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Other insects have been considered over the years, and some of these were released but did not establish. Briefly, their current status is as follows: 


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


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


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
 
 
 


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


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.