Little Cherry Virus; Vector Insect Trasmission; Epidemiology Detection
Abstract :
[en] Introduction
In the early 80’s the presence of Little cherry disease in Belgium was detected in ornamental cherry trees (1) but the presence of both viral agents [Little cherry virus 1 (LChV-1) and Little cherry virus 2 (LChV-2), Closteroviridae] was only recently confirmed by PCR (2). During several years leaf samples of ornamental and sweet cherry trees with suspicious symptoms were sampled and tested. The infection rate of both viruses varied but LChV-2 was the most abundant, single or in combination with LChV-1. Two mealybug species (Pseudococcidae) are known to transmit this virus but as no data were available on their presence in Belgian orchards, the population diversity of this and other phloem sucking insects was monitored in infected cherry trees.
Materials and Methods
On a two-weekly interval starting in July until end of October, insects were collected on leaves on yellow sticky traps, by beating into a tray and with a motor-driven aspirator on trees in orchards, cultivated low-stemmed and private high-stemmed, with a single or a mixed infection of LChV-2. All specimens were classified and counted.
Results and Discussion
In all orchards scale insects, aphids, leafhoppers and thrips were found to be present in different numbers but mealy bugs, in particular the apple mealybug Phenacoccus aceris, could only be detected on leaves of high-stemmed abandoned cherry trees. As this vector does not occur in cultivated cherry orchards, probably due to the application of insecticides, other insect species in the collections have to be investigated on their ability to transmit LChV-2.
