In an attempt to overcome the problem of catching Glossina austeni Newstead in reasonable numbers, which hitherto has hindered studies of its ecology in Zanzibar, a new tsetse trap (the Chuka trap) was developed. Its sky-blue coloured version proved superior to the white-and grey-coloured versions, the biconical trap, the Epsilon trap and the 3-dimensional “target” respectively, in catching G. austeni. The Chuka trap helped to establish that G. austen is a very low flyer and most trappable in the “forest floor” biotope of Jozani Forest.

Catantops spissus spissus were reared in groups of 10 using Calapogonium mucunoides, Zea mays, Elaeis guineensis and Manihot esculenta separately. The proximate compositions of these various food types were analysed and energy contents calculated. This was to establish how food types can influence the rate of development of the insects.

The results showed that insects reared on C. mucunoides and Z. mays had the fastest maturing period in days while insects reared on E. guineensis and M. esculenta developed much later. The rate of food consumption could not be related directly to the amounts of individual nutrients nor the total energy content of the food. On the other hand the rate of development of the insect appeared to be directly related to total energy derivable from the overall food consumed. In addition, differences in the rate of development were noticed at the various instar stages. This was also related to the amount of energy consumed from the food types at the particular instar stage.

Cassava leaves damaged by green spider mite, Mononychellus tanajoa (Bondar) and undamaged leaves were analysed in the laboratory for chlorophyll content by spectrophotometry. Proximate analysis was also carried out on the leaves in the laboratory using the Association of Official Analytical Chemists methods.

More light was absorbed by the chlorophyll extract from the undamaged leaves than in the mite-damaged leaves. More light was also absorbed at the wavelength of 663 nm than at 645 nm. The concentrations of chlorophyll a and b were higher in the undamaged leaves than in the mite-damaged leaves. The concentration of chlorophyll a was higher than that of chlorophyll b both in the undamaged and mite-damaged leaves.

Mite-damaged leaves weighed less than the undamaged leaves, both when fresh and when dried. The proximate products values were less in the mite-damaged leaves than in the undamaged leaves.

The paper reviews the work done on the population patterns of Chilo spp. in relation to the phenological stages of sorghum, maize and millets. The stem borer Chilo partellus entered sorghum and maize crops at 2–3 weeks after emergence and continued till harvest. There were 3–4 peaks of larval population during a cropping season. Such studies not only reveal the relationship between the larval population density and the phenological stage of the plants at infestation time, but are also helpful in scheduling and timing pest management strategies.

The development and pest status of Aspavia armigera on two cowpea varieties viz: Ife Brown and TVU1890 and alsoon two upland rice varieties viz: ITA 128 and ITA 257 were studied under ambient conditions in the laboratory and at the roof-top garden, Department of Agricultural Biology, University of Ibadan, Nigeria.

The oviposition periods on rice were 15.1 and 6.0 days respectively on ITA 257 and ITA 128; and on cowpea 10.6 and 8.5 days respectively on Ife Brown and TVU 1890. Fecundity was low. Mated females laid the highest number of eggs (24.6) on the cowpea Ife Brown and this was significantly higher than in the other cultivars. Mated and unmated males and females lived longer on Ife Brown and ITA 257 than on ITA 128 and TVU 1890.

The developmental period (nymph to adult), was shorter on ITA 257 (23.3 days) and Ife Brown (22.9 days) than on ITA 128 (23.3 days) and TVU 1890 (25.3 days). There were five nymphal instars and the mean growth ratio of head capsule measurements was 1.32.

Infestation at the level of two A. armigera per peduncle caused total seed losses in the two cowpea varieties whereas four and eight bugs per panicle caused 39.1 and 31.7 % grain yield losses in ITA 257 and ITA 128 rice varieties respectively.

