Molecular screening of Heterorhabditis bacteriophora inbred lines for polymorphism and genetic crosses for the development of recombinant inbred lines

Males and females of two entomopathogenic nematode (EPN) inbred lines, H. bact -1 and H. bact - 2, whose infective juveniles expressed contrasting performance for stress factors, were used as candidates in genetic crosses. The crosses produced an initial pool of 108 F2 progenies and these were advanced by self-fertilization for 6 generations, each starting from a single hermaphrodite. After 6 generations and about 96% of homozygosity, 60 separate recombinant inbred lines (RILs) were recovered. The parental lines were previously subjected to molecular screening for polymorphism. The polymorphic markers detected in the parental inbred lines were screened across the genomic DNA of all the RILs for segregating allelic loci. Presence or absence of gel bands were scored as alleles due to the homogeneity attained by the inbred lines after 6 generations of self-fertilization. From the polymorphic markers detected, 19 were scored throughout the RIL population. This indicates the existence of a genetic heritable component for traits observed in the parental line of H. bacteriophora and therefore can be used to screen new population for desirable traits through marker assisted selection and could be useful for developing a genomic linkage map.Keywords: Genetic-crosses, RILs, Polymorphisms, Genetic-Markers, EP

Facilitating the registration of biocontrol organisms, plant extracts and semiochemicals in Europe

The legal regulation of plant protection products (Dir. 91/414/ EEC) is a bottleneck in the market introduction of new microbial biocontrol agents, plant extracts and pheromones. In contrast, invertebrate biocontrol agents (“beneficials”) are not registered at EU level. The EU-funded project REBECA suggested improvements to accelerate the regulation process and make it more cost-effective, without compromises to the level of safety. Representatives of all stakeholder groups participated in the REBECA workshops. The EU Commission and Member States are encouraged to improve the registration of biocontrol organisms, plant extracts and semiochemicals at EU and/or national level. The full proposals can be found at www.rebeca-net.de

Optimierung der Massenvermehrung entomophager Nematoden der Gattungen Steinernema (Neoaplectana) und Heterorhabditis fuer die biologische Bekaempfung von Schadinsekten im Boden Schlussbericht

Available from TIB Hannover: DtF QN1(25,30) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Biological control of Tipula paludosa (Diptera : Nematocera) using entomopathogenic nematodes (Steinernema spp.) and Bacillus thuringiensis subsp israelensis

Tipula paludosa (Diptera: Nematocera) is the major insect pest in grassland in Northwest Europe and has been accidentally introduced to North America. Oviposition occurs during late August and first instars hatch from September until mid-October. Laboratory and field trials were conducted to assess the control potential of entomopathogenic nematodes (EPN) (Steinernema carpocapsae and S. feltiae) and Bacillus thuringiensis subsp. israelensis (Bti) against T. paludosa and to investigate whether synergistic effects can be exploited by simultaneous application of nematodes and Bti. Results indicate that the early instars of the insect are most susceptible to nematodes and Bti. In the field the neonates prevail when temperatures tend to drop below 10 °C. S. carpocapsae, reaching >80% control, is more effective against young stages of T. paludosa than S. feltiae (80% with 0.5 million nematodes m¿2 at soil temperatures ranging between 3 and 18 °C. Results with Bti were strongly influenced by the larval stage and concentration. Against early instars in autumn between 74 and 83% control was achieved with 13 kg ha¿1 Bti of 5,700 International Toxic Units (ITUs) and 20 kg ha¿1 of 3,000 ITUs. Applications in spring against third and fourth instars achieved between 0 and 32% reduction. The results indicate that application of Bti and nematodes will only be successful and economically feasible during the early instars and that the success of S. carpocapsae is dependent on temperatures >12 °C. Synergistic effects between S. carpocapsae and Bti require more detailed investigations in the field to determine maximal effec

