Chemicals used for control are classified as either fumigants 

 or contact nemat icides . The chemicals mentioned are those listed 

 in the EPA compendium, but before using, the grower should check 

 with the Regional Fruit Specialist. 



Fumigants - are liquids that, when injected 6-8" de 

 turn into a gas which penetrates the soil mass. These c 

 are toxic to all forms of life including nematodes, inse 

 and apple trees. They are used before planting and do n 

 properly unless old roots and plant materials are remove 

 temperatures are above 50°F and the soil is worked up to 

 condition." Standard soil fumigants are formulations of 

 dichloropropene (Shell D-D*, Telone*, Vidden-D*] or ethy 

 mide (Dowfume W-85*]. The fungicidal activity of dichlo 

 is increased with the addition of chloropicrin to make T 

 or methyl isothiocyanate to make Vorlex* or both chlorop 

 methyl isothiocyanate to make Vorlex-201*. The increase 

 responses from the broader spectrum compounds are largel 

 plained but nonetheless profitable. 



ep in soil, 

 hemicals 

 cts, fungi 

 ot work 

 d, soil 



"seedbed 



either 

 lene dibro- 

 ropropene 

 elone-C* 

 icrin and 

 d growth 

 y unex- 



Contact nematicides - are liquid or granular formulations 

 that can be used on nursery or other trees during a nonbearing year. 

 Only two chemicals are presently registered for apples: Zinophos* 

 as a bare root dip during planting and oxamyl (Vydate-L*) as a pre- 

 plant soil treatment, a foliar spray or a root dip. 



Both are highly toxic to humans and both will have some sys- 

 temic insecticidal activity. Both work best when used to prevent 

 infection and are part of an overall control program. 



It is important to start with clean planting stock, preferably 

 produced on fumigated soil with any type of replanting program. 

 Lesion nematode populations decline with cover crops of sudangrass, 

 perennial ryegrass or fescue, and one or two cover crops com.bined 

 with plowing to get rid of old tree roots will greatly improve the 

 results from fumigation. Time-of -planting treatments work best 

 when coupled with fumigation and both work best when integrated with 

 the cultural procedures described above. 



Because nematode control is expensive and takes a lot of care 

 to do properly and because every orchard soil is different, it will 

 be important to proceed with caution. In Massachusetts, most fumi- 

 gation is done by custom applicators who are able to meet special- 

 ized needs. Enough evidence exists to show that in many cases, 

 howev'er, it could be a profitable venture. 



*Trade name 



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