Fate of Benzoxazinoids from Rye (Secale cereale) in soil and the implication on Plant-Parasitic Nematode Management.

Authors: Zasada, Inga; Meyer, Susan; Rice, Clifford

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2007
Publication Date: 3/30/2007
Citation: Zasada, I.A., Meyer, S.L., Rice, C. 2007. Fate of benzoxazinoids from rye (Secale cereale) in soil and the implication on plant-parasitic nematode management [abstract]. Journal of Nematology. 39:88.

Interpretive Summary: The concept of utilizing organic amendments to manage plant-parasitic nematodes is not new, but the widespread implementation of this management practice has still not been realized. The use of organic amendments for plant-parasitic nematode management is a complex process requiring an understanding of the transformation and generation of active compounds. As a result, research endeavors to understand and maximize the use of this management practice require a multi-disciplinary approach which draws upon the expertise of nematologists, microbiologists, natural product chemists and soil scientists. Factors that require analysis and clarification include lethal concentration levels of organic amendments necessary to kill nematodes; chemical composition of incorporation material; fate and exposure potential to nematodes of compounds released into the soil; understanding of how the environment (i.e., temperature, microbial community, soil type) influences the activity of organic amendments. Examples of research conducted in a collaborative manner on rye (Secale cereale) and brassiceous cover crops, as well as a biosolid amendment, will demonstrate the power of multi-disciplinary research. Only through collaborative research can consistent and reliable nematode suppression with organic amendments be achieved.

Technical Abstract: A rye (Secale cereale) cover crop plays an important agronomic role in southern and eastern United States crop rotation systems. The contribution of this cover crop to plant-parasitic nematode management is unclear. To understand the potential of consistently utilizing this cover crop for plant-parasitic nematode management, the fate and partitioning coefficients of the benzoxazinoids DIBOA (2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one) and DIMBOA (2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one) were determined. Both compounds were spiked into three soil types: a sandy loam, silt loam and loam. The concentration of the compounds in soil solution as well as in sediment was determined at 0, 1, 2, 4, and 8 hrs and 1, 2, 3, 4, and 5 days. Availability and exposure times of DIBOA and DIMBOA in soil varied with soil type. This research demonstrates that the exposure potential of these compounds to plant-parasitic nematodes will vary with soil type, suggesting that a rye cover crop will differ in effectiveness for nematode management depending upon soil type.