Field surveys carried out in Mozambique showed that two indigenous cereal stemborers, Busseola fusca Fuller (Lepidoptera: Noctuidae), Sesamia calamistis Hampson (Lepidoptera: Noctuidae) and one exotic stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), are the main pests of maize and sorghum in the country. Busseola fusca was abundant at high altitudes (> 800 m) and Ch. partellus was abundant at low altitudes (< 800 m). Sesamia calamistis occurred at all elevations but in low numbers. Of the three stemborers, Ch. partellus was the most widespread and abundant pest of maize followed by B. fusca. Therefore, a programme was initiated to introduce the exotic parasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae) to increase natural suppression of Ch. partellus populations. Cotesia flavipes was introduced into southern Mozambique for the first time in November 1996. Additional releases were subsequently carried out in several places in southern and central Moz imbique from 1998–2000. The parasitoid was recovered from all localities sampled 1 to 3 years after its introduction, indicating that this exotic parasitoid had established in the southern and central regions of Mozambique.

Fourteen differential rice cultivare under four major donor groups were evaluated at 11 field locations in seven Indian states during 13 years against the rice gall midge, Orseolia oryzae (Wood-Mason) (Diptera:Cecidomyiidae). Three basic variations, which qualify to be called biotypes 1,2 and 3 could be identified based on overall reaction patterns against Eswarakora and Siam 29 differential groups. Biotype I cannot damage entries involving either Eswarakora or Siam 29. Biotype 2 is capable of damaging the group of Eswarakora and its derivatives but not able to damage the group of Siam 29. Biotype 3 can damage the Siam 29 group while being incapable of doing so with Eswarakora group.

Two β-glycosidases were purified from the termite Macrotermes subhyalinus (Rambur) workers by chromatography on gel filtration, ion exchange and hydrophobic interaction columns. The preparations were shown to be homogeneous on polyacrylamide gel. Both enzymes have a similar molecular mass (68 KDa) and optimum pH (5.4) but differ in optimal temperature and thermal stability. The β-glycosidases preferred β-fucosides to β-glucosides, β-galactosides and β-xylosides, and hydrolysed glucose-glucose-β-(1–4) linkages better than β-(1–3), β-(1–2) and β-(1–6) linkages. They did not hydrolyse saccharides such as melibiose, sucrose, lactose, xylobiose, melizitose, stachyose, lactose, raffinose, laminarin, arabinogalactan, carboxymethylcellulose, inulin, lichenan and starch. β-Glycosidase A and β-glycosidase B of M. subhyalinus workers are capable of catalysing transglucosylation reactions. The yields of glucosylation of hydroxyamino acid derivatives and phenylethanol, catalysed by the two enzymes in the presence of cellobiose as glucosyl donor, were lower than those reported previously with conventional sources of β-glycosidases. In addition, the optimum pH is different for the hydrolysis and transglucosylation reactions. On the basis of this work, it is proposed that the physiological role of β-glycosidase A and β-glycosidase B of M. subhyalinus workers is the digestion of di- and oligosaccharides derived from hemicelluloses and celluloses.

A nuclear polyhedrosis virus isolated from the Egyptian cotton leafworm, Spodoptera littoralis, was found to infect termite castes of Kalotermes flavicollis. Laboratory studies indicated that no specific trend toward mortality responses among the different individuals of termites was noted. All test castes of termites, young, middle-sized, old and reproductive nymphs, and soldiers, were quite equal in their response to the virus infection, regardless of whether the virus concentration was high or low; a concentration of 6.4 × 108 polyhedra/ml, killed only 64% of the treated individuals, while the dosage of 6.4 × 107 polyhedra/ml produced over 90% mortality. Also, thesame trend of response was recorded with the survivors which received challenge doses of NPV suspension each 9 or 10 days. On the other hand, these results revealed that if the NPV is used to control termites, periodic applications would be more efficacious thanone treatment. Virus symptoms were recorded in all affected insects.

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.

The abundance and distribution of Ceratitis capitata (Wiedemann) in Late Valencia citrus orchards and other alternative host crops was investigated using trimedlure-baited traps at the University of Ghana's Agricultural Research Centre in the Eastern region of Ghana. The effect of some climatic factors on the population dynamics of the pest was also studied. The population of C. capitata increased from September to October 2006 and from February to March 2007, when Late Valencia citrus fruits were ripening or ripened. The fruit fly population was the lowest from November 2006 to January 2007 when citrus fruits were in the immature green stage. Ceratitis capitata was not trapped in mango, pawpaw and pepper fields and did not emerge from fruits of these crops. Multiple regression analyses also revealed that rainfall and temperature significantly influenced the pest population. The results of this study have important implications on the decision-making process for the safe, effective monitoring and management of C. capitata in Late Valencia citrus orchards in the study area in Ghana and probably in other areas as well.

