Efeito da estrutura da paisagem e do genótipo de Eucalyptus na abundância e controle biológico de Glycaspis brimblecombei Moore (Hemiptera: Psyllidae)

Abstract

Effects of Landscape Structure and Eucalyptus Genotype on the Abundance and Biological Control ofGlycaspis brimblecombei Moore (Hemiptera: Psyllidae)ABSTRACT -Glycaspis brimblecombei Moore is an Australian native pest of Eucalyptus detected in Brazil in 2003. Since then, it has spread fast and colonized plantations in several states of the country. This study aimed to investigate the influence of cerrado remnants on the abundance and biological control of G. brimblecombei. We placed yellow sticky card traps to capture insects in four plantations of hybrid clones of Eucalyptus urophylla x Eucalyptus grandis ("Urograndis") and four plantations of E. urophylla x Eucalyptus camaldulensis ("Urocam"). Traps were placed in three areas of these plantations: center, border with cerrado and border without cerrado. We also collected leaves from the same clones to estimate psyllid egg and lerp abundance. The abundance of G. brimblecombei was lower in the plantation-cerrado border, and the inverse pattern was observed for microhymenopterans. The leaf abaxial surface showed a higher abundance of eggs and nymphs, probably as a consequence of a lower parasitism rate and mechanical removal by wind and rain. Egg number was higher on Urograndis than in Urocam clones, but the number of psyllid lerps was higher in the latter. Thus, the establishment of first instars is probably a critical event to psyllid infestation, and these differences may be caused by morphological, anatomical and biochemical leaf features of distinct clones. Our results suggest that the maintenance of native vegetation around plantations is a promising management practice to promote the natural biological control of G. brimblecombei, a strategy that would also enhance the preservation of cerrado remnants.

Sarsina violascens spatial and temporal distributions affected by native vegetation strips in eucalyptus plantations

“…The lower number of S. violascens adults in the system WNVS suggests that higher plant species richness in the landscape, compared to that of the system ONVS, can maintain a low frequency of this pest species due to biological factors. This agrees with the fact that several small shelters and higher proportions of native forest provide better conditions of biological balance than a few or no native vegetation compartments (Silva et al, 2010;Dall'Oglio et al, 2013;Macedo-Reis et al, 2013). Therefore, the lower occurrence of S. violascens individuals in the system WNVS might be explained by the higher heterogeneity in plant species richness and by the higher quantities of sources of pollen, nectar, and alternative hosts in this system, which favors natural enemies Macedo-Reis et al, 2013).…”

“…The expansion of Eucalyptus spp. plantations in areas of the Brazilian Cerrado contributes to this outcome, because the poorer understory favors the unbalance of insect pest populations Silva et al, 2010). The studied species was reported as a dominant one with wide distribution and abundant, floating populations Lopes et al, 2007;Bernardi et al, 2011).…”

Herbivory on Handroanthus ochraceus (Bignoniaceae) along a successional gradient in a tropical dry forest

“…Thus, the increase expected in general forest insect diversity because of higher niche availability or better microclimatic conditions in advanced, more complex successional stages may not be reflected in the fauna associated with single plant species in those forests. It has also been proposed that herbivores suffer higher rates of predation in more complex habitats, because they are expected to harbor a higher diversity of natural enemies (Siemann et al 1999;Sanders et al 2008;Silva et al 2010). However, no statistical differences in spider abundance were observed between successional stages (except for February, see Fig.…”

Effect of silicon application to Eucalyptus camaldulensis on the population of Glycaspis brimblecombei (Hemiptera: Aphalaridae)

“…For potassium silicate, the same tendency was observed with the number of eggs and immatures in treatments 5 being the smallest compared to the control. Silva et al (2010) mention that the resistance of some eucalypt clones is related to mechanisms that affect the survival of immatures soon after hatching. It is likely that leaf characteristics are important factors in the adhesion of the first instar immature process, affecting their ability to form lerps.…”

“…Since the detection of G. brimblecombei in Brazil studies have been conducted on the biology (Ferreira et al, 2009;Firmino-Winckler et al, 2009;Wilcken et al, 2010), population dynamics (Ferreira Filho et al, 2008), influence of environmental factors (Silva et al, 2010;Oliveira et al, 2012), biological control (Santana et al, 2003;Wilcken et al, 2010) and plant resistance (Pitta et al, 2006;Huerta et al, 2010;Pereira et al, 2013;Camargo et al, 2014). Based on geographical records the potential distribution of G. brimblecombei was predicted with different models using bioclimatic variables (Queiroz et al, 2013).…”