This study was conducted on both station and farmers' fields during the 2010 dry cropping season in the Vallée du Kou rice scheme. We investigated the effect of three rice-transplanting periods (8–10 days) on the population dynamics, damage and parasitism associated with rice stem borers. The on-station experiment was designed as a randomized complete block with three treatments (planting dates) and four replications. Regular intervals of 14 days were observed between subsequent planting dates. Weekly agronomic and entomological assessments were performed from the 21st day after transplanting (DAT) to the 84th DAT. The on-farm experiment covered 1200 ha divided into two zones in which 48 farmers' fields were selected according to the periods of rice transplanting (resulting in 16 fields per period). On-station results indicated 10.1% of deadhearts and 7.5% of whiteheads due to stem borers in the first transplanting period, resulting in the lowest yield (2 metric tons/ha). In farmers' fields, the genus Chilo was found to be the most injurious rice stem borer in Vallée du Kou. The highest larval parasitism (38.5%) was recorded in the third treatment. These results provide important data that can be used in the development of an integrated management strategy for rice insect pests in Vallée du Kou.

In this study, the basic biology of and artificial rearing techniques for Bactrocera pyrifoliae (Drew and Hancock), a pest of peaches and plums in high-elevation areas of northern Vietnam and Thailand, were investigated for 5 years. Bactrocera pyrifoliae was found only between elevations of 1000 and 1500 m, heavily infesting peaches and plums from early June to harvest in mid-July. The durations of the egg, larval and pupal stages were determined under controlled environmental conditions in the laboratory, indicating that B. pyrifoliae is a multivoltine species. Larvae were successfully reared on a carrot and corn powder-based diet. Determinations of the appropriate adult density in colony cages, and also optimal temperature conditions for holding adults, were made. Bactrocera pyrifoliae performed better when the temperature was lowered during the night, as would be expected for a species adapted to temperate-like environments. Interestingly, adults originating from field-collected pupae emerged with a 3:1 female-biased sex ratio. Laboratory colonies, by generation seven, appeared to exhibit signs of inbreeding depression and required periodic incorporation of wild insects to restore egg hatch. To develop sound management techniques for populations of B. pyrifoliae infesting peaches, alternate commercial and native hosts infested outside the peach and plum fruiting season must be identified or some form of overwintering mechanism such as reproductive diapause be discovered. Documentation of mating behaviour in the field (a key to developing efficient traps), improvement in fertility in laboratory colonies, and eventually sterile insect technique-based integrated pest management for pest population management in the expanding low-chill temperate fruit-growing areas of northern Vietnam are also needed.

The green cassava mite, Mononychellus tanajoa (Bondar) and the red spider mite, Tetranychus urticae Koch infest all varieties of cassava in Sierra Leone. Both tetranychid species are widely distributed in the country and are causing severe damage to the crop mainly in the major cassava producing areas in the north-western regions. M. tanajoa caused chlorosis and 91° loss in photosynthetic area of the attacked leaves and defoliation of the plant either by acting alone or in concert with T. urticae. Late planted crop was particularly vulnerable to the infestation. M. tanajoa and T. urticae appeared to avoid severe interspecific competition on the plant by habitat stratification.

The biology of Maruca lestulatis Geyer was studied on different parts of 18 cowpea cultivars to determine the role of antibiosis in their levels of resistance. M. testulalis larvae were successfully reared from first instar to adult stage on floral buds, flowers and sliced pods, but not on stems, terminal shoots and intact (unsliced) pods, where there was complete larval mortality. The mean pupal weight ranged from 43.5–54.5 mg on floral buds, 38.5–58.6 mg on flowers and 42.7–58.6 mg on sliced pods, with highly significant differences between (P ≺ 0.01) resistant and susceptible cultivars on each part. Growth indices showed that sliced pods were the most suitable for larval growth and development, followed by flowers and floral buds.

