TITLE:

Use of Remote Sensing with Aerial Infrared Photography for Root-knot Nematode Density at AG-CARES, Lamesa, TX, 2001.

AUTHORS:

Terry Wheeler (TAES) and Harold Kaufman (TCE), Associate Professor and Extension Specialist

RESULTS AND DISCUSSION:

Aerial images were taken in early July (Fig.1A) and mid August (Fig. 2A) of the AG-CARES facility. These images were processed to form classification groupings (Fig. 1B and 2B), which are an indication of plant species, vigor or maturity. Root-knot nematode has been sampled annually in the circle for the last several years. Fall sampling provides information about the risk potential of root-knot nematode for the next year. Root-knot nematode population density within the long-term minimum tillage area of AG-CARES averaged 8160, 4906, and 3885 nematodes/pint soil during 1999, 2000, and 2001, respectively. There were large plot Temik rate studies conducted in each of these years, and only during 1999, was the high rate of Temik (5 lbs at planting) also associated with the highest yields. In 2000 and 2001, 3.5 lbs of Temik 15G at planting gave similar yields as the higher rates of Temik 15G. In all three years, root-knot nematode density was correlated with reflectance obtained from infrared images. However, the correlations are not sufficiently accurate to completely eliminate the need to sample for root-knot nematode.

The average root-knot nematode density within a crop or tillage system is monitored each year during the fall. In 2001, there were some unusually low nematode counts, which may be related to rotation crops during 2000, and the replant situation (Table 1). Part of the circle was replanted in 2001 because of hail damage. It is believed that when the original cotton was destroyed with Buctril, many of the root-knot nematodes in the roots were also killed.

 Figure 1A.

Figure 1B.

Figure 2A.

Figure 2B.