Host fruits, density carry-over effect and potential of ozone as an alternative for controlling Drosophila suzukii in the Neotropical region

• Ano de defesa: 2019
• Autor(a) principal: Mendonça, Larine de Paiva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Drosophila suzukii - Controle; Frutas - Doenças e pragas - Controle; Relação hospedeiro-parasito; Drosophila suzukii - Criação - Efeito do stress; Entomologia agrícola
• Link de acesso: https://locus.ufv.br//handle/123456789/32243

Invasive pests are a constant threat to agricultural production. The adequate management of invasive pests, such as Drosophila suzukii Matsumura (Diptera: Drosophilidae), requires a better understanding of potential hosts and the establishment of control practices. Drosophila suzukii, differently from other drosophilids, is considered a pest due to its capacity to oviposit in ripe soft skinned fruits. In this way, this study was divided in three chapters aiming to evaluate new potential hosts, effect of density in biological traits of D. suzukii and finally, the susceptibility of the flies to ozone treat- ment. Once that D. suzukii is a polyphagous insect, its capacity of dispersion is facilitated in the presence of new possible hosts. The attempt to mass rearing of this insect in laboratory can expose the pest to stresses affecting its biology as well as the results of toxicological tests. Lastly, it is always important to research new and safer options to add to control strategies of invasive pest. Thus, in the current study, the capacity of D. suzukii to oviposit and complete its life cycle in fruits of jabuticaba, Plinia cauliflora, Barbados cherry, Malpighia emarginata, bonnet pepper, Capsicum chinese and coffee, Coffea arabica was evealuted. Once confirmed this capacity, field surveys were realized to look for possible infestations. The new host and also two different food sources were assessed for their effects on biological and physiological traits of D.suzukii. Furthermore, the transgenerational effect of density was measured by the exposure of insect to high and low density on artificail diet under laboratory conditions. The effect on this stress was evaluated by the toxicological bioassays and how this affected the survival and the average fecundity of the pest. Finally, the toxic effect of ozone gas was tested in egg phase of D. suzukii, where it was tested four different concentrations of ozone (i.e. 0.2, 1.2, 2.3 and 3.0 mg/L) for 30 minutes of exposure. Our results showed the capacity of the fly to lay eggs in all the substrates that were offered, but it was only capable of putting their eggs inside fruits of M. emarginata. Furthermore, field surveys confirmed the occurrence of D. suzukii in fruits of Barbados cherry. The effect of den- sity was possible to notice in the survival reduction of insects whose parents where reared in high density. The susceptibility was not affected, but the sublethal exposure associated with parental density, affected the survival and the fecundity of the flies following a hormetic pattern. Finally, even the exposure to the higher concentration of ozone (3.0 mg/L) was not capable to prevent the emergence of D. suzukii and the treatments also did not affect the weight of insects. As conclusions, the studies showed the suitability of Barbados cherry as host for D. suzukii, the stress of density can affect adaptive traits of these flies, and alternatives, such as ozone in the conditions used in these experiments, was apparently not effective to control the egg phase of D. suzukii.