Preliminary Investigations for Biological Control

 of Brassolis sophorae in Guyana

 M. Yaseen
 West Indian Station
 Commonwealth Institute of Biological Control
 Curepe, Trinidad


 The coconut Cocus nucifera is an economically significant
crop in Guyana. Brassolis sophorae inflicts serious damage and
causes yield loss. Native natural enemies do not provide ade-
quate control. Biological control by importation of exotic
natural enemies from other parts of South America has com-


menced recently and Spilochalcis sp. nr. erythnna has been in-
troduced. Attempts are under way to procure other known
parasites.
 Keywords: Biological control, Cocos nucifera, Brassolis
sophorae, Guyana, Spilochalcis sp. nr. erythrina.


 The coconut, Cocos nucifera, constitutes an important source
of edible fats and ranks third in importance to sugar cane and rice
in the agro-economy of the Cooperative Republic of Guyana. The
coconut butterfly Brassolis sophorae is a serious pest of coconut.
 B. sophorae occurs in Trinidad and throughout tropical South
America (Fruhstorfer, 1924; Kaye, 1921). Damage to coconut
palm is inflicted by the larvae, popularly known as the coconut
caterpillar, which strip the foliage leaving only the mid-ribs. Such
trees lose an entire crop of nuts and usually the trees will only
produce another crop a year or a year and a half after such an at-
tack has subsided. Continuous and repeated attacks can result in
mortality of the palm. Rai (1973) reported 20% loss of palms in
one estate as a result of continuous infestation over two years.
 Manthriratna (1980) assessed the current uneconomic situation
of the coconut industry and suggested measures to improve it, in-
cluding attempts for biological control of B. sophorae. An in-
vestigation sponsored by the Food and Agricultural Organization
of the United Nations was undertaken in 1982 to:
 1. Evaluate the naturally occurring parasites and predators;
 2. Introduce, breed and release exotic parasites; and
 3. Evaluate control after release of parasites.
The following is a preliminary report of the investigations so far
made.

Biology
 The biology of B. sophorae has been investigated by Cleare
and Squire (1934) and van Dinther (1960). Eggs are laid in
groups arranged in a single layer on the leaf bases, the fibrous
material in the crown and the spathe covering the inflorescence
and the trunk. The hatching larvae live gregariously and pass
through seven instars. Larger larvae construct nests by webbing
together several leaflets. They hide during the day in these nests
or other protected places, e.g., the narrow spaces between the
bases of the leaf stalks and the fibrous material at the base of the
crown, coming out at night in a procession to feed on leaves. On
completion of larval development, they pupate in protected
situations, viz., leaf bases under coconut husks on the ground.
The egg, larval and pupal stages, respectively, last for 20-25,
76-91 and 11-15 days under ambient conditions in the Guyanas.
The total egg to adult development period spans 110-129 days.
 In addition to coconut, they feed on several other palm species
including the oil palm, royal palm and cabbage palm.

VOL. XX-PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY


Natural Enemies
 Cleare and Squire (op. cit.) have reported egg parasites
Telenomus nigrocoxalis Ashm. and Anastatus reduvii How., a
larval parasite Chaetolyga pyrrhopyga Wied. and pupal parasites
Brachymeria annulata F., B. incerta Cress. and Spilochalcis
morleyi Ashm. from Guyana. C. pyrrhopyga was considered
unimportant as it only parasitized 1% of the larvae.
 During the present investigations, field work was undertaken
in affected areas along East Coast Demerara, West Bank
Demerara and Berbice County. Collections of eggs, larvae and
pupae were made in several large coconut estates, viz., Drill, Let-
ter T', Robinson and Park estates, as well as in small holdings at
Black Bush Polder, Lesbeholden, Corryverton, Advenutre,
Village #63 along Corentyne Coast and along Canal #2 along the
West Bank of River Demerara. The parasites reared included
Telenomus sp. (Scelionidae) and Anastatus sp. (Eupelmidae)
from eggs; Brachymeria sp. nr. annulata F., Spilochalcis sp. nr.
burmeisteri Kirby (Chalcididae), Paraphrissopoda chrysostoma
Wied. and Sarcodexia innota Walk. (Sarcophagidae) from
pupae.
 No larval parasite was encountered. The specific status of egg
parasites could not be ascertained, but presumably these are the
same reported by Cleare and Squire (op. cit.). The two Chalcid
pupal parasites also determined at the Commonwealth Institute of
Entomology are perhaps the same reported by the aforementioned
authors. The status of the two Sarcophagids is not known. Larvae of
most species of this family are scavengers and only a few are
parasites of other insects.
 The two egg parasites were obtained from collections of eggs
along East Coast Demerara; only a few batches of eggs were collec-
ted in the Berbice county and none yielded parasites. The inci-
dence ofAnastatus sp. was negligible; only a few eggs in three egg-
masses out of 89 collected at Drill and Letter T' estates, yielded this
Eupelmid. Only ten of the egg-masses yielded Telenomus sp. and
only three of these had all the eggs parasitized.
 Of the two Chalcids, Brachymeria was less abundant than
Spilochalcis. Both were obtained mostly from pupae under heaps
of husks, with very few pupae in the base of the crown yielding
parasites.
 It is quite evident that the native parasites of B. sophorae do
not exert adequate control and there is a need to import exotic
parasites which, if established, may regulate the pest populations


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