Preventive control consists in appropriate monitoring of locust habitats at key periods of their development in order to allow early detection of number increase and behaviour change, and results in adequate early warning and early reaction; it aims at reducing occurrence and intensity of locust outbreaks and preventing their development into major upsurges.

WHY IS THE BEST SOLUTION? WHAT ARE THE COMPARATIVE ADVANTAGES?

Alternatives to preventive approach are curative or palliative responses implemented in an emergency context, i.e. when crisis already arose, which is not satisfactory. In addition to its efficiency as it generally targets hoppers, which are more sensitive to pesticides and less mobile than adults and against which a larger range