|
Dader, B. (2015). Elevated CO2 impacts bell pepper growth with consequences in the feeding behaviour and performance of the green peach aphid, Myzus persicae (Vol. 5).
Abstract: Future CO2 predictions estimate an increase up to 550 ppm within only few decades away. Among the observed effects on plants, increasing CO2 stimulates growth, reduces stomatal conductance and transpiration, improves water-use efficiency and induces photosynthesis. These changes have an indirect impact on pest biology and behaviour, e.g. altering their population growth or feeding habits.Our first aim was to study the effect of ambient (400 ppm) (aCO2) and elevated CO2 (650 ppm) (eCO2) on pepper (Capsicum annuum L.). Height, leaf area, dry weight and leaf temperature by thermal imaging were measured. Chlorophyll was measured in SPAD units as an indirect indicator of nitrogen foliar content. Peppers under eCO2 were significantly taller although they had the same number of leaves than under aCO2. SPAD was significantly lower under eCO2. Leaf, stem and above-ground dry weight were significantly higher under eCO2. There was a significant decrease in specific leaf area under eCO2. Canopy temperature was 1.2 °C higher under eCO2.Secondly, pepper plants were used to assess the development and fecundity of M. persicae. The pre-reproductive period was 11% longer in eCO2 peppers. Aphids grew significantly slower and produced fewer nymphs under eCO2. Lastly, aphid feeding behaviour was studied using the Electrical Penetration Graph (EPG) technique, which provides a live visualization and recording of plant penetration by aphid mouthparts. EPG results will be presented and discussed. No Label
|
|
|
Dáder, B., Moreno A, Fereres A. (2013). Direct and plant-mediated impact of UV-absorbing films on plant growth and performance of insect vectors of plant viruses..
|
|
|
Dáder, B., Fereres, A., & Moreno, A. (2014). Effects of UV radiation on pests and plant pathogens. Keynote lecture..
|
|
|
Dáder, B., Fereres, A., & Trebicki, P. (2014). Studying Myzus persicae performance and feeding behaviour, and associated plant viruses under increasing CO2..
|
|
|
Dáder, B., Gwynn-Jones, D., Moreno, A., Winters, A., & Fereres, A. (2014). Impact of UV-A radiation on the performance of aphids and whiteflies and on the leaf chemistry of their host plants. J. Photochem. Photobiol. B, 138, 307–316.
Abstract: Ultraviolet (UV) radiation directly regulates a multitude of herbivore life processes, in addition to indirectly affecting insect success via changes in plant chemistry and morphogenesis. Here we looked at plant and insect (aphid and whitefly) exposure to supplemental UV-A radiation in the glasshouse environment and investigated effects on insect population growth. Glasshouse grown peppers and eggplants were grown from seed inside cages covered by novel plastic filters, one transparent and the other opaque to UV-A radiation. At a 10-true leaf stage for peppers (53 days) and 4-true leaf stage for eggplants (34 days), plants were harvested for chemical analysis and infested by aphids and whiteflies, respectively. Clip-cages were used to introduce and monitor the insect fitness and populations of the pests studied. Insect pre-reproductive period, fecundity, fertility and intrinsic rate of natural increase were assessed. Crop growth was monitored weekly for 7 and 12 weeks throughout the crop cycle of peppers and eggplants, respectively. At the end of the insect fitness experiment, plants were harvested (68 days and 18-true leaf stage for peppers, and 104 days and 12-true leaf stage for eggplants) and leaves analysed for secondary metabolites, soluble carbohydrates, amino acids, total proteins and photosynthetic pigments. Our results demonstrate for the first time, that UV-A modulates plant chemistry with implications for insect pests. Both plant species responded directly to UV-A by producing shorter stems but this effect was only significant in pepper whilst UV-A did not affect the leaf area of either species. Importantly, in pepper, the UV-A treated plants contained higher contents of secondary metabolites, leaf soluble carbohydrates, free amino acids and total content of protein. Such changes in tissue chemistry may have indirectly promoted aphid performance. For eggplants, chlorophylls a and b, and carotenoid levels decreased with supplemental UV-A over the entire crop cycle but UV-A exposure did not affect leaf secondary metabolites. However, exposure to supplemental UV-A had a detrimental effect on whitefly development, fecundity and fertility presumably not mediated by plant cues as compounds implied in pest nutrition – proteins and sugars – were unaltered.
|
|