The behaviour of shootfly resistance is examined over the Fl, F2, F3 and advanced generations. The Fl is almost intermediate between two parents with an added heterotic advantage of a lower ‘dead-heart’ percentage. Resistance shows partial dominance under low to moderate shootfly infestation but this relationship may shift under heavy infestation conditions.

The resistance is polygenic in nature and governed by additive genes. In the absence of host immunity, gradual accumulation of favourable genes is possible by line breeding from R × I and I × I crosses by selecting 1 SD below the population mean. Selection for multiple characters limits the genetic advance for shootfly resistance—resulting in 0- 5% selection intensity and relatively less resistant but high yielding desirable progenies. Multilocation tests enable the selection of varieties stable for shootfly resistance.

Malaise traps are often used in trapping Muscidae flies for studying species dynamics, but there has been no specific evaluation of the influence of the duration of exposure of the traps in the field and their normal wear and tear on the relative richness and abundance of individuals of different species caught. To evaluate the possible influence of these factors, we installed Malaise traps at Arroio Grande and Pelotas, Rio Grande do Sul, which are located inside the Campos Sulinos biome in Brazil. In Arroio Grande, new and 18-month-old Malaise traps were installed between March and May, 2004, and in Pelotas, new and 12-month-old traps were installed between April and June of the same year. At each site, the traps were installed 10 m apart, and collections of trapped insects were made at intervals of 7 days. The age of the traps significantly influenced both abundance and richness of the Muscidae trapped, probably because of the changing colour profile at the top of the traps. From these results, we concluded that the use of Malaise traps in the field for long periods to evaluate richness and abundance of muscid flies in biodiversity studies needs re-evaluation.

To develop management strategies for the mango seed weevil (Sternochetus mangiferae), we surveyed infestation levels of the pest in three agroecological zones of Benin and determined the influences of abiotic factors on mango infestation levels and population dynamics in mango orchards at IITA-Benin from 2009 to 2011. We collected immature and mature fruits from the canopy and fallen fruits from under the canopy from three randomly selected trees per cultivar, per orchard. Samples were examined to determine the number of the mango seed weevil eggs to adults during the rainy seasons of three years of the study. Our results show that the highest abundance of both the weevil and its eggs was from March to May of each year. In the first year of sampling, the cultivar Eldon was more infested than the other two cultivars, while during the second and third years, the cultivar Alphonse was most infested. The occurrence of the weevil was almost nil in the hot agroecological zones, while for the mango cultivars of IITA-Benin the percentage of infested fruit increased or decreased according to the studied variables, such as temperature, rainfall, and relative humidity. We found that the period from March to May with low temperatures and high rainfall was favourable to the population increase of mango seed weevils. We discuss possible implications of our findings for the management of the pest.

Insect species can respond adaptively to stress temperature conditions including both thermal limits and reaction norms. In this study, we considered two populations of the whitefly Bemisia tabaci (Gennadius), in which adaptive differentiation was detected for tolerance to upper thermal limits. These two populations are found in two regions of Colombia with climatic differences: the Caribbean region with high environmental temperatures and the Southwest region with lower temperature regimens. We assessed the thermal responses to a range of 1 h heat shocks (37, 39, 41, 43 and 44 °C) performed below the thermal limits for this species. Thermal responses were measured using three life-history traits involved in fitness: survival, fecundity and viability of the offspring after heat shocks. Survival or fecundity as a response to heat shocks did not differ among populations; however, there were significantly different responses for viability between populations. The Southwestern population showed higher viability responses to low heat shocks than the Caribbean population. This relationship suggests a potential trade-off, which appears to be associated with climatic regions. In addition, these results suggest that adaptation under thermal limits does not necessarily involve similar responses throughout the reaction norm. A potential ongoing evolutionary response is taking place through the thermal reaction norms for viability after the invasion by this pest in Colombia.

