorded. Petroleum ether extract of this seaweed was highly toxic to females at 4 g/ml. At 1 g/ml ca. 48% of the individuals were killed. Chloroform and ethyl alcohol extracts were found to be poorly effective against the females even at high concentrations (4 g/ml) where less than 50% of the individuals died after 96 hr. Toxicity of crude extracts to the egg stage was less pronounced and chloroform extract was found to be more efficient than the other extracts tested.

The effects of various concentrations of Neem Azal-T and Neem Azal-T/S as natural insecticides on the biology and percentage mortality of adult Aphis craccwora Koch were studied under laboratory conditions. Both extracts had an aphicidal effect against the adults and significantly decreased their fecundities and longevities. Addition of synergists such as ethyl oleate, sesame oil and dimethyl sulphoxide (DMSO) improved the aphicidal effects of both insecticides. The biological activity of Neem Azal-T/S only could be enhanced with suitable additives as they adversely affected the fecundity and longevity in comparison to the extract alone. Addition of CaCO3 to the above extracts had no clear effect on either neem seed extract formulation.