Leaf Penetration Pattern of Aulacaspis tubercularis (Hemiptera: Diaspididae) Stylet in Mango
Keywords:
mango, white mango scale, stylet bundle, mesophyll, leaf vascular bundlesAbstract
Mango (Mangifera indica L.) is an intensively cultivated fruit in Mexico, the leading exporter of this product in the world. One important limiting factor in mango production is the white mango scale (Aulacaspis tubercularis Newstead; Hemiptera: Diaspididae). White mango scale infestation causes irreversible leaf yellowing and death, and it lowers fruit quality below export requirements. Feeding mechanisms of these diaspidids have not been extensively studied; no histological studies on this subject are known. We histologically analyzed leaf tissues penetrated by the stylet bundle (SB) of white mango scale females, in order to follow the SB cellular path, to observe the extent of visually-detectable leaf cell damage, and to determine if this insect feeds on phloem sap. Mango plants of cv. ‘Manila’ were artificially infested with this insect in the laboratory. Histological slices from infested leaves were processed for microscope observation of the intact SB. Through this process a complete SB could not be observed, so its full accurate length could not be reported. However, the SB length was estimated at 3 mm, i.e., 3 times the total length of the female body length, which was 1 mm. The SB path inside the leaf was mostly intracellular through the mesophyll, but it also pierced lignified xylem cells and nutrient-rich phloem tissues in the vascular bundles. Thick red masses were formed along the SB path, possibly containing phenolic compounds. Cell lysis or collapse was not observed in the SB-injured leaf tissue.
El mango (Mangifera indica L.) es uno de los principales cultivos frutícolas en México, el primer exportador mundial de este producto. Una limitante de su producción es la escama blanca del mango (Aulacaspis tubercularis Newstead; Hemiptera: Diaspididae), cuyas hojas infestadas cambian de verde pálido a amarillo y al final se necrosan, y la infestación demerita la calidad de los frutos de modo que no se pueden exportar. La alimentación de los diaspídidos no se ha estudiado extensamente y en la literatura revisada no se encontraron reportes histológicos sobre el tema. En este estudio se hizo un análisis histológico de hojas penetradas por el haz de estiletes (HE) de la hembra de escama blanca del mango, para determinar su ruta celular, detectar daños celulares en la hoja, y determinar si el insecto se alimenta de savia del floema. Plantas de mango var. ‘Manila’ fueron infestadas con este insecto en laboratorio. Cortes histológicos de porciones de hojas infestadas se procesaron para observar el HE intacto al microscopio. No se encontró el HE completo hasta su punta, por lo que no se pudo determinar con precisión su longitud total. No obstante, se pudo estimar que al menos miden 3 mm, el triple de la longitud de la hembra (1 mm). La penetración del HE es predominantemente intracelular a través del mesófilo, pero también puede atravesar células lignificadas del xilema y tejidos del floema ricos en nutriente en los haces vasculares. El HE encuentra tejidos vasculares ricos en nutrientes, pero no permanece ahí sino que atraviesa por completo el haz vascular, incluyendo las fibras que lo envuelven, para continuar atravesando el mesófilo. En la ruta de penetración del HE se observaron unas zonas engrosadas y rojas, posiblemente constituidas de material fenólico. No se observó lisis ni colapso celular en el tejido vegetal atravesado por el HE.
Downloads
Published
Issue
Section
License
Copyright for any article published in Florida Entomologist is held by the author(s) of the article. Florida Entomologist is an open access journal. Florida Entomologist follows terms of the Creative Commons, Attribution Non-Commercial License (cc by-nc). By submitting and publishing articles in Florida Entomologist, authors grant the FOJ and Florida Entomologist's host institutions permission to make the article available through Internet posting and electronic dissemination, and to otherwise archive the information contained both electronically and in a hard printed version. When used, information and images obtained from articles must be referenced and cited appropriately. Articles may be reproduced for personal, educational, or archival purposes, or any non-commercial use. Permission should be sought from the author(s) for multiple, non-commercial reproduction. Written permission from the author(s) is required for any commercial reproduction.