Precision Control of Nematodes In Arizona Cropping Systems.

This paper summarizes work completed over the past five years evaluating the effectiveness of precision placement of the nematicide Telone II for control of nematodes in Arizona cropping systems.  A high degree of correlation between nematode population distributions and soil texture has allowed for the implementation of precision placement of Telone II in areas where nematode distribution, and thus damage to cotton, is spatially variable.  This work was completed on grower-cooperator fields across Arizona in a wide variety of environments.  Techniques involved in this work included directed spatial sampling for nematodes, soil apparent electrical conductivity (EC_a) surveys with Veris and EM38 sensors, and yield mapping analysis.  All techniques were used in an effort to develop accurate prescription application maps that could then be used to guide the variable placement of Telone II for effective control of southern Root-knot Nematode (Meloidogyne incognita).  Results have demonstrated effective use of these technologies, under certain conditions, to enhance both economic and environmental efficiencies with respect to nematode control.  Yield response to Telone II application was positive in nearly all locations and across all soil texture zones and ranged from 0% to over 120% increase in yield over the control.  The highest level of response was consistently observed in zone 1 (coarsest soil texture).  However, return on investment was not always positive.  In fields with a high degree of soil texture variability, zone 1 consistently produced a positive economic return while application of Telone II in finer soil texture zones resulted in loss of income.