Field experiments were conducted for two seasons to assess the efficacy of the entomopathogenic fungus Metarhizium anisopliae in the control of termites in maize. Application of the fungus at planting was found to significantly reduce maize lodging and increase grain yield in both seasons. However, data from treatment application at tasselling were not consistent. Our results suggest that a granular formulation of M. anisopliae might be a useful option for the management of termites in the maize agroecosystem.

The influence of banana weevil, Cosmopolites sordidus (Germar)(Coleoptera: Curculionidae), population density on oviposition rates and larval survivorship was studied in the laboratory at the Kawanda Agricultural Research Institute in Uganda. This study was undertaken to elucidate the relationship between density-dependent factors and rates of banana weevil increase in the field. Oviposition substrates (corm pieces) were offered to a range of densities of weevils maintained in buckets. Mean oviposition rates per female at densities of 10, 20 and 40 females per bucket were 29, 37 and 53%, respectively, lower than that at a density of 5 females. Nevertheless, total oviposition for the same groups was 1.4, 2.5 and 3.7 times higher than that of the 5-female group. Providing fresh corms daily instead of every five days did not increase oviposition. Larval survivorship was slightly higher at lower densities of immatures following insertion of different densities of eggs or first instars into banana corms. The results suggest that density-dependent factors can influence oviposition rates of individual weevils and survivorship of immatures, but appear to exert only modest influence in reducing banana weevil population growth. More likely, high mortality of weevil immatures under field conditions and/or higher rates of adult mortality and emigration than previously postulated contribute to the slow population build-up of this pest.

—Midgut trypsin and lectin levels were determined in three tsetse species, namely Glossina morsitans morsitans, G. longipennis and G. fuscipes fuscipes. In addition, the abilities of midgut homogenates prepared from these flies to transform bloodstream-form Trypanosoma brucei brucei and T. congolense were compared in vitro. In all the species examined, trypsin levels did not differ significantly up to 24 h post-bloodmeal. There were similar rates of transformation of the bloodstream-form trypanosomes into procyclic (midgut) forms in vivo, so that all species had similar levels of infection in the midgut. However, trypsin levels continued to increase beyond 24 h, reaching a peak between 48 and 72 h. The peak was lowest in G. m. morsitans. The midgut homogenates in this species also had the lowest levels of lectin. The species had the highest levels of mature T. congolense and T. brucei infections. We propose that the lower levels of peak midgut tryspin and lectin in G. m. morsitans is important in the establishment of trypanosome infections in this species of tsetse.

Once a minor pest, the pea aphid, Acyrthosiphon pisum (Harris) has recently become a major pest of field pea (Pisum sativum L.) in Ethiopia, particularly in the northwestern region. To determine the population dynamics of the pest, field experiments were carried out at Adet and Zema in northwestern Ethiopia in 1994, 1995 and 1996. Treatments were planting dates at 15-day intervals in May, June and July and sampling was carried out weekly until crop maturity. Combined ANOVA, over seasons and locations, showed significant effects of sowing dates, seasons and locations. Pea aphid populations increased and decreased with delay in planting at Adet and Zema, respectively. At Adet, peaks of weekly counts of aphid numbers were observed in August and seasonal totals of aphids on individual planting dates increased as planting was delayed. At Zema, peaks of weekly counts of aphid numbers were observed in mid-July (1996), late August and early September (1995) and mid-September (1994); peas planted on June 16 gave the lowest seasonal totals of aphids. Natural enemies (predators and parasitoids) appeared in considerable numbers in 1996 and these tended to increase as planting date was delayed. For most planting dates and years, weekly aphid populations showed positive correlation with maximum temperature, and negative correlation with minimum temperature and relative humidity. Increasing maximum temperature promoted the buildup of aphid populations while increased minimum temperature, rainfall and relative humidity suppressed it. Grain yield increased and decreased as planting date was delayed at Adet and Zema, respectively. From these results, it is recommended that planting of field peas should take place from mid- to late June at Adet and during the first week of June at Zema to obtain higher yields; by doing so a mean of 0.32 t/ha and 0.50 t/ha higher yield was obtained, respectively.

