Burrowing nematode (Radopholus similis)
Symptoms:

• It is a migratory endoparasite, completing its entire life cycle within the root and causing decay of the whole root cortex.
• On roots, initial damage can be seen as small dark purplish-red lesions on the outer part of the roots. 
• Nematode enters the roots as well as corms and causes usually induce reddish brown cortical lesions which are characteristic feature of the disease.
• Lesions are clearly seen when an infected root is split longitudinally.
• Root and rhizome necrosis is manifested by the retarded growth, leaf yellowing and falling of mature plants.
• Lesioning of primary roots together with girdling and death of anchoring roots leads the plant prone to ‘tip over’ under wind pressure.
• In the presence of R.similis the banana wilt menace caused by Fusarium oxysporum f.sp. cubense was double.

Spiral nematode (Helicotylenchus multicinctus)
Symptoms:

• Ecto as well as endo parasite. The nematode feeds on the cortical cells close to the epidermis, root lesions are relatively shallow and superficial necrotic lesions on banana roots and corm.
• Development of feeder roots is affected in case of high population of nematodes in the soil.
• The infected plant root and corm show reddish brown/ black in colour.

Root lesion nematode (Pratylenchus coffeae)
Symptoms:

• Migratory endoparasites and are very similar to R. similis in habit.
• In case of severe infestation the cortical region of the root is completely damaged and turns black in colour.

Decay of root cortex	Dark purplish-red lesions on the roots	Banana plants falling over (toppling disease)