On dwarfing apple rootstocks this nematode can sometimes build to high population levels in the first five years then subside after trees become established. P. integerrima do not host this nematode nor root knot species. Pratylenchus vulnus does best in loam textured soils. By contrast, Pratylenchus thornei does best in clay and clay loam soils where wheat or milo are grown and P. scribneri does best in sandy loam soils. Now take another look at the photo.
Nematodes are as different as horses and cows or butterflies and sharpshooters.
In California a nematode sample from a field of alfalfa, with few exceptions, means Meloidogyne hapla whereas a field of Acala-type cotton means Meloidogyne incognita race 3. A citrus planting is where you find citrus nematode, Tylenchulus semipenetrans , not root knot. There are only about seven other hosts for citrus nematode. Take soil samples when your plants are of low vigor or chlorotic. What you learn might be very helpful.