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The term "Integrated
Pest Management" (IPM), implies integration of approaches and methods
into a pest management system, which takes into consideration the ecology of the pest(s)
and of the crop. When IPM
principles are applied to a given pest problem, the intention is to minimise environmental impact and economic risks.
Insect and mite pests and diseases are among the important constraints to
sweetpotato production. When these problems become severe, the
yield may significantly be reduced and/or the quality of storage roots may be
affected thus reducing marketability. However,
pest problems vary from one place to another so implementation of IPM should be
tailored to meet the local needs. The following are general methods in
controlling pests and diseases of sweetpotato. Any of these could be integrated
depending on their availability and suitability in the area.
Cultural control
Cultural methods can significantly contribute in controlling or reducing
damage caused by pests and diseases in the sweetpotato crop. These include the
following:
-
Selection of
cultivars/varieties. Use cultivars which are resistant or tolerant to pests and
diseases and with high marketability.
-
Use of clean
planting materials. Planting material is often the primary source of pest
infestation or disease. Select vine cuttings that are free of soil, insects,
insect eggs or any sign of insect presence, and any disease symptoms.
It is good to establish and maintain a nursery for production of planting materials
to provide continuous source of more disease-free and insect-free mother roots or cuttings.
-
Field
sanitation. Plant residues often serve as source of pest infestation and
inoculum of disease-causing organisms, affecting succeeding or neighbouring crops.
Removal of all crop residues is recommended. These may be composted or
fed to cattle or hogs. Removal of weed species which serve as alternate
hosts also helps reduce population build up of pests and disease inoculum.
-
Crop rotation.
Continuous planting of sweetpotato will encourage
population build up of the pests and inoculum of disease-causing pathogens. Planting sweetpotato before or after vegetables
or cereals may reduces incidence of insect and mite pests and diseases attacking
sweetpotato.
- Hilling up. Hilling up reduces the incidence of weeds and prevents
exposure of storage roots to weevil infestation.
- Mulching. Mulching using rice straw or plastic mulch reduces weevil
population and weed infestation.
- Timely harvesting. This is especially true for sweetpotato weevil
management since weevil populations build up when harvesting is delayed,
especially during the dry season.
Biological Control
Beneficial organisms such as predators, parasitoids and entomopathogens help
maintain the ecological balance of sweetpotato ecosystem. A number of
arthropod pests are preyed upon by arthropods, parasitised by other insects, and
most of them are attacked by bacterial, fungal or viral pathogens. Specific
weeds may be controlled by insects with specialized feeding habits. In some
instances, a biological control agent may be introduced by the farmer. In
other cases, it is a matter of understanding and encouraging the naturally
occurring beneficial organisms.
Chemical Control
Pesticides are the most readily recognized method of pest management.
However, in sweetpotato pest management, pesticides should only be used when
necessary. The risks and benefits attributed to pesticides to the sweetpotato
ecosystem should be the main point to consider.
Generally pest populations recover more quickly than those of their predators and parasitoids,
so pesticide use can actually increase pest problem. Continuous unjudicious use of
pesticides creates a lot of problems such as development of pesticide resistant
biotypes and strains, resurgence of secondary pest outbreaks and health hazard
to the users.
References
Amalin, D.M. and E.A. Vasquez. 1993. A handbook on Philippine sweetpotato
arthropod pests and their natural enemies. International Potato Center (CIP),
Los Baņos, Philippines. 82 pp.
Harold R. Willson. 1992. OPMS Circular: FC-1 IPM. Department of Entomology.
The Ohio State University.
Talekar, N.S. 1990. Integrtated pest management of sweetpotato weevil. A
Training Guide. AVRDV. Taipei. 10 pp.
Vasquez, E.A and C.E. Sajise. 1989. Pests of Sweet Potato: Insects, mites and
disease. PRIS and PRCRTC, Visayas State College of Agriculture, Baybay, Leyte,
Philippines. 66 pp.
Contributed by: Erlinda
Vasquez and
Vilma Amante |
