Termites are an important component of savannah ecosystems throughout Africa. Despite their importance in the ecosystem, they can be serious pests of structures, houses, rangelands, tropical forestry, and agriculture. For many decades, chemical insecticides have remained popular for termite management worldwide. However, with the growing environmental concerns over pesticides, biological control using entomopathogenic fungi such as Metarhizium anisopliae (Metschnikoff) Sorokin has become an often-considered alternative. Metarhizium anisopliae is an ubiquitous, naturally occurring pathogen, which has been reported infecting over 200 insect species; therefore, there is concern that use of M. anisopliae may affect non-target organisms. The effects of M. anisopliae isolate ICIPE 30 were experimentally tested on the ants which associate with Odontotermes spp. termite mounds. Laboratory bioassays were carried out to assess the effects of direct exposure to M. anisopliae on Crematogaster mimosae and Camponotus spp. In addition, ant diversity was monitored over 18 months from termite mounds treated with M. anisopliae in situ near the Mpala Research Centre in Laikipia District of central Kenya. Results obtained revealed no effects of direct exposure to M. anisopliae isolate ICIPE 30 on the mortality of C. mimosae (F1 = 7.29, P = 0.0072) or Camponotus spp. (F1 = 13.01, P = 0.0004) in the laboratory. No significant difference in Shannon indices of ant diversity from treated and untreated mounds (F1 = 0.016, P = 0.8989) was found. It is evident that M. anisopliae has no negative effects on ants that are associated with Odontotermes spp. termites.

Using examples from surveys to collect natural enemies of the indigenous African sugarcane borer Eldana saccharina Walker throughout Africa, insight is given into what factors should be investigated should biological control of other indigenous African stemborers be considered. Indigenous host plant range, parts of indigenous and crop hosts attacked, types of natural enemies found in these different niches and natural enemy attack strategies are all important factors to consider when planning redistribution of indigenous natural enemies from one part of Africa to another. This knowledge is important when choosing the correct natural enemy for mass rearing and release into the affected crop, and can be used to manage the crop habitat, using the indigenous tritrophic systems identified, to increase crop diversity and thus effectiveness of indigenous natural enemies.

The efficacy of natural embelin isolated from berries of Embelia ribes Burm. against Tribolium castaneum Herbst is discussed. Embelin mixed with wheat samples at concentrations of 0.1875% and above exhibited high efficacy by bringing about adult mortality even after 8 months of storage. Productivity (progeny/adult-day) of the test insect was also reduced significantly in treatments as compared to controls at different intervals of storage. After 8 months of storage, significant reduction in F1, progeny at the lowest concentration was mainly due to larvicidal action of embelin. In the present study, embelin did not exhibit any chemosterilant action or contact toxicity to adult beetles. Germination of wheat treated with embelin even at the highest concentration of 0.750% was not impaired to any significant extent.

Root bark extracts of five Meliaceae species (Turraea abyssinica Hochst., Turraea wakefeldii Oliv., Turraea mombassana Hiern ex C.DC., Trichilia roka (Forsk) Chiov. and Melia volkensii Guerke.) and different fractions thereof (following chloroform extraction and column chromatographic separation) were compared for their immediate toxicity and long-term effects on Anopheles gambiae Giles sensu stricto (Diptera: Culicidae). Larvicidal effects of the extracts appeared to be largely associated with limonoids of medium polarity with M. volkensii and T. mombassana extracts being more potent than those of the other Meliaceae. Long-term (6–8 days post-exposure) observations at lower doses showed that 100% cumulative mortality can be achieved with some extracts (particularly those of T. mombassana and M. volkensii) with interesting growth-inhibition effects. Follow-up studies that are needed and practical implications of the results in terms of development of larval control strategies for African malaria vectors are discussed.

