African Stem Borer Research Articles

Progress in developing and deploying drought-tolerant and insect-pest resistant climate-resilient droughtTEGO® and TELA® maize varieties

Currently, drought stress and associated insect-pest damage pose a huge threat to food and nutrition security for over 300 million people in Africa who depend on maize as their main food source. Recurrent drought events cause an annual 17 to 25 percent yield loss of maize in Africa [1]. Compounding the impact of drought, is the ravaging effect of insect-pests infestation on maize production, especially for pests whose population pressure is highly triggered under dry conditions. The crop under weakened conditions created by drought stress and pest effect further becomes constrained biologically and physiologically, thus limiting the crop’s ability to use already limited water and nutrients from the soil. The major insect pests of maize in Africa are fall armyworm (FAW, Spodoptera frugiperda) and various stem borer species (Spotted stem borer (Chilo partellus), African stem borer (Busseola fusca), and the pink stemborer (Sesamia Calamistis). For instance, in Kenya alone, an average of 13 percent or 400,000 tons of maize is lost to stem borer, which is equivalent to the annual maize imports, valued at USD 90 million [2]. The FAW, a transboundary pest, first observed in the continent in 2016, is a maize pandemic that if not controlled adequately, could potentially destroy up to 20 million metric tons of maize annually, enough to feed 100 million people in Africa [3].

Impact of different types of green manure on pests and disease incidence and severity as well as growth and yield parameters of maize

The emergence of pests and diseases, including the maize streak virus, leaf blight, the African stem borer, and gray leaf spot, poses a persistent threat to maize production (Zea mays L. cv: DMR-ESR-Yellow) around the world. A field experiment was conducted at the School of Agriculture experimental site, Njala University, Sierra Leone, during a two-year period (2020–2021) to assess the effects of green manure on pest and disease incidence and severity as well as growth and yield parameters of maize. The experiment was laid out in a randomized complete block design (RCBD) with three replications and four treatments: Cal. 3 t.ha−1, Cal. 6 t.h−1, Pan. 3 t.h−1, Pan 6 t.ha−1 and a control plot amended with 200 kg ha−1 of N (urea) and NPK 15:15:15 ha−1 split application. The study showed that gray leaf spot damage was the most severe infection among all treatments. Therefore, the effects of the most severe disease and pest of maize in Sierra Leone can be minimized by applying green manure. Moreover, results reveal that Calopogonium- Pueraria mixture amended plots showed significant performance in the measured growth parameters viz. highest leaf number, large leaf area stem girth, superior plant height, best ear height (64.6–78.5 cm), higher cob yield (1.2–1.4 t.ha−1) ear (1.8–2.1 t.ha−1) and dry grain yield (0.5–0.7 ha−1). Panicum green manure results showed that prompt and adequate application, as well as decomposition of green manures, is imperative for the successful conservation and sustainability of maize farming systems. The findings of this research could improve the efficiency of green manure use in pest, disease, and crop management systems.

Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda

Stem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda.

Phenotyping of Sorghum Lines for Resistance to African Stem Borer (Sesamia Calamistis)

Stem borer ( Sesamia calamistis ) is a serious insect pest of sorghum (Sorghum bicolor) resulting in grain yield losses ranging between 15-80%. However, genotypes showing complete resistance to these borers have not been identified in Nigeria. Utilization of resistant varieties in combination with other methods of control would offer a sustainable strategy for S. calamistis management in sorghum production. The objective of this study was to validate the acclaimed resistance in the materials received from Kenya and India in Nigerian environment and to screen and ascertain the status of some Nigerian Sorghum to Sesamia calamistis . Eighty-eight sorghum lines were artificially infested with the eggs of the stem borers at two different environment (Field and Screen House) using alpha-lattice design, consisting of 11 plots in eight blocks, replicated twice. Data were collected on leaf feeding, number of dead-hearts, cumulative stem tunnel length, number of exit holes, and selected agronomic traits. There were significant (p<0.01) differences among the test genotypes for all the traits measured. Based on the selection index, 15% of genotypes were categorized as resistant, 42% as moderately resistant,33 as moderately susceptible and 10% as susceptible.13 genotypes showed resistance across the environments (field and screen house): ICSB464, ICSL71086, SSV20041-2YELLOW, ICSL71018, ICSR94032, ICSV700, ICSL71193, ICSR94030, ICSL71253, ICSL71268, ICSL71023, ICSL71061 and ICSL71137 were resistant with selection index ranging from 0.0 to 0.5. These sorghum lines with various resistance to S. calamistis could be used as source of resistance and as parents in sorghum improvement programme in breeding for resistance to stem borer. Keywords: Genotypes, novel source of resistance, Sesamia calamistis , Sorghum bicolor DOI: 10.7176/JBAH/11-18-04 Publication date: September 30 th 2021