The structural components and physical characteristics of sorghum kernels were studied as factors of resistance against Sitotroga cerealella (Oliv.) and Sitophilus oryzae (L.). Specifically, the effects of kernel glumes, weight, size and hardness on larval entry site, oviposition site, emergence site, progeny production, and kernel damage and weight loss, were investigated. The larvae of S. cerealella entered kernels primarily in the germ end and its periphery. Females of S. oryzae oviposited eggsmainly in the endosperm portion of kernels. Larval entry into kernels, and subsequent development of S. cerealella was enhanced in kernels that were enclosed by glumes. In addition, S. cerealella caused greater damage and weight loss in kernels with glumes. In contrast, kernels with glumes yielded less adult progeny of S. oryzae, and sustained less kernel damage and weight loss. The emergence holes of S. cerealella were located mainly in the crown end, whereas those of S. oryzae were mostly in the endosperm portion of kernels. The heavier and larger kernels produced heavier and larger adult progeny of both species of insect.

Population trends of Chilo suppressalis during the past 20–35 years in Japan, Korea and Taiwan were compared in terms of light trap records and the area infested by Chilo. In all three countries, Chilo showed a declining population trend, first observed in the late 1950s in Japan, followed by the same pattern in Taiwan and Korea, successively. Among the contributing factors, the early planting of rice was suggested as one common factor. This early planting of rice is also followed by, or associated with, various agronomic practices, e.g. the use of varieties with a larger number of tillers, more intensive pesticide control, early harvesting, the mechanization of agricultural practices, etc. An integrated technology system based on early planting was considered the primary factor responsible for the recent decrease in Chilo. The increased utilization of machinery in rice production will encourage a further decline in Chilo in this region. Local and small scale outbreaks of Chilo were observed in all three countries, due to the widespread use of straw for the culture of special crops. However, so long as the current production system remains the same, there is no scope for Chilo's revival.

Effects of topical application of two juvenile hormone analogues (JHAs), R-20458 (6, 7-epoxy-1(p-ethylphenoxy)-3, 7-dimethyl-2-octene) and ZR-512 (ethyl 3, 7, 11-trimetnyl-2, 4-dodecadienoate) on reproduction and longevity of mustard aphid, Lipaphis erysimi (Kalt.) were investigated. Doses of the JHAs as high as 2 μg per aphid failed to reduce the fecundity of the aphid though initial reduction in the daily reproduction was observed. Also, the doses which induced morphogenetic abnormalities at the third-instar, could not affect embryogenesis.

A study of population ecology and vectorial capacity of Glossina fuscipes fuscipes Newstead was initiated on Rusinga island and mainland of Mbita Division, South Nyanza District, Kenya. As part of the overall study, investigations into fly distribution and diel activity patterns were carried out using biconical traps. The distribution of flies was found to be confined to a strip of dense vegetation of several metres in width along the lake shore. Trap catches indicated unimodal diel activity patterns for both sexes. Catches were recorded between 0700 and 1900 hr with peaks for females at 0900 hr and for males at 1000 hr. Of the physical factors (solar radiation, relative humidity, temperature and windspeed), solar radiation was found to be the main factor significantly influencing the catches of both males and females during the day. For males Y = −29.46 + 6.30X1 + 0.40X2, (r2 = 0.59, P = 0.0053 and P = 0.0425, where X1 = solar radiation and X2 = relative humidity, respectively). For females, Y = 3.63 + 5.13X1, (r2 = 0.20, P= 0.0960, where X1 = solar radiation).

Studies were conducted on components of resistance to sorghum midge on four resistant (DJ 6514, AF 28, TAM 2566 and IS 15107) and two susceptible (CSH 1 and Swarna) cultivars. Short floral parts, faster rate of grain development and high tannin content of grain were apparently associated with resistance to sorghum midge, Contarinia sorghicola Coq. Genotypic and phenotypic correlations between the factors associated with resistance to sorghum midge were in the same direction (positive or negative) as their association with resistance to this insect. Glume g2, lemma 12, anther and lodicule length, rate of grain development based on dry weight (except oviposition), and tannin content of mature grain showed correlation and path coefficients (direct effects) in the same direction. These characters can serve as a useful criteria to select for resistance to sorghum midge.

Using D2 and canonical cluster analysis, AF 28 was found to be distinct from other sources of midge resistance. However, based on larvae/100 florets, DJ 6514 was also placed distantly from TAM 2566 and IS 15107. Based on egg numbers, adults emerged and grain damage, DJ 6514 was grouped with TAM 2566 and IS 15107. Susceptible hybrid check, CSH 1 was generally placed distantly from the self pollinated susceptible variety, Swarna. These results indicate that the sources of resistance to sorghum midge are diverse, and there is a distinct possibility of increasing the levels and diversity of resistance to this insect.

