Bruchidius atrolineatus appears at the end of the rainy season when pods of its host plant Vigna unguiculata begin to mature. The eggs are deposited along the ventral suture of pods in the vicinity of the seeds. When the eggs are not attacked by Trichogrammatidae their larvae penetrate the seeds and mortality is low during the post-embryonic development. Most of the adults emerging at pod maturity have functional reproductive organs. In that case the females laid on the same mature pods and larvae develop inside the seeds during the first part of the drying season characterised by high diurnal temperature and low relative humity. If the first emerged adults have functional reproductive organs, the following (60% of the population) are in reproductive diapause. Such diapausing insects have been found during the dry season in shelters near the cultivated fields of Vigna unguiculata. Induction or termination of this reproductive diapause are not yet studied. This diapause probably allows the maintenance of populations during the dry season in absence of host plant.

This paper is a compilation of abstracts of 91 published articles on the red locust, Nomadacris septemfasciata (Serville) for the period 1940–1998. The summaries have been compiled from material held in the library of IRLCO-CSA at Ndola, Zambia and the University of Zambia, Lusaka. The articles deal with different aspects of the biology, ecology and control of the red locust with about equal coverage.

Interspecific competition within larvae of the fall army worm (FAW), Spodoptera frugiperda (J. E. Smith), by the larval parasitoids, Cotesia(= Apanteles) marginiventris Cresson and Microplitis manilae Ashmead, and the egg-larval parasitoid Chelonus insularis Cresson was studied. Chelonus insularis was not able to compete successfully against Cotesia marginiventris, but was a successful competitor against Microplitis manilae. Multiple parasitization of larvae by either Cotesia marginiventris or Microplitis manilae, which as eggs were parasitized by Chelonus insularis, did not result in additional host mortality. Percentage parasitization under greenhouse conditions by Cotesia marginiventris of larvae parasitized previously by Chelonus insularis was two-fold higher in corn compared to sorghum and more than four-fold higher compared to Bermuda grass and itch grass. The host finding and behavioural sequence of oviposition of Cotesia marginiventris in FAW larvae already parasitized by Chelonus insularis consisted of nine steps. Microplitis manilae females changed their behaviour significantly by displaying a reduction of ca. fifty per cent in host examinations, 45% in ovipositor probes, and 55% in apparent ovipositions when Chelonus insularis parasitized larvae were presented. Cotesia marginiventris and Microplitis manilae exhibited no significant behavioural changes in the per cent contacts, examinations and apparent ovipositions when attacking larvae parasitized previously by either Cotesia marginiventris or Microplitis manilae.

Studies on the vertical distribution of phlebotomine sandflies were carried out at Marigat (Kenya) at determined heights above ground level in both wooded and open fields. Traps set up at different heights from 0–11 m (in wooded area) and 0–9 m (in open field), showed a clear vertical zonation of sandflies as large numbers were collected between 0–7 m in the first site and 0–4 m in the second ones. Among the nine sandfly species collected, Sergentomyia bedfordi Newstead and S. antennatus Newstead were the only species recorded at a height of 11 m above the ground and the commonest sandflies at all studied heights. Overall, more sandflies were collected from the wooded area than the open field. The relationships between the sandfly relative abundance and their heights of flight above the ground showed significant negative correlation coefficients.

The biological effects of six insect growth regulators (IGRs) AI3-37634-c, AI3-36877-b, AI3-37603-b, AI3-36807-b, AI3-37837-a and AI3-36809-a against immature stages and adults of Aedes aegypti have been evaluated. According to IC50 values obtained (concentration to inhibit the emergence of 50% of adults), AI3-36809-a (0.02μg/ml) proved to be the most effective compound, followed by AI3-37603-b (0.04μg/ml), AI3-37837-a (0.11μg/ml), AI3-36807-b (0.17 μg/ml), AI3-37634-C (0.48 μg/ml) and AI3-36877-b (1.4 μg/ml), respectively. The results showed also that the duration of the fourth instar larvae of A. aegypti was prolonged when these larvae were exposed to the effective concentrations of the above compounds.

Apart from delayed lethal action, possible effect of the compounds tested on the basal follicle numbers developed by females of A. aegypti which survived after larval treatment with IC50 of the above-mentioned compounds has been considered. Generally, the results indicate that the females treated have more follicles than the untreated ones of similar age and grown under identical conditions.

The effect of pod angle on the resistance of cowpea, Vigna unguiculata (L.) Walp. to the legume pod borer, Maruca testulalis Geyer, was investigated under field conditions at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, using two cowpea cultivars: IT82D-716 (susceptible to borer damage) and TVu 946 (resistant to borer damage). Three different pod angles were used In the study — a normal angle, a decreased angle and an increased angle. Negative and highly significant (P < 0.01) relationships were found between pod angle and per cent pod damage, as well as the seed damage Index In the two cowpea cultivars. Pods with wide angles (≥ 89°) were damaged on only one and rarely on both pods. Apart from biochemical and other bio-physical factors, selection and breeding for wide pod angle is suggested as a strategy for reducing M. testulalis damage to cowpea pods.