Genetics of dual resistance to african stem borer, busseola fusca and spotted stem borer, Chilo partellus in sorghum

African stem borer, Busseola fusca Fuller (Noctuidae) and spotted stem borer, Chilo partellus Swinhoe (Crambidae) cause more than 40 % of grain yield loss in cereals and bothpests co-exist in mid-altitudes in Kenya. Development of sorghum with dual resistance to B. fusca and C. partellus has been difficult due to the inadequate understanding of inheritance of resistance traits to the two species. The objective of this study was to investigate the genetics of dual resistance to the two insect species in sorghum. Thirty sorghum populations derived from crossing sorghum lines with varying levels of resistance to the two insect species were studied. The experiments were conducted in two separate sites at Embu and Kiboko in Kenya with two replications per site. North Calorina Design II mating design was used. Artificial infestation with first instar neonates of each pest species was done at 30 days after planting in both sites. Data collected included sorghum damage due to the two borer species and agro-morphological traits. Genetic analyses were performed using line x tester method using Genstat statistical software. Data analyses revealed that general combining ability (GCA) and specific combining ability (SCA) effects were significant for foliar and stem damage traits, indicating that additive and non-additive gene effects conditioned resistance to B. fusca and C. partellus. Sorghum lines ICSA 464, ICSB 474, ICSB 464 and ICSA 472 and ICSB 473 exhibited desirable high negative GCA effects to B. fusca and C. partellus. These parents could be used in development of sorghum with dual resistance to B. fusca and C. partellus thus contributing to sustainable integrated management of these two stem borer species in sorghum via host plant resistance management.

QTL Mapping of Traits Associated with Dual Resistance to the African Stem Borer (Busseola fusca) and Spotted Stem Borer (Chilo partellus) in Sorghum (Sorghum bicolor).

Sorghum (Sorghum bicolor (L.) Moench) is an important food crop in semi-arid tropics. The crop grain yield ranges from 0.5 t/ha to 0.8 t/ha compared to potential yields of 10 t/ha. The African stem borer Busseola fusca Fuller (Noctuidae) and the spotted stem borer Chilo partellus Swinhoe (Crambidae), are among the most economically important insect pests of sorghum. The two borers can cause 15% - 80% grain yield loss in sorghum. Mapping of QTLs associated with resistance traits to the two stem borers is important towards marker-assisted breeding. The objective of this study was to map QTLs associated with resistance traits to B. fusca and C. partellus in sorghum. 243 F9:10 sorghum RILs derived from ICSV 745 (S) and PB 15520-1 (R) were selected for the study with 4,955 SNP markers. The RILs were evaluated in three sites. Data was collected on leaf feeding, deadheart, exit holes, stem tunnels, leaf toughness, seedling vigour, bloom waxiness, and leaf glossiness. ANOVA for all the traits was done using Genstat statistical software. Insect damage traits and morphological traits were correlated using Pearson's correlation coefficients. Genetic mapping was done using JoinMap 4 software, while QTL analysis was done using PLABQTL software. A likelihood odds ratio (LOD) score of 3.0 was used to declare linkage. Joint analyses across borer species and sites revealed 4 QTLs controlling deadheart formation; 6 controlling leaf feeding damage; 5 controlling exit holes and stem tunneling damages; 2 controlling bloom waxiness, leaf glossiness, and seedling vigour; 4 conditioning trichome density; and 6 conditioning leaf toughness. Joint analyses for B. fusca and C. partellus further revealed that marker CS132-2 colocalised for leaf toughness and stem tunneling traits on QTLs 1 and 2, respectively; thus, the two traits can be improved using the same linked marker. This study recommended further studies to identify gene(s) underlying the mapped QTLs.

