Cosmopolites sordidus is considered to be the most serious pest affecting banana crops.
It is a dark brown weevil, 9 – 16 mm long with an oval-cylindrical body and a rostrum that extends into a curved beak, hence its name. This adult attacks at night, taking refuge during the day on the ground among the fallen leaves of the banana tree; in old or parent banana plants; or at the base of the pseudostem. It feeds on both fresh and decomposed plant remains, although it can last for up to 6 months without eating. It has been estimated that an adult can live for about 2 years.
The female lays the eggs individually at the base of the pseudostem, excavating a small hole with its rostrum. The larva that emerges from this egg has a rough, whitish coloured body that contrasts with the bright brown colour of its head. The larva causes the main damage, given that it feeds by opening galleries in the banana plant with its chewing mouth parts. The larva completes its life cycle inside this gallery and places itself near the exit hole, then starts to turn into a pupa.
The pupa or nymph is a whitish colour and stays motionless until it emerges as an adult. When the adult emerges, it is a yellowish colour that quickly turns brown.
Due to the nocturnal activity of the adults and remaining larvae inside the plant, the presence of weevils in the crops goes unnoticed.
The external symptoms are quite characteristic in the plant because they can be confused with other phytosanitary problems: slight yellowing of the leaves followed by necrosis and death of the tree, plant not growing properly, hardly any fruit produced, etc.
Source: COPLACA (Cooperativa Platanera de Canarias).
EOSTRAP® COSMOPOLITES SUPER (Code: TA192) and pheromone diffusers ECONEX COSMOPOLITES SORDIDUS 90 DAYS (Code: VA181).
EOSTRAP® COSMOPOLITES SUPER are wet traps that are used together with pheromones for the detection and mass trapping of the banana weevil: Cosmopolites sordidus
They are made of plastic polymer that does not emit odours when heated by the sun and can withstand ultraviolet rays. On average, they last for 6 or 7 years in field conditions. They consist of three parts that are easy to assemble: a base, a lid and a special hanger for the pheromone diffuser.
The traps should be placed half-buried up to the entry holes to capture Cosmopolites sordidus. They die by drowning in 3 to 4 cm of detergent (1-3%) that the traps contain. The traps should be checked each week or every two weeks.
The traps include an EOSTRAP® CAMISA SUELO, a hollow cylinder of 12.5 cm high x 11.5 cm diameter that facilitates the placement of traps in the soil and their subsequent monitoring and maintenance.
The ECONEX COSMOPOLITES SORDIDUS 90 DAYS diffuser must not get wet and the traps should never be without water. The traps should be covered with the remains of leaves from the banana tree because in this way the capture of the weevil is optimised.
The traps should be identified by using a cane in the ground near each one, to be able to find them and carry out maintenance in the field.
DETECTION AND MONITORING
One EOSTRAP® COSMOPOLITES SUPER should be placed per hectare. The trap should be inspected once a week to count the captured weevils.
The tolerance threshold for Cosmopolites sordidus is very low. In general, it is between 5 and 10 captures per trap and per week (medium level of infestation). For mass trapping, traps should be placed throughout the plots.
For mass trapping, the number of traps must be increased depending on the location, surface area and homogeneity of the plots.
The aim of mass trapping in certain areas is achieved by using different options:
Mass trapping with EOSTRAP® COSMOPOLITES SUPER in movable positions:
4 traps per hectare should be used. Owing to the fact that Cosmopolites sordidus is not a flying insect, these traps should be placed all along the infected area with the purpose of covering as much surface area as possible, thereby reducing the pest population.
At first, the traps should be placed 20 metres apart from each other and 10 metres apart from the plot borders. The line of traps should be moved 20 metres in the same direction each month. This practice requires a density of 4 traps per hectare to attract insects throughout the capture area for 4 or 5 months.
Mass trapping with EOSTRAP® COSMOPOLITES SUPER in fixed positions:
8 to 16 traps per hectare should be placed in fixed positions. The number of traps depends on the population level of Cosmopolites sordidus.
In cases like this, less time is required for its maintenance and the traps are used in plots where labour costs are high. In both options, it is recommended to use oil to reduce the evaporation of water.
If specialists or farmers use the traps and pheromones correctly, as previously described, especially during the early stages when adults of the first generation appear, this monitoring system is very effective. A very low level of damage, mainly on organic land, has been demonstrated.
After 12 months of mass trapping, a reduction of more than 80% in corm damage is quite common, especially in large areas of crops. As well as an increase in bunch weight of more than 20%.
A limiting factor of this system could be when there are small plots distributed all around and the neighbours have a high level of infestation of this pest.
Despite some important basic rules for an effective monitoring of Cosmopolites sordidus, every farmer or specialist has to find their own system of control to achieve it. They can experiment with this system, even establishing their own tolerance thresholds.
FACTORS THAT INFLUENCE THE NUMBER OF TRAPS NEEDED
The pest population of Cosmopolites sordidus, bordering crops, level of control required, etc…. One important factor is the size of the crops. In small and irregular crops, a greater number of traps are required than in larger and more uniform plots.
Another important factor is the distance between plots that have the same pest. In cases like this, the borders of the plots must be reinforced, so it could be necessary to place up to 16 traps per hectare or even more for mass trapping.
STORING THE DIFFUSERS
The diffusers should not be stored for long periods of time. The diffusers must be stored in their original packaging and in the refrigerator at 4 oC; or in the freezer at -18 oC, in which case they will last for 2 and 4 years respectively.
Corrugated cardboard box of 1.250 units (125 packs of 10 units).
Box size: 0.60×0.40×0.35 m (length x width x height)
Box weight: 13.1 kg.
No. of boxes per pallet: 20.
Pallet size: 1.20×0.80×1.90 m (length x width x height).
Pallet weight: 269 kg.
ECONEX WEB RESOURCES
Section of the ECONEX corporate website that allows you access to online information about ECONEX solutions for the biocontrol of other relevant agricultural and forest pests.
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