Impact of the leaf miner Cameraria ohridella on whole-plant photosynthetic productivity of Aesculus hippocastanum: insights from a model

Abstract

The leaf miner Cameraria ohridella causes premature defoliation of Aesculus hippocastanum trees. In order to assess the whole-plant loss of productivity caused by the parasite, we monitored seasonal changes of leaf gas exchange and leaf area losses in horse chestnut trees freely infested or chemically treated to prevent moth infestation (controls). Data were integrated in a model and the annual loss of net primary productivity (NPP) was calculated for infested trees with respect to controls. Measurements showed marked vertical stratification of C. ohridella attacks, with lower crown strata being more infested than higher ones. Leaf gas exchange was maximum between May and early June, but it strongly decreased starting from mid-June even in controls. Model calculations showed that NPP loss of infested trees was about 30% on an annual basis (when the first moth attack is recorded at the end of April). Model simulations showed that postponing the start day of attack would have important positive effects on plant's NPP. For example, if the start day of attack was postponed to 20 May, the annual loss of NPP would be about 15%. Our study suggests that A. hippocastanum trees attacked by C. ohridella are not facing serious risks of decline, especially if methods are adopted to postpone the start day of attack (e.g. removal of fallen leaves in autumn). Our data do not support the view that plants need to be totally protected from the parasite by application of insecticides.

Seasonal changes of plant hydraulics, water relations and growth of Aesculus hippocastanum seedlings infested by the leafminer Cameraria ohridella

“…1). This attack time course is in accordance with that observed for adult horse chestnut individuals over previous years [9] and has important consequences for plant fitness. In fact, most temperate woody plants complete their leaf expansion and growth by late spring, already, so that any reduction of photosynthetically active leaf surface area after this time can be expected to have limited impact on annual growth.…”

“…Previous studies [13,16,17] have shown that A. hippocastanum plants attacked by the parasite suffer a major damage in terms of reproductive potential (they produce smaller seeds with limited viability). On the contrary, whole-plant photosynthetic productivity and hydraulics of adult plants did not seem to be heavily affected [13,16], as recently confirmed on the basis of a mathematical model taking into account seasonal changes of photosynthetic rate and damage to foliage [9]. However, little is known of the potential impact of C. ohridella on the hydraulics and productivity of horse chestnut seedlings.…”

Revisión de las influencias de los insectos minadores de hojas en sus plantas huésped

“…Different leaf-mining depths thus have different impacts on leaf hydraulics, gas exchange, water use and chlorophyll fluorescence (Johnson et al, 1983;Parrella et al, 1985;Trumble et al, 1985;Kappel, 1986;Raimondo et al, 2003Raimondo et al, , 2013Pincebourde et al, 2006;Bueno et al, 2007;Wagner et al, 2008;Lombardini et al, 2013). However, the wholeplant photosynthetic loss from most leaf miners is slight because insect populations are small in natural vegetation (Hileman & Lieto, 1981;Nardini et al, 2004) and the photosynthetic loss does not extend beyond the mined leaf area (Lombardini et al, 2013;Raimondo et al, 2013). While in some economic plants, photosynthesis is negatively correlated with leaf miner density and injury leaf area (Fujiie, 1982;Johnson et al, 1983;Lombardini et al, 2013).…”

“…One interesting phenomenon is that mined leaves fall earlier than unmined leaves (Owen, 1978;Fujiie, 1982;Maier, 1983Maier, , 1989Nagasaki, 2004;Nardini et al, 2004;Bueno et al, 2007;Wagner et al, 2008). The effects of leaf-mining on leaf life span are stronger than other herbivore guilds .…”

“…Leaf-mining may have a detrimental effect on whole plant primary productivity (Nardini et al, 2004). Leaf miner outbreaks have strong negative influences on plant development and aboveground biomass production: more basal sprout dieback, lower plant height, lower girth, smaller leave size, fewer leaf number, fewer petiole number, and fewer shoot number (Trumble et al, 1985;Norris, 1997;Kozlov, 2005;Wagner & Doak, 2013).…”