Evaluación de dos cepas comerciales de entomonematodos como agentes de control de Cyrtomenus bergi Froeschner (Hemiptera: Cydnidae) = Evaluation of two commercial strains of entomonematodes as control agents of Cyrtomenus bergi Froeschner (Hemiptera: Cydnidae)

Cyrtomenus bergi Froeschner es un fitófago subterráneo importante en cultivos tropicales. Se evaluaron dos cepas comerciales de nemátodos entomopatógenos (nep) (Steinernema feltiae (Filipjev) y Heterorhabditis bacteriophora Poinar) como antagonistas biológicas bajo invernadero (18-28°C y 55-85% humedad relativa). Se utilizaron las concentraciones comerciales recomendadas por la casa commercial E-nema: 1000 y 500 nep/ml de S. feltiae y H. bacteriophora, respectivamente. Estas soluciones se aplicaron en potes de 1,5 dm3 con suelo agrícola y arena (1:1) con 20 individuos de C. bergi (adultos o inmaduros del quinto instar) confinados por pote. Los insectos fueron alimentados con plantas de maní (Arachis hypogaea L.). La tasa de infestación en el chinche y la mortalidad fueron medidas por medio de evaluaciones destructivas a los 15 y 30 días después de infectados (ddi), tres potes por época. Solo los adultos resultaron infectados (P£0,05). Considerando ambas evaluaciones y todas las cepas, se observó la mayor tasa de penetración en S. feltiae (93,9%) comparado con H. bacteriophora (72,1%). En términos de mortalidad, a 15 ddi H. bacteriophora (42,2%) mató a más insectos que S. feltiae (8,6%); sin embargo, a los 30 ddi no se encontraron diferencias entre las dos cepas de nep (ca. 54,3%). Adicionalmente, se observaron nemátodos melanizados, probablemente como respuesta inmunológica de C. bergi al entomopatógeno, donde S. feltiae (37,5%) fue más susceptible que H. bacteriophora (13,1%) a los 30 ddi. Se concluye que solo los chinches adultos son significativamente susceptibles a los entomonemátodos; H. bacteriophora es la cepa más promisoria al obtener las mayores mortalidades en menos tiempo y presentar el menor porcentaje de melanización bajo estas condiciones. = Cyrtomenus bergi Froeschner is a subterranean phytophage important in tropical crops. We tested two commercial entomopathogenic nematode (epn) strains (Steinernema feltiae (Filipjev) and Heterorhabditis bacteriophora Poinar) as biological antagonists in the greenhouse (18-28°C and 55-85% relative humidity). We used the concentrations recommended by the supplier E-nema: 1000 and 500 epn/ ml of S. feltiae and H. bacteriophora, respectively. These solutions were applied to pots of 1,5 dm3 filled with agricultural soil and sand (1:1) with 20 burrower bugs (adults or 5th instar immatures) confined to each pot. The insects were fed on groundnuts (Arachis hypogaea L.). Infestation rate of the burrower bug and mortality were measured through destructive evaluations 15 and 30 days after application (daa), three pots per time period. Only adults were infested (P£0,05). Considering both evaluations and all strains, we observed the greatest penetration rate for S. feltiae (93,9%) compared to H. bacteriophora (72,1%). In terms of mortality, H. bacteriophora killed more bugs after 15 days (42,2%) than S. feltiae (8,6%); however, after 30 days no differences were found between the two epn strains (54,3%). Moreover, we observed melanized nematodes, probably as an immune response of C. bergi against nematodes, where S. feltiae (37,5%) was more susceptible than H. bacteriophora (13,1%) at 30 daa. We conclude that only adults of C. bergi are susceptible to entomonematodes; H. bacteriophora is the most promising strain for producing greater mortality in less time and presenting a lower percent of melanization under these conditions

Application and persistence of entomopathogenic nematodes : Proceedings Cost 819 Workshop, Tody

Proceedings Cost 819 Workshop, Todi, Italy, EUR 18873-E