The Problem of the Coconut Mite,

 Eriophyes guerreronis (Keifer),

in the Coconut Groves of Trinidad and Tobago

 Reginald Griffith
 Director, Red Ring Research Division
 Central Experiment Station
 Centeno


 The coconut mite, Eriophyes guerreronis Keifer,
Eriophyidae, is now a serious coconut pest of the Caribbean
and Latin America. It causes a range of damage to the coconut
fruit from scarring and early fruit-fall, to fruit distortion and
fruit-stunting. Losses in copra often reach a 60% level due to
the reduction in fruit size. The mite lives under the calyx of
the coconut fruit, which it infests at the flower stage, and per-
sists there until several weeks after the mature fruit fall to the
ground. Only in Brazil is the mite known to affect developing
coconut seedlings in the field. Mites which become exposed on
the surface of the maturing fruit are easily dispersed by the


wind to female flowers in the dry season or become washed off
by the rains during the wet season as dissemination becomes
restricted. The epidemic is therefore oriented towards dry con-
ditions with cool, windy nights. Successful control measures
employ the injection of the infested tree trunk with 50 to 100
ml vamidothion ("Kilval"), a phosphorus ester with systemic
properties, towards the end of the wet season when the mite
population is lowest. The permanent reduction of the epidem-
ic is related to the organization of farmer control programmes
which integrate unfavorable climatic conditions with effective
chemical control.


 The coconut mite, Eriophyes guerreronis Keifer, belongs to the
family of mites called Eriophyidae. Generally, these are known as
gall, bud, rust and blister mites also. They are almost always
nearly invisible to the naked eye. The coconut mite measures be-
tween 200- 260 microns in length. It is a slender, cream-coloured,
worm-like mite. It is easily recognizable under the calyx of the
coconut fruit since it has only 2 pairs of legs. The featherclaws are
six-rayed, the sclerotized dorsal shield is marked with
longitudinal ridges and the cover flap of the female genitalia has,
on the average, between 9-12 longitudinal ribs.
 A well-known feature of these mites is that they suck up plant
juices, which are usually pre-orally digested with enzymes
secreted from salivary glands, by means of a strongly muscled
pharynx acting as a sunction pump. Thus, during their feeding
on the coconut fruit, starting from the button-stage, they cause
fruit-hardening, fruit-fall, fruit malformation and fruit-stunting.
When the injury is not severe, the mature fruit has long, har-
dened, superficial furrows in the pericarp. These often begin
from the calyx and extend towards the base of the fruit. General-
ly, on maturing fruit, the injury begins around the calyx, extend-
ing downwards when colonization by the mite is dense.

Economic Effects and Distribution
 Economically, the effects of coconut mite infestation in a plan-
tation or grove may be very severe since, in copra-growing areas,
as many as six fully-grown nuts of the reduced size might be
necessary to produce a pound of copra, when normally two nuts
would be adequate. The mite can be, therefore, a serious
eriophyid pest affecting the development of the fruit and the
profitability of the enterprise.
 E. guerreronis was initially reported from the state of Guerrero,
in Mexico, around 1960. Mention, however, was made of the pest
near Africa in the islands of Sao Tome and Principe only around
1970. Official records date its presence in Dahomey, Benin and
the Ivory Coast around 1967 and 1968. About that time also,


128


1967, its presence was recorded in the state ofZulia in Venezuela.
Brazil, in 1968, recorded its presence and Colombia in 1969. It
has been observed in Guyana, Trinidad (1975), St. Vincent
(1981), Grenada, St. Lucia (1982), the Virgin Islands, and
Jamaica (1975). In general, it would appear that the coconut mite
is on its way to colonize all the coconut growing regions of both
Latin America and the Caribbean. As such, immediate control
measures should be devised to restrict its spread since it is virtual-
ly the newest coconut pest in the region.
 Only in Brazil, so far, has the coconut mite been seen to attack
the growing point of the seedlings. The heart-leaves show a
necrosis and secondary infection often follows when the attack is
severe. Generally, though, the seedlings recover during the active
growing season. The major damage, then, is normally confined to
the fruits. Still, it is not known under what conditions the mite
will attack the growing seedling.

The Coconut Mite in Trinidad
 The coconut mite was first observed in the coconut groves of
the Cedros peninsula in 1976. This southwestern region of
Trinidad is only nine miles away from the mite infested areas in
Venezuela. From this port of entry, the mite progressed most
rapidly along the leeward and western coast of Trinidad, which
has only a minor distribution of coconut palms. Figure 1 shows
the rate of progress of the coconut mite in Trinidad. On the other
hand, progress along the eastern coast, which was generally wet-
ter with about ten times more coconut palms, was slower. The
mite reached only the mid-Nariva/Mayaro district in 1984.
Whereas the average annual rainfall is 70.5 in in Trinidad, the
windy east coast receives as much as 124 in while the western,
leeward side receives only 50 in as an annual average.

Movement of the Coconut Mite Across Groves
 The movement of the coconut mite in the islands of St. Vin-
cent and St. Lucia has been studied for comparison with that in


 PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX