MOLECULAR TESTS TO DETERMINE APPLE PROLIFERATION PHYTOPLASMA PRESENCE IN PSYLLID VECTORS FROM APPLE TREE ORCHARDS IN THE CZECH REPUBLIC

A spectrum of thirty-seven Hemiptera species was captured during the vegetative season in different apple tree orchards using the same system of insecticide treatment. The main emphasis was devoted to the occurrence of psyllid species Cacopsylla picta and C. melanoneura, considered as vectors of apple proliferation phytoplasma and an apple sucker C. mali. Very low abundance of C. picta and C. melanoneura was discovered inside the apple orchards; species C. mali was almost entirely absent. Single adults of the three species were tested using PCR/RFLP analyses for apple proliferation phytoplasma. Individuals of both overwintering and new generation of C. picta and of overwintering generation of C. melanoneura were found to carry the phytoplasma. Infected adults of overwintering generation of both species seem to be crucial for a vector phytoplasma transmission because they start to colonize orchards in early spring before first insecticide application. No specimen of C. mali was positive for phytoplasma DNA.