The Tomato Borer Tuta Absoluta Meyrick (Lepidoptera, Gelechidae) Invading The Region of Ouargla (Desert of Algeria): Biology and Damage

Tuta absoluta (Meyrick) is an invasive pest of tomato native to South America, where it is responsible for extensive damage. The study of this bioaggressor under greenhouse tomato in the region of Ouargla by pheromone traps showed that the global dynamics of populations T. absoluta 5 shows the difference in successive generations of six months is the growth cycle of tomato. There were a maximum of 1922 individuals in the three greenhouses studied. The life cycle of T. absoluta in tomato plants (T: 34 ° C H%: 50 - 60%) lasts 23.85 days. This pest has caused losses of up to 100% in leaves and fruits of tomato in February. Observation and direct capture to identify the natural enemies of T. absoluta as Chrysoperla carnea Coccinella algerica. and the parasitoid Trichogramma sp. Damage is directly related to the reduction of plants photosynthetic capacity and of production levels in tomato crops; indirect damage can be also caused by secondary infections, with pathogens developing on the infested plant and fruit tissues.

Investigating Resistance to Emamectin Benzoate in the Tomato Borer Tuta Absoluta

The tomato borer Tuta absoluta is a major pest of tomato mainly controlled by chemical insecticides. However, development of resistance to specific chemical classes has made control of the pest extremely difficult. Emamectin benzoate belongs to the avermectin mode of action and to date, low or no resistance levels against this insecticide have been documented. Recently, reduced efficacy of emamectin benzoate was documented, in a field population from Crete (9-fold resistant ratio (RR)). Subsequent laboratory selections with emamectin benzoate for eight sequential generations, resulted in an increase of the RR to 60-fold, the highest resistance level reported to the particular insecticide. Hereby, we are presenting the characterization of emamectin benzoate resistance in T. absoluta. Sequencing of the GluCl and GABA receptor (rdl) genes, the molecular targets of emamectin benzoate, indicted absence of non-synonymous SNPs. The use of known enzyme inhibitors (PBO, DEF and DEM) revealed that P450s partially synergized emamectin benzoate resistance, suggesting potential implication of metabolic resistance. RNA-seq approach was used to identify differentially expressed genes, from emamectin benzoate resistant and susceptible T. absoluta populations. Twelve libraries were sequenced using the Illumina platform, which generated 81 Gbp, thus substantially increasing the number of publicly available genomic resources for this species. The de novo transcriptome assembly consisted of 549,601 contigs, grouped in 233,453 unigenes. Differential expression analysis and qPCR validation revealed over-expression of one unigene similar to cytochrome P450 (Clan 4) potentially implicated in emamectin benzoate resistance, supporting further the involvement of P450s in the observed resistance phenotype.

Application of tomato borer Tuta absoluta (Meyrick) pheromone in the tomato protection in protected ground

The article presents the results of experiments conducted in Bulgaria and Kabardino-Balkaria in protected ground on tomato crop. Efficiency of pheromone application for mass trapping of tomato borer males to reduce the use of pesticides and increase the yield and quality of tomatoes are presented. The study’s results of the attractiveness of different structures of pheromone traps located at different levels are presented.

Performance of Trichograma spp in small tomato borer (Neoleucinodes elegantalis Guenée): Pest management with egg parasitoid

The tomato is a crop of great importance for Brazilian agriculture. Among the most damaging pests, the small tomato borer, Neoleucinodes elegantalis Guenée (Lepidoptera: Crambiadae) has caused great losses, since they directly reach the fruits to be commercialized, being used for its handling a large volume of insecticides. In this way, the use of alternative techniques that help in the management of this pest becomes of great importance. Among them, the use of the egg parasitoid Trichogramma spp. has been promising. Thus, the present study aimed to evaluate the performance of Trichogramma species and/or strains in N. elegantalis by selection of strains. The selection was made based on four lineages maintained in the Nucleus of Scientific and Technological Development in Phytosanitary Management of Pests (NUDEMAFI), being three strains of the species T. pretiosum and one of T. galloi species. The parameters evaluated were percentage of parasitized eggs, egg viability, number of individuals per eggs, sex ratio and number of Trichogramma spp. to be released. The T. galloi (T. g1) showed the best parameters for selection of the strain. Estimating the optimal number of T. g1 in eggs of small-fruit-borer was 82 individuals per egg parasitoid. Therefore, this strain was selected for the management of the small tomato-borer, whose eggs presented favorable physicochemical characteristics for the development of the parasitoid.