The influence of host presence, age and mating on calling behaviour of the female spotted bollworm, Earias vittella, was studied under a 14L:10D photoperiod. Onset of calling was earlier in the presence of a host and 93% of the females initiated calling in its presence on day one after emergence, compared to 67% in its absence. A majority of the females initiated calling during the 10th hour of the first scotophase and thereafter the initiation shifted to earlier hours as age advanced. Females generally called longer in the presence of a host. The mean time spent in calling, from the 1st to the 10th day increased from 56 to 152 min in the absence of a host, and from 77 to 234 min in its presence. Most of the females resumed calling after mating, but the mated females exhibited a significant reduction in calling performance when compared with the virgin females.

A technique for infecting adult tsetse with an entomopathogenic fungus was developed and tested in the laboratory. A nitrocellulose filter membrane (Millipore) was used as substrate for retaining conidia after fitration, and a cylindrical plastic tube served as a chamber for the flies. The technique was designed to allow accurate estimation of inoculum on the substrate, thereby permitting comparison of virulence during the screening of fungal pathogens against tsetse flies. Glossina morsitans centralis adults were susceptible to Metarhizium anisopliae at all doses tested, and mortalities were dose dependent. No significant differences in mortalities were observed when flies were exposed for different durations to the pathogen. The number of conidia picked up by flies varied considerably with exposure time and concentration.

Species diversity of animals and plants is relevant to pest management in very different ways. Plant diversity provides sources of biologically active natural products and of genes for plant resistance. Animal diversity is involved in both harmful and beneficial interactions between crops and weeds or uncultivated land and in provision of potential biological control agents. The pest management implications of changes in biological diversity therefore need to be considered at a smaller scale in the management of cropping systems and on a larger scale in development programmes and national land use planning.

A survey of planthopper and leafhopper assemblages and insect predators was conducted in the rice fields of Kaluvanchikudi in Batticaloa District and Kohabana and Central Camp in Amparai District during the dry (yala) season in 1989. Nilaparvata lugens (Stål) was the predominant planthopper species in these rice fields; Sogatella furcifera (Horvath) comprised less than 10% of the sample in any field. The leafhopper species collected included Nephotettix nigropictus (Stål), Nephotettix virescens (Distant), Recilia dorsalis (Motschulsky), and Cofana (= Tettigella) spectra (Distant). Nephotettix species were predominant in Kaluvanchikudi and Kohabana, while R. dorsalis was dominant in Central Camp. Insect predators included the mirid, Cyrtorhinus lividipennis Reuter, an anthocorid, Onus tantillus (Motschulsky) and two coccinellids, Harmonia octomaculata (Fabricius) and Micrapsis discolor (Fabricius). Application of furadan granules reduced the planthopper and leafhopper populations drastically, but did not appreciably reduce the insect predator population.

Leaf extractables/fractions obtained from the leaves of soybean PI 227687 showed greater antifeedant activity towards the third-instar larvae of the cabbage looper, Trichoplusia ni (Hub.). Extraction of leaves with ethyl acetate followed by 60% methanol, and counter-current partitioning of leaf extractables between ethyl acetate, water and hexane was not convenient for isolation of antifeedants. Methanol (60%) in water extracted most of the antifeedants from leaves, and this extract when partitioned between ethyl acetate and water (the latter repeatedly extracted with the former), concentrated the antifeedants from soybean leaves for further processing on thin layer chromatography or high performance liquid chromatography.

There were quantitative differences in ethyl acetate fraction of PI 227687 (6%) and Davis (3.2%), and in flavonoids resolved at Rf 0.10–0.20 in benzene: ethyl acetate: methanol (4:3:3). Most of the flavonoids with antifeedant activity resolved at Rf 0.10–0.80. The antifeedant activity of flavonoid bands from PI 227687 was greater than the corresponding bands of Davis.

Studies were commenced to collect and identify the phlebotomine sandflies found in Nairobi. These studies were also aimed at determining their numbers as well as assessing the effects of seasonal changes on the sandfly population. Four trapping methods, namely, light traps, sticky traps, aspiration and human bait were employed. Eight species and one undescribed species were recorded over a period of 6 months. The identified species included Phlebotomus guggisbergi (Kirk and Lewis), P. rodhaini (Parrot), Sergentomyia adleri (Theodor), S. harveyi (Heisch, Guggisberg and Teesdale) and S. bedfordi (Newstead) and an undescribed species. Most of the sandfly species trapped showed seasonal prevalence. The seasonal variation was closely related to the weather conditions. Sandflies were found in termite mounds, animal burrows, caves and dugouts some of which were near human habitations. Termite mounds and animal burrows were the most preferred habitats.