The levels of resistance found were inadequate for solving the M. testulalis problem in cowpea. Selection and breeding for cowpea ideotypes (architypes), to combine such resistance with morphological, biochemical and biophysical traits, could enhance the low levels of resistance in the cowpea crop and ultimately lead to the effective management of this pest. The correlations between growth and development parameters showed that larval period had the most influence on M, testulalis survival and population build-up in the succeeding generations.

Four cultivars of maize, Zea mays L. viz., CM 600, Basilocal, CM 500 and Kisan were examined for their relative resistance to the maize stem borer, chilo partellus (Swinhoe) in relation to nutrition. Freshly hatched larvae of C. partellus were allowed to grow on the leaf whorls of the cultivars in the laboratory at 27 ±.2°C and 70–90% r.h. The rate of growth, food consumption and its utilization, egg laying and egg hatchability were studied. The insects showed better growth when fed CM 600 or Basilocal maize; this was shown by a higher percentage pupation (56.8 and 54.8, respectively on CM 600 and Basilocal) as compared to (24.4 and 5.6 respectively) on CM 500 and Kisan. Pupal weights were higher (40.2, 45.2, 34.4 and 32.8 mg for male pupae and 57.6, 63.7, 51.8 and 35.8 mg for female pupae), when larvae were reared on CM 600, Basilocal, CM 500 and Kisan, respectively. The growth index decreased from 1.65 on CM 600 and 1.49 on Basilocal to 0.40 on CM 500 and 0.09 on Kisan. A better consumption and utilization of the cultivars CM 600 and Basilocal was shown as also expressed by the higher weights attained by larvae grown on these two than on CM 500 and Kisan. Growth rate slowed down to 0.068 on CM 500 from 0.161 on CM 600 maize. A similar trend was observed in egg-laying and hatchability of eggs. Number of eggs laid per female decreased from 290 on CM 600 reared C. partellus to 157 on Kisan reared insects and none of the eggs laid by the latter could hatch. The degree of resistance of the cultivars to C. partellus on the basis of nutritional factors in a decreasing order is: Kisan > CM 500 > Basilocal > CM 600.

In the laboratory, adults of Prostephanus truncatus (Horn) preferred artificially or naturally (insect) damaged maize kernels to sound kernels when adults were tested individually or in groups. Survival of P. truncatus was similar when 1, 10, 40 or 80 adults were fed 100 g of shelled maize for 20 days; but more kernels were damaged at the highest adult density in comparison to the other densities of adults. Single P. truncatus adults on average damaged 9 maize kernels, but 10, 40, and 80 adults damaged approximately 15, 21 and 45 kernels, respectively, indicating that adults confined their feeding to only specific kernels. Survival of adults and number of kernels damaged were significantly affected when different quantities of shelled maize (25–500 g) were infested with 25 adults of P. truncatus. Adult surv at 25, 50, 100, and 200 g of maize/0.95–1 jar was similar (70.7–76.0%), but the number of kernels dama increased significantly from approximately 15 at 25 g to 61 at 200 g. These results suggested that shelled maize grain compaction, which is influenced by the quantity of grain, may affect survival of and damage by adults of P. truncatus. Adults of P. truncatus successfully infested 25 g of shelled maize and damaged about 15 kernels, indicating that adults could temporarily survive on such small quantities of grain spilled in and around storages before infesting stored-maize.

Chilo species are the most important stem borers of sugar-cane. They cause heavy losses to sugar-cane crop and continue to suppress yield in the sugar industry. The control of these borer species through insecticides has been difficult as the damaging larvae spend most of their life-cycle within the cane plant. The breeding of borer resistant varieties is an ideal approach for controlling the damage as it does not cost the grower anything extra, is effective at all levels of pest infestation and its effects are cumulative and long lasting in reducing the pest population. Many plant characters such as leaf surface, rind hardness, leaf sheath tightness, fibre content, stalk pith and diameter and plant vigour have been associated with borer resistance. In sugar-cane breeding, the inclusion of borer resistance characters, in addition to many other agronomic characters required of a commercial variety, is rather difficult due to the segregating nature of this plant. Therefore, it is better to use, as parent varieties the few varieties showing marked resistance without knowing the actual reasons of resistance. The joint efforts of sugar-cane breeders and entomologists in production and selection of a large number of seedlings for desired characters can help to solve this problem to a greater extent.