In the Zambezi Valley of Zimbabwe, ULV applications of non-residual insecticide (endo-sulphan and NRDC 161) were made to a 1.8 × 1.8 km block of woodland infested with Glossina morsitans morsitans Westw. and G. pallidipes Austen. The recapture rates of marked flies released in the centre of the block, and recaptured in odour-baited traps in and around the block, indicated that the insecticides killed about 97% of flies that had been released 1–4 hr before spraying. Catches of unmarked male G. m. morsitans in the centre of the block declined after the insecticide applications, but there was no clear effect on catches of female G. m. morsitans and both sexes of G. pallidipes. Data for the movement of marked flies suggested that the minimum daily rates of movement were about 700 m for male G. m. morsitans and about 800 m for the other tsetse. An increase in dawn temperatures, from 17.5 to 27.5°C, was associated with an increase in the rate movement of G. pallidipes in the early morning. The failure to detect changes in the unmarked populations of female G. m. morsitans and both sexes of G. pallidipes was attributed to the high mobilities of these flies and demonstrated that unmarked populations could not be studied satisfactorily in small plots; studies based on marked populations are recommended for such plots.

Kerria lacca (Kerr) is commercially harnessed for lac resin, which is principally an ester complex of aleuritic acid (9,10,16-trihydroxyhexadecanoic acid) and jalaric acid. The present study is an attempt made to identify the possible pathways involved in the biosynthesis of lac resin. It is proposed that acetyl-CoA is the common precursor for the biosynthesis of aleuritic acid and sesquiterpenic acids (jalaric acid). Prenyltransferases are involved in the biosynthesis of sesquiterpenes; hydroxylation of hexadecanoic acid, after chain elongation, appears to occur through the action of cytochrome P450 enzymes. Two related genes as proposed above were identified and sequenced. The diurnal rhythm of resin secretion and protein concentrations were also studied and correlated for ascertaining the active secretory phase.

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.

Successful attempts made for biological control of sugar-cane pests by introduction, redistribution, conservation and augmentation are discussed.

In Pakistan, Apanteles flavipes (Cameron) became established on Chilo partellus (Swinhoe), following its introduction from Japan, but it seldom attacked sugar-cane borers. Sugarcane-adapted strains were introduced which became established in Punjab and NWFP, but were not recovered after winter in Sind. A hybrid between sugar-cane-adapted strain and strain found locally on maize borer, was released. This resulted in its establishment.

In Sumatra (Indonesia), a local strain of A. flavipes was being encapsulated in Chilo auricilius Dudgeon. Following introduction of its strain from Thailand, it is giving very high parasitism of C. auricilius and C. sacchariphagus (Bojer).

A parasitoid, Epiricania melanoleuca (Fletcher) is giving excellent control of sugar-cane Pyrilla pe pusilla (Walker) in NWFP following its redistribution from the Punjab and in Sind after redistribution from the Punjab and NWFP. In Sind it is also being controlled by conserving its egg parasitoid Parachrysocharis javensis (Grault) by keeping some trash unburnt near the fields.

In Sind, infestation of Chilo infuscatellus Snellen was reduced to sub-economic level by augmentative releases of Trichogramma chilonis Ishii in March as soon as the pest started laying eggs.

The antifeedant activities of Piper guineense Schum et Thonn (Piperaceae), Aframomum melegueta (Rosk) K. Schum (Zingiberaceae), Aframomum citratum (Pareira) K. Schum (Zingiberaceae) and Afrostyrax kamerunensis Perkins and Gilg (Huaceae) seed extracts were investigated in laboratory dual- and no-choice bioassays using third-instar Spodoptera littoralis (Boisduval) larvae. In the dual-choice test, the hexane and methanol extracts of A. melegueta showed potent dose-dependent antifeedant activity at concentrations of ≥300 ppm and the water extract at ≥500 ppm, as illustrated by significantly lower leaf consumptions. Aframomum citratum methanol and water extracts exhibited antifeedant activity at ≥300 and ≥1000 ppm, respectively, but the hexane and ethanol extracts did not affect feeding at any concentration. Piper guineense ethanol and water extracts showed dose-dependent antifeedant effects at ≥300 and ≥500 ppm, respectively, and the methanol extract was active only at 1000 ppm. None of the extracts of the highly aromatic A. kamerunensis exhibited antifeedant activity at any of the tested concentrations. In the no-choice bioassays, extracts with antifeedant activity in the dual-choice tests also showed dose-dependent feeding inhibition. The hexane and methanol extracts of A. melegueta were effective in the no-choice tests at ≥100 and ≥500 ppm, respectively, and the water extract at ≥300 ppm. Similarly, the A. citratum water and methanol extracts were active at ≥500 ppm and the P. guineense water and ethanol extracts at ≥100 ppm. GC/MS chromatography of A. melegueta hexane and methanol extracts revealed volatile constituents with known anti-insect activity. The hexane and methanol extracts of A. melegueta, the methanol extract of A. citratum and the water and ethanol extracts of P. guineense may have potential for use by subsistence farmers.

