Longidorus species The Needle Nematode Damage to Corn.   Needle Nematode can be one of the most devastating diseases of corn- causing yield reductions of up to 62% in severely affected areas. Biology.   Longidorus breviannulatus  is a large nematode, females measure about4 -5 mm long, (males are rare). Ecology.   Largest populations of Longidorus occur in soil with a sand content of 90% or more.  Most nematodes are found early in the growing season. Damage may be noticed within two weeks after seedling emergence. Symptoms.   Stunted plants appear to be under drought stress, and appear in oval or oblong patches in an affected field.  Scarcity of small feeder roots may give the root system a coarse appearance. Damage to other crops.  Control.  Crop rotation will help if graminaceous weeds are kept in check.

One or more of these nematode species currently is or could potentially be an APHIS quarantine pest.