Impacts of plant spacing and nitrogen fertiliser on incidences and density of spotted and African pink stem borers in Tanzania

Nitrogen fertilisation and plant spacing hold potential for the integrated management of rice insect pests. Field experiments were conducted in Kilombero, Tanzania to evaluate the effects of plant spacing and nitrogenous fertiliser on incidences and density of spotted and African pink stem borers. A 3 × 4 × 4 factorial experiment was used in a randomized complete block design with three replications. Treatments included application of urea fertiliser at four levels (0, 40, 80, and 160 kg N ha−1) and spacing at four levels (10 cm × 10 cm, 15 cm × 15 cm, 20 cm × 20 cm, and 25 cm × 25 cm). Nitrogen significantly increased dead hearts by 4.8%, white heads by 2.8% and stem borer larvae density from 0 to 5.6 larvae/m2. Decreasing the planting density significantly increased dead hearts by 4.7%, white heads by 2.7% and stem borer larvae density from 0 to 5.4 larvae/m2. The interaction of nitrogen fertiliser rates and plant spacing did not affect stem borer incidences nor larvae density, but did influence the rice yield.

Relative Influence of Host, Wolbachia, Geography and Climate on the Genetic Structure of the Sub-saharan Parasitic Wasp Cotesia sesamiae

The parasitoid lifestyle represents one of the most diversified life history strategies on earth. There are however very few studies on the variables associated with intraspecific diversity of parasitoid insects, especially regarding the relationship with spatial, biotic and abiotic ecological factors. Cotesia sesamiae is a Sub-Saharan stenophagous parasitic wasp that parasitizes several African stemborer species with variable developmental success. The different host-specialized populations are infected with different strains of Wolbachia, an endosymbiotic bacterium widespread in arthropods that is known for impacting life history traits, notably reproduction, and consequently species distribution. In this study, first we analyzed the genetic structure of C. sesamiae across Sub-Saharan Africa, using 8 microsatellite markers. We identified five major population clusters across Sub-Saharan Africa, which probably originated in the East African Rift region and expanded throughout Africa in relation to host genus and abiotic factors, such as Koppen-Geiger climate classification. Using laboratory lines, we estimated the incompatibility between the different strains of Wolbachia infecting C. sesamiae. We observed that incompatibility between Wolbachia strains was asymmetric, expressed in one direction only. Based on these results, we assessed the relationships between the direction of gene flow and Wolbachia infections in the genetic clusters. We found that host specialization was more influential on genetic structure than Wolbachia-induced reproductive incompatibility, which in turn was more influential than geography and current climatic conditions. These results are discussed in the context of African biogeography, and co-evolution between Wolbachia, virus parasitoid and host, in the perspective of improving biological control efficiency through a better knowledge of biological control agents’ evolutionary ecology.

