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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #206054

Title: Epidemiology of Xiphinema americanum and Tomato ringspot virus on Red Raspberry, Rubus idaeus.

Author
item Pinkerton, John
item Kraus, Jennifer
item Martin, Robert
item Schreiner, Roger - Paul

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2007
Publication Date: 3/3/2008
Citation: Pinkerton, J.N., Kraus, J.E., Martin, R.R., Schreiner, R.P. 2008. Epidemiology of Xiphinema americanum and Tomato ringspot virus on red raspberry, Rubus idaeus. Plant Disease. 92(3):364-371.

Interpretive Summary: Tomato ringspot virus (ToRSV) is an economically important disease of red raspberry worldwide. This virus is vectored by a plant-parasitic nematode, Xiphinema americanum. Once the virus and the nematode are established in a field, the disease is very difficult to eradicate. It is important to understand the epidemiology of the virus and X. americanum in order to develop strategies to manage the spread and impact of the disease. Field research was conducted in a red raspberry field in Clark County, WA, USA to investigate the relationship of nematode biology, virus spread, and disease management. Based on the sequence of coat protein, the isolate of the ToRSV in this field was very similar to raspberry isolates from other areas in the Pacific Northwest. Nematode population densities were greatest in the winter, but nematodes capable of vectoring ToRSV were present in the soil throughout the year. All nematode stages were present throughout the year, but the proportion of juveniles was greatest in the winter. Gravid females were observed only in the spring indicating at least a one year lifecycle. Nematodes feeding on roots readily transferred ToRSV to raspberry plants. However, ToRSV spreads slowly through the plant, requiring one year to infect the entire plant. ToRSV signficantly reduced root and top growth after one year and killed the plants the second year. The rate of virus spread in field studies was 70 cm per year along the plant row, which suggests that spread of ToRSV is a function of the rate of systemic spread of the virus in the plant, not the movement of nematodes. Modifying agricultural practices to limit the movement of nematode infested soil in the field, such as planting grass in the alleyways, should greatly restrict the virus spread in a raspberry field.

Technical Abstract: The population dynamics and the ability of Xiphinema americanum to transmit Tomato ringspot virus (ToRSV) are poorly understood in the raspberry pathosystem. Soil samples were collected monthly from 1999 through 2002 in a ToRSV infected 'Willamette' red raspberry field in Clark County, WA, USA. Population densities of X. americanum were highest in the winter, lowest in the summer, and correlated with monthly precipitation and soil moisture. All nematode stages were present throughout the year, but the proportion of juveniles was greatest in the winter. Gravid females were observed only in the spring indicating at least a one year lifecycle. Cucumber seedlings were planted in soil collected each month and evaluated for nematode transmission of ToRSV with ELISA. The proportion of assay plants in which virus was detected showed only weak seasonal trends. Infection and systemic spread of virus was studied in 'Meeker' raspberry plants planted in field soil infested with viruliferous nematodes or fumigated soil. ToRSV was detected by ELISA in fine roots five months after planting, in all subterranean portions of plants after 12 months, and in all aerial tissues collected the second year. In 2002, plant growth was reduced significantly in nematode-ToRSV infested plants compared to those planted in fumigated soil. From 1999 to 2006, the rate of spread of ToRSV from a disease focus in a 'Meeker' raspberry field was 70 cm per year in the plant row. These results suggest that the rate of ToRSV spread is limited by systemic spread of virus in the plants when nematode infested soil is not transported in the field. The sequence of the coat protein of the ToRSV from the research area was similar to other raspberry isolates from the Pacific Northwest.