An experimental test of rainfall as a control agent of Glycaspis brimblecombei Moore (Hemiptera, Psyllidae) on seedlings of Eucalyptus camaldulensis Dehn (Myrtaceae)

Glycaspis brimblecombei (Hemiptera: Psyllidae) attack patterns on different Eucalyptus genotypes

“…This pattern was already observed in previous studies with G. brimblecombei (Firmino-Winckler et al, 2009; Oliveira et al, 2012) and was explained by the higher nutrient flow for nymph development and reduced desiccation on the abaxial surface, especially during insect molt (Phillips, 1992; Firmino-Winckler et al, 2009). Thus, a preference-performance link would be expected, with higher nymph density on the abaxial surface.…”

“…Instead, our results clearly indicate a strong effect of rainfall on the egg and nymph density, a pattern already described for G. brimblecombei in Mexico (Ramirez, Mancera & Guerra-Santos, 2003) and Mauritius Islands (Sookar, Seewooruthun & Ramkhelawon, 2003). Furthermore, a controlled experiment of rainfall simulation showed that the mechanical removal of the psyllid lerps by water droplets and/or lerp solubilization by leaf moisture may decrease its population (Oliveira et al, 2012). In addition, the higher humidity during the rainy season increases entomopathogenic fungi occurrence, which may kill psyllid nymphs (Ramirez, Mancera & Guerra-Santos, 2003).…”

“…The susceptibility of Eucalyptus genotypes to insect species varies (Firmino-Winckler et al, 2009; Queiroz, Burckhardt & Majer, 2012) and plant mechanisms responsible for reducing damages by these organisms must be further investigated. Given that both temperature (Ferreira-Filho et al, 2015) and rainfall (Oliveira et al, 2012) affect G. brimblecombei abundance, further studies are necessary to determine of correct time of management interventions.…”

Seasonal occurrence and adaptation of the exoticGlycaspis brimblecombeiMoore (Hemiptera: Aphalaridae) in Italy

“…The effects of high temperatures were also evaluated in Brazil (Ferreira-Filho et al 2008), where no influence of rainfall was found on population dynamics, because, as pointed out by the authors, during the observations there were no distinct periods of rainfall and drought. Regarding the effects of the rainfall, Oliveira et al (2012), with an experimental test conducted on seedlings of E. camaldulensis, have proven the effects of artificial rain in reducing the abundance of lerps through solution and mechanical removal by water. Conversely, but not in contrast with the cited data, we have shown that the rain during summer and after a period of dryness is favourable for the psyllid, intuitively, because it acts on the physiology, the lymphatic circulation and the degree of hardening of the leaf tissue of the host tree.…”

Influence of temperature and rainfall on the population dynamics of Glycaspis brimblecombei and Psyllaephagus bliteus in Eucalyptus camaldulensis plantations

“…The lowest numbers of G. brimblecombei and P. bliteus captured during summer 2006 and 2007 coincided with periods of better distributed rainfall and it increased after 106 days of evaluation (May 9 th , 2006), in the fall, with less intense rain, as reported for the beginning of this psyllid with heavy rain in Mauritius (Sookar et al 2003). The number of G. brimblecombei lerp per E. camaldulensis seedling was reduced by more than 50 %, and then, by 100 % after two and five days of simulated rain, respectively (Oliveira et al 2012). This finding indicates, again, that the mechanical removal of the G. brimblecombei lerp by rain explains its population decrease under these conditions.…”