Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2001
Publication Date: 1/1/2002
Citation: WRATHER, J.A., STEVENS, W.E., KIRKPATRICK, T.L., KITCHEN, N.R. SITE-SPECIFIC APPLICATION OF ALDICARB EFFECTS ON COTTON IN A MELOIDOGYNE INCOGNITA INFESTED FIELD. JOURNAL OF NEMATOLOGY. 2002. V. 34. P. 115-119.
Interpretive Summary: Infestation of pests in crops is not uniform. In many cases, an insect, disease, or weed pest may be nonexistent over much of a field, but where present, may cause sufficient crop injury that application of a pesticide field wide is cost-effective. While it may pay a producer to control a pest, pesticide application where the targeted pest does not exist is wasteful and potentially creates an environmental problem. An example of this is cotton farmers commonly apply a single rate of a pesticide called aldicarb over fields to protect cotton from root-knot nematode. Nematodes were thought to be aggregated. Determination of the nematode is done by soil sampling and counting, an expensive procedure. This research was initiated to determine whether site-specific application of aldicarb based upon grid soil sampling and mapping would adequately control root-knot nematode in cotton and be cost-effective. The research was conducted on one efield over 3 years in SE Missouri. Yields for the uniform rate of aldicarb and site-specific rate of aldicarb were similar and significantly greater than the no aldicarb treatment. Much less aldicarb was used for the site- specific treatment than with the uniform treatment. Costs with the site- specific treatment were high compared with the uniform rate treatment due to sampling and nematode counting costs. Based on amount of aldicarb used, site-specific applications for root-knot nematode control in cotton would likely pose less environmental risks than the uniform applications. The end result will benefit cotton farmers and crop consultants by helping to understand the nature of nematode population variability. If a more cost- effective way could be developed for mapping nematode population, site- specific applications would result in less pesticide used.
Technical Abstract: Missouri cotton farmers commonly apply a single rate of aldicarb field wide at planting to protect their crop from root-knot nematode (Meloidogyne incognita Chitwood), even though these nematodes are generally spatially aggregated. This research was initiated to determine the effect of site- specific application of aldicarb on cotton production in a field infested with these nematodes. A 5-ha field near Horersville, MO was grid soil- sampled (32 m-grid spacing) for nematodes in September 1996, 1997, and 1999 and June 1997. Geostastistical analysis was performed to assess the spatial structure of nematode population. Yields for the control (no aldicarb), 0.58 kg ai/ha aldicarb (the uniform rate recommended for this field), and a site-specific rate of aldicarb (application at each 0.1 ha area and based on nematode population) treatments were compared. Yields for the uniform rate and site specific rate treatments were similar and significantly greater than the no aldicarb treatment. Less aldicarb was used for the site-specific treatment than with the uniform treatment. Costs associated with the site-specific treatment were very high compared with the uniform rate treatment due to the cost of soil sampling and determining the spatial patterns of nematode population. Based on amount of aldicarb used, site- specific applications for root-knot nematode control in cotton would likely pose less environmental risks than the uniform rate applications.