Inheritance of resistance traits to African stem borer in grain sorghum

The African stem borer (Busseola fusca [Fuller]) is an important insect pest of cereals, mainly maize, sorghum and millets. The pest causes up to 80% reduction in grain yield, depending on the pest population in the field, cultivar and the management practices employed. This reduction in yield translates into food insecurity, especially in semi-arid lands (ASALs) where sorghum is cultivated by small holder farmers. This study investigated the inheritance of resistance traits to the African stem borers in grain sorghum in Kenya. The experimental material consisted of seventeen sorghum lines with varying levels of resistance to the African stem borer. The mating design employed was North Calorina Design 2, where 15 sorghum lines were used as females on two males. The crosses were evaluated in two seasons at University of Embu farm in 2011/2012 short and long seasons replicated twice. Artificial infestation with African stem borer neonates was done 30 days after planting using a camel brush. Data collected included stem borer damage and agro-morphological traits. Genetic analyses were performed using a line x tester method using Genstat statistical software. It was found that both additive and non-additive gene effects were important in conditioning resistance traits to the African stem borer. This implies that expression of high leaf glossiness, plant vigour and bloom waxiness in F1 hybrids is conditioned by additive genes and these traits can be used as morphological markers to select for resistance to the borer in sorghum. ICSB 464 x ICSB 473 was the best combiner for stem borer resistance and grain yield. Parents ICSA 464, ICSB 464 and ICSB 474, were among the good combiners for resistance to the stem borer. These parents can be utilised in developing superior sorghum hybrids resistant to the insect pest.Key words: Gene action, heritability, Sorghum bicolor

Fusarium ear rot and fumonisins in maize kernels when comparing a Bt hybrid with its non-Bt isohybrid and under conventional insecticide control of Busseola fusca infestations

Maize production in South Africa is negatively affected by Fusarium verticillioides, an endophytic maize pathogen, as well as by Busseola fusca larval damage. Fusarium verticillioides causes ear, stem and root rot, and also produces fumonisin mycotoxins which are toxic to humans and livestock. The African stem borer (Busseola fusca) is a pest of economic importance in maize plants in South Africa. In this study, the interaction between F. verticillioides and B. fusca was investigated to elucidate its effects on Fusarium ear rot and fumonisin production in a Bt hybrid (MON810 event) and its B. fusca-susceptible non-Bt isohybrid. Field trials were conducted over three seasons using a randomised complete block design with six replicates per treatment. The effect of Beta-cyfluthrin (non-systemic, granular) and Benfuracarb (systemic, seed treatment) insecticide applications on the incidence of Fusarium ear rot and fumonisin production in maize was also determined in an unrelated conventional hybrid. For B. fusca infestations, larvae were dispensed into the whorl of each plant at the 12th leaf stage prior to tasselling, while a F. verticillioides MRC826 spore suspension was inoculated through the silks at the silking stage. Maize ears were harvested at physiological maturity and Fusarium ear rot, total fumonisin levels, stem borer damage and target DNA of fumonisin-producing Fusarium spp. quantified. Significantly less Fusarium ear rot and fumonisin were produced in the Bt maize hybrid compared to the non-Bt isohybrid under natural farming conditions, but fungal colonisation and fumonisin production under artificial F. verticillioides inoculation did not differ significantly between the Bt and non-Bt maize. Fumonisin production correlated moderately with the quantity of target DNA of fumonisin-producing Fusarium spp. extracted from maize plants. Benfuracarb application to control stem borer infestation resulted in a significant reduction in Fusarium ear rot and fumonisin production while Beta-cyfluthrin did not. Moreover, B. fusca damage to maize ears significantly increased when both insecticides were not applied to the B. fusca-infested plants. This study indicated that Bt maize and the application of Benfuracarb reduce B. fusca damage to maize ears thereby indirectly reducing Fusarium ear rot and fumonisin production. However, this was not consistent over seasons due to differences in climatic conditions.

CytochromecOxidase I and CytochromebGene Sequences Indicate Low Genetic Diversity in South AfricanBusseola fusca(Lepidoptera: Noctuidae) from maize

The African maize stem borer, Busseola fusca, feeds on a limited number of host plant species (Calatayud et al. 2014), which include crops such as maize, pearl millet and sorghum. This pest occurs throughout sub-Saharan Africa where it causes economic damage to maize and sorghum crops (Kfir et al. 2002). In an attempt to combat lepidopteran stem borers, genetically modified Bt maize that express insecticidal Cry toxins were developed to kill larvae that feed on these plants (George et al. 2011). Bt maize was introduced into South Africa during 1998 and within the first decade after release, field-evolved resistance of B. fusca to Bt maize was reported (Van Rensburg 2007). Since this first report, resistant populations have been reported from several parts of the maize-production region of South Africa (Kruger et al. 2011; Van den Berg et al. 2013). Explanations provided for this rapid resistance development were confined to agronomical reasons (VanRensburg 2007; Kruger et al. 2009, 2011),non-compliance to refuge requirements (Kruger etal. 2009) and non-recessive inheritance of resistance (Campagne et al. 2013). Notmuchis however understood about the molecular genetics of B.fusca. Previously, Sezonlin et al. (2006b) noted that limited population genetic and phylogeography data are available for B. fusca.