In April–May 1986, 180 male and 218 female Glossina morsitans morsitans Westwood, each less than 1 day old, were marked uniquely and released unfed on Redcliff Island, Lake Kariba, Zimbabwe. Flies were recaptured on ox fly-rounds carried out twice daily for 6 months; marks were recorded and the flies released. For females, 56% were recaptured at leastonce; the capture probability for a given 9-day period changed with age, falling from 0.32 after birth to 0.16 by 30 days and rising above 0.5 by 80 days. For males, 57% were recaptured; the probability was 0.21 for age less than 9 days, but > 0.77 for all older flies. The capture probabilities and fly-round catches were used to estimate the change with age in the daily mortality. Female mortality was 6.8% shortly after emergence, < 1% for ages 20–50 days and rose to 5% by 130 days—a pattern similar to that for laboratory reared tsetse. Male daily mortality was 8.3% after emergence, fellto 5.5% by 9 days, then rose continuously to more than 10% by 30 days. The mortality changes are related to age rather than climate. Tsetse caught on ox fly-rounds from a natural population were aged using ovarian dissection and wing-fray analysis. The age distribution (corrected using the capture probabilities from Redcliff) was consistent with the idea that, here too, mortality increased with age.

Four species in the genus Amblyseius Berlese are reported from Tanzania, A. serengati sp.n., A. fustis Pritchard and Baker, A. largoensis (Muma) and A. sawaga Pritchard & Baker. Descriptions and comparisons with similar species are provided for the new species.

Spatial pattern of distribution of populations of three insect species, namely, Amrasca biguttula biguttula (Ishida), Bemisia tabaci (Genn.) and Aphis gossypii Glov. was studied in Upland cotton (Gossypium hirsutum L.) at an interval of 13–15 days during July, August and September in Punjab. The populations were found to be aggregated from the beginning of season upto 25 August in jassid nymphs, 12 August in whitefly adults and the end of season in apterous aphids. Environmental heterogeneity at low population in July and innate behaviour at high population were responsible for the aggregated dispersion in each of the three homopterans. Based on these observations the appropriate number of samples required to be drawn for population studies were determined which varied with change in pest density in each case.

The developmental periods of the immature stages of Exochomus troberti Mulsant were studied in the laboratory at the prevailing temperature range of 26–30°C. That of the second instar larva was the shortest (2.1 days) followed by the third instar larva (3.1 days). The longest developmental period (approximately 5 days) was recorded for the egg, first- and fourth-instar larvae and pupa.

Oviposition commenced after 1 week of adult life and peaked in the 5th week with 37.2 female eggs/female. All ovipositing females survived the first 9 weeks of adult life when 82% of the total eggs were laid. By the 13th week, which was the effective end of reproduction (98 % fecundity) only 40% of the females had died.

Both capacity for increase (rc) and intrinsic rate of increase (rm) were calculated for E. troberti and found to be 0.092/day and 0.105/day, respectively.

Mean daily predation rates in non-choice experiments on the second instar nymphs of P. manihoti by the fourth, third and second instar larvae of E. troberti were 28.3, 15.6 and 8.0, respectively. On the third instar nymphs and fourth instar young adults of P. manihoti the mean daily predation rates by the fourth, third and second instar larvae of E. troberti Were 17.6, 8.3 and 4.5; and 4.0, 3.0 and 1.0, respectively.

The populations of E. troberti, other coccinellid predators and P. manihoti were monitored in two small local farms for three seasons. E. troberti was found to be the dominant coccinella predator in terms of numbers of individuals found in the field during the years of this experiment.

The cyclical population oscillations of P. manihoti were similar in all the experimental years but differed only in the amplitude of oscillations. Those of E. troberti and the other coccinellid predators were lower than those of P. manihoti.

A review of the losses caused by various species of Chilo, methodologies adopted for the assessment of losses and information generated on the models for the effect of Chilo species on the yield of graminaceous crops is given.

