106 Papaya
deleterious effect on plant nematode populations. Control that is economically
feasible has been obtained by using 1,2-dibromo-3-chloropropane (Nemagon) at
20.0–25.0 kg per acre, a mixture of dichloropropane and dichloropropene (D–D) at
80.0–85.0 kg per acre.
9.9 Earthworms
The immature earthworms (Megascolex insignis) feed on rotting tissues of papaya
plants and they hasten the demise of plants affected with stem rot from Pythium
aphanidermatum and may act as vectors for this fungus. Some time, the nurseries
of papaya are also disturbed and damaged through gallery formation by earthworm.
Application of carbofuran 3G (10.0 g/m^2 nursery area) during bed preparation to
overcome the damage through gallery formation by earthworm was very effective.
Application of carbofuran 3G at (40.0 g/tree) at pit filling and before flowering is
also effective method for stem rot vector management (Ram 2005).
9.10 Ants
Ants rarely feed directly on plants, but can cause damage in other ways. There are
many species and they lead complicated lives with fascinating social structures.
Papaya is infested with insects that excrete honeydew; ants can often be seen col-
lecting it and protecting the insects that produce this sugary substance. By eating
the honeydew, ants actually help plants. Honeydew, while not damaging in itself,
supports the growth of sooty moulds. These moulds have dark spores which turn
the leaves black. The shading of the leaves by these spores reduces photosynthesis.
Ants can be small to large, yellow, red brown or black, winged or wingless live in
FIGURE 9.5 Root-knot nematode infections on roots of papaya. (From Dobson, H. et al.,
2002, Integrated Vegetable Pest Management, Natural Resources Institute, University of
Greenwich, UK.)