Combining ability for stem borer resistance and heterotic orientation of maize inbred lines using CIMMYT single cross testers under Busseola fusca infestation

The African stem borer, Busseola fusca Fuller, is one of the most devastating insect pests of maize in tropical environments. Understanding of combining ability and heterosis may be useful for designing insect resistant hybrids. However, among the adapted maize inbred lines used in this study, the combining ability and heterotic orientation for grain yield and borer resistance is not known. The objective of this study was to determine combining ability and heterotic orientation of maize inbred lines under B. fusca infestation. Sixty six inbred lines were crossed to two single cross testers from CIMMYT in accordance with the line 9 tester mating scheme. The 132 three-way testcross hybrids and four checks were evaluated at two locations in Kenya. Data were analysed using PROC GLM of SAS statistical package. The genotypes 9 environ- ment interactions were significant, therefore the two test locations were considered as ideal environments for genotype comparison. General combining ability effects were significant for B. fusca stem borer resistance and grain yield, suggesting a preponder- ance of the additive gene effects for borer resistance traits. Specific combining ability effects were sig- nificant for B. fusca borer resistance traits and grain yield indicating that non-additive effects were also influential. Based on grain yield heterosis data at Embu, 22 lines were allocated to group A, 18 to group B and 8 to group AB, while at Kakamega, 24 lines were oriented to group A, 13 to group B and 9 to group AB, whilst the remainder could not be classified. Based on the SCA effects, at Embu, 20 lines revealed positive SCA effects with both testers and were considered to be AB-oriented; while 12 and 7 lines were oriented towards A and B, respectively. A similar trend was observed at Kakamega but only one line exhibited positive SCA effects for grain yield with both testers, while the remainder had negative SCA effects. The identified lines and heterotic groups may be used by maize programmes that emphasize stem borer resistance in hybrids.

Identification of new sorghum genotypes resistant to the African and spotted stemborers

Lepidopteran stemborers, mainly the African stemborer Busseola fusca Fuller and spotted stemborer Chilo partellus Swinhoe, are among the economically important pests of sorghum in Kenya. Identification of sources of resistance is valuable for the development of an integrated pest management strategy to minimize losses. This study evaluated 27 genotypes with artificial infestations (mostly for tolerance) in two different agroecological zones. Data on damage from leaf feeding, dead heart, exit holes, and stem tunnelling; plant height; days to 50% flowering; total grain yield; and hundred-grain mass were collected. Significant differences (P ICSB 464>ICSB 467>ICSA 472>ICSB 472>ICSA 473>ICSA 474>IESV 91131 DL>Macia. The relative contributions of the damage parameters to grain yield loss were partitioned into direct and indirect relationships by path coefficient analysis with grain yield as the resultant variable. The results revealed that damage from exit holes, dead heart, leaf feeding and stem tunnelling had a negative indirect effect on grain yield. The identified genotypes can be used to enhance resistance to both pests in susceptible cultivars that farmers prefer.

Genetic Diversity and Population Structure of Busseola segeta Bowden (Lepidoptera; Noctuidae): A Case Study of Host Use Diversification in Guineo-Congolian Rainforest Relic Area, Kenya.

