Cultural management
- As
a prophylactic measure, the first affected leaves may be cut and burnt
during the beginning of the summer season.
- Biological
control is most successful method. Among the larval parasitoids, the
Bethylid, Goniozus nephantidis,
(Elasmus nephantidis (brown
species) and Brachymeria nosatoi)
is the most effective in controlling the pest. The optimum level of
release is 1:8 of host parasitoid ratio. The parasitoid should be released
@ 3000/ha under the coconut trees when the pest is in the second or third instar larval stage. Parasitoid release trap may be used
to release the parasitoid at the site of feeding. Parasitoids should not
be released in the crown region, since they will be killed by predators
like spiders and reduviid bugs. This should be released only three weeks
after chemical spray.
- Release the larval (Bethylid, Braconid and
Ichneumonid) and pupal (Eulophid and chalcid) parasitoids and predators
periodically from January, to check the build up of the pest during
summer.
- Bacteria like Serratia
marcescens and Bacillus
thuringiensis cause disease in larvae.
- Predatory carabid beetle Parena laticincta
- A host of parasites
attack different stages of the pest. For obtaining effective control, scheduled
release of a combination of these parasites should be adopted four times depending
on the stage of the pest.
- First release immediately when the infestation is observed.
- Second – a fortnight after the first
- Third – a month after the second
- Fourth – a fortnight after the third
- The stage wise parasitoids are listed below
Egg parasite |
Trichogramma chilonis |
Early larval |
Cotesia taragamae |
Mid larval |
Bracon brevicornis |
Late larval |
Goniozus nephantidis |
Pre pupal |
Elamus nephantidis |
Pupal |
Stomatoceros sulcatiscutellum, Trichospilus pupivora Brachymeria nephantidis Tetrastichus israeli |