Indirect methods for determination of root-knot nematode density for use in precision agriculture

Objective 5: Establish an effective network for technology transfer through the AgriPartners program.

All of the work in this project with the exception of the development for the height sensor was done in conjunction with IPM specialists. Additional work with aerial infrared photography is planned for 2000 if funding can be obtained, with the bulk of the extension related work being conducted with the IPM agents, while the nematologist will conduct the nematode sampling. The partnership with the IPM agents is established and the number of producers cooperating with this project is growing yearly (seven different cooperators for variable rate Temik experiments); four different cooperators with the use of cover crops to detect root-knot nematode density; and 10 different cooperators in 1998 and 1999 with the use of aerial infrared photography.

Table 1. Correlation coefficients and probability of significance for reflectance at near-infrared (NIR), red and green bands taken from an aerial, color, infrared photograph of cotton fields in 1998.

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NIR Red Green NIR/Red NIR/Green Red/Green

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Hockley County^a

Root-knot nematode -0.10 (NS) 0.01 (NS) -0.08 (NS) -0.18 (NS) -0.10 (NS) 0.39 (0.001)

Sand -0.34 (NS) 0.65 (0.001) 0.57 (0.002) 0.38 (0.05) -0.42 (0.03) 0.50 (0.008)

Silt -0.34 (NS) -0.39 (0.05) -0.34 (NS) 0.38 (0.05) 0.25 (NS) -0.30 (NS)

Clay -0.50 (0.009) -0.56 (0.002) -0.50 (0.009) 0.55 (0.003) 0.36 (NS) -0.44 (0.02)

Lubbock County^b

Root-knot nematode -0.18 (NS) -0.32 (0.006) -0.30 (0.01) 0.36 (0.002) 0.36 (0.002) -0.31 (0.009)

Sand 0.42 (NS) 0.59 (0.01) 0.49 (0.03) -0.66 (0.008) -0.51 (0.03) 0.74 (0.003)

Silt -0.13 (NS) -0.28 (NS) -0.23 (NS) 0.35 (NS) 0.29 (NS) -0.37 (NS)

Terry County^c

Root-knot nematode 0.67 (0.001) 0.58 (0.001) 0.64 (0.001) -0.27 (0.003) -0.39 (0.001) -0.09 (NS)

Sand 0.52 (0.009) 0.50 (0.01) 0.48 (0.02) -0.25 (NS) -0.11 (NS) 0.16 (NS)

Silt -0.51 (0.01) -0.50 (0.01) -0.47 (0.02) 0.28 (NS) 0.13 (NS) -0.18 (NS)

Clay 0.30 (NS) 0.35 (NS) 0.31 (NS) -0.35 (NS) -0.14 (NS) 0.24 (NS)

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^aThis site which was under the direction of IPM agent Kerry Siders, was photographed on 3 of July, 1998.

^b This site which was under the direction of IPM agent Brant Baugh, was photographed on 16 of September, 1998.

^cThis site which was under the direction of IPM agent Phillip Kidd, was photographed on 3 of July, 1998.

Table 2. Correlation coefficients and probability of significance for reflectance at near-infrared (NIR), red and green bands taken from an aerial, color, infrared photograph of cotton fields in 1999 and root-knot nematode density.

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# of acres NIR Red Green NIR/Red NIR/Green Red/Green

County samples sampled

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Dawson 118 120 -0.15 (NS) -0.10 (NS) -0.10 (NS) 0.35 (0.001) 0.21 (0.04) -0.32 (0.001)

Hockley 48 60 -0.53 (0.001) -0.35 (0.01) -0.45 (0.001) 0.39 (0.007) 0.38 (0.007) -0.27 (NS)

Lubbock 71 160 0.07 (NS) -0.08 (NS) -0.08 (NS) 0.03 (NS) 0.12 (NS) -0.05 (NS)

Lubbock 70 80 -0.07 (NS) 0.14 (NS) 0.12 (NS) -0.14 (NS) -0.14 (NS) 0.13 (NS)

Terry 64 160 0.14 (NS) 0.33 (0.008) 0.06 (NS) -0.33 (0.008) 0.07 (NS) 0.10 (NS)

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C. Education/technology transfer -

Height sensor (to be reported on by Steve Searcy)

D. Milestones achieved:

Determined that root-knot nematode density can be adequately described with minimal sampling in cotton fields by using aerial, color, infrared photography to choose sampling sites.