There were significant variations in oxygen consumption and carbon dioxide evolution of Macrotermes carbonarius (Hagen) among the soldiers and workers over a 10-hr experimental period. This suggested that the insects exhibited rhythmic respiratory behaviour in spite of being separated from their nest system and in the stressful situation of confinement of a respiratory flask at 29°C. The correlation between body fresh weight (mg) and respiratory rate ml O2/mg fresh wt/hr was significant. A respiratory quotient of 1.0–1.1 suggested that glucose was the respiratory metabolic substrate utilized and that both aerobic and anaerobic processes could have been taking place. Most of the leaf litter imported into the mound was utilized by the fungus on the fungus comb for metabolism with the release of carbon dioxide, heat and water. The heat released was sufficient to maintain the brood chamber temperature at 29.1 ± 03°C despite fluctuations of the ambient temperature and the temperature of the surrounding soil.

The main thrust of the article is to present the historical development of the idea of Integrated Pest Management (IPM) from the heyday of “pestophobia” (the insistence of elimination of any vestige of insect interference with the cosmetic appearance of our crops), which leads to the misuse and abuse of insecticides, to the era of employing IPM concepts, which leads to pest interventions which are necessarily knowledge-intensive. Illustrations are given using ICIPE's research experience in developing an IPM approach to the control of Chilo through adaptation of relevant intercropping patterns, plant resistant cultivars and biological control agents. In this task, the IPM specialist needs to have three assets to be successful in the tropics: he needs to be a first-class natural historian; he requires to build his new knowledge on the traditional knowledge of the rural farmer, and to rationalize it scientifically, and he needs to be able to manipulate new innovations—both technical and social.

A bioassay was developed to assess the in vitro feeding responses of Chilo partellus larvae to susceptible (Inbred A) and resistant (MP 704) maize varieties. Consumption of internode tissues from the two maize varieties differed while the reverse was true for the nodes. Aqueous extracts from the two varieties caused a decrease in feeding and weight gain, but these effects were more evident in MP 704 than in Inbred A treatments. This suggests that MP 704 has a water extractable factor affecting weight gain negatively. Dose-response curves of neural responses from the maxillary styloconica sensilla showed that aqueous extracts from the two maize varieties evoked different functional forms of impulse frequencies especially in the lateral sensilla. These observations suggest that the quality of gustatory stimuli in the two maize varieties differs.

Apanteles taragamae is a major parasite of Diaphania indica, a serious peston cultivated cucurbits. Variations in the parasitism of D. indica infesting different cucurbits in thefield were observed. Four cucurbits viz: ivy gourd, cucumber, bitter gourd and musk melon were screened to identify the host plant(s) favourable to A. taragamae. Maximum parasitism was recorded on bitter gourd andivy gourd. These two cucurbits were favoured over musk melon and cucumber when leaf hairness was examined. Both ivy gourd and bitter gourd had smoother leaves than cucumber or musk melon and parasitism of larvae on smooth leaf plants was greater. However, on the basis of parasite development on the four cucurbit reared host larvae, it was concluded that D. indica's preference for bitter gourd and ivy gourd was due to the influence of the host habitat (leaf hairness) and not due to physiological factors.

The development of simple models for describing the population dynamics of species with overlapping generations is briefly described. The paper then presents a minimally complex simulation model for tsetse populations in which seasonally varying density-independent mortality, generally applied only to the adult stage, is combined with density dependence acting on both puparia and adults. Density dependence regulates population size within limits determined by an interaction between the strength of the density-dependent relationships and the variability of the seasonal density independence. Population data sets for Glossina palpalis and G. morsitans in Nigeria, and G. pallidipes in Kenya are adequately described by the model. Relationships discovered between the density-independent mortality and climatic variables for the Lambwe Valley data set allow predictions of population changes in other sites on the basis of their climatic conditions. Attempts to predict changes in the population of G.pallidipes in Somalia highlight the difficulties of this exercise. A tsetse's demographic response to climate may vary from region to region, making extensive predictions from local data sets difficult. There seems, however, no need to make more complex models to describe observed changes in tsetse populations.