Habitat modification and fragmentation are considered as some of the factors that drive organism distribution and host use diversification. Indigenous African stem borer pests are thought to have diversified their host ranges to include maize [Zea mays L.] and sorghum [Sorghum bicolor (L.) Moench] in response to their increased availability through extensive cultivation. However, management efforts have been geared towards reducing pest populations in the cultivated fields with few attempts to understand possible evolution of "new" pest species. Recovery and growing persistence of Busseola segeta Bowden on maize (Zea mays L.) in Kakamega called for studies on the role of wild host plants on the invasion of crops by wild borer species. A two-year survey was carried out in a small agricultural landscape along the edge of Kakamega forest (Kenya) to assess host range and population genetic structure of B. segeta. The larvae of B. segeta were found on nine different plant species with the majority occurring on maize and sorghum. Of forty cytochrome b haplotypes identified, twenty-three occurred in both wild and cultivated habitats. The moths appear to fly long distances across the habitats with genetic analyses revealing weak differentiation between hosts in different habitats (FST = 0.016; p = 0.015). However, there was strong evidence of variation in genetic composition between growing seasons in the wild habitat (FST = 0.060; p < 0.001) with emergence or disappearance of haplotypes between habitats. Busseola segeta is an example of a phytophagous insect that utilizes plants with a human induced distribution range, maize, but does not show evidence of host race formation or reduction of gene flow among populations using different hosts. However, B. segeta is capable of becoming an important pest in the area and the current low densities may be attributed to the general low infestation levels and presence of a wide range of alternative hosts in the area.

Novel source of sorghum tolerance to the African stem borer, Busseola fusca

Sorghum (Sorghum bicolor) is an important cereal food crop in semi-arid tropics, but its productivity is curtailed mainly by insect pests and diseases. The African stem borer,Busseola fusca Fuller (Lepidopteran: Noctuidae), is among the most injurious pests of sorghum in sub-Saharan Africa and is responsible for >15% sorghum grain yield losses. Sorghum from India with records of stem borer invasion could provide supplementary and novel resources of tolerance to this pest. Utilization of tolerant varieties in combination with other methods of control is likely to offer a sustainable strategy for B. fusca management in sorghum production. The objective of this study was to evaluate several local and exotic sorghum genotypes for tolerance to B. fusca. Genotype Swarna from India which is known to be susceptible to Chilo partellus was used as a susceptible check. There is limited information regarding tolerant/resistant sorghum to B. fusca. Seven commercial cultivars and 20 introductions from India were evaluated for B. fusca tolerance at Kabete, in central province of Kenya, during long and short rainy seasons in 2010. Selection index were based on leaf damage, dead hearts, exit holes and stem tunneling. The following genotypes named ICSA 467, ICSA 473, MACIA and ICSB 464 were found to be the most tolerant to B. fusca. These tolerant genotypes, can be used as novel sources of tolerance, and could be introgressed into the local common varieties since they are well adapted to the local environment. Key words: Busseola fusca, Sorghum bicolor, resistance, tolerance, Kenya.

Success of the high-dose/refuge resistance management strategy after 15 years of Bt crop use in North America

Transgenic maize and cotton expressing Bacillus thuringiensis (Bt) toxins were first commercialized in 1996. By 2009, Bt crops were planted on ca. 47.6 Mha in 22 countries worldwide, with the USA and Canada accounting for 54% of this area. Resistance (virulence) development in target insect pests is a major threat to the sustainable use of Bt crops. Four major target pests of Bt crops in the USA and Canada – European corn borer, Ostrinia nubilalis (Hubner), southwestern corn borer, Diatraea grandiosella Dyar (both Lepidoptera: Crambidae), tobacco budworm, Heliothis virescens Fabricius (Lepidoptera: Noctuidae), and pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) – remain susceptible to Bt toxins after 15 years of intensive use of Bt maize and Bt cotton. The success in sustaining susceptibility in these major pests is associated with successful implementation of the ‘high-dose/refuge’ insecticide resistance management (IRM) strategy: (i) Bt crop cultivars express a ‘high dose’, (ii) initial frequency of resistance alleles is very low, and (iii) a refuge is maintained nearby in the environment. Field resistance (including control failure) to a Bt crop has been clearly documented in three situations: fall armyworm [Spodoptera frugiperda JE Smith] in Puerto Rico, African stem borer [Busseola fusca Fuller (Lepidoptera: Noctuidae)] in South Africa, and P. gossypiella in India. Factors associated with these cases of field resistance include: failure to use high-dose Bt cultivars and lack of sufficient refuge. These observations support the claim that implementation of the ‘high-dose/refuge’ IRM strategy has been successful in substantially delaying field resistance to Bt crops.