Chromosomal inversion polymorphism was investigated in samples of Anopheles gambiae sensu lato collected from different localities of Tanzania. An. merus was found monomorphic, while two widespread inversion polymorphisms were recorded in both An. gambiae sensu stricto (2Rb/+ and 2La/+) and An. arabiensis (2Rb/+ and 3Ra/+). Two additional polymorphic inversions (2 Rbr and 2Rq), generally associated, were observed in An. arabiensis from the Rift Valley. Observed karyotype frequencies were in agreement with those expected according to the Hardy-Weinberg equilibrium suggesting conditions of panmixia in both An. gambiae s.s. and An. arabiensis in the studied areas.

On exposure of maize grains mixed with groundnut oil at a dose of 20 ml/kg, 100% mortality of the rice weevil, Sitophilus oryzae (L.) was observed within 24 hr and 100% at 10 and 5 ml/kg in 2 and 3 days.

Egg-laying and progeny development in the rice weevils were completely prevented at groundnut oil doses other than 1 ml/kg at which the number of eggs laid and progeny developed were 27 and 38% of those in the oil-free control during the same period. When maize treated with oil at 10–20 ml/kg was reinfested after 19 weeks with fresh adult rice weevils, less than 42% of them had died. The total number of progeny that emerged on week 23 from the two higher doses of oil was 38% of that emerging from the control.

Groudnut oil does not affect the viability of maize grains and damage after 25 weeks. Viability of maize grains was only 6–13% after oil treatment at 10–20 ml/kg compared to 100% in the untreated control.

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.

Commercial Bacillus thuringiensis (B.t.) Berliner products, namely Delfin®, Agree®, Halt® and Spicturin® were evaluated in the laboratory and on an intensively managed teak plantation for the control of the teak defoliator, Hyblaea puera Cramer (Lepidoptera: Hyblaeidae). A 2 g/litre concentration showed highly significant lethality against defoliator larvae, the early instars being more susceptible (99.8% mortality) than late ones (63.6–81.2% mortality). The order of effectiveness was Delfin = Agree > Halt > Spicturin. At 2 g/litre the B. t. preparations were as effective as at 0.07% (2 ml/litre) monocrotophos 36% when sprayed on one-year-old saplings in a plantation. However, at 1 g /litre concentration, monocrotophos 0.07% was superior to the B. t. products.

At room temperature (diurnal range 23–28°C), Sarcophaga haemorrhoidalis (Fallen) developed from egg to adult in approx. 32 days. Survival ( ± SE%) was generally high (76.63 ± 5.67 for the egg, 80.69 ± 3.20 for the larval and 89.83 ± 3.80 for the pupal stages). Adults emerged over a 4-day period between 07.00 and 13.00 hr local time, with daily peak emergence occurring between 07.00 and 10.00 hr. Their immediate post-emergence period was characterized by a highly active and mobile phase lasting 10–15 min followed by an immobile phase lasting about 1.5 hr. Copulation commenced 4.35 ± 0.43 days after adults emerged and was not preceded by elaborate courtship. After a pre-oviposition period of 12.96 ± 0.47 days, females deposited eggs in batches (1.57 ± 0.23 egg-batches/female) each containing a mean of about 37 ± 4 eggs. Fecundity was 52 ± 6 eggs/female during a mean adult life span of 18.68 ± 1.76 days. Although the foregoing life history parameters are strongly suggestive of K-selected ecological strategy, S. haemorrhoidalis may in fact be adopting an opportunistic r−selected ecological strategy since it habitually breeds in unstable environments.

The design and construction of the Nitse trap are described. The materials required are: royal blue cotton, black cotton, mosquito netting, brass pipe, metal rods and galvanised wire. The cutting and joining of the various parts to produce the trap and the method of placement are also described. Finally a rough estimate of the cost of the trap is given.

Oedaleus senegalensis is a mainly sahelian non gregarious grasshopper which is today considered as the most important crop pest acridid, especially on millet. The species has three generations per year (rarely four) and spends the dry season as diapausing/quiescent eggs. Both photoperiod and temperature influence the induction of diapause in which O. senegalensis eggs can survive several years. Migratory movements have been reported by many authors; adults may migrate up to 350 km per night. These factors enable the species' adaptation to its natural hostile environment. The current control strategies are based on monitoring of the oviposition sites of the dry season to predict the subsequent outbreaks in order to control early hatchlings during the following rainy season. The present work gives an overview of the current knowledge on the morphology, biology, ecology and control methods of the grasshopper.

The effect of exposing 1, 3 and 5 days old pupae to 10°C for periods of 7, 14, 21 and 28 days on the emergence, pre-oviposition and fecundity of Cryptolaemus montrouzieri Mulsant was studied. The emergence was delayed significantly when 1 and 3 days old pupae were subjected to 10°C for 28 days when compared to 5 days old pupae. The initiation of oviposition was delayed with the prolongation of holding time. The fecundity of females emerging from 5 days old pupae subjected to 10°C for 21 days was found to be significantly higher than in any other treatment.