Sorghum is one of the most important cereal crops in West Africa, and the head bug, Eurystylus immaculatus Odh. (Hemiptera: Miridae) is the key pest of grain sorghum in this region. A range of sorghum genotypes were evaluated for resistance to sorghum head bug at Sotuba (Mali) and Kamboinse (Burkina Faso). Genotypes CSM 388, IS 14332, Malisor 84–7, Sakoika, S 29 and Kamboinse local were resistant to head bugs, both under natural and headcage screening. Head bug resistant genotypes had a lower percentage of head bug damaged grain. The food quality of head bug damaged grain was very poor and unacceptable.

Cultivar non-preference was identified as a component of resistance to head bugs, and CSM 388 was nonpreferred compared to E 35–1. Panicle compactness was positively associated with head bug numbers and grain damage. However, genotypes with loose panicles were also susceptible to bugs. Long glumes (>5 mm), days to glume opening (>20 days after anthesis), >50% covering of the grain by the glumes, and grain hardness contribute towards resistance to Eurystylus immaculatus. This information will be useful for developing a programme to breed for resistance to this insect in West Africa.

Phagostimulant activities of sucrose, sitosterol, stigmasterol, campesterol, and soybean leaf extractables were evaluated towards the third-instar larvae of the cabbage looper, Trichoplusia ni Hubner (Lepidoptera: Noctuidae) on elderberry-pith discs under laboratory conditions. There was a linear relationship between sucrose dosage and larval feeding on the pith discs. Water fraction from PI 227687 soybean leaf extractables at dosages > 400 μg/disc inhibited feeding by T. ni larvae. Ethyl acetate fraction showed phagostimulant properties comparable to sucrose. Sterols (5 μg/disc) and soybean leaf extractables (40 μg/disc) in combination with sucrose (400 μg/disc) showed synergistic effect as phagostimulants. Implications of genotypic differences in sterol content in relation to host plant resistance are discussed.

The spore replication rate of the parasitic microsporidian, Nosema bombycis, was investigated in the pupal and adult stages of two popular tropical silkworm races of India, Pure Mysore (multivoltine race) and NB18 (bivoltine race). The rate was assessed in terms of spore yield per unit weight of tissue. In pupae, spore replication in the bivoltine race was higher than that in the multivoltine race. Spore replication in both races followed a logistic pattern. Spore production increased substantially with age of moths in both races. The cephalothoracic region of each race had the highest spore concentration, especially around the wing and wing muscles.

Crop losses caused by pests are a major problem in both developed and developing countries. Increasing awareness of the environmental consequences of indiscriminate use of chemical pesticides has provided new impetus for the search for alternative ways of managing pests. Particular emphasis has been placed on strategies that cause less pollution to the environment and those that are affordable, especially for the less developed countries. One concept that has received a lot of attention is integrated pest management (IPM), which seeks to manage pests and minimise crop losses by using methods that are economically viable and less harmful to the environment.

At least three distinct classes of new biotechnologies can have impacts on integrated pest management. These include microbial biotechnologies, plant molecular biology and genetics, and insect molecular biology and genetics. For example, recent advances in molecular biology have enabled scientists to overcome species barriers and to genetically alter plants, animals and microorganisms in ways that were not possible before. Already, several genetically altered plants which express genes that confer protection against pests have been produced. The techniques of biotechnology have also played important roles in elucidating pest populations and in studying the population dynamics of biological control agents and other types of organisms that live in association with crop plants. This article examines some of the major developments in the areas of molecular biology, genetics and biotechnology and the potential impacts that they could have on integrated pest management worldwide.

A life table was constructed for the mustard aphid, L. erysimi during January, February and March corresponding to 14 ± 2°C, 16 ± 2°C, 20 ± 2°C and 74 ± 5%, 74 ± 6% and 54 ± 5% R. H. under laboratory conditions. The study revealed that the values of intrinsic rate of natural increase (rm) and finite rate of increase (λ;) were 0.1035, 0.096, 0.023 and 1.109, 1.101, 1.023 females/female/day. The doubling time (DT) was higher in the case of alate morph during March (13.088 days) than apterous morph during January (6.697 days) and February (7.220 days). On reaching the population at a stable age distribution, the nymphal population estimated was 84.36, 93.87 and 92.67 in January, February and March respectively. The life expectancy (ex) of newly born nymphs of L. erysimi declines monotonically with advancing of age in these months.

Between 1984 and 1988, a survey of fruit-infesting ceratitid fruitflies was conducted in 11 agricultural districts in Kenya. Samples of up to 18 different fruit crops were examined for infestation. The four species of fruitfly found were Ceratitis capitata, C. rosa (Pterandrus rosa), C. nigra (Trirhithrum coffeae) and C. cosyra (Pardalaspis cosyra). The first three were sympatric infestants of coffee, while the latter was exclusively found in mangoes. In addition, C. rosaalso infested loquat, guava and custard apple. C. capitata infested commercial orange cultivars. This species was predominant in the main arabica coffee growing areas in the central highlands. C. rosa and C. nigra were more widespread, occurring in high proportions in most parts of the country. Generally, the proportions of the three species per coffee sample, and the mean number of each species per kg of coffee, tended to vary considerably over time and space.

