Pear decline in Spain, associated with the presence of phytoplasmas in sieve tubes, was studied. Samples of healthy and diseased pear trees were tested to confirm the presence of the pathogen. The polymerase chain reaction (PCR) technique was used, with universal and specific primers. Specimens of Cacopsylla pyri were also analysed by PCR. Phytoplasmas were detected in 79% of trees with premature reddening, in 67% of trees with weakness and necrotic spots (cv. Limonera) and in 20% of trees without symptoms. The pathogen was also detected in the psyllids, indicating that C. pyri could be the vector of the disease in Spain.

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