All about potatoes.pdf - Vegetableipmasia.org

7.
MAJOR POTATO PESTS
to eat them. They can be removed from the rice bran the following day and
destroyed.
• Biofumigation- The use of biofumigation derived from brassica residues could be
considered on soils heavily infested with cutworms.
• Flooding field prior to planting- Where/whenever possible farmers can consider
temporarily flooding fields, particularly on severely infested fields.
Observation methodology
You can make observations in the morning, by looking for signs of cutworm damage
and dismantling soil around affected plants. However, it is sometimes difficult to find
the remains of affected plants as they are pulled into the ground. It is relatively easy
to identify the larvae of the cutworm; when picked up, the caterpillar will curve itself in
a characteristic C-shape.
7.6 White grub
Many plant species host this pest. White grubs live in loose soil, leaf mould or
manure. This pest attacks potato tubers. Affected tubers can still be sold or
consumed by farmers themselves.
Life cycle
White grubs are the larval form of beetles. They are
large reaching 2-3 cm in length, are shaped like the
letter C, and have three pairs of legs on their thorax.
Their heads are hard and ruddy-brown in color, and they
have strong mandibles. This insect develops by laying
eggs. White grubs develop for up to seven months, and
then have a rest period of 40 days after which they
pupate and remain in that form for two months.
Damage symptoms
Tubers damaged by white grubs have irregular holes. More than two holes are often
found in one tuber. These holes are not so deep, as white grubs do not enter and live
inside tubers. Severe infestations usually occur in fields previously covered with
grasses.
Management
This pest can be managed by:
• Collecting larvae when tilling soil, planting, weeding and hilling up. Any larvae
collected should be destroyed by fire or fed to chicken.
• Avoiding to use uncomposted organic fertilizer, as it is a suitable breeding ground
for this pest.
• Avoiding to plant potatoes in fields that were previously covered with grasses. If
there is no choice, then you should plant several weeks after tilling the soil.
• Biofumigation- The use of biofumigation derived from brassica residues could be
considered on soils heavily infested with cutworms.
• Flooding field prior to planting- Where/whenever possible farmers can consider
temporarily flooding fields, particularly on severely infested fields.
Observation methodology
It is difficult to observe this pest, as it lives in the soil. Some plants can be pulled up
at 70-75 DAP to look for signs of damage.
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ALL ABOUT POTATOES