Search

Bactericera cockerelli is an economically relevant pest of solanaceous crops. The presence of leaf trichomes that certain wild species have constitutes important genetic resources for plant breeding programs in terms of resistance to pests. In this study, the influence of leaf trichomes of wild species and commercial tomato cultivars on the preference, development and fecundity of B. cockerelli was evaluated. The results showed that wild species were less preferred by the psyllid than commercial cultivars. Insects showed a lower settlement percentage in S. habrochaites compared to the other species. Regarding survival, the lowest percentage developed in S. habrochaites with 24% and S. arcanum with 40%. The lowest oviposition average was found in S. habrochaites with two eggs, which did not hatch, in addition to being the only species that showed the presence of glandular trichomes type IV (113.86 ± 48.1) and VIc (27.3 ± 2.3) per mm2, and its presence was negatively correlated with the number of perched adults. S. arcanum was another species that negatively influenced the behavior and development of the insects; however, these attributes were not due to the presence of trichomes. The defense mechanisms expressed by S. habrochaites and S. arcanum towards B. cockerelli can be used as a resource for gene introgression for the management of this pest by reducing its biological potential. [ABSTRACT FROM AUTHOR]

Copyright of Informacion Tecnica Economica Agraria is the property of Asociacion Interprofesional para el Desarrollo Agrario (AIDA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plutella xylostella is a major pest of cruciferous crops in more than 100 countries. The main control method for P. xylostella is based on the use of chemical insecticides. However, this moth species is characterized by its rapid development of resistance to almost all insecticides. The application of low concentrations of insecticides can affect the physiology, biochemistry, and ecology of insects. In this study, a cypermethrin resistance selection was performed during eight generations of P. xylostella and the sublethal dose (LC20) of the resistant line and the susceptible line was determined. Later, the sublethal dose was applied to third instar larvae to investigate its effect on the percentage of pupation, weight of pupae, emergence of adults in two generations (parents and offspring), as well as the development times of each phase of development of P xylostella. A decrease was observed in the percentage of formed pupae, emerged adults and pupal weight. On the other hand, the number of oviposited eggs increased when individuals were exposed to the insecticide. The above can be an important factor for the management and control of this pest when problems of resistance to cypermethrin occur. [ABSTRACT FROM AUTHOR]

Copyright of Investigación y Ciencia de la Universidad Autónoma de Aguascalientes is the property of Universidad Autonoma de Aguascalientes, Direccion General de Investigacion y Posgrado and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ten tomato varieties were examined for resistance to Tetranychus urticae by bioassays on leaf discs. A colony of T. urticae from different ornamental crops of Saltillo, Coahuila, Mexico, was established in bean seedlings (Phaseolus vulgaris L.) in a Biotronette chamber. At 25 ±2 °C, 60- 70 HR and 12:12 h L: D. According to the design of the experiment, the females were placed in leaf discs of the 10 tomato varieties under study in a proportion of 10 disc with 90 repetitions, the behavior was evaluated based on survival, repellency and mortality. Subsequently, 100 freshly mated and fertilized one-day-old females were transferred to discs of tomato leaves (Solanum lycopersicum L.) of 1.3 cm in diameter of cultivars ‛Tsan-101', ‛Toro', ‛Saladette' and ‛Cereza' in such a way that each experimental unit included 1 female per disk. The demographic parameters in this experiment showed a lower growth potential of this pest in the cultivars ‛Tsan-101' and ‛Toro' than in ‛Saladette' and ‛Cereza'. [ABSTRACT FROM AUTHOR]