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Several steps are needed to control the weevil. The first step is to uproot
and destroy all morning glory plants in the vicinity of the
sweet potato field. Most morning glory plants are perennial.
All efforts should be made to uproot them to prevent regrowth.
Since weevil eggs, larvae and pupae may be living in the stems,
destroy morning glory vines by burning. |
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The second step is to use clean cuttings.
The ends (25-30 cm portions) of tender vines are normally used
to plant a new crop. These distal tips are free of weevil eggs
and larvae. However,
older portions of vines may be infested.
Never use tips longer than 30 cm
to plant a new crop.
Sometimes, even when cuttings are free of
weevil eggs and larvae, weevil adults can hide under the
leaves and hitch-hike to the newly-planted area. This will start
a weevil epidemic. |
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To prevent this from occurring, soak cuttings
in an insecticide solution. Follow the instructions on the
label of the insecticide to prepare the solution. Use protective
clothing, gloves and face masks.
Soak the cuttings in the solution for 5-10 minutes. Drain excess
solution in the container. Use the same solution again and again
to dip more cuttings. This is a very inexpensive and effective
way of cleaning the cuttings of weevils.
Plant the cuttings in the field. The insecticide treatment, besides
cleaning the cuttings of weevils will also protect the crop in
the field for up to one month from any new weevil infestation. |
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Another important step is to eliminate
land cracks. Weevils
travel through land cracks to gain access to storage roots and
lay eggs. These
cracks are caused by the underground storage roots becoming larger
and larger. Land cracks may also be caused by lack of soil moisture,
which is common in the dry season. To
protect your crop, stir the soil to close cracks as soon as they
appear. |
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Another method of controlling weevil is to
use crop rotation. Do not plant sweet potato after sweet
potato. It is good to use sweet potato in a rotation (rice or
sorghum are often used). This rotation will help break up the
cycle of the weevil (and diseases, too). |
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If you must plant sweet potato continuously,
remove all debris and even small pieces of root from the previous
crop. |
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If water availability is not a problem,
and if feasible, flood the field for one or two weeks.
This will rot any leftover materials and kill weevils by drowning.
Furthermore, weevils cannot survive on decaying plant parts.
If all farmers follow these measures, it is easy to control the
weevil cheaply and with minimal use of toxic insecticides.
If all farmers within a region follow these measures, it will
be possible to practically eradicate the weevil. This has been
accomplished in some regions of the USA and in island communities.
Let's learn about some new and emerging
strategies for controlling this weevil .... |
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