Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 23, 2011
Publication Date: February 2, 2012
Citation: Schreiner, R.P., Pinkerton, J., Zasada, I.A. 2012. Delayed response to ring nematode (Mesocriconema xenoplax) feeding on grape roots linked to vine carbohydrate reserves and nematode feeding pressure. Soil Biology and Biochemistry. 45:89-97. Interpretive Summary: The long-term impact of ring nematode feeding on grapevines was studied using potted vines. Some vines were grown under low light conditions or were partially defoliated to further stress vines. Whole plants were destructively harvested after each year of exposure to ring nematode, and biomass, mineral nutrients and carbohydrates were analyzed to better understand how the ring nematode alters vine physiology. Ring nematode had a greater impact on carbohydrate reserves in vines than on mineral nutrients, and vines grown under low light suffered greater damage due to the presence of nematodes. The greater damage in low light vines was associated with higher nematode numbers per mass of roots. Viticultural practices to increase carbohydrate reserves in the vine are recommended to reduce the impact of this pest on vine productivity.
Technical Abstract: The chronic impact of ring nematode (Mesocriconema xenoplax) feeding on grapevine (Vitis vinifera) was studied under controlled conditions. 'Pinot noir' grapevines were exposed to ring nematode or kept nematode-free for three growing seasons, and vines were either grown in full sunlight, 15% of full sun, or partially defoliated to manipulate vine carbohydrate status. Whole plants were destructively sampled to assess the impact of ring nematode on whole plant biomass, carbohydrate, and mineral nutrient accumulation. Vine shoot growth and total biomass were unaffected by ring nematode in the first growing season, although reserves of nonstructural carbohydrates (NSC), P, K, and Ca in the roots and wood were reduced in all canopy management treatments. Vine shoot growth and total biomass were reduced by ring nematode in year 2, and greater declines in reserve NSC and most mineral nutrients had occurred. Reserves of NSC were affected more than biomass or nutrients during the second year. During the third year of exposure to ring nematode, vines in the 15% sun treatment were dying (prompting an earlier destructive harvest), even though these vines had similar biomass and NSC reserves as the partially defoliated vines at the end of the second year. The demise of the 15% sun vines was associated with higher ring nematode numbers per unit of root mass, as compared to either full sun or defoliated vines. Practical implications of this work are to adopt practices to enhance carbon availability to roots and recharge NSC reserves in permanent vines parts, such as limiting crop load or earlier harvest of fruit.