How to Manage Pests
UC Pest Management Guidelines
Nematodes are microscopic roundworms that live in diverse habitats. Plant parasitic nematodes live in soil and plant tissues and feed on plants by puncturing and removing cell contents with a spearlike mouthpart, called a stylet.
Nematode problems in pecan have not been reported in California. The following genera of plant parasitic nematodes have been detected in pecan orchard soils in other states: Meloidogyne, Mesocriconema (formerly Criconemella), Trichodorus, Paratrichodorus, Helicotylenchus, Pratylenchus, Tylenchorhynchus, Hoplolaimus, Gracilacus, Longidorus, and Xiphinema. Of these only Meloidogyne incognita is considered likely to be pathogenic.
In other states root knot nematode causes galling on some rootstocks; galls vary in size from 0.0625 to 0.25 inch. Aboveground symptoms include chlorotic foliage, stunted trees with sparse foliage, and some trees may be barren. If you suspect nematodes are causing a problem in pecans, contact your farm advisor.
UC IPM Pest Management Guidelines:
UC ANR Publication 3456
B. B. Westerdahl, Nematology, UC Davis