Ecology of Noorda Blitealis (Walker) (Lepidoptera: Crambidae) and Its Management Using Botanicals in Konso Special Woreda
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Date
2005-06
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Addis Ababa University
Abstract
Some ecological aspects of Noorda blitealis as the major defoliating pest of Moringa
stenopetala, were studied in Konso area, Ethiopia. The density of immature stages of
Noorda blitealis on Moringa trees were investigated in different months of the year. In
addition, the host range, major predators of the pest and control aspect of this pest using
botanical extract from seeds of Melia azedarach has been conducted
The result showed significant (P < 0.05) difference on the egg densities of the pest on the
host trees during the study period, with maximum and minimum numbers recorded
during March and February, respectively. The difference in the number of caterpillars per
host plant in different months was significant (P < 0.05), where heavy infestation was
recorded in April and relatively minimum infestation in February. Pupal density of the
pest showed significant (P < 0.05) difference during the study period, where the
maximum number was found during February and the minimum number during April.
The relationship between pest density and weather factors was significant (P < 0.05) and
positive correlations (r = 0.899; r = 0.823) of rainfall and relative humidity respectively
with larval density. In the contrary, significant (P < 0.05) but negative correlations (r = -
0.992; r = -0.885) of rainfall and relative humidity respectively with pupal density was
observed. Noorda blitealis was found to have only one host plant, Moringa stenopetala in
the study area. In this study, Myrmicaria sp. and praying mantids were found to be the
larval predators of the pest where significant (P < 0.05) difference was observed in the
number of larvae between Myrmicaria sp. nested trees and trees where this species were
not nested. However, the number of larvae recorded between the Hymenopodidae nestedand the Hymenopodidae non nested host trees was not significant (P > 0.05). Melia seed
water extracts of different concentrations; (the 50g L-1, the 75g L-1) and 2ml L-1 (Dursban
48% EC) showed significant (P < 0.05) difference from the untreated control, for their
oviposition deterrence on the moths, and repellent activities against the caterpillars.
However, there was no significant difference (P > 0.05) among the Melia and insecticide
treatments. Melia seed extracts at 25g L-1 was not found to be significantly different (P >
0.05) from the control. The toxicity effects of all the concentrations of these extracts on
filter paper showed no significant difference from the control while the chemical
pesticide showed significant (P < 0.05) difference. All the concentrations of the Melia
seed extracts were not significantly different from the control in causing mortality on the
predatory ants, where as significantly (P < 0.05) different mortality of the predatory ants
was observed on the insecticide treated filter paper.
Key words: Botanicals, Extract, Melia azedarach, Moringa stenopetala, Noorda
blitealis, Predators,
Description
Keywords
Botanicals, Extract, Melia azedarach, Moringa stenopetala, Noorda blitealis, Predators