The efficacy of neem kernel cake powder water extract (NKCP-WE) and Dipel 2x (Bacillus thuringiensis var. kurstaki) in controlling the diamondback moth (DBM), Plutella xylostella Linn. (Lepidoptera: Yponomeutidae), on cabbage was evaluated in screenhouse experiments. All concentrations of NKCP-WE tested were larvicidal and plants treated with 25 and 50 g/l NKCP-WE retained larvicidal activity for up to 2 weeks after application. The efficacy of 25 and 50 g/1 NKCP-WE and 0.5 g/1 Dipel 2x was compared by observing DBM development on the treated plants and yields of those plants. Dipel 2x-treated plants had less DBM larval infestation than the neem-treated plants but the latter treatment gave better yield. The implications of these observations are discussed.

The effects of temperature on the development of Orius albidipennis (Reuter) (Hemiptera: Anthocoridae), reared on its prey, Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), were studied in the laboratory. Nymphal mortality was 87, 48 and 38 % at 20, 25 and 30 °C, respectively. With the exception of first-instar nymphs, percentage mortality was lowest at 25 °C. Pre-oviposition period and longevity decreased with an increase in temperature. Mean daily and total fecundity were 2.1 and 76.4 respectively at 25 CC. The mean developmental period from oviposition to adult eclosion was 27.7, 14.1 and 10.9 days at 20, 25 and 30 °C respectively. There was a linear relationship between temperature and developmental rate (1/day) of O. albidipennis. Lower thermal thresholds were 13.8, 13.5, 12.7, 15.0, 13.8 and 12.5 °C for eggs and nymphal stages 1 to 5, respectively, with the corresponding average degree-day requirement of 46.9, 42.6, 33.3, 29.2, 26.1 and 51.4 days, respectively. The implications of these results for biological control of thrips are discussed.

The population dynamics of the coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae) infesting the coconut fruits was studied during September 1999-May 2000 in Tamil Nadu, India where the mite is a new pest. The densities of active mites and eggs were not significantly correlated with weather factors. Mites were more abundant on the post-fertilisation bunch 3 drupes (fruits) (6.0 mites/7 mm2) than on the other drupes. They were most crowded on the fourth (outer to inner) tepal (bract) of the bunch 3 perianth (2.6 mites/7 mm2). No significant difference was evident between populations of A. guerreronis from the drupe and tepal surfaces. However, eggs were more numerous on the tepal surface (4.9 eggs /tepal) than on the drupe surface (2.5 eggs /drupe). Egg density was highest on bunch 5 drupes (8.6 eggs/tepal) than on the drupes of other bunches. The inner tepals (4–6) carried more eggs (4.6–5.6/tepal) than the outer (1–3) ones (1.2–3.8/tepal). Mite population declined by 62.6 % when the tepal area decreased by 24.3 % due to mealybug (Pseudococcus cocotis Mask.) infestation which caused the tepals to deform. The predatory mites Amblyseius sp. and mealybugs were most abundant on tepals 5 and 6 (2.5–2.6 predatory mites; 4.6–4.7 mealybugs/ tepal). Eggs of A. guerreronis could be stored in the freezer at 3.9 ± 0.3 °C for one month although hatchability decreased from 98 % one day after storage to 54.7 % one month after storage. Loss of the eriophyid mites from sample drupes after five days was minimal (54.7 %) when the drupes were stored in a thermocool box containing ice at 23.7 ± 0.4 CC. Most mites (75.8 %) died when the drupes were stored in the open at room temperature (35.3 ± 0.9 °C).

—Bioassays were conducted with Bacillus sphaericus (Neide) 1593M (Bsph) and a neem based biopesticide formulation, Neemtox® (0.03% azadirachtin), independently and in different combinations, to evaluate any synergistic effects on Culex quinquefasciatus Say (Diptera: Culicidae) larvae susceptible to Bsph. The results indicated that the two biopesticides have no synergistic interaction on the larvae. These results are discussed in light of earlier experiments with resistant C. quinquefasciatus, in which Bspfc-Neemtox synergism was seen.

