Results of 7 years' experiments conducted in South China indicated that root-zone application of systemic insecticides effectively controlled nearly all the potential insect pests of rice—the yellow stem-borer, the striped stem-borer, the pink borer, the rice leaf folder, the rice gall midge, the brown planthopper, the greem leafhopper, the rice thrip and the rice weevil. Altogether, 16 compounds have been evaluated for the control of various species. Applications of carbofuran mixed with derivatives of nereistoxin (padan, thiocyclam or dimehypo) in the root-zone were found to be most effective against the major insect pests. The merits and demerits of root-zone applications has been discussed in this paper.

Field investigations were conducted at Mwea-Tebere Agricultural Research Station, situated in Central Province of Kenya, to evaluate the effects of the infestation of cotton by red spider mites, Tetranychus sp., on its growth and yield components. The results obtained revealed that mite damage adversely affected vegetative growth as measured by the amount of leaf and plant dry matter, number of leaves per plant, leaf surface area and mean size of leaves which were reduced by 67.07, 48.46, 68.18 and 60.37% respectively.

In addition to these effects, it was estimated that seed cotton yields could be reduced by 46.93% per plant due to mite injury. Seed development was adversely affected through the reduction of their weight (seed index), oil content and viability by 9.30, 10.07 and 36.67%, respectively. Similarly, mite damage to cotton plants caused the reduction of lint weight (lint index) and lint ginning percentage by 15.42 and 4.5%, respectively.

An evaluation of 17 chemicals was conducted in the field at Mwea-Tebere Agricultural Research Station to ascertain their efficacy against the red spider mites Tetranychus sp. attacking cotton in Eastern Kenya. The study became necessary owing to the inadequate control of red spider mites by the recommended acaricide, Dimethoate. Of the chemicals that performed well against the red spider mites, Kelthane, Akar, Morestan and Neoron were considered to be the most suitable replacements for Dimethoate because of their low levels of mammalian oral toxicity. Judged from the overall performance against the red spider mites, these acaricides were also about twice as effective as Dimethoate.

The individual histories of a herd of up to 671 goats used as hosts for rearing the haematophagous tsetse are summarized in terms of reproductive performance, morbidity and mortality during the period 1976–1978. The data are presented and discussed in relation to the unique management conditions imposed by a fly-rearing programme. The average kidding interval was 11.6 months, with 29.6% twinning. Kids had average birth and weaning weights of 2.3 and 13.6 kg, respectively. The average weaning rate of 40.5% was accompanied by 10.9% cull and 48.6% death losses. The reproductive performance of the East African doe compared well with that of improved breeds, although its lifespan was shorter in confinement. Monthly mortality averaged 2.7% while morbidity averaged 15.9%. The causes of disease are summarized by age groups, and a seasonal pattern of disease incidence was associated with weather extremes and availability and quality of nutriment.

A survey of phlebotomine sandflies was carried out in northern Nigeria to determine the distribution of Phlebotomus (Phlebotomus) duboscqi which is suspected to be the vector of cutaneous leishmaniasis in West Africa. P.(P.) duboscqi was found to be confined to the very dry areas of the Sudan savanna vegetation zone, where it utilizes termite hills as the main breeding habitats in association with rodents and lizards. Rock hyrax were located in some adjacent rocky areas. The restricted distribution range includes locations where cutaneous leishmaniasis has been recorded in Nigeria.

In Acanthoscelides obtectus (Say) (Coleoptera, Bruchidae) several first instar larvae can use a hole made in the seed coat by a conspecific to enter the seed. The present study tests whether there exists different seed-coat piercing abilities related to the hatching rank. The hatching rhythm was found to be well synchronized with the periodic conditions. The hatching rank had no influence on the piercing behaviour. On the basis of these observations the hypothesis of a behavioural dimorphism as has been suggested in the literature may be rejected.

The eggplant budworm inflicts severe damage to eggplant in the Gezira area of the Sudan, the larvae feeding inside the buds on the developing stamens and ovaries. Cv. “Black Beauty” was very susceptible with often more than 80% damaged buds, cv. “Long Purple” supported lower populations. Solanum dubium a common weed, was the only alternative host among several solanaceous species examined. Insecticidal screening trials indicated the effectiveness of several synthetic pyrethroids, whereas many other chemicals were ineffective. A possibility of breeding for resistance to this pest is discussed.

The population and distribution pattern of the black parlatoria scale, Parlatorio zizyphus (Lucas) have been investigated. This scale had two annual peaks of abundance in September and May. It passed through three annual generations, the first in September–October, the second in March–April and the third in June–July on grape fruit trees. The build up of insect population on different zones of grape fruit trees in different seasons of the year was studied. The insect distribution of different insect items were significantly affected at different heights and directions of the trees. The highest population tended to be accumulated on the lower and middle shady zones of the trees in different seasons. With regard to directions the central core of the tree harboured the highest population followed by the west direction and the lowest population was accumulated on the north or south direction in the fall and spring. In summer, the highest population settled on the south direction in contrast to the east or north directions, which harboured the lowest population. The mode of insect distribution is discussed in correlation with the environmental conditions.

