The Prodiplosis longifila (Gagne), commonly referred to as Prodiplosis, negrita or scab, is a small and polyphagous neotropical fly, considered one of the main phytosanitary problems for the cultivation of tomatoes.
According to Yuri Mercedes Mena Perez, a masters student in Agricultural Sciences from the National University of Colombia in Palmira, the complexity of this insect has forced most tomato growers to indiscriminately use chemical insecticides that promote a high degree of pollution in the environment and in the fruit. This, in turn, leads to the deterioration of the biological balance, the fly developing resistance to the insecticides, yield loss, and the abandonment of this crop.
"This pest's habits allow it to be present in the phenological development of the crop, which limits management options and forces producers to seek for varietal resistance as the best alternative for crop protection," said the student.
In face of the tomato crop's susceptibility to this pest and the need to find solutions to the damages is has made, identifying sources of resistance is a step forward for the future production of resistant cultivars, which would allow farmers to control the plague in a clean, environmental and lasting way.
In that sense, the graduate student undertook a project to evaluate the resistance that wild tomato accessions and recurrent populations derived from interspecific crosses, previously selected for resistance to the vector N. elegantalis, another important pest, have to this powerful plague.
The researcher conducted assessments in field conditions and in screen houses, using a completely randomized design with four replications.
"We evaluated the number of healthy shoots per plant, the number of shoots with pest damage, the number of outbreaks with the presence of live and dead insect larvae and the number of living and dead larvae per shoot buds," said the researcher.
According to Yuri Mercedes Mena Perez, during the field experiment, the wild accessions presented some degree of resistance as they showed no damage or were not preferred by the fly for oviposition. However, Unapal-Maravilla and three genotypes of the RC3 interspecific crosses were susceptible to the insect; and the 4212P4 genotype was considered to be the least preferred by the insect pest.
Source: Agencia de Noticias UN