Radopholus similis Burrowing nematode Damage to trees.  With over 200 known hosts, Radopholus similis may be most important nematode pest on fruit crops (especially citrus and banana) in the tropics. Biology.  Small nematodes, adults less than 1 mm long, they feed within the root cortex of their hosts. Ecology.   Distribution:  Widespread in tropics, West Africa, Central and South America, Hawaii, Florida, Puerto Rico, Cuba, Australia. Symptoms.  Burrowing nematodes burrow within the roots and other underground parts of their hosts forming extensive cavities. It is the casual agent of a citrus disease called spreading decline; with severe infestations root systems are totally destroyed and the plants collapse ("toppling-over disease").  Damage to other crops.  The most important hosts are banana, pepper , citrus fruits and sugarcane. Control.  Nematicides used for chemical control. Links and References.  Radopholus similis.  University of California.