The ability of peasant farmers in the third world to monitor environmental occurrences around them has often been ignored. This study looks at Nigerian fanners' perception of pests and pesticides and determines the relevance of such knowledge as an input to efforts to devise effective integrated pest management strategies.

Farmers in Kabba area of Kwara State, Nigeria were extensively interviewed and the following findings were highlighted: they had a deep knowledge of all insect, animal and fungi pests; could identify each pest, know their breeding cycles and their general behaviour characteristics; were able to make a relatively accurate assessment of damage caused by pests; and developed an indigenous integrated pest management strategy.

Due to massive pest damage in the last few years, and strenuous advertisement by the Ministry of Agriculture, many farmers are now turning to chemical pesticides for solution to the pest problem. Prognosis of future trends in pesticide usage among farmers reveal the likely danger of farmers becoming pesticide-dependent with the consequent possibilities of human poisoning and eventually aggravating the pest problem.

Steam distillates of seven Nigerian plants, Lippia adoensis Hoschst, Azadirachta indica A. Juss, Monodora tenuifolia Benth, Piper guineense Schum & Thonn, Petiveria alliacea L., Citrus sinensis L. (variety Nigerian green orange), and Cymbopogon citratus L. were tested for acute toxicity on four major insect pests. The pests were larvae of Acrae eponina Cramer, adult cotton stainer Dysdercus superstitiosus (F.), the cowpea flea beetle, Ootheca mutabilis Sahlberg and the pod sucking bug Riptortus dentipes F. Essential oils of L. adoensis, M. tenuifolia and P. guineense were toxic to the insects. O. mutabilis was the most susceptible with LD50 of 0.15, 0.32 and 0.52 respectively for M. tenuifolia, L. adoensis and P. guineense, while R. dentipes was the least susceptible. There was cessation of feeding in A. eponina treated with essential oil of C. sinensis and P. alliacea.

Diaeretiella rapae (M'cintosh) was the only parasitoid of the cabbage aphid, Brevicoryne brassicae L., during studies reported here.

Percentage parasitism of B. brassicae ranged from 27.1 to 76.1% in studies carried out around Nairobi area during 1978/79. It was highest during the month of September, when the aphid population density had reached maximum, and lowest in May when aphid numbers were low. High parasitism coincided with a decline in aphid population.

Because of these high levels of parasitism and other attributes of the parasitoid, it was concluded that D. rapae played a significant role in suppressing populations of B. brassicae and should be taken into consideration in any control programme aimed at protecting brassica crops against aphid pests in Kenya.