This paper reviews major concepts and achievements made in the tropics in tackling; five major social and economic issues associated with research, development and adoption of integrated pest management technologies during the past two decades. Major focus has been placed on (i) integrating IPM into farming systems, (ii) monitoring pest populations, (iii) information and management intensity of IPM, (iv) economic viability of IPM, and (v) institutional factors affecting IPM. Emphasis is placed on pinpointing ways in which success can be achieved and how constraints can be overcome in order to make IPM work better in future.

Eleven mosquitocidal Bacillus thuringiensis isolates from Nigerian soils were screened for the degree of toxicity against Aedes aegypti larvae. The six most larvicidal isolates, code-named OBGI, OBG8, BUS4, BAR3, GSC3 and GNA13, were identified as subsp. israelensis (B.t.i). Spores of the six isolates of a B. t. i. from a commercial powder (R-153–78, Roger Bellon Laboratory, Belgium) and of IPS 82 (Institut Pasteur (Standards)) were subjected to ultraviolet irradiation (280–350 nm) for up to 75 min. After irradiation, the toxicity of OBG8, OBGI, BUS4, and BAR3 was higher than that of R-153–78 but lower than that of IPS 82.

Dysdercus fasciatus and D. cardinalis were studied in the field to ascertain their occurrence and relative abundance on different host plants at Masongaleni near Kibwezi, Machakos District, Kenya. It was carried out using a complete randomized block with four replicates. It was shown that D. cardinalis occurred more commonly on its wild host plants than D. fasciatus. D. cardinalis was also commonly found feeding on Sterculia spp. on which D. fasciatus was not recorded during these studies. Neither species was recorded from baobab trees.

The ovisite preference of Goniozus nephantidis (Hymenoptera: Bethylidae) was studied in relation to its hosts, Opisina arenosella, the coconut pest and Corcyra cephalonica, the flour pest. In both hosts, eggs were laid on all the segments except the first thoracic and the last four abdominal segments. Among the abdominal segments, the most preferred were segments 2 and 3 in the case of O. arenosella and 4 and 5 in the case of C. cephalonica. The percentages of eggs located intrasegmentally were 91.35 and 86.19; those of eggs located intersegmentally were 8.65 and 13.80 in the case of O. arenosella and C. cephalonica respectively. The left side was preferred in each host. In most of the egg clutches on O. arenosella, the head end faced the caudal end of the host; on Corcyra cephalonica, the head end faced the head end of the host.

This paper examines social and economic aspects of integrated vector management in relation to the control of various vector-borne human diseases. The role of the human environment and activities in transmitting and in controlling human diseases is described. Common vector-borne human and domestic animal diseases in the tropics are listed and described in relation to their carriers (vectors), geographical regions of prevalence, approximate numbers of humans affected and likely remedial strategies. The benefits of integrated vector control as opposed to chemical control are discussed and supported with examples from various parts of the world. The paper ends by listing World Health Organisation recommendations on how to control human vector-borne diseases.

The diversity and abundance of insect predators of the bean aphid, Aphis fabae Scop. (Homoptera: Aphididae) on common beans, Phaseolus vulgaris L., were evaluated in Central Kenya. Predators included species in the Orders Coleoptera, Diptera, Hemiptera and Neuroptera. Coccinellidae were the most abundant and diverse group and several species, such as Hippodamia variegata Goeze and Platynaspis capicola Crotch, had hitherto not been recorded on common beans in Kenya. Higher numbers of predators developed on beans during the short rains (up to 540/100 m2 plot) as compared to the long rain season (182/plot) of 1985. In both seasons, numbers of coccinellid larvae were high after the fourth week of bean growth. The study provides evidence of an important build-up of insect predators on beans.

The morphology of immature stages of a species of Glyptapanteles was studied. Measurements of the egg, larval and pupal stages are presented. The head sclerites of the three larval instars are also described.

The leucaena psyllid, Heteropsylla cubana, was studied under constant temperatures ranging from 21.5 to 35.0°C. Total mean development time was 11.2, 9.6 and 8.1 days at 21.5, 25.0 and 30.0°C respectively. For these temperatures, the mean number of eggs laid was 532.3, 758.3 and 374.7 with hatch rates of over 90%. At 35.0°C, a mean of only 4.5 eggs/female were laid in 24 h, egg hatch (9.0%) was very low and nymphs did not complete their development. Nymphal survival was only 65% at 30.0°C, compared to 84.2 and 87.6% at 21.5 and 25.5°C, respectively. Adult longevity was highest at 25.0°C; females outlived males at all temperatures. Age-specific life table statistics are given for the three temperatures. The calculated intrinsic rates of natural increase (rm) at 21.5, 25.0 and 30.0°C were 0.226, 0.293 and 0.324 respectively. Relative humidities in the range of 25 to 84% did not affect egg hatching, nymphal survival, or adult emergence of H. cubana.