E. Publications: (does not include those written by S. Searcy)

- Wheeler, T. A., Kaufman, H. W., B. Baugh, P. Kidd, G. Schuster, and K. Siders. 1999. Comparison of variable and single-rate applications of aldicarb on cotton yield in fields infested with Meloidogyne incognita. Annals of Applied Nematology (Accepted).

- Wheeler, T. A., B. Baugh, H. Kaufman, G. Schuster, and K. Siders. 2000. Variability in time and space of Meloidogyne incognita fall population density in cotton fields. Under review for Journal of Nematology.

F. Precision agriculture Proposals: (does not include those written by S. Searcy)

Funded

- Kaufman, T. Wheeler, B. Baugh, P. Kidd, and K. Siders. 1998. Variable rate application of aldicarb to control root-knot nematode on cotton. TPMA/TDA IPM Grant Program. $10,200.

- - T. A. Wheeler, S. Searcy, H. Kaufman, K. Siders, and P. Kidd. 1997-1999. Indirect methods for determination of root-knot nematode density for use in precision agriculture. Texas Precision Agriculture Initiative. $60,000.

- - W. Keeling, A. Onken, R. Lascano, R. Bowman, and T. A. Wheeler. 1997. Precision agriculture in cotton. Cotton State Support Committee. $25,000.

- - T. A. Wheeler, H. W. Kaufman, and J. R. Gannaway. 1999. Use of reflectance to identify root-knot nematode and verticillium wilt in cotton. Resource 21. $500.

- - K. F. Bronson, R. Bowman, S. Searcy, W. Keeling, P. Dotray, E. Segarra, T. Wheeler, K. Siders, C. Green, A. Brashears, C. Trostle, T. Provin, R. Lascano, and T. Wilson. Texas Precision Agriculture Initiative: Strategies for on-farm testing of precision agriculture technologies for Texas High Plains. $30,000.

- - M. Schubert, D. Porter, J. Bordovsky, K. Bronson, P. Dotray, W. Keeling, T. A. Wheeler, E. Segarra, H. Kaufman, C. Trostle, P. Porter, C. Crumley, P. Kidd, J. Farris, G. S. Osborn, and L. Thompson. 10/99 - 8/01. Texas Precision Agriculture Initiative: Precision Agriculture in peanut systems. $276,000.

Pending:

- T. A. Wheeler, K. Siders, and H. W. Kaufman. Testing the reliability of remote sensing directed scouting for integrated pest management. Southern Regional IPM Program. $62,000.

Submitted but not funded.

- - T. A. Wheeler and J. Wayne Keeling. 1999. Determining value of nematicides for cotton affected by multiple pests. Southern Regional IPM Program. $85,000. Submitted to the Southern Regional IPM program for 1999.

- - T. A. Wheeler, C. Crumley, A. M. Schubert, and H. Kaufman. 1999. Management of peanut pod rot diseases with variable rate application of fungicides. IPM program with TPMA/TDA.

G. Precision Agriculture meetings attended/paper presented:

- Wheeler, T. A., H. W. Kaufman, K. Siders, P. Kidd, and S. Searcy. 1999. Indirect methods of assessing potential for damage on cotton by root-knot nematode. Journal of Nematology 31: Presented at the Society of Nematologists Annual Meeting in Montery, CA.

- Wheeler, T. A., H. W. Kaufman, and G. L. Schuster. 1997. Distribution of root-knot nematode densities in cotton fields and proposed nematicide rates. Journal of Nematology 29: 614-615. Presented at the Society of Nematologists Annual Meeting in Tucson, AZ.

- Schuster, G. L., T. A. Wheeler, and H. W. Kaufman. 1997. Variable and single-rate application of Temik 15G in cotton fields infested with root-knot nematode. Journal of Nematology 29:605. Presented at the Society of Nematologists Annual Meeting in Tucson, AZ.