Abstract
AbstractThe control of carrot psyllid Trioza apicalis Förster largely relies on chemical measures, and the current integrated pest management (IPM) strategy is based on pest scouting. The number of active ingredients available for psyllid control will further decline in the coming years. The need for alternative control measures is therefore urgent. In this work the efficiency of different control programs including a kaolin particle film and plant‐derived, crude saponin extract, chemical control, insect net and IPM (kaolin in combination with insecticides) programs to reduce psyllid feeding damage, reproduction and the spread of “Candidatus Liberibacter solanacearum” (CLso) in carrots was studied. Each year in 2016–2018, four replicates of each treatment were randomised in a row‐column design on a commercial carrot farm. After the treatments were executed, the psyllid nymphs and eggs were counted. At the harvest, the carrot roots and shoots were weighed, damages assessed, and samples were taken for CLso detection from 50 plants at each replicate. Kaolin treatment alone and in combination with insecticides effectively reduced the number of psyllid nymphs and eggs in all the years studied. Saponin was applied only on the first year, since it significantly increased the number of T. apicalis eggs compared to other treatments. The insect net was superior to other treatments in all the studied aspects in all the years. Under normal weather conditions, the highest root weight was harvested under the insect net, followed by the chemical control program consisting of pyrethroids, kaolin treatment, untreated control and saponin treatment. During extreme weather conditions, chemical control programs were not effective at protecting the carrots from psyllid feeding, which was reflected as low root yield. In all years, the carrot leaf damage percent negatively correlated with the root weight. Similarly, the shoot:root ratio increased as the leaf‐curling percentage rose, which was even pronounced under drought stress. The effect of climatic stress should be considered when developing IPM strategies.
Highlights
The carrot psyllid, Trioza apicalis, has been a serious carrot pest since the early decades of 1900 in northern Europe and in parts of central Europe (Bey, 1931; Burckhardt & Freuler, 2000; Krumrey & Wendland, 1973; Láska, 1974; Lundblad, 1929; Markkula, Laurema, & Tiittanen, 1976; Nehlin, Valterová, & Borg-Karlson, 1994; Rygg, 1977)
Nissinen, Vanhala, Holopainen, and Tiilikkala (2007) and Nissinen et al (2012) showed that one female psyllid feeding for 3 days at the cotyledon or one leaf stage led to a 35–50% root weight reduction
Candidatus Liberibacter solanacearum” (CLso) haplotype C causes leaf discolouration and phloem blockage leading to a reduction of sugars in the roots (Nissinen et al, 2012; Nissinen, Haapalainen, Jauhiainen, Lindman, & Pirhonen, 2014), whereas the leaf-curling symptoms are caused by the vector (Nissinen et al, 2014)
Summary
The carrot psyllid, Trioza apicalis, has been a serious carrot pest since the early decades of 1900 in northern Europe and in parts of central Europe (Bey, 1931; Burckhardt & Freuler, 2000; Krumrey & Wendland, 1973; Láska, 1974; Lundblad, 1929; Markkula, Laurema, & Tiittanen, 1976; Nehlin, Valterová, & Borg-Karlson, 1994; Rygg, 1977). In addition to the reduction of the root yield, the curled leaves protect the developing carrot psyllid nymphs from non-systemic pesticides This in turn, ensures the emergence of the overwintering generation leading to gradual population growth in the areas of intensive carrot cultivation, which has been observed by increasing trap catches during the last decades (Haapalainen et al, 2018; Nissinen et al, 2007; Tiilikkala et al, 1996). The aim of this study was to assess the effect of different control programs, especially a kaolin particle film and plant-derived, crude saponin extract, on T. apicalis host plant selection, reproduction, feeding damage and CLso transmission on carrots. The aim was to assess suitability of kaolin and saponin for control programs following IPM guidelines in order to suppress the use of insecticides
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
