Biomedical Engineering Reference
In-Depth Information
Threats and Problems
Although abaca has been an established Philippine industry, it is still plagued with
problems. Areas that continue to be addressed are (1) farm productivity and (2) fiber
quality. Also among the serious challenges in the Philippine abaca industry
includes:
1. Aggressive moves by Indonesia to massively produce abaca under the govern-
ment's reforestation program, increasing market competition
2. Availability of similar materials from China and India and technological
advances and breakthroughs which make possible production of cheaper sub-
stitutes, whether from natural (e.g., sisal, Ecuadorian abaca) or synthetic-based
materials
3. Threat from destructive pests and diseases, natural calamities, use of a few
genotypes, overexploitation due to over-harvesting of natural stands, and chang-
ing land use brought about by development and population pressure
As early as 1980, there was a rapid decline in abaca production not only due to
the unavailability of improved varieties but also due to three major virus diseases -
abaca bunchy top (ABT), abaca mosaic (AM), and abaca bract mosaic
(BM) (Fig.
12.2
). There were resistant lines identified from the abaca germplasm
collection. However, these have often fibers of inferior quality. Control of these
viruses is difficult even with different disease control strategies. Other diseases
remain important as they affect production of abaca. Superior hybrids developed by
conventional breeding could be adopted directly by abaca farmers if they possess
resistance to diseases caused by viruses and other pathogens. Continuing effort on
identifying sources of resistance to these diseases is being done to be able to sustain
abaca production in the country.
Abaca bunchy top, abaca mosaic, and bract mosaic virus are economically the
most devastating virus diseases in abaca. These often occur in the same growing
area. The average incidence of abaca bunchy top and abaca mosaic diseases in
Bicol in 1991 was 5.19 % with an estimated fiber yield loss of more than 800,000 kg
valued at about
18 million [
7
]. The estimate for the same year in the Eastern
Visayas was disease incidence of 8.16 % valued at about
₱
8 million. These diseases
₱
are known to reduce fiber quality as well.
The symptoms of bunchy top disease were first observed in Albay (Bicol
Region) in 1910 and 1911 [
8
], then in abaca plantations in Silang, Cavite, in
1915. The disease was not a serious threat to abaca cultivation until 1923
[
9
]. Since that time, increased virulence caused the abandonment of plantations in
the provinces of Cavite and Laguna (Paete). Presently, bunchy top which is
widespread in abaca-growing areas is considered the most destructive of the
abaca diseases because the plants are very much stunted (Fig.
12.2
) and are not
productive. The most striking characteristic of bunchy top is the crowding of the
leaves into more or less a rosette arrangement [
8
], accompanied by a transparent
appearance of the main and secondary veins of the leaves.
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