The presence of biofertilizers can affect the life and movement of subterranean organisms in the soil. In the current study, the effect of three biofertilizers (Unigrow, Rhizogold and Rhizogold Plus) alone and in combination with diatomaceous earth (DE) and insecticides on mortality and movement of subterranean termites, Coptotermes heimi (Wasmann), was investigated under laboratory conditions. The mortality of termites in soil mixed with biofertilizers was low as compared to the control treatment, which led to significant mortality. Length of galleries formed by termites with the addition of Unigrow in the soil was significantly higher as compared to the other two biofertilizers and control treatments. Mortality increased in the presence of insecticides and DE in the soil substrate. Unigrow mixed soil having chlorfenapyr had maximum mortality and minimum gallery length followed by Rhizogold and Rhizogold Plus. The addition of DE and insecticide further enhances mortality, and we recommend that some toxic elements should be incorporated in biofertilizers to control subterranean termites.

Floral fragrance oils related to pollination were studied in three species of Theobroma and one Herrania species (Sterculiaceae) in Costa Rica. This study was prompted by field observations that floral odours and floral visitors are markedly different between Theobroma and Herrania, as well as between species of Theobroma.

Floral fragrance in cultivated T. cacao consisted of 78 components, primarily saturated and unsaturated hydrocarbons, with 1-pentadecene the major constituent followed by n−pentadecane. The distribution of 1-pentadecene was similar at 0900 hr (43.6%), 1130 hr (52.5%) and 2000 hr (51.1%) sampling times but only 1.2% at 1600 hr. The ratio of 1-pentadecene to n−pentadecane in the 1600 hr sample, approximately 1:6, contrasted with a 3:1 ratio at 0900 and 1130 and a 6:1 ratio at 2000 hr. The greatest concentration of volatiles was found in the 1130 hr sample, with 0900 and 2000 hr concentrations being essentially equal and intermediate between the high (1130 hr) and the low (1600 hr).

Of the 58 compounds detected in T. mammosum steam distillate at 0815 hr, an array of linalool oxides accounted for 12.5% of the oil followed by isoeugenol (8.9%). Saturated hydrocarbons were also present but, unlike T. cacao, n-tricosane was the major hydrocarbon (12.2%). The major constituents of T. mammosum oil clearly distinguish this species from T. cacao.

A markedly different profile of major floral volatiles was found in T. simiarum: major constituents included the monoterpenoids citral, geraniol, nerol, and citronellol. Unlike the oily, hydrocarbon fragrance of T. cacao and T. mammosum, T. simiarum floral fragrance is citrus-like both in the field and laboratory. Our fragrance studies suggest considerable evolutionary divergence within Theobroma.

The floral fragrance of H. cuatrecasana contained volatiles characteristic of dipteran-pollinated plant species. Unusual volatiles found in Herrania fragrance included iridomyrmecin, guaiol, and other azulenic derivatives. No such monoterpenoids and bicyclic sesquiterpenoids (with the exception of longifolene, 0.1%, in T. simiarum) were found in Theobroma. The profiles of floral fragrance chemotaxonomically support the exclusion of Herrania spp. from the genus Theobroma.

In recent years, the serpentine leaf miner Liriomyza trifolii (Burgess) has become a major pest of cotton (Gossypium spp.) in India, with high levels of incidence observed at the seedling stage, particularly in transgenic Bt cotton. We monitored the severity of infestation and damage by L. trifolii to transgenic and non-transgenic genotypes of Gossypium arboreum L. and G. hirsutum L. between 2002 and 2007. Overall, significantly lower L. trifolii damage occurred in G. arboreum varieties than in G. hirsutum varieties and hybrids. Among the G. hirsutum genotypes, damage was significantly lower in varieties than in hybrids. However, no significant differences in damage were observed between Bt and non-Bt cotton hybrids. Abiotic factors had a major influence on the severity of damage; there was a significant and negative association of L. trifolii damage with open pan evaporation (E), maximum temperature, solar radiation and sunshine, and a significant and positive association with relative humidity and rainfall (RF). Multiple stepwise regression analysis indicated that 99% of the variation in L. trifolii damage was accounted for by RF, open pan E and relative humidity.