The cryptic nature and lack of consistent biological control of the stem fly, Melanagromyza sojae Zehntner, an emerging pest of soybean, Glycine max (L.) Merrill, necessitated the monitoring and assessment of the impact of the parasitoid complex on seasonal regulation of the pest population. In this paper, we measure and relate, using the host density as a predictor variable, the seasonal density dependence of M. sojae parasitoids and the level of parasitism in soybean fields. The results revealed density dependence of parasitioids. The populations built up concomitant with the host insect, reached their peak during the mid-season, and declined towards the end of the crop season. A complex of 10 species of hymenopteran parasitoids comprising six species from Pteromalidae and one species each from the families Eurytomitidae, Eucoilidae, Braconidae and Eulopidae had a significant impact on M. sojae populations with a peak parasitism of ~50%. The seasonality and relative abundance of parasitoids were explored. Eurytoma sp. (Eurytomitidae) and Gronotoma sp. (Eucoilidae) were the most prevalent parasitoids throughout the season, whereas the pteromalid Sphegigaster sp. was dominant during the mid-season. The modulation of management practices aimed at conservation of these bioagents could improve the biological control of M. sojae populations. We discuss the practicality of several management options aimed at achieving this goal.

Six field pea Pisum sativum (L.), lines (Holetta Local-90, 305PS210687, 061K-2P-2/9/2, 061K-2P-14/7/1, JI-898 and 304WA1101937) were screened in a greenhouse for their resistance to the pea aphid Acyrthosiphon pisum (Harris) and compared to NEP874UK line (control). The total number of progeny and the average and maximum number of nymphs produced per female during a 24-h period were significantly lower in the six lines compared to the control. The intrinsic rate of increase was also significantly higher in the control than in the other lines (except Holetta Local-90). The aphid preferred to feed on the control than on the tested lines. Line 061K-2P2/9/2 was the most resistant genotype as its height and weight were less affected by aphid attack. Based on antibiosis, antixenosis and tolerance effects, lines 061K-2P2/9/2, JI-896 and 304WA1101937T performed better against A. pisum.

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.

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.

The spatial distribution and abundance of galls of Phytolyma lata were investigated. There was significant correlation between gall counts and the proportion of young leaves. It is suggested that the preference for young leaves not only ensures that good quality food is available but also that the insect is able to complete development before leaf fall. The distribution was also found to be influenced by the surface of leaf, region of leaf and size of veins.

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.

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.

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.

A laboratory study was carried out to assess the effects of seed treatment and fumigation of artificially infested cowpea with the volatile oil of air-dried leaves of Ageratum conyzoides L. (Asteraceae). The oil exerted acute toxicity on adults of the cowpea weevil, Callosobruchus maculatus F. upon fumigation. Maximal mortality of 95–97% was inflicted by 60 μl oil. Application of oil dressing on cowpea seed exhibited remarkable insecticidal activity-against the weevil. Significant oviposition deterrency and complete inhibition of emergence of adult insects (F1 offspring) from oil-treated beans were evident at doses of 2.5 μl to 10 μ1/9.5 g beans. No adverse physical effects on the beans were noticed at these doses. The major isolate of the essential oil, precocene I, was four times as active as the oil.

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.

Cotton mealybug, Phenacoccus solenopsis Tinsley is an important polyphagous insect pest and causes severe losses to different crops worldwide. In the current study, we investigated the effect of different host plants, such as Caesalpinia pulcherrima, Plumeria rubra, Anthurium andraeanum, Jasminum sambac, and Hibiscus rosasinensis, on the biological parameters of P. solenopsis. The survival rate from crawler to adult, female nymphal duration, development time from crawler to female adult, and female adult weight were significantly different on the different hosts. Male nymphal duration, development time from crawler to male adult, pupal weight, emergence rate of male adults, and mean relative growth rate for male were similar on all the tested host plants. Pupal duration and generation time of male and female on H. rosasinensis were significantly shorter than on the other hosts. Adult male and female P. solenopsis longevity was significantly shorter on H. rosasinensis compared to other hosts. The fecundity was lower on C. pulcherrima and A. andraeanum and hatchability was lower on C. pulcherrima than on the other hosts. The net reproductive rate, the intrinsic rate of natural increase, and biotic potential and mean relative growth rate for female of P. solenopsis were significantly different on the tested hosts. Our results point to the role of host plants in increasing the populations of P. solenopsis and could help to design cultural management strategies.

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.

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.