Agriculture Reference
In-Depth Information
The results of these greenhouse experiments should further be verified
through advanced research in the laboratory (extracting secondary metabolites
which favored/ disfavored pea aphids, and at molecular level) and also more
field research. Moreover, the plant and the aphid side of the interaction may
have to be studied for the complete understanding of the reaction of aphids on
various hosts. This includes, among others, what the origin of the aphid clones
are, the history of the test crops in relation to pea aphids, etc. These actions
may help identify the more reliable mechanisms (chemical, physical and
ecological) for the diverse interactions. None of the plants were completely
avoided; pea aphid was able to build its population on all the host plants
included in the study. However, its growth rate varied indicating potential for
future exploitation.
8.
B
OTANICALS AGAINST
A
PHIDS
Like in many other places in Ethiopia, grass pea is grown extensively in
northwestern Ethiopia, specifically at Wondata area, near the banks of the
Blue Nile River. This place differs from other grass pea growing areas of
Ethiopia in one point, that the crop here suffers from pea aphid infestation to
the point of total loss. Grass pea is popularly known as the poor man‟s
insurance crop, the ultimate source of protein for the poor. Grass pea growing
is at the verge of collapse due to pea aphids, and although this pest can easily
be stopped by chemical pesticides, these are not recommended for their
drawbacks on the environment. More environment friendly and less expensive
local products should be identified to replace the all too common, but
effective, chemical pesticides.
Therefore, the relative efficacy of some locally available botanicals was
tested against pea aphids on grass pea along with detergent, kerosene and
pesticide. In search of a potentially more sustainable and environmentally
friendly alternatives to the commonly used insecticides, some botanicals
(neem, garlic and hot pepper), soap, kerosene, and the aphicide pirimicarb (as
treated control) were tested for their efficacy against pea aphids at Wondata
village, about 1 km far from the Blue Nile River, near Bahir Dar, Ethiopia
from 1999 to 2002 (Wale, 2004). Juices of botanicals were sprayed on to
plants at various growth stages of the crop. Next to pirimicarb, hot pepper was
consistently the most effective botanical in keeping aphid numbers down and
increasing the grain yield (Wale, 2004). Compared to the untreated control,
pirimicarb gave 83% and hot pepper 55% less aphid population. The