Bionomics, morphometric measurements and partial mitochondrial cytochrome oxidase I gene (mtCOI) sequences were examined for a population of Bemisia afer (Priesner & Hosny) (Hemiptera: Aleyrodidae) collected from cassava in Uganda. The development of the eggs, first to fourth instar nymphs and adults required respectively, 12, 31 and 10 days, with a total life duration of approximately 53 days on the cassava cultivar Ebwanateraka. Each female laid one egg per day for 13 days and about 40% of the eggs failed to develop into adults. The male: female sex ratio was 1:4. The length and width of the four nymphal instars were positively correlated (correlation coefficient=0.97). Females were bigger than males and the sexes differed significantly based on body length (P<0.001) and width (P<0.001). Overlaps in their body sizes, however, makes sex assignment based on size alone unreliable. The B. afer population shared 68% mtCOI sequence (817 nucleotides) identity with a cassava Bemisia tabaci population (Namulonge) from Uganda. This is the first study on B. afer fecundity and morphometrics, and the variability that might exist in this species is discussed.

A survey was conducted in Ibadan, Nigeria, between 1 November and 30 December 2000 to examine the mango mealybug Rastrococcus invadens Williams infestation. Results obtained prompted another study in which the population of R. invadens and its parasitism were monitored from January 2001 to December 2005 on smoke-polluted infested mango trees after relocation of smoke sources. A third study was conducted between January and April 2007 in Ibadan, Nigeria, where mealybug-infested mango trees were searched for and the levels of pollution around them characterized using a derived rating scale. The survey results showed that only 7.5% of a total of 489 mango trees examined in 2001 were infested with mango mealybug and were located in exhaust, car park, motorway or converging environments. In study 2, the mango mealybug population significantly (P < 0.05) declined, and parasitism significantly increased on trees from where pollution sources were relocated. All the 86 mango mealybug-infested trees scouted for in study 3 were located in smoke-polluted areas. Significantly higher numbers of infested trees and mealybug population, and significantly lower parasitism levels were found on mango trees in exhaust areas, compared with others. Pollution level was correlated with mealybug population (positively) and parasitism (negatively) in 2000 and 2007. Whereas mealybug population gradually built up on hitherto clean trees where pollution sources were relocated, parasitoid activity seemed to be enhanced by the relocation of smoke sources. The effectiveness and conservation of the parasitoids may therefore depend on the air quality around the infested trees.

From 2002 to 2004, three field trials were conducted in Senegal to compare the efficacy of a new biopesticide for grasshopper control, based on the entomopathogenic fungus Metarhizium anisopliae var. acridum Driver & Milner, with mixtures of this biopesticide and cyhalothrin, a widely used pyrethroid insecticide to control the Senegalese grasshopper Oedaleus senegalensis Krauss. The aim of these trials was to obtain a knockdown effect without compromising the environmental credentials of the biopesticide too much. During the first two trials, 50 ha (2002) and 25 ha (2003) plots were treated with Metarhizium at a rate of 50 g/ha, cyhalothrin at a rate of 40 g/ha, a mixture of Metarhizium at a rate of 25 g/ha and cyhalothrin at a rate of 20 g/ha. For the third trial in 2004, several mixtures of cyhalothrin at a rate of 10 g/ha and Metarhizium at dose rates of 6.25, 12.5 and 25 g/ha were prepared. These mixtures were compared with 50 g/ha of Metarhizium, 40 g/ha of cyhalothrin and 10 g/ha of cyhalothrin on 25 ha experimental plots. The volume application rate for all trials was 1 l/ha. The Metarhizium applications resulted in a slow but long-lasting reduction of grasshopper numbers. By contrast, cyhalothrin produced a rapid reduction, but grasshopper numbers re-increased a few days after application, except in 2003, when grasshopper densities in the surrounding areas were low. The mixtures caused a similarly fast reduction in grasshopper numbers, but this lasted throughout the 3 week post-application assessment period. These trials demonstrated that adding a low dose of a pyrethroid insecticide to a slow-acting biopesticide can increase the speed of population reduction, while retaining the latter's long-lasting effect. A bonus is that the price of the combination is lower than that of each product at the recommended dose rates. Since the insecticide is added at a low dose, its environmental impact is reduced compared with the full-dose insecticide only treatment.

This paper reports observations made on the sensory biology of Chilo partellus larvae and adults. The larval and adult antennae of this insect have hygro/thermosensitive sensilla equipped with receptor cells sensitive to minute changes in temperature. Inputs through those cells may partly be responsible for the light evasive and other light/temperature-dependent behaviour patterns. The grooved basiconic sensilla especially those found on the male antennae are sensitive to the female sex pheromone components of C. partellus. Host-plant odours are most likely perceived by one or two of the other antennal olfactory sensilla, namely the smooth-surfaced basiconica and coeloconica sensilla. Chilo partellus moths have a limited number of gustatory sensilla on the tarsi, ovipositor, antennae and the proboscis. Electrophysiological bioassays done on the ovipositor and tarsal sensilla are discussed. Similar tests on the larval maxillary styloconica sensilla showed that the lateral and medial sensilla differed in their sensitivity. Their taste receptor cells can detect differences between saps from susceptible and resistant host-plants.

Essential oil of sweetflag, Acorus calamus L. was fed (in artificial diet) to the variegated cutworm, Peridromo soucia Hubner, to assess its antifeedant and growth inhibitory effects. The oil decreased food consumption and larval growth in a dose-dependent manner in both neonate (first instar) and second instar larvae. Calamus oil applied to cabbage leaf discs significantly inhibited feeding by fourth and fifth instar larvae in a choice test. Nutritional experiments with fourth instar larvae using topical application or dietary exposure confirmed that sweetflag oil induces both antifeedant and growth inhibitory effects in Peridroma saucia, the latter possibly being independent of feeding behaviour.

Besides distinguishing between ‘zooplankton’ and ‘phytoplankton’, one of the more useful ways for oceanographers to classify planktonic organisms is by size (e.g. Sieburth et al., 1978). Of the free-living protozoa in the marine plankton, most fall into the ‘microplankton’ (20–200 μm, including many of the sarcodinans and ciliates as well as a number of larval metazoa and the larger phytoplankton) and ‘nanoplankton’ (2–20 μm, including the smaller ciliates and most of the heterotrophic flagellates as well as most of the phytoplankton).

Various species of sandflies were collected from outdoor natural resting sites from three districts in Kenya which are endemic for kala-azar (Machakos, West Pokot and Baringo). Their blood-meals were analysed to find out host preferences. Female fed-flies were dissected for parasitological investigation. Lizards from these areas were also trapped and blood and internal organs were examined and cultured for isolation of leishmania parasites. Only the lizards obtained from West Pokot and Baringo revealed leishmania parasites in cultures. Bloodmeal analysis showed that Phlebotomus anten-natus, P. bedfordi, P. schwetzi, P. africanus, P. martini, P. affinis and P. rodhaini fed on reptiles. Additionally, promastigotes were seen and isolated from these sandfly species. The disease incidence appears to be less in areas where leishmania parasites were encountered both in lizards and the sandflies in the same locality.

Upwind flight has been elicited in tsetse, Glossina morsitans exposed to host odour and to active components of host odour (carbon dioxide, acetone and 1-octen-3-ol) in a wind tunnel. With the exception of octenol the odours also produce marked kinetic effects in G. morsitans, G. austeni, G. pallidipes and G. palpalis. Threshold concentrations for G. morsitans are in the region of 0.2% for ox odour, 0.01% for carbon dioxide and 400 μgl−1 for acetone.

An account of the history of tick control in Uganda is given. It is presented in three phases. Phase one covers the years 1935–1970, being a period of relative stability, while phases two and three cover the periods 1971–1985, characterized by wars and political instability, and 1986 to-date, years of calm and national rehabilitation, respectively.

Mention is also made on the future strategies for the control of ticks based on new technologies and earlier experience.

Control of cowpea insect pests has been almost entirely achieved through the use of chemicals by progressive farmers. However, the peasant farmer has traditionally tended to rely on chance and has often been unable to obtain yields that would be profitable. This paper examines the farmer's dilemma and the jrossibility of using host plant resistance (HPR) as an adjunct to other control methods in developing a sound integrated pest management of cowpea pests. The status of HPR in cowpea is reviewed with a view to identifying the areas where progress has been made with respect to the measurement and identification of resistance to formulate an effective integrated pest control program. The difficulties in achieving this are discussed in the light of our present data bank and the diversity of cowpea pests.

The biology of the aphid, Cerataphis variabilis H.R.L., on Raphia hookeri Mann & Wendl., was studied in the laboratory and the field using a ‘clip-on’ cage and a sleeve cage. The first instar lasted 5.1 days. The second and third instars each lasted 2.45 days, while the fourth instar lasted 2.4 days. The total developmental period of the nymphs was 11.3 days at 26.4 ± 1.43°C and r.h. 83 ± 1.46%; 11.6 days at 26.4 ± 1.63°C and r.h. 85 ± 1.19%; 12.9 days at 27.9 ± 1.04°C and r.h. 75.5 ± 1.64%; 12.95 days at 27.8 ± 0.33°C and r.h. 69 ± 1.23%; 15 days at 21.4 ± 0.58°C and r.h. 45 ± 1.77%. These periods were significantly different at 5% level (LSD = 0.59 days). The higher the temperature and relative humidity the shorter the developmental period (with temperature: r = −0.69, 20.8–28.9°C; r.h.: r = −0.97, 43.2–86.2%). The number of progeny per adult ranged from 54 to 60 in a period of 28–31 days. The longevity ranged from 31 to 34 days.

The effects of neem seed kernel extract (NSKE), neem oil (NO) and nucleopolyhedrovirus (NPV) of the Spodoptera litura Fabricius (Lepidoptera: Noctuidae) on the mortality, feeding and development of S. litura were evaluated in the laboratory. Dose-dependent mortality was evident after NPV treatment, which also depended on larval age at treatment. Upon combining NPV with neem products, the percentage mortality was enhanced threefold even at reduced concentrations. The NSKE and NO significantly inhibited the growth and development of S. litura, and extended the duration of its larval and pupal stages. Oviposition period, adult longevity and fecundity were significantly reduced following treatment with neem products and with neem + NPV treatment. The efficiencies of conversion of ingested food (ECI) and digested food (ECD) were also significantly decreased by treatment with NSKE, NO and NPV, either alone or in combination.

Preliminary studies on the life history and behaviour of the legume podborer, Maruca testulalis (Geyer), at Mbita Point on the shores of Lake Victoria have shown that most of the eggs (86%) of M. testulalis are laid on the leaf. Over 90% of such eggs laid on the leaf are oviposited on the lower leaf surface. Most adults were found to emerge between 2000 and 2300 hr. The number of eggs laid per female varied between 6 and 194, and over 72% of these were fertile. No larval or pupal diapause was observed.

Larval duration was 8–14 days and the pre-pupal stage lasted only 12–24 hr. The whole life cycle at Mbita Point was found to be about 20–57 days.

An important factor that previously discouraged detailed studies on the biology of M. testulalis is the fact that the eggs are translucent and extremely difficult to see against the background of the oviposition site. The discovery of these eggs was a major step in beginning to work on this important pest.