Contents References

Deepwater Rice - investigations into the yellow stem borer in Bangladesh - 13 - 1982 research cont.

The anatomy of deepwater rice plants and the feeding of Scirpophaga incertulas larvae - continued

Summary of effects of YSB infestation on a model DWR plant

Most varieties of deepwater rice normally show profuse development of aquatic or nodal roots approximating to the height of the plant at maximum flooding. Larval feeding damage lower than these roots was not found to have affected the development of the upper plant. A schematic drawing of the mature plant and the positions of larval feeding is shown in Figure 3.

1988 Figure 3

full stem

The stem at this stage would have been growing for some four to five months and the following evidence of infestation by four separate S. incertulas broods is indicated: in internodes 9 and 10, mainly exit holes in decayed stems; in internodes 5-7, relatively intact dead pupae and pupal skins; in internode 4, fourth- to sixth-instar larvae and pupae; and, in internodes 1-3, small, first- or second-instar larvae.

As shown on the previous page deadhearts and whiteheads have a common cause - in these, the damage is usually due to small, first- or second-instar larvae which, after boring down between the flag leaf sheath and the stem, enter just above the top node. The larval feeding cuts a ring right around the narrow apical stem, almost severing the stem and the result is a total interruption of the vascular system. The apex then dies.

Go to 1982 research - discussion

©2000 - Brian Taylor CBiol FIBiol FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.
Visiting Academic in the Department of Life Science, University of Nottingham

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