Tuesday, December 11, 2007 - 9:29 AM
0900

Nitrogen/insect model for precision cotton production

Joe J Ellington, joelling@nmsu.edu1, Tracey Carrillo, tcarrill@nmsu.edu1, Jane Pierce, japierce@nmsu.edu1, Jay Lillywhite, lillywhi@nmsu.edu2, and Jeff Drake, jefdrake@nmsu.edu3. (1) New Mexico State University, Entomology, Plant Pathology and Weed Science, Box 30003, dept 3BE, Skeen Hall College and Knox, Las Cruces, NM, (2) New Mexico State University, Agriculture Economics, Box 30003, dept 3AE, Gerald Thomas Hall College and Knox, Las Cruces, NM, (3) New Mexico State University (USDA), Entomology, Plant Pathology and Weed Science, Box 30003, dept 3BE, Skeen Hall College and Knox, Las Cruces, NM

A new high clearance Research Vehicle (RV) with precision IR (GreenSeeker™) plant stress sensors precision granular/liquid fertilizer applicators and a high vacuum insect collector was designed and assembled for the project in early 2006. Data analysis showed a high correlation between NDVI readings, yield and nitrogen levels (R˛=0.93 and 0.83 in years 2004-2005) in cotton. Five irrigations and 80-lbs of nitrogen/acre were optimal for profit on Harkey clay loam soils in New Mexico. Overall densities of Lygus spp. adults were reduced in insecticide free years (2005 and 6) ~ 30% when nitrogen use rates were reduced from 135 to 80 -lbs N/acre while profits were increased. Although yields can be increased with higher nitrogen use rates, the highest crop yields do not necessarily give the highest profits and future insect control practices should be based on profit analysis rather than yield. Three applications of chlorpyrifos in 2003 did not control Lygus spp. adults or suppress the beneficial complex [predator/Lygus spp. ratio (P/L) was 4.2 - 4.8] but five chlorpyrifos applications in 2004 suppressed Lygus spp. adults and the beneficial complex (P/L was 5.4 - 7.2). In 2005, there were no insecticide applications and the P/L adult ratios were between 12.1 and 30.5. Precision/conservation farming methods [using NDVI (stress) readings, and improved insect sampling,] results in lower nitrogen fertilizer, water, insecticide, plant hormone and defoliant use, sustains natural predator/prey ratios, requires fewer expenditures of time and money and improves profit margins.


Species 1: Hemiptera Miridae Lygus spp (lygus bug, plant bug)