—A revision of the Neotropical species of the Forcipomyia squamitibia group, revealed three new species, F. (F.) catarinensis from southern Brazil, Colombia and Costa Rica, F. (F.) quechua from northwestern Argentina and F. (F.) rioplatensis from northeastern Argentina and northwestern Uruguay, which are described and illustrated. Forcipomyia (F.) squamitibia Lutz is redescribed from the original type material, a lectotype is designated, and F. (F.) soriai Wirth is recognised as a junior synonym. The remaining known species of this group are diagnosed, and keys to males and females are provided for the identification of the nine recognised species.

A commercially produced palm oil brand, Palmin oil, was evaluated for its effect on eggs and larvae of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) on cowpea (Vigna unguiculata) (L.) Walp. Application of 1 μ1 of the oil on eggs deposited on 10 cowpea seeds, or directly on larvae growing inside seeds resulted in their death. Embryo mortality occurred only when the oil was placed at the anterior end of the egg. The nutritive content of cowpea seeds treated with Palmin oil remained unchanged. Furthermore, the oil did not go rancid following six months of storage.

The influence of temperature on the age-specific fecundity of an aphidophagous ladybeetle, Micraspis discolor (Fabricius) (Coleoptera: Coccinellidae) feeding on the cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae) at four different temperatures, viz. 20, 25, 27 and 30 °C, was investigated. The age-specific fecundity function was triangular and oviposition rate (no. of eggs/ day) increased with increase in reproductive age of the ladybeetle, attaining a peak then gradually decreasing before finally ceasing. Young adults were more efficient at converting aphid biomass into eggs than older ones. The oviposition peak tended to shift towards younger females and the oviposition rate increased with increase in temperature from 20 to 27 °C. The maximum fecundity and percent egg viability was 750 eggs and 95 % at 27 °C and minimum 385 eggs and 65 % at 20 °C, respectively.

The hormetic influence on silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) of the juvenile hormone mimic ω-formyl longifolene oxime propargyl ether (NL13) was assayed. Emulsions containing 2.5, 5.0 and 10.0 ppm of the compound were administered topically as a single dose, to two popular commercial silkworm hybrids, viz. KA × NB4D2 and PM × NB4D2, at 24,48, 72 and 96 h into the 5th instar, and economic characters of the larvae and resultant cocoons measured. A medium and absolute control were maintained in parallel. It was found that administration of 5 ppm of NL13 to 48-h-old 5th instars resulted in the maximum improvement in commercial traits. The possible role of exogenous JH-like compounds in eliciting this response in silkworm is discussed.

Plumbagin, a napthoquinone from the plant Plumbago zeylanica, delayed pupation when topically applied to newly moulted final instars of the leaf eating caterpillar Opisina arenosella Walker (Lepidoptera: Oecophoridae). Pupae from treated larvae emerged into non-viable adults and had abnormalities such as deformed wings and shrunken abdomens; they also died much before the control insects. The results suggest that plumbagin interferes with the process of development and ecdysis of the insect.

Exposure of fouth instars of Spilarctia obliqua Walker (Lepidoptera: Arctiidae) to excelsin over a 24 h period resulted in reduced feeding and growth rates. To distinguish between antifeedant and toxic effects, growth efficiency, calculated as the slope of the regression of the relative growth rate on relative consumption rate, was compared with results from antifeedant simulation and contact toxicity bioassays. From the results, it is concluded that excelsin exerts its toxic effects at the physiological level.

Spodoptera litura (F.) (Lepidoptera: Noctuidae) is a serious pest of several crops in India and other countries. Prothoracicotropic hormone (PTTH) release from the brain of penultimate fifth instars of the noctuid was followed in the laboratory and a spiracle index developed to assess PTTH action. PTTH release from the brain occurred during the scotophase at 4.30 h of day 1 (AZT). Ecdysone secreted in the prothoracic gland was released from the 7th hour of day 1 (AZT), reaching a maximum in the haemolymph on the 9th hour of day 1 (AZT). The prothoracic gland showed three distinct phases, namely growth, synthesis and release. Injected PTTH of 5th instar brain extract induced larval moulting in head-ligated larvae. Partially purified PTTH from 6th-instar S. litura brain induced moulting in 6th instars. Abdomen-ligated penultimate instars administered β-ecdysone showed variable moulting response. The phenomenon of hormonal interaction with development of the penultimate instar of S. litura is discussed.

