Abstract:
Comfortable water environment for Neochetina weevils’ survival have potential to affect
water hyacinth plant parts. The Effect assessment of water hyacinth plant affected by
Neochetina weevil species was conducted through physical observation and quantified
measures in comparsion treatment and control earthen ponds. The weevils’ affect water
hyacinth plant growth and reproduction through feeding different plant parts. The study
was conducted in January, 2023; by triplicated (treated and controlled) through planting
35 water hyacinth plants in each ponds and 5 weevils’ per plant treatments that aimed
(1) To investigate temporal environmental variability on the survival and development of
the weevils’, (2) To determine the abundance of weevils population in the experimental
ponds and quantify damage parts of E. crassipes caused by weevils’ and (3) To evaluate
the effects of weevils’ on the growth and proliferation of water hyacinth compared to the
control ponds. Sampling were design randomly in triplicate sample biweekly gap for 3
months that weevils’ could affect WH; maximum leaf diameter (treatment WH plant
decreased by 1.7 ± 0.3cm whereas control WH plant increased by 2.9 ± 0.3cm in mean ),
minimum leaf diameter (treatment WH plant decreased by 1.4 ± 0.3cm and control WH
plant increased by 2.7 ± 0.3cm in mean ), shoot length (treament WH plant decreased by
9.3 ± 1.7cm and control WH plant increased by 21 ± 1.7cm in mean), root length
(treatment WH plant increased by 13.8 ± 1.8cm whereas control WH plant increased by
15 ± 1.8cm rate of increase differ) and fresh WH biomass (treatment WH plant increased
by 1258.2 ± 37.8grm and control WH plant increased by 1985.9 ± 37.8grm but rate of
increased different). The number of Neochetina weevils’ to feeding scar had direct
relationship (y=26.8 + 16.9x).Even though insignificant statistical difference was there
between experimental and control groups water quality parameter; WH affect the water
quality of ponds water temperature (0.1 ± 0.5 and 2.2 ± 0.5
0
C), dissolved oxygen (0.1 ±
0.3 and 0.4 ± 0.3mg/L), pH (0.2 ± 0.1 and 0.1 ± 0.1) and electrical conductivity (157.7 ±
62 and 105 ± 62 µS/cm) of experimental and control groups respectively. Thus, based on
their damage potential and positive impact on water quality parameter, Neochetina
weevil species are considered as the best promosing control agent for this invasive weed
to Ethiopia water bodies so that before introducing consider area coverage and growth
stage of WH.