Population of Spodoptera litura F. were monitored through pheromone-baited traps during the rainy season 1988 and 1989 in groundnut fields in relation to oviposition on leaves. Four peaks of adult catches were recorded. First and second peaks were smaller and caused no threat to crop. Third peak was observed at the pegging and pod-initiation stage during first week of September and coincided with the greatest oviposition on leaves. The fourth peak was greatest and occurred between 40th and 43rd standard week. However, no oviposition was recorded on groundnut during this period. The moths possibly dispersed and/or migrated to other areas with crops at an appropriate stage of susceptibility.

Xylosandrus compactus (Eichhoff) is a serious pest of Coffea canephora and Theobroma cacao in Uganda and also attacks several common shade tree species often associated with these crops. Seedlings of 10 common hosts of X. compactus were screened for preferential infestation by X. compactus, with a view to analysing the potential role of the shade trees in escalating incidence and damage by the pest. The experiment was conducted for 8 weeks in a garden of mature C. canephora infested by X. compactus that served as a natural source of infestation for the seedlings. The seedlings that became infested by X. compactus were counted weekly and the counts subjected to generalized linear modelling. Results show marked host preference by X. compactus, with T. cacao and C. canephora being the most preferred, while Eucalyptus sp. and Albizia chinensis being the least preferred. Four simulated scenarios of incidence and damage by X. compactus on a preferred crop such as C. canephora are discussed. It is suggested that it is most unlikely for unpreferred alternate host shade tree species to markedly increase populations of X. compactus on shaded preferred host plants. However, these simulations, which are based on results from potted seedlings, need to be validated in a real field situation, taking into account other ecological parameters that are likely to influence pest populations.

The present study was undertaken to determine the occurrence of virus particles in male accessory reproductive glands and to describe the changes in the affected tissues. Using electron microscopy techniques, it was possible to identify rod-shaped virus-like particles in accessory reproductive glands of male tsetse, Glossina morsitans morsitans Westwood. The viruses occurred intracellularly within the epithelial cells and in the lumen of the glands. Cell degeneration characterized by abundant clear vacuoles, membrane-bound vesicles, disorganization and elimination of cell organelles typified the infection. The inference, therefore, is that virus infection may be primarily responsible for the necrotic changes identified in the gland cells. It is suggested that the lesions caused in the gland epithelium by the infection would disturb the glandular cells and disrupt synthesis of the secretion. This may eventually destroy the male accessory reproductive glands leading to inability of the male flies to form spermatophores for transferring spermatozoa to the female tsetse. Lack of sperm transfer would consequently result in no egg fertilization.

Neem products are often perceived as harmless to natural enemies, pollinators and other non-target organisms. For this reason, several integrated pest management (IPM) programmes have adopted neem as one of the prime components. This study revealed toxic effects of neem on soil-inhabiting and aerial natural enemies in chickpea to an extent of 41 and 29% population reduction, respectively, compared with 63 and 51% when using a conventional insecticide (endosulfan). Neem also affected the parasitization of Helicoverpa armigera (Hübner) larvae by Campoletis chlorideae Uchida up to 20%. The natural enemy population started building up from the vegetative phase and reached their peak during the reproductive phase, and there was a gradual decline from pod formation to pre-harvest phases of the crop. Adapting the currently used IPM system in chickpea using neem during the vegetative phase, followed by an application of Helicoverpa nuclear polyhedrosis virus (HNPV) at flowering and need-based application(s) of chitin inhibitors like novaluron or flufenoxuron instead of endosulfan during pod formation would strongly augment natural enemy populations. This paper discusses the relative toxicity of neem and other IPM components on soil-inhabiting and aerial natural enemies in the chickpea ecosystem.

Millipede diversity in tropical regions, and in Mexico in particular, is still mostly unknown. A modest but recurrent source of new Mexican species is the colonization of exotic species, due to human activity. The invasive species Cylindrodesmus hirsutus Pocock, 1889 has spread from its area of origin in Indonesia or Melanesia and become a virtually pantropical species. Although long known from South and Central America, reports from the Caribbean are sparse and limited to some eastern islands and southern Central America. On 9 March 2016, two adult specimens were found on Cozumel Island, Quintana Roo, in an area of medium semideciduous tropical forest. This paper comprises the first record of this species from Mexico and the northern Caribbean. Given the intense commercial activity in the region, the presence of more populations both in Cozumel Island and in the mainland coast is highly probable.

Pebrine caused by Nosema bombycis in the silkworm Bombyx mori L. causes severe economic loss to the sericulture industry. Several species of microsporidia and strains of N. bombycis have been isolated from infected silkworms. The study of the developmental stages of any parasite is important, as it leads to the identification of stages that may be susceptible to control measures. For this study, five microsporidian isolates from B. mori were collected from five different locations in West Bengal, India and a study of the developmental stages from mid-gut smears and histological techniques was undertaken. The observations of mid-gut smears and histological specimens revealed differences in the morphometry and duration of different developmental stages of the parasites.