Control of Busseola fusca and Chilo partellus stem borers by Bacillus thuringiensis (Bt)--endotoxins from Cry1Ab gene Event MON810 in greenhouse containment trials

Previous testing of several public Bacillus thuringiensis (Bt)-maize events did not show control of the African stem borer (Busseola fusca Fuller), an important stem borer species, without which stewardship would be compromised by the possibility of rapid development of resistance to Bt deltaendotoxins. This study was carried out to test Bt-maize Event MON810 as an option to control all major stem borer species in Kenya. Two Bt-maize hybrids, DKC8073YG and DKC8053YG, both containing Bt Event MON810 of Cry1Ab gene were imported to carry out greenhouse containment trials. The hybrids together with the controls were grown in 10 replications upto the V6 and V8 stages. Infestations on whole plants were carried out at two stages of growth using 5 neonates of the spotted stem borer (Chilo partellus Swinhoe) and B. fusca. Bt-maize Event MON810 hybrids showed resistance to both stem borer species with low leaf damage scores and few surviving larvae recovered from the whole plant. The public Bt-maize Event 223 did not control B. fusca. Deploying Bt-maize Event MON810 may, therefore, be used to control the two species of stem borers. However, the efficacy of Bt-maize Event MON810 will, need to be evaluated under field environments.

Buakea(Lepidoptera: Noctuidae), A New Genus of African Stem Borers: Morphological, Ecological and Molecular Data

A new genus of African stem borers of the subtribe Sesamiina (Lepidoptera: Noctuidae), Buakea gen. n., is described as well as the three species it includes, two new, B. venusta sp. n. and B. kaeuae sp. n., and a species that until now was placed in the genus Busseola Thurau, B. obliquifascia (Hampson) comb. n. The three species are monophagous on different graminaceous host plants, and the two sister species B. kaeaue and B. obliquifascia were collected in different ecological zones and altitudes, which suggests an ecological mode of speciation. Bayesian and maximum likelihood phylogenies inferred from two mitochondrial genes showed that the genus is monophyletic and does not share a recent common ancestor with the genus Busseola. However no strongly supported phylogenetic relationship could be established with the other six genera of the subtribe included in the analysis.

ChemInform Abstract: Desymmetrization of 1,4-Dien-3-ols and Related Compounds via Ueno-Stork Radical Cyclizations.

Desymmetrization of 1,4-dien-3-ols and related compounds via Ueno−Stork radical cyclizations is reported. The stereochemistry of the cyclization is controlled by the acetal center. Excellent stereocontrol at C(4) and C(5) of the newly formed tetrahydrofuran rings is observed. Use of a chiral auxiliary allows the preparation of enantiomerically pure material. The utility of this method has been demonstrated by achieving a short synthesis of (+)-eldanolide, the pheromone of the male African sugarcane stem borer Eldana saccharina.

A review of research achievements on maize stem borer, Busseola fusca (Fuller) and Diplodia ear rot caused by Stenocarpella maydis (Berk. Sutton)

Research that focused on maize production on the central Highveld of South Africa was traditionally, since the early twentieth century, dealt with by the Department of Agriculture at Potchefstroom. During the 1970s the Highveld Region at Potchefstroom assigned a group of researchers with an interest in maize to a unit termed the Summer Grain Centre that in 1992 became part of the Agricultural Research Council’s Grain Crops Institute. Members of this group in particular gave research attention to various aspects of crop protection in maize, including the soil insect complex, the maize stem borer complex, maize streak disease, the ear rot complex and various leaf diseases. This paper deals with research progress on the African stem borer, Busseola fusca, and ear rot caused by Stenocarpella maydis. The emphasis is on research with a practical application rather than that of an academic nature.