Scanning electron microscopic examination of the egg shell and associated structures of Eocanthecona furcellata (Wolff.) (Hemiptera: Pentatomidae) reveals a distinct pattern of structural elements, viz. microsculpture of the chorion, pseudoperculum, egg burster and aeromicropylar processes. The egg shell has a highly decorated chorion with a structural difference at both the anterior and posterior ends. A reticulate type of microsculpture with varying sizes of spine-like projections measures 4.02 ± 0.06 to 8.12 ± 0.05 μm and forms an asteroid-like shape at the anterior pole, while the surface at the posterior end has elongated striations over the chorion measuring 72.00 ± 0.074 μm. The pseudoperculum of the egg shell is a circular lid measuring 518 ± 11.43 μm in diameter. During hatching the line of rupture follows the micropylar ring, and this sometimes extends beyond the ring of micropylar processes. An inverted T-shaped black egg burster measures 202 ± 4.63 μm in length, is well developed and can be seen prior to hatching within a thin and transparent egg shell. It is a median sclerotised part of embryonic cuticle. The aeromicropylar processes are situated at the anterior pole of the barrel-shaped eggs. There are 26–28 aeromicropylar processes arranged in a circle at almost equidistance and each micropylar process is slightly curved opposite to the pseudoperculum lid with a bulbous end at the apex. The aeromicropylar processes are 25.40 ± 0.083 μm in length and 3.02 ± 0.07 μm in width. Each micropylar process has a central canal for the passage of sperm whereas the rest of its body is porous, and allows respiratory interchange.

The predation of the booklouse, Liposcelis entomophila (Enderlein) (Psocoptera; Liposcelidae) by the mite Blattisocius dentriticus (Berlese) (Acari; Ascidae) was studied in a series of laboratory experiments. Known numbers of mites and booklice were placed together in small tubes and counted after various durations. Fewer booklice were found in mite-infested tubes and it was possible to rear the mite on booklice, which supports the view that the mite is a natural predator of L. entomophila. Comparative susceptibility of the mite and booklouse to deltamethrin and fenitrothion was assessed by exposing both arthropod species to deposits of the two insecticides. The mite was found to be very susceptible to both deltamethrin and fenitrothion whereas the booklouse was only susceptible to the latter. The increased prevalence of L. entomophila in tobacco storage and grading buildings in recent years may therefore be attributed, at least in part, to the use of deltamethrin which suppresses its natural enemies.

A study was conducted in Muswishi area, Zambia, with the objective of assessing indigenous technical knowledge (ITK) and relating this knowledge to integrated pest management (IPM) in maize production. The methods used included surveys, participatory rural appraisal (PRA), transect walks and semi-structured interviews (SSI). It was found that ITK does exist among some Muswishi smallholder farmers. Eighty-nine percent of respondent farmers never used any chemical pesticides. However, 22% used natural products to manage insect pests. The most widely used natural plant products were Swartzia madascariensis Desv, Tephrosia vogelli Hook.f, Euphorbia tirucalli L, wood ash and cow dung. Farmer's own assessment indicated that the integration of ITK into IPM technology led to increased maize yields (> 37.5%). This study demonstrated the continuing need for integrating ITK into IPM technology. Such an approach could ensure household food security and enhance sustainable livelihoods of rural smallholder farmers.

A simple method for storing mosquito bloodmeal samples, which permits extraction and detection of human DNA after polymerase chain reaction (PCR) amplification of target DNA sequences, was tested. Abdomens of bloodfed field-collected Anopheles gambiae s.l. and An. funestus mosquitoes (Diptera: Culicidae) were directly expressed onto filter paper, air-dried and stored at room temperature. DNA was extracted and amplified at human hypervariable loci TC11, VWA and D1S80. The amplified products were separated using polyacrylamide gel electrophoresis, visualised by silver staining, and results compared with those from mosquitoes that had been preserved in liquid nitrogen. DNA from blooded abdomens stored on dried filter papers could be amplified with greater than 95 % success for any locus, storage temperature, mosquito species or storage duration. Collection and drying of mosquito bloodmeals directly onto filter paper appears to be a more convenient method for sample transportation and storage than the conventional method involving cryopreservation.