Introduction

Plantain and banana are grown on a wide range of soil types throughout Guyana and are affected by insect pests, diseases and weeds which adversely affect yields.  The most devastating pests is the Moko disease to which all commercially grown varieties are susceptible.  Insects, particularly the Banana root weevil, are also responsible for sustainable yield loses.  Weeds contribute to yield losses through competition for water nutrients, and by serving as alternate hosts for insects and diseases.

It is essential that the establishment of cultivations be done with clean and healthy planning material.  Proper field sanitation ensures a clean environment for crop growth.  The utilization of adequate agronomic practices e.g. fertilizer application and weed management contribute to plant vigour.

Plantain and banana are affected by three major insect pests:

	Banana root weevil - Cosmopolites sordidus
	Pseudostem borer - Lapaeumides licus
	Fruit scarring beetle - Colaspis hypochlora

Banana Root Weevil

This pest is widely distributed throughout the country, but is more problematic in areas that cultivate the crop on a large scale.

The larva causes damage through feeding and tunneling in the corm.  Continuous feeding and tunneling cause the corm to become a blackened mass of decaying tissue.  Above ground symptoms are the yellowing of leaves, withering and eventual death of plants.  Infested plants are easily blown over by wind, since roots are weakened.

The adult weevils live under or in newly cut or decaying pseudostems.  They are about 1-1.3 cm long and have a pronounced snout.  The mature larva is also about 1-1.3 cm long, creamy white, fleshly and legless.

Control

Use clean planting material:  Ensure that suckers to be used for  planting new fields are free from the pest.  Remove all trash from the sucker and part the corm to remove all roots and discolored portions.

Pared suckers are further dipped in a 4% monocrotophos, basudin or vydate L solution.  Allow suckers to dry for a t least 24 hours before planting.  Suckers so treated will be protected against weevil attack for three months.

Cultural control:

	Weeding and fertilizing contribute to plant vigour, which enables the plant to better withstand weevil attack.
	Desucker and clean matts regularly and remove all dead and decaying matter.
	Remove all residue from the previous crop.

Field treatment of infested plants:  Plants that are infected in the field can be given an insecticidal treatment.  The insecticides recommended are Basudin 60% EC and Vydate L at a rate of 0.1%.

The insecticide should be sprayed unto the pseudostem immediately above the corm, and the soil immediate around the base of the plant.  The treatment should give control for a minimum of three months.

Trapping:  The adult weevil is attracted to cut or damaged pseudostem.  During harvesting, the pseudostem from those plants which would have already borne fruit can be split longitudinally and cut into 45cm (18 inches) long pieces.  The cut surface of each piece can be treated with 0.05% monocrotophos or 0.05% Basudin solution.  Each cut piece should then be placed, with its cut surface downwards on the soil surface between the standing crop.  Traps will attract and kill weevils between a 7-10 day period.

Untreated traps can be placed in the field as described above, however, these must be serviced and replaced every 48 hours.

Pseudostem Borer

The larva, 3.75cm long, bores into the pseudostem at any point up to 1 meter from ground level.  Evidence of infestation is the continuous emission of slimy, colourless exudate.  Occasionally, the larvae attack the core of the plant and reach the growing point, thus killing the plants.

Control

	Practice proper field sanitation.
	Injection method:  Make 2-3 holes, 9cm (3 inches) about 60cm (2 ft) from the ground.  The hole should go down and sideways into the trunk.  With the use of a dispensing bottle pour monocrotophos 60% EC into the holes.

DO NOT APPLY THIS TREATMENT TO PLANTS WHICH HAVE IMMATURE OR MATURE FRUITS.

Fruit-scarring Beetle

The adult beetles feed on the surface of the fruits thereby causing wounds.  A clear fluid, which eventually turns black, is exuded from wounds.  The wounds are only superficial and do not extend to the edible portion of fruits.

Conditions suitable for the development of this pest are:

	heavy shade
	water logged conditions
	poor field sanitation

Control

Good cultivation practices:  The adherence to proper cultural practices will greatly reduce the incidence of this pest. Such practices include:

	fields being relatively free from weeds
	fields must have adequate drainage
	sunlight must be able to penetrate the crop canopy

Chemical:  Bunches can be sprayed with a 0.1% sevin (carbaryl) solution, or 0.05% malathion solution or any contact insecticide with limited residual power.

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