P. costella adult specimen ex R.E. Cruttwell's original
collection, CABI Trinidad
Young P. costella gall with frass
| Rachel Cruttwell tested the moth identified as Mescinia
parvula (Lepidoptera: Pyralidae), whose larvae form galls in the stem tips
of chromolaena, in Trinidad and found it to be host specific. It was
subsequently released in Guam but did not establish. As it could not be reared in the laboratory, little further
work was conducted although it remained as a priority candidate. A culture of a similar moth imported from Jamaica into SA
quarantine in 2004 was successfully bred for one generation only. More recently, the Jamaican material was identified as
Phestinia costella and a comparison to Cruttwell’s material from
Trinidad indicated that it was the same species (Solis et al., 2008).
Although most of the necessary host-range studies were done
by Cruttwell (1977a), the difficulty of breeding this insect together with the
successful culturing of D. odorata has resulted in this candidate
decreasing in priority. |
Gall opened to reveal characteristic dark green P. costella larva  Mature P. costella gall. Larva has probably left the gall to pupate among the leaves
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 Longitarsus sp. adult ex Venezuela | Several Longitarsus (Coleoptera: Chrysomelidae)
species have been found feeding on chromolaena in the neotropics over the years
(Zachariades et al., 1999), and the species was considered a high
priority by some because it fed on the roots of the plant. A species initially identified as L. horni and then
Longitarsus sp. was collected in Trinidad and Venezuela in the 1990s
and successfully reared in SA quarantine. However it was subsequently found feeding on a range of
Asteraceae in the field, and was able to develop on other Asteraceae in the
laboratory, and has thus been rejected as a possible agent (Zachariades et
al., 2007) |  Longitarsus sp. adult damage |
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 A brunneonigrum adult speciman ex R.E. Cruttwell's original
collection, CABI Trinidad | The flower-feeding weevil Apion brunneonigrum
(Coleoptera: Apionidae) was also tested by Cruttwell (1973b) in Trinidad and
found to be host specific. It was released in the early 1970s in Nigeria and
Malaysia but did not establish.
It has not been considered since. |
 P. pseudoinsulata (individual at top right) and P. aurata aurata
(other two) adults | Pareuchaetes aurata aurata was collected in Argentina
off C. hookeriana (= C. jujuiensis), found to be host specific
(Kluge & Caldwell, 1993b), and released in SA in the early 1990s. It did not establish (Zachariades et al.,
1999). |
 P. basilica adult | Polymorphomyia basilica Snow (Diptera: Tephritidae)
galls stems of chromolaena in the Greater Antilles, where C. connexa is
absent. It was considered as a replacement for C. connexa on
the SA biotype, but attempts in the mid 2000s to rear it in quarantine were
unsuccessful (Zachariades et al., 2007). Galls are often formed on side branches.
The effect of a gall on the growth of a branch can be severe.
|  The galls of P. basilica appear on the stem between nodes, and are spiral. They contain only one larva each. Emergence windows visible |
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 C. curabilis adult | Conotrachelus curabilis Blackwelder (Coleoptera:
Curculionidae) occupies a similar niche to C. reticulatus in northern
Venezuela. Work was conducted on C. reticulatus rather than
C. curabilis because the former has a wide geographical range,
occurring in Brazil also. |  C. curabilis gall, Venezuela |
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 Ophiomyia sp. herringbone mine on C. odorata
| A species of Ophiomyia causes herringbone leaf
mines on chromolaena in the Caribbean but has not been considered as a priority
agent. |
| Several species of cecidomyid gallers have been recorded on
chromolaena (Gagne, 1977) and some of these may be good agents. |
 Adaina sp. galls on C. odorata, Florida
| Adaina n.sp. (Lepidoptera:
Pterophoridae) larvae have been found in chromolaena stem galls in Florida and
elsewhere. However, they do not appear highly damaging and proved difficult to
breed in quarantine. |
| Various flower attackers other than A. brunneonigrum
were recorded by Cruttwell (1974) some of which are likely host specific.
However, at the moment the flowerheads are not considered a priority target for
biocontrol. |