Cowpea, Vigna unguiculata (Walp) and beans, Phaseolus vulgaris are attacked by several insect pests worldwide. The pests include economically important borers, the control of which often requires the use of more than one tactic. In Africa, the major borer species of cowpea is Manica vitrata Fab. (syn. M. testulalis [Geyer]); in Southeast Asia and eastern Africa the beanfly or bean stem maggot complex, Ophiomyia spp., is important on beans. The bean borer, Etiella zinckenella (Treitschke), is also of considerable importance in Asia. In South America Epinotia apotema (Wals) and Cydia fabivora (Meyrick) are the most important borers on beans, while Helicoverpa armigera (Hïbner) and M. vitrata to a lesser degree are important on beans in some parts of Africa. Presently, only chemical control provides complete protection against crop borers, but despite its usually favourable cost-to-benefit ratio, insecticide use is not a sustainable option. Other tactics such as cultural control, host plant resistance and the use of beneficial organisms are more dependable in the long-term. They form the core of the new vision for environmentally friendly pest management, or bio-intensive pest management, which minimises the use of synthetic insecticides. In recent times, research efforts directed at these measures have been intensified. This paper discusses the various interventions and presents different IPM models on how they can be combined to optimise the control of borers. Suggestions are made on the future outlook of IPM on cowpea and beans.

In the present study, we aimed to assess the suitability of predatory parameters, namely voracity, consumption index, conversion efficiency and growth rate, as measures of prey suitability. For this purpose, fourth-instar larvae and 10-day-old adult females of four co-occurring ladybirds, namely Coccinella septempunctata (L.) (C7), C. transversalis F., Cheilomenes sexmaculata (F.) and Propylea dissecta (Mulsant), fed on two essential species of aphid prey, Aphis craccivora Koch and Lipaphis erysimi (Kaltenbach), were observed. The results revealed that, with the exception of C7, the other three ladybirds performed better on A. craccivora. Previous studies based on reproductive and developmental attributes have also shown that A. craccivora is a more suitable prey for these three ladybirds, indicating a strong correlation and affirming the viability of using these measures as a mark of prey suitability. In a similar manner, fourth instars and adult females of C7 performed better on L. erysimi over A. craccivora. This detectable difference in consumption and utilization of aphid prey species by the four ladybirds indicates that these predatory parameters can be used as tools for assessing prey suitability in ladybirds.

An outbreak of the sugarcane whitefly (Neomaskellia andropogonis Corbett) recently occurred in sugarcane fields in Khuzestan Province of Iran. This pest sucks plant sap producing large amounts of honeydew. In Khuzestan Province, populations of all developmental stages increase from early August until late November. At this time, when sugarcane is at the ripening stage, nymphs suck the sap, and in cases of severe infestation, retard the growth of sugarcane plants. In this study, we investigated the biology of the pest on different cultivars of sugarcane and under different temperatures. Also, we conducted experiments to determine the damage caused by the pest in the field. Mean pre-adult developmental times were 24.09, 28.06, 27.27 and 26.64 days on CP69-1062, CP57-1062, CP48-103 and NCO-310 cultivars, respectively, and only female progeny were produced. Mean longevity of females on the four cultivars was 6, 8.49, 4.15 and 4.60 days, respectively. Adult females laid an average of 61.80, 58.80, 41.10 and 39.38 eggs on the four cultivars, respectively. Results show that the optimum temperature for development of different stages of N. andropogonis is 30±1°C during the day and 25±1°C at night, and at this temperature, egg and nymphal duration (including first, second, third instars and pupae) and adult longevity were 6.2, 17.0 and 7.6 days, respectively. Females of cultivar CP69-1062 laid an average of 50.09 eggs. Analysis of data on the quality of damage (including Brix, pol and refined sugar factors) shows that damage was inversely and significantly correlated with the number of infested leaves. Whitefly damage differed among cultivars; and, based on the quality of damage, early maturing cultivars were more susceptible to whitefly damage. We collected two parasitoid wasps from nymphs—Encarsia inaron (Walker) (Hym.: Aphelinidae) and Eretmocerus delhiensis Mani (Hym.: Aphelinidae). To the best of our knowledge, this is the first study to assess the biology, damage and natural enemies of N. andropogonis on sugarcane in Iran.

