7.2.1 The practice and future of IPM for cocoa
With the general push to reduce or limit the use of the most hazardous pesticides in agriculture (i.e. EU Green Deal, discussed in Chapter 1), more emphasis is being placed on IPM for pest management.
The EU and FAO define IPM as ‘careful consideration of all available plant protection methods and subsequent integration of appropriate measures that discourage the development of populations of harmful organisms and keep the use of plant protection products and other forms of intervention to levels that are economically and ecologically justified and reduce or minimise risks to human health and the environment. ‘Integrated pest management’ emphasises the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.’
The principles of IPM in its simplest form rely on prevention, monitoring and selection of the least harmful interventions.
Since the announcement of the Green Deal and Farm to Fork Initiative, there has been a considerable amount of interest in the application of biopesticides. Biopesticides include a range of substances from living organisms (bacteria, fungi, viruses, nematodes) to natural substances (minerals, plant extracts, fatty acids), semiochemicals (i.e. pheromones) and new technologies such as RNAi.
Unfortunately for cocoa farmers, there are currently only a handful of biopesticide options registered for management of cocoa pests and diseases (see Appendix 3).
Of the products currently registered for use on cocoa, little is known about their local availability and cost/ efficacy in comparison to chemical pesticides. Therefore, at this point in time, is may seem to some a little hasty to reduce the number of ‘tried and tested’ Ais available for cocoa pest management.
There is some light at the end of the tunnel, as part of the Green Deal, the EU has said it will revise legislation to facilitate the use of biopesticides.
Currently in many countries, biopesticides must go through the same process of registration as chemical pesticides, so a revision may allow access of commercial biopesticide products to market more quickly.
The availability of a more diverse range of biopesticides will not on its own be a magic bullet, there are other aspects of IPM that need to be addressed and improved if it is to be a successful approach.
Monitoring is a critical part of IPM which requires identification of the target pest in order to take appropriate remedial action. The widely used term “economic threshold level” (ETL) is essentially a theoretical concept, so many practitioners prefer “action thresholds”: where management should be taken to avoid pest levels reaching economic injury levels.
Widely agreed action thresholds do not appear to currently exist for many cocoa pests and management still relies on general recommendations, and a recent report from Ghana [1] highlights the issue that a large proportion of farmers are still able to recognise the major cocoa pests and diseases on their farms.
In any case, monitoring techniques and action thresholds may be country or more locally specific, and are still subject to unresolved scientific debate.
Three of the most important African cocoa pest problems are:
On a cautionary note – although both authors subscribe to ‘minimum pesticides’ approach for management of cocoa pests and diseases, pesticides remain a very important part of the IPM ‘toolbox’ and must not be excluded prematurely, particularly when no effective substitutes have been identified.
Considering the major West African field problems (above), most IPM practitioners would agree that cultural control measures, especially crop sanitation (e.g. diseased pod and chupon removal) provide the principal foundation for pest management; in the case of CSSVD, replanting after complete removal of old trees may be the most realistic long-term solution.
However, we would challenge those advocating no pesticide use (including copper compounds) to actually experience smallholders’ quandaries: when facing high black pod pressure, for example.
