Galls are plant structures formed by the abnormal growth of cells, tissues or organs induced by several organisms including fungi, nematodes and insects. Gall-inducing insects are specialist plant feeders with most species confined to one specific host plant. The aim of this work was to investigate the morphoanatomy and histochemical characteristics of galls, in leaves of three species of Euphorbiaceae: Cnidosculos quercifolius Pohl; Croton blanchetianus Baill.; and Manihot epruinosa Pax & K. Hoffm. Leaves with and without galls were collected in February, May and June 2013 from marked plants. The morphological study was carried out by scanning electron microscopy (SEM) with microtome sections of the leaves stained with astra blue and basic fuchsin. The galls from C. quercifolius occur isolated or agglomerated on the abaxial and adaxial surface of the leaf. They are globoid, green, glabrous, and in longitudinal section the developed larval chamber is observed with only a single inducer orange larvae. The histochemical analysis revealed the presence of lipids, starch grains, and tannins in galled and ungalled tissues, with higher concentrations in the galls. Croton blanchetianus bears green, globoid, pubescent leaf galls distributed on the abaxial and adaxial surface of the leaf. We observed a large amount of lipids in this galled tissue. The Manihot epruinosa leaf gall is clavate in form, occurring on the abaxial and adaxial surfaces. The larval chamber is unilocular bearing beige larvae containing a higher concentration of lipids. The insects inducing the galls in the three species belonged to the Diptera.
Cite this article as:
de Lima Santos, L.M., Tavares, F.M., de Arruda, E. and Almeida-Corte, J.S. (2014). Morphological and histochemical study of leaf galls in three species of Euphorbiaceae from north east Brazilian seasonal tropical dry forest. Plant Protection Quarterly 29(1), 2-6.