Bruchidius atrolineatus (Pic) is present in crops of Vigna unguiculata towards the end of the dry season at the beginning of September when pods start to form. Females lay many eggs on most available green pods. However, this oviposition behaviour results in an important egg mortality. During September, pods gradually reach maturity whilst new pods are formed. Females therefore have at their disposal a growing number of differently mature pods. Confronted with such a situation, B. atrolineatus females show an opportunist behaviour and lay most of their eggs on the most abundant stage, i.e. the most easily discovered stage (ripening green pods in mid-September or dry pods towards the end of September). However, they also lay eggs on other phenological stages no matter how abundant they are. B. atrolineatus females therefore show a certain behavioural plasticity enabling them to reproduce on all stages of pods whose maturity, chemistry and texture may differ. Larvae can develop either in maturing or dry seeds. The number of eggs laid from mid September is lower and lower whatever the phenological stage attacked. This decrease would be due to a reduction of the first generation adult bruchids and of the reproductive potential of females.

Callosobruchus maculatus appears in crops at the same time as B. atrolineatus, but oviposits preferentially on dry pods. Eggs are observed during the whole period of study, but the numbers laid are always low. With the increase in pod number, eggs are dispersed among the different substrates available. However, the average number of eggs laid on the pods remains constant. Despite the high mortality due to the oviposition behaviour of B. atrolineatus and to other factors (impact of hymenopterous parasitoids), these two bruchids cause important losses to seeds of V. unguiculata. Control methods against these pests should be envisaged in the field before harvesting.

Tetramethrin, deltamethrin and cypermethrin formulated as fumigant tablets or spray(ing) solutions showed flushing out activity on Triatoma infestans. Fumes arising from the tablets were analysed by gas chromatography. The proportion of pyrethroid liberated was between 10 and 20% of the original amount formulated. The flushing out activity shown was dependent on the pyrethroid compound, insect stage and sex. In general deltamethrin proved the most active flushing out agent and cypermethrin the least active. Maximal activity was shown in the combination of nymphs and tetramethrin. Nymphs of Rhodnius prolixus were only flushed out by deltamethrin. In all cases, deltamethrin and cypermethrin yielded 100% mortality 7 days after exposure to the pyrethroid fumes, while tetramethrin was not a killing agent.

The essential oil extracts of six Malaysian plants, i.e. Curcuma longa, Zingiber officinale, Pandanus odorus, Cinnamomum zeylanicum, Syzygium aromaticum and Cymbopogon citratus, were evaluated for repellent activity against Periplaneta americana using a modification of the ‘two-cylinders’ method. Dose-dependent repellency ranging from 57.1 to 100% was exhibited by all six extracts at the lowest concentration tested (12 ppm).

One hundred and five okra cultivars were evaluated in the field for resistance to the leafhopper Amrasca biguttula biguttula (Ishida) during the 1989–1990 season. On the basis of nymphal abundance and leafhopper injury index two resistant (Siswal Local and IC 7194) and nine moderately resistant [IC 6653, IC 8899, IC 13617, Sel. 1, HB 94, IC 6316,6 Dhari, Sel. 2–2 and Line 6(1)] genotypes were identified. Both of the resistant, two moderately resistant (Line 6(1) and IC 13617) and two highly susceptible (Pusa Sawani and Pusa Reshmi) genotypes were retested in 1990–1991. Resistant genotypes had significanlty (P < 0.05) fewer nymphs (18.5 to 22.0 nymphs/leaf) and lower values of injury index (2.2) compared with the other varieties. Nymphal duration was also longer (9.3 to 9.8 days) and nymphal survival lower (41.7 to 47.5%) in resistant cultivars. Higher trichome density, longer trichome length and higher concentration of sugars, silica, potassium, tannins and phenols in the leaves of resistant cultivars were associated with resistance to leafhopper.

The effect of diet on the biology of the predatory mite Amblyseius denmarki Zaher & El-Borolosy (Acari: Phytoseiidae) was studied in the laboratory. Predatory mites fed on the eriophyid mites eriophyes dioscoridis, E. olivi and Cisaberoptus kenyae had a faster development, higher fecundity and a more female-biased sex ratio than those fed on the other diets tested, namely pollen of the palm Phoenix dactylifera, the scale insect Parlatoria ziziphus and the whitefly Bemisia tabaci.