Nematode Management


  • Reniform nematode - Rotylenchulus reniformis
  • Root-knot nematode - Meloidogyne incognita
  • The symptoms include yellowing of leaves and gall formation in leaves.


  • To control nematodes in the nursery, apply carbofuran 3 G @ 1g/polybag after germination.
  • Root knot nematodes (Meloidogyne sp.) and Reniform nematode (Rotylenchulus reniformis) are the two nematodes affecting papaya.

Main field

Root knot nematode

  • Root knot nematodes occur in large numbers in all kinds of soil.

Symptoms of injury

  • The larvae of root knot nematodes, when entering roots cause very slight mechanical injury except where large numbers enter in a limited area. Most of the effects on the surrounding plant tissues are caused by the secretion ejected through the stylet while the larvae are feeding. Sometimes root tips are devitalized and their growth is stopped. Such damage will impair root spread and thus the ability of the plants to take up water and nutrients, greatly affect the seedlings. The infected roots of papaya tend to form very small galls which look like beads on a string. The symptoms may be characterised as a combination of galls and coarse roots resulting in stunting, yellowing and drying of leaves.

Lesion nematode

  • The reniform nematodes (Rotylenchulus reniformis) is also a serious pest in papaya growing areas. The loss of fruit yield and stunting of growth have not been noticed in the field.

Symptoms of injury

  • The root injury caused by reniform nematode is different from the injury of root knot nematodes. Reniform nematodes do not cause swelling or retardation of the root. Their presence in the roots may be detected by observing the small grains of sand like bodies which are found attached to the root surface after washing the root system carefully. In case of heavy infestations, the above ground symptoms are similar to those of root knot nematodes. Generally, nematode infected trees of papaya are more sensitive to the stresses and wilt than the non-infested trees. The size of the fruits may become smaller and of poor quality.

Management practice

  • Employ both the combination of cultural and chemical methods for effective control of nematodes in papaya.


  • Test the soil for nematode population before using for raising the seedlings. As far as possible remove all the undecomposed roots, debris etc. of the soil. Heap all the clearings from the site separately away from the sowing/planting site as greatly enhanced nematode population develops under these heaps. Follow crop rotation as a preventive measure.


  • Apply carbofuran 3 G @ 20 g per pit before transplanting the seedlings to the main field.

Physiological disorders

Stamen carpellody or cat-faced fruit

  • This melady occurs only in gynodioecious form of papaya. When temperature goes below 20oC during flower initiation in bisexual flowers, the stamens adhere to the ovarian wall and thus the developing fruit possess a mis-shapened appearance.


  • Do not grow gynodioecious papayas in areas having extremes of temperature.