All about potatoes.pdf - Vegetableipmasia.org

8.
MAJOR NATURAL ENEMIES OF POTATO PESTS
biological insecticide or for the next propagation. It is
best to remove larvae when they have just died and
their bodies are still intact.
• Keep larvae infected with GV in a refrigerator at 4-7°C.
tubers in solution
GV formulation
• Crush up 20 infected larvae and add 1 liter of water and some emulsifier.
• Add 1 kg talc (magnesium silicate), stir thoroughly and allow the mixture to air dry
for several days in shallow trays.
• The formulation is ready for application when storing tubers in the storage areas.
C. Applying GV at storage
• Apply the GV formulation before storing tubers. You will need 5 kg of GV
formulation for every ton of tubers.
• Place GV formulation into a sack(amount according to recommended dose and
volume of sack). Put the tubers for storage into the sack and shake it until you
think all the tubers are evenly coated with GV formulation.
• The coated tubers can then be put into storage.
8.3.2 Bacillus thuringiensis (Bt)
Bt is found naturally in soil and plants. There are numerous strains of Bt capable of
infecting various insect types including larvae and beetles that can affect potatoes. Bt
is now available in commercial formulations in farming supplies shops. Example of
commercial formulations of Bt are Thuricide, Dipel, and Delfin.
Bt poisons and kills insects when they eat it. It is best to apply Bt directly to the parts
of plants being eaten by pests. Apply Bt in the late afternoon as Bt-toxins are easily
inactivated by direct sunlight. After application, the insect will die only after 2-3 days,
but will stop eating very soon.
8.3.3 Nematodes
Nematodes (tiny worms) can be a component in biological control as they can attack
and kill pests. One insect susceptible to nematodes is the leafminer fly in its pre-adult
and adult forms. Various species of nematodes, both those in the ground and on
plants, can infect leafminer flies. They infect them by entering their bodies, growing
inside them and eating their bodies from the inside. Affected flies will eventually die.
8.3.4 Fungal pathogens
There are many types of fungal pathogens that can infect insects. Some examples
are Beauveria bassiana and Metarhizium anisopliae. Collecting diseased insects and
observing their symptoms will provide a lot of information about these pathogens that
can be developed as agents of control. Some commercial formulations are currently
available on the market.
A HANDBOOK TO THE ECOLOGY AND INTEGRATED MANAGEMENT OF POTATO 53