The influence of soil moisture and temperature on hatchling weight during the solitary phase of Locusta migratoria migratorioides (Reiche and Fairmaire) was studied. Soil moisture is an important weight determining factor; heavier hatchlings are produced in relatively wetter soils. Temperature has no apparent influence on hatchling weight. Hatchling weight and hatchling survival to the second instar showed a positive significant correlation.

Trypanosomiasis outbreaks of great severity, both medical and veterinary, still occur. At the present time some of these outbreaks can be contained by implementation of plans based on sound knowledge of tsetse distribution. However, for many countries such knowledge is fragmentary. For this reason the second edition of tsetse distribution maps is to be regarded as provisional only, pending the availability of more accurate data. Some of the new information that has been received since 1973 is reported. It is concluded that a programme of intensive revision is needed before it can be claimed that tsetse situation in Africa is well understood.

The activities of mankind which introduce excess nutrients and/or pollutants of various kinds into lakes, streams, estuaries, soils and the air, can, and often do, cause significant changes in aquatic and terrestrial environments world-wide. The pollution problem is critical because of the pressures of increasing populations, industrial growth and intensification of agricultural production. Conflicts of interest arise everywhere as challenges to resource use and natural state (‘beauty’) are turned into public issues.

The effect of planting dates on beanfly infestation was investigated in successively planted bean plants during cropping seasons. The population tended to build up in the course of the season following the initial invasion by egg-laying females. Ophiomyia spencerella (Greathead) and Ophiomyia phaseoli (Tryon) were the species of beanflies infesting the bean plants in all seasons. The number of beanfly leaf punctures, eggs, larvae and puparia were more in late planted than early planted bean crop. The bean crop planted late in the season was severely damaged due to the generally higher population levels which had been building up in the course of the season.

The assumption was made that for a complete understanding of the feeding behaviour and nutrition of Atherigona soccata larvae on various cultivars of sorghum, it was necessary to investigate the relationship between plant chemicals occurring in resistant sorghum plants and the digestive enzymes of larvae. However, at least an introduction to the anatomical organization of the alimentary canal of larvae is needed to understand the digestion and absorption of food taken from resistant and susceptible sorghum lines.

The present preliminary investigation was undertaken to determine qualitatively some of the enzymes present in the gut and salivary glands of the third instar by locating enzymes histochemically on polyacrylamide gels.

Animals were trapped in Marigat, Baringo District to investigate animal reservoirs of visceral leishmaniasis in an endemic focus of the disease. Several species of rodents, carnivores and reptiles were captured. Specimens of spleen, liver and blood tissues were taken from the animals. The specimens were triturated into sterile saline and then cultured into NNN medium, and some of it injected into hamsters intraperitoneally. Skin biopsies were also taken and cultured in NNN medium. Slide smears of all the tissues taken were made stained with Giemsa stain and examined under the microscope for amastigotes. Four isolates of leishmanial parasites were made from a gerbil and three monitor lizards.

The xerophytic perennial plant, Agave cantala Roxb. was studied for its biological activity on diamondback moth Plutella xylostella (L.). When cabbage leaves treated with acetone extract of A. cantala leaf were fed to the larvae in all instars, the extract was found to be weakly toxic at the highest concentration of 60 mg/ml, but it prolonged the larval and pupal periods, decreased the percentage of adult emergence and adult longevity. The fecundity and egg hatchability of adults emerging from final instar larvae fed with treated leaves decreased significantly. The eggs laid on treated leaves showed reduced hatchability.

Available pieces of information on Cicadulina sp. leafhopper biology, with specific references to the suitability of various species for mass rearing and resistance screening for maize streak virus (MSV) are critically reviewed. The following are summarized: (a) effect of distribution pattern and species composition on the efficiency of collection of live specimens for establishing a colony for mass rearing; (b) species biology and fecundity as affected by temperature and humidity; (c) species specificity in MSV transmission; (d) host plant preference and adaptation to mass rearing conditions. All these parameters affect the suitability of various Cicadulina species used as vectors in maize resistance screening and breeding to MSV disease.

The African armyworm, the larva of the night flying moth Spodoptera exempta (Walk.), feeds on young stages of cereal crops, sugar-cane and all types of grasses in some 30 countries of Africa, from Mauritania and Senegal in the north-west to Ethiopia and Somalia in the north-east, and southwards to Namibia and South Africa. Between 1960 and 1982, outbreaks of armyworms were recorded regularly in East Africa during the ‘outbreak season’ between November/December and June/July, often from southern Tanzania towards the north or north-west at monthly intervals. Analysis of occurrence of outbreaks in Tanzania, Kenya and Uganda in the 1971/72–1973/74 seasons, and rainfall records in Tanzania for 1969–1975, showed that the occurrence of armyworms in Tanzania coincided with the onset and northward progression of the rains up to Kenya and Uganda. Additional results from monthly maps, tables, graphs and histograms of armyworm occurrences in administrative units (Districts and Provinces) in Tanzania, Kenya and Uganda for 20 years (1960–1979), showed that the onset, progress and duration of armyworm attacks in all districts and provinces in each country, tend to follow certain geographical patterns which can be monitored through the use of insect traps and Agricultural Extension Services. In this way, coordinated surveillance of priority areas could enable farmers, pastoralists, Plant Protection and Pest Control Units of the Ministries of Agriculture to identify likely areas and periods of armyworm attacks, so that they could organize strategic or emergency control of armyworms with insecticides when the larvae are still young.

Mussidia nigrivenella Ragonot is the main cob borer of maize in Ivory Coast. An accurate description of male and female genitalia is given. Rearing in the laboratory has permitted determination of the number and duration of the pre-imaginal instars, fecundity of adults and fertility of eggs as also the sex-ratio. An artificial diet has been elaborated which provides conditions of similar development to those observed in the field: The insect has 5 to 6 larval instars and the total duration of development from the egg-laying to the adult emergence is 46 days for the male and 49 days for the female.

Female sexual receptivity was studied in F1 laboratory-reared Glossina pallidipes Austen, 1903 originating from Nguruman in the Rift Valley of Kenya. Females mated as early as 6 days old but reached peak receptivity at 9–13 days old (60–80%). Females did not immediately mate with more than one male. The mean spermathecal value (MSV) was highest between 7 and 14 days of age, and declined thereafter. The duration of copulation was comparatively short (mean = 24 min), and did not vary significantly with age. High female receptivity corresponded with maturity of ovariole A, which reached maximum length at an age of 10 days. These results are discussed in relation to mass rearing of G. pallidipes.

The cotton whitefly, Bemisia tabaci (Genn.), is parasitized by four Aphelinid species: Eretmocerus diversiciliatus Silv., E. mundus Merc., Encarsia lutea Masi. and an unidentified Encarsia sp Whitefly adults move from field weeds onto cotton during the period September–November. The application of broad-spectrum insecticides to control other cotton pests early in the season prevents the establishment of the host-stage of B. tabaci needed by the parasitoids within cotton fields during September and October. The rate of parasitism is consequently decelerated to peak in January towards the end of the season. Peak per cent parasitism for treated cotton fields was 36.7 as compared to 76.8 in untreated fields. This has promoted B. tabaci to an all season pest instead of an early and mid-season occasional pest. Alternative control strategies for early season pests are discussed.

Evaluations of toxicity, antifeedant, growth-regulatory activity of the methanol extract of Gliricidia sepium leaves were carried out against Dysdercus koenigii Fabr. (Heteroptera: Pyrrhocoridae), Achaea Janata Linn, and Spodoptera litura Fab., (both Lepidoptera: Noctuidae). Topical application of 100-300 μg of the extract to different stages of the test insects resulted in dose-dependent effects including larval-pupal intermediates and deformed adults. The highest tested dosage (300 μg/ μl) resulted in reduced survival rate and morphological abnormalities. At certain doses a strong antifeedant activity was evident against the lepidopteran insects.