Agriculture Reference
In-Depth Information
However, both mechanical and chemical control methods are expensive and
require frequent applications. Since classical biological control offers a long-
lasting, effective and economical solution to this problem, it has been explored
and implemented in several countries.
Biological control
In 1966, the Nigerian Oil Palm Research Institute, recognizing the seriousness
of chromolaena, requested Commonwealth Institute of Biological Control
(CIBC) (now CABI Bioscience) to initiate a biological control program by
conducting exploration for natural enemies in the neotropics. In this project,
207 insect and 2 mite species that attack chromolaena in neotropics were iden-
tified [25], of which about a quarter were host-specific [26].
Pareuchaetes pseudoinsulata
Rego Barros (Lepidoptera: Arctiidae)
This was one of the first natural enemies identified in the CIBC project. It was
host specificity tested in Trinidad and India and initial field releases were made
in Sabah, Malaysia, from 1970-74, India in 1973 and 1978, Sri Lanka in 1973,
Ghana in 1970-74, and Nigeria in 1973-78 [26-30]. Of these releases, only
in Sri Lanka was the establishment of the moth confirmed [28]. About a
decade after the release in Sabah the establishment was confirmed [31]. The
recovery of
P. pseudoinsulata
in the Palawan Island of the Philippines in 1985
[32] could possibly have been a fortuitous introduction from Sabah, Malaysia.
Releases of
P. pseudoinsulata
from 1984 onwards in India resulted in estab-
lishment [29, 33].
Pareuchaetes pseudoinsulata
, introduced to Guam from India and
Trinidad, became established in 1985. Subsequently it was introduced to the
neighboring islands in the Commonwealth of the Northern Marianas (Rota,
Tinian and Saipan) in 1986-87 [34-36]. Introduction to Yap in 1989-91,
Pohnpei in 1988-92, Kosrae in 1992, and Chuuk in 2004 resulted in its estab-
lishment [37-39] in Micronesia. It was imported into Palau in 2004 and is
currently being field released (Muniappan, personal observation). Release of
P. pseudoinsulata
from Guam to Ghana from 1991-93, Indonesia in 1991
and 1993 and Papua New Guinea in 1999 resulted in establishment [40-42],
however, releases in Thailand in 1987, South Africa in 1988 and the Ivory
Coast in 1991-93 did not establish. Experience from the introductions of
P.
pseudoinsulata
in the above-mentioned countries indicates that release of
several thousand caterpillars on constant intervals for a long period in one
area is necessary to overcome the predatory pressure and to allow establish-
ment. The failure of establishment of
P. pseudoinsulata
in South Africa was
due to the incompatibility of the biotype of chromolaena that grows there [16,
17, 43].
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