Plant Disease (2002) 86, 759-763

C.L. Blomquist and B.C. Kirkpatrick (2002)
Identification of phytoplasma taxa and insect vectors of peach yellow leaf roll disease in California
Plant Disease 86 (7), 759-763
Abstract: Two peach diseases in California, western X-disease (WX) and peach yellow leaf roll (PYLR) are caused by two genetically distinct phytoplasmas. Based on symptoms alone, WX and PYLR cannot be reliably distinguished. The objectives of this study were to determine which phytoplasma was causing PYLR disease in peach orchards planted near pear orchards and which phytoplasmas were present in potential insect vectors captured in both peach and pear orchards. Leafhoppers and pear psylla were collected from yellow sticky traps placed in three pear orchards and four peach orchards located in the Sacramento Valley from 1994 to 1996. DNA was extracted from potential vectors and suspect diseased trees, and analyzed for the presence of the WX and PYLR phytoplasmas using strain-specific DNA hybridization or polymerase chain reaction (PCR) assays. The most abundant phytoplasma detected in diseased peach trees was the PYLR phytoplasma. In 1994 and 1995, 10 to 25% of groups of pear psylla tested positive for the PYLR phytoplasma, while no psylla groups tested positive for the WX phytoplasma. Only one captured leafhopper tested positive for the WX phytoplasma. These results indicate the pear psylla is the primary vector of PYLR in northern California.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: English)
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Database assignments for author(s): Bruce C. Kirkpatrick

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
transmission/dispersal of plant diseases

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cacopsylla pyricola	Peach/nectarine (Prunus persica)	U.S.A. (SW)
	Phytoplasma pyri	Peach/nectarine (Prunus persica)	U.S.A. (SW)