COMPARATIVE EFFICACY AND COST:

COMPOUND VOLATILITY $/ACRE
  HIGH HIGH
FUMIGANTS    
Methyl Bromide - Tarped 5  
Methyl Bromide - Nontarped 5  
Chloropicrin 7  
1,3-Dichloropropene(1,3-D) 30  
Methyl isothiocyanate ( Metam Sodium, Vapam, Basamid) 500  
ORGANOPHOSPHATES & CARBAMATES    
Ethoprop(Mocap) 100,000  
Carbofuran(Furadan) 1,000,000  
Aldicarb(Temik) 1,500,000  
Fenamiphos(Nemacur) 10,000,000  
Oxamyl(Vydate) 100,000,000  
  LOW LOW
POTENTIAL OF NEMATICIDES TO VOLATILIZE FROM A WATER/AIR INTERFACE IN THE ABSENCE OF SUBSTRATE ABSORPTION:

KWA=(ug pesticide/ml water)/ (ug pesticide/ml air)

This chart illustrates the relative volatility of nematicides and their relative costs. The most volatile products, aptly called fumigants, actually move through air in soil pores for variable distances (inches to feet) related to their volatility and then dissolve into the film of water surrounding soil particles which contains nematodes.

Metam-sodium is the least volatile fumigant and, on its own, will only move about four inches through the soil. For greatest effectiveness, it and the organophosphates and carbamates must be moved through the soil either in irrigation water or by mechanical tillage.

Because of the differences in volatility, one will often hear that the true fumigants are better nematicides than the nonfumigants. In reality, if any of the products listed contact nematodes at the proper concentration, they will result in death. The perceived variability in nematicidal efficacy results from the difficulty in application of the nonfumigant products. It is also common to hear the fumigants spoken of as being very forgiving products. This, again, refers to the ease with which they can be applied effectively compared to the nonfumigants and their ability to essentially distribute themselves in the soil.

Nonfumigant nematicides can be applied either preplant, atplanting, or postplant depending on label specifications. If some areas are left untreated, effectiveness can be evaluated by comparing treated and untreated areas with respect to both nematode populations and yields.

The comparative cost figures are related to the spectrum of activity and ease of effective application of products as much as to the cost of production.

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