Both
weevils, Neochetina bruchi (Hustache) and Neochetina eichhorniae Warner
feed on water hyacinth plants as a biocontrol agents. Tetranychus urticae
Koch infested the plants grown under light and thermostatic controlled aquatic
weed green house, and caused repellency of the weevils. Studying some
histological structure, of water hyacinth leaves infested with mites, showed increase
of the thickness of upper epidermis, number of palisade cell and thickness of
leaf petiole, compared with the control and leaves infested with weevils which
recorded decrease in the thickness of leaf petiole and increase in lower
palisade tissue. The mites infested plants lost chlorophyll, turned brownish
and lost size of vacuoles or air chambers used to store the oxygen. The volume
of these vacuoles was very small in case of mite infested plants compared with
leaves infested with weevils as the same as control. The weevils feeding reflected
in increase in both, length and width of fed upon leaves.