months in this situation while the fruit is developing, maturing
and ripening. It feeds by inserting styletlike chelicerae into the
epidermal cells of the calyx members and those in the undersur-
face of the developing fruit. Eriophyid mites are very prolific
reproducers though they ingest only minimal quantities of fluid
from the cells they puncture.
 By comparison with other Eriophyid plant parasites which feed
superficially, like the citrus rust mite in Florida, Texas and
California, where it has reportedly been eradicated, the coconut
mite is very well protected from direct changes in weather, air-
borne parasites and predators generally. Moreover, chemical
sprays do not normally affect it directly in that secure location.
Occasionally, associated with E. guerreronis under the calyx of
some mature coconuts is a Tarsonemid mite, Tarsonemusfurcatus
which is also present in Venezuela. This mite survives for a much
longer period on exposed nut parts, yet in Trinidad its numbers
are always few when compared with the hundreds of E. quer-
reronis occupying the same protected ecological niche.
 In considering an approach to the control of the coconut mite,
apart from its location, attention should be paid to whether or
not the particular option for control is attempting to restrict the
dispersion of the mites which migrate to the surface of the fruit,
or reduce the population of the mite under the calyx. It is very
unlikely that an approach preventing initiation of infection at the
inflorescence would be successful because of the inaccessibility of
sprays to the mite in the female flower. More than likely, such
regular spraying would kill any likely insect pollinators to the tall
palms and thereby reduce fruit numbers.



A Review of Applied Methods for Control
of the Coconut Mite
 In the Ivory Coast, Julia and Marian (1979) cited the possibility
of employing predatory mites of the families, Bdellidae,
Phytoseidae and Tarsenominedae against the coconut mite.
However, they utilized two pesticides, monocrotophos and
cyhexatin, without much success. In Mexico, the pesticides
nubacron and carbicrom were sprayed onto the inflorescences
every 20 to 25 days during the major periods of flowering without
much success. Extensive applications were made, also in Mexico,
with the Besidiomycete fungus, Hirsutella thompsonii without
any success against mite population development.
 Generally, the above methods were deprived of any significant
success on mite population control because of the habitat of the
mite. Some chemicals might have reduced mite dispersal from
the surface of the fruits, but were unable to attack the reserve
population under the calyx. In the case of the fungus, Hirsutella
thompsonii, the mite population was not available to it, and
migrating mites on the exposed surface of the nuts were washed
away by rains in the epoch when the fungus was most likely to
have some minimal effect in reducing dispersal. Noted successes
of this fungus with phytophagous mites have been only on those
species which are exposed for a long enough time and feed on the
surfaces of leaves and fruits. Such mites as the citrus rust mite,
Phyllocoptruta oleivora and the blueberry mite, Acalitus (Aceria)
vaccinii which lives in the bud, have been successfully attacked.
However, convincing work done in the coconut groves in Mexico
indicate the inefficiency of the fungus in this situation since it
does not occupy the same ecological niche as the coconut mite.
 Quite logically, therefore, the reserve population of the mite
protected under the calyx must be attacked either by a parasite
within the same habitat, or a chemical capable of entering the
pest through the epidermal cells of the calyx where it feeds. Such
a chemical must be systemic and capable of persisting for at least
one generation of new eggs to hatch and then be broken down to
harmless components by the plant.


TABLE 1. Movement of coconut mite, E. guerreronis, by experimental wind cur-
rents during 24 h period.

 Bunches less than Bunches more than
 7 months old. No, of Mites Collected 7 months old.

 Bunch No. 1 435 1,000 Bunch No.
 2 640 437 2
 3 1,202 753 3
 4 836 465 4
 5 538 401 5



Control of the Coconut Mite Using a Systemic Acaricide
 Preliminary experiments of this approach consisted of studies
of the movement of a water solution of 1% crystal violet through
the xylem of the coconut palm and into the inflorescence and
fruit bunch. This was necessary because there does not exist
enough reliable information about the movement of chemicals
into the coconut fruit when such are injected in the stem. The use
of the dye was a simple device for those first observations.
 Generally, it was found that when the dye was injected on one
side of the trunk to a depth between 4-6 in, it became present in
all the inflorescences around the tree. This was so because of the
manner of internal branching of the xylem bundles. On the other
hand, when it was injected to a depth less than 2 in the dye re-
mained only on one side. Different volumes were injected: 5 ml,
10 ml, 20 ml, 50 ml, 75 ml and 100 ml. Effective demonstration
of the movement of the dye into the bunches was seen with 50
ml, 75 ml, and 100 ml; the largest volume being most effective
after 20 days from injection.
 The relative uptake of the dye by the fruits in different stages
of maturity was one of the main purposes of these observations.
Fruits which were between six to seven months old had already
reached their maximum size externally and were just forming the
solid endosperm or kernel (coconut meat). For our purposes these
were mature nuts. The ages of the older nuts could only be
estimated less accurately.
 It was found (Fig. 1) that when 100 ml of the dye was injected
by means of a 7/8 in auger at the base of the trunk, it entered the
fruits differentially. Generally, in all fruits up to four months
old, the dye entered the calyx and penetrated almost all the
pericarp. In fruits between four and seven months, the calyx was
penetrated, but the dye tended to concentrate only under the
soft protected area of the calyx. In some 7-months old fruit, the
dye was only seen with difficulty. The dye was seen in the calyx
only in fruits between seven and nine months old. It was not
detectable in any fruit with dark coloured shell, nor fruits in
which the husk was drying out.
 Apparently, since the dye travelled in the xylem, movement
up the plant to the inflorescence depended on the transpiration
stream and any water deficit anywhere in the plant. The sensitivi-
ty of younger nuts to water movement in the plant might be
related to the high hydrostatic pressure in these nuts. A large
amount of the dye would have gone to the leaves and only a pro-
portional amount, dependent on transpiration pressures, would
reach the maturing nut. These conclusions favoured the use of
the water-soluble systemic acaricide which was likely to follow the
same pattern of movement as the water-soluble crystal violet solu-
tion. The acceptable chemical should move as fast, so as to
penetrate all the tissues entered by the dye in the preliminary ex-
periments.

Trials with Vamidothion (Kilval)
 Vamidothion is a phosphorus ester with systemic properties. It
is soluble in water to about 4 kg./l. Although its metabolite, the


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