The Role of Source-Sink Dynamics in the Assessment of Risk to Nontarget Arthropods from the Use of Plant Protection Products.

The concept of source-sink dynamics as a potentially important component of metapopulation dynamics was introduced in the 1980s. The objective of the present review was to review the considerable body of work that has been developed, to consider its theoretical implications as well as to understand how source-sink dynamics may manifest under field conditions in the specific case of nontarget arthropods in the agricultural environment. Our review concludes that metapopulation dynamics based on field observations are often far more complex than existing theoretical source-sink models would indicate, because they are dependent on numerous population processes and influencing factors.

Key considerations to inform operational EU-specific protection goals: An example for non-target terrestrial plants.

This paper complements recent considerations of specific protection goals (SPG) to inform risk assessments for non-target terrestrial plants (NTTP) in the European Union. The SPG options in-field appear to be of the most disruptive potential from agronomic perspective and are therefore investigated in more detail. Overarching prerequisites have been identified that need to be accounted for to ensure that any of the potential SPG options remain operational in a sustainable agricultural context.

Cacopsylla melanoneura has no relevance as vector of apple proliferation in Germany.

Long-term field surveys on the distribution and natural infection rates of Cacopsylla melanoneura were carried out in commercial and abandoned apple-proliferation-infected orchards throughout Germany, northern Switzerland, and eastern France. Although the infection rates of some orchards reached up to 80%, only 0.09% of all C.

Pathogen-induced release of plant allomone manipulates vector insect behavior.

Infochemicals mediate communication within and between different trophic levels. In this study, we identified a new type of plant allomone induced by a plant pathogen and perceived by its vector insect Cacopsylla picta. This phloem-feeding psyllid is the main vector of Candidatus Phytoplasma mali, a cell wall-lacking bacterium that causes the so-called apple proliferation disease.

Phytopathogen lures its insect vector by altering host plant odor.

Many phytopathogens that cause worldwide losses of agricultural yield are vectored by herbivorous insects. Limited information is available about the interactions among phytopathogens, host plants, and insect vectors. In this paper, we report that the cell wall-lacking bacterium Candidatus Phytoplasma mali can alter both the odor of its host plant (apple) and behavior of its vector, the univoltine psyllid Cacopsylla picta.