| Autor: |
Ortiz, Brenda V., Perry, Calvin, Sullivan, Dana, Kemerait, Robert, Ziehl, Amanda R., Davis, Richard, Vellidis, George, Rucker, Keith |
| Zdroj: |
Proceedings of the Beltwide Cotton Conferences; 2008, p573-582, 10p |
| Abstrakt: |
Cotton (Gossypium hirsutum L.) lint yield losses by southern root-knot nematode [Meloidogyne incognita] (RKN) have increased during the last 20 years. Site-specific management (SSM) of nematicides is a promising method to reduce yield losses, increase profitability and reduce adverse environmental impacts associated with excess allocations of agrochemicals. The impact of two nematicides applied at two rates on RKN population density and lint yield were compared across previously determined RKN risk zones in commercial fields during the 2007 growing season. Root knot nematode risk zones were delineated in 2006 using fuzzy clustering of elevation and slope of the terrain, normalized difference vegetation index (NDVI) calculated from a bare soil spectral reflectance, and apparent soil electrical conductivity [shallow (ECa-shallow) and deep (ECa-deep)]. Four different treatments of nematicides were randomly allocated among blocks that spanned the entire length of the fields. Test bare soil spectral reflectance plots (16 rows by 100 feet long) including the four treatments were also randomly selected within each zone to collect RKN population density, soil water content, and plant height, root galling, and final yield. In general, there were no benefits associated with a high rate of Telone (6 gal ac-1) versus a lower rate of 3 gal ac-1. Similarly, the higher Temik rate of 6 lbs ac-1 did not provide additional nematicide control compared to the low rate (3 lbs ac-1). Comparing treatment results across management zones, Telone provided better RKN control compared to Temik in high risk zones, comprised of more coarse-textured, sandy soil. However, in low risk zones, which were comprised of relatively heavier textured soil compared to the high risk areas, the application of Temik would provide sufficient nematicide control. The results from this study clearly showed that RKN control and final yield varied with respect to the nematicide type and rate across management zones (MZ). These results are promising and support the idea of variable rate nematicide applications based on RKN risk zones. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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