Probing behavior of Dysmicoccus brevipes mealybug in pineapple plants1

Empresa De Pesquisa Agropecuária De Minas Gerais, Brazil ,Lenira Viana Costa Santa-Cecília,Brígida Souza,Ernesto Prado,Universidade Federal De Lavras, Brazil

doi:10.1590/1983-40632016v4642278

Empresa De Pesquisa Agropecuária De Minas Gerais, Brazil , Lenira Viana Costa Santa-Cecília + Show 3 more

Open Access

https://doi.org/10.1590/1983-40632016v4642278

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Abstract

ABSTRACT Differences in susceptibility to viruses in plants may be partially explained by the insect vector probing behavior and by the presence of phenolic compounds, which are often associated with defense strategies. This study aimed at detecting barriers that may difficult the probing activity of the Dysmicoccus brevipes (Pseudococcidae) pineapple mealybug, a vector of the pineapple mealybug wilt-associated virus, as well as evaluating the phenolic content of plants, in order to verify any possible relationship with the probing behavior, by using the electrical penetration graphs (EPG) technique. Seedlings of 'Smooth Cayenne' and 'Pérola' pineapple cultivars were used in the experiments. Only 28 % and 21 % of the mealybugs reached the phloem of the 'Smooth Cayenne' and 'Pérola' cultivars, respectively, over 16 h of recording, with an average of 9 h to reach the phloem vessels. The xylem phase was extended in both cultivars and represented approximately 31 % ('Smooth Cayenne') and 44 % ('Pérola') of the recording time. The phenolic contents of both cultivars were similar.

Highlights

The pineapple mealybug [Dysmicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae)] is a significant limiting factor for the pineapple production, as it restricts the expansion of cultivated areas and reduces plant yield (Santa-Cecília et al 2004)
pineapple mealybug wilt-associated virus (PMWaV), which belongs to the Ampelovirus genus (Closteriviridae family), is semi-persistently transmitted via mealybug saliva, during the stylet penetration (Jahn et al 2003)
This study aimed at identifying possible constraints to stylet penetration in pineapple cultivars, as a way of explaining the differences in susceptibility between them, and determining whether phenolic concentrations differ between these cultivars

Summary

Introduction

The pineapple mealybug [Dysmicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae)] is a significant limiting factor for the pineapple production, as it restricts the expansion of cultivated areas and reduces plant yield (Santa-Cecília et al 2004). Sap-sucking mealybugs weaken plants directly, but, more importantly, they are major vectors of the pineapple mealybug wilt-associated virus (PMWaV) (Gunashinghe & German 1989, Setter et al 1998). Particles of this virus are primarily restricted to the phloem, from where they are acquired by vectors. PMWaV, which belongs to the Ampelovirus genus (Closteriviridae family), is semi-persistently transmitted via mealybug saliva, during the stylet penetration (Jahn et al 2003). The underlying mechanisms of how this semi-persistent virus is acquired and inoculated are not well understood, phloem-sap feeding seems to be an essential step in the transmission process (Moreno et al 2012). Individual plants or cultivars that exhibit resistance to phloem-sap feeding should be, theoretically, less susceptible to infection

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