The effectiveness of Bacillus thuringiensis var. galleriae HD-129 against the moths and egg masses of the cotton leafworm, Spodoptera littoralis, has been demonstrated in laboratory experiments. The longevity and egg production were significantly affected when the moths were fed on a sucrose diet containing 17.2 × 103 IU of the tested formulation/mg or higher rates. At lower concentrations (4.4−8.7 × 103 IU/mg), the females gave normal egg production, but the longevity was adversely affected. Investigations show that a formulation with spores alone affects the egg production and hatching, while a formulation with active crystals alone had no effect on egg production. Sprays of B. thuringiensis combined with sucrose on flowering cotton plants seem to affect the biology of the moths released on it. Egg masses sprayed with B. thuringiensis hatched normally, but the survival of the hatched larvae was reduced when treatment was made shortly before egg hatching. Based on the results obtained, B. thuringiensis showed a promising effect in the control of the moth S. littoralis as well as an ovicide larvicide agent.

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.

In a survey carried out in 1979–1982 in Sudan, 5830 tick immature stages were collected from cattle, sheep and camels and identified. Hyalomma anatolicum anatolicum, Rhipicephalus evertsi and Amblyomma lepidum immatures were feeding on cattle and sheep. Amblyomma variegatum immatures were collected from cattle. H. impeltatum nymphs were found, for the first time, to feed on camels and sheep, while H. dromedarii nymphs were recorded from camels.

Feeding H. a. anatolicum larvae on rabbits, 53.4% of the ticks behaved as three-host feeding cycle.

Factors regulating activity of adult Rhipicephalus appendiculatus ticks were investigated. Observations were made on ticks treated to 100% hydration, 85% hydration and 65% hydration during the hot dry, hot wet (rainy) and cool dry seasons. Two-months old and 6-months old ticks of each sex were released in two different habitats in 25 × 25 cm enclosures.

Comparisons were made between the number of ticks in each group seen on the upper part of the vegetation at intervals of 2 hr during daylight hours only. Although temperature changes seemed to be the cue to tick activity, the immediate activity shown by the 100% hydrated ticks and the delayed activity of the dehydrated groups after release, suggested that only fully hydrated ticks were responsive to temperature changes.

The most commonly recorded temperatures were within the range at which tick activity appeared to be at its maximum. During the daily temperature cycle, reduced activity was observed when the temperature was outside these limits. Activity increased again as soon as the temperature returned to the optimum range.

Groups of Rhipicephalus appendiculatus adults were prepared at three levels of hydration (100, 85 and 65%) and placed in small field enclosures. Some of the ticks were broadcast over the vegetation, while others were confined in nylon gauze bags and placed at soil level. Weight changes in the bagged ticks were monitored for 3 consecutive days by twice-daily weighing. Observations were made in the hot dry season, rainy season and the cool dry season. During the hot dry season there was a progressive loss in weight over the observation period, as during the night the ticks could not fully replace the water lost by day. In the rainy season there was an initial rapid uptake of water at night by the dehydrated groups and any weight losses during the day were easily replaced at night. In the cool dry season water losses were slight, and though ticks regained water at night, neither of the dehydrated groups became 100% hydrated during the period of observation.

The relative toxicity of seven fumigants to the four life cycle stages of Callosobruchus chinensis (L) was determined in the laboratory. Their relative toxicities to all stages of the insect were, phosphine > methyl iodide > acrylonitrile > methyl bromide > ethylene dibromide > methyl formate > ethyl formate.

The behavioural responses of Adisura larvae to different concentrations of the Lablab niger plant extract was tested under laboratory conditions. The concentrated plant extract did not elicit positive response from Adisura larvae. The first instar Adisura larvae preferred 10% concentration of the extract over higher concentrations (i.e. > 10%). First instar Adisura larvae were found more sensitive in discriminating non-host from the host than last instar larvae. Adisura gravid females laid no eggs on blackgram, cowpea, broadbean, redgram and PLS-24, a field bean (L. niger) variety. This study suggests that redgram, cowpea, broadbean, blackgram and soybean are not the primary hosts of A. atkinsoni.

Observations of the diurnal resting behaviour of Glossina longipalpis and Glossina fusca congolensis were carried out at Ele forest, Oke-Ako between September 1975 and May 1976 both inclusive. The two species of tsetse were observed resting most frequently on underside of stems and branches with diameter range 1–60 mm. Some G. fusca congolensis rested vertically. Whether resting vertically or obliquely, this species always rested with head pointing downwards. More than 95% of G. longipalpis and G. fusca congolensis rested between the heights of 20–240 cm. Preferred resting objects included shrubs, young saplings, climbers and, during high temperatures, bases of tree trunks.

For control purposes it is suggested from the above information that a discriminative and selective spraying of the area be planned for the late dry season and early rains when fly populations are more concentrated and individual flies tend to rest at lower heights. The spraying which should be directed to the undersurface of resting objects will help to reduce the risk of trypanosomiasis at the Oke-Ako cattle ranch.

A large pond, up to 2000 m2 area, adjacent to the sea at Jimbo, near Vanga, on the south coast of Kenya was studied for salinity and the presence of mosquito larvae 1980–1981. Rainfall peaked in November–December 1980 and again in March–May 1981, while salinity of the pond-water fluctuated inversely from dryness in February, more than 100% seawater equivalent in months before main rains, to below 13% seawater after the onset of rain in March.

Five types of mosquito larvae occurred in the pond: Aedes albocephalus mostly at 21–30% salinity (range 13–30%); Culex sitiens mostly at 31–40% salinity (range 13–54%); Culex tritaeniorhynchus and Culex thalassius mostly at 41–50% salinity (range 13–50%) and the Anopheles gambiae complex from 13 to 54% salinity, at least those at higher salinities being Anopheles merus. No larvae were present when salinity surpassed 54% through evaporation, or fell below 13% after rain. The most reliable way to limit or control these pest and vector mosquitoes at Jimbo would be to drain the pond into the sea after rainfall, so that mosquito populations could not increase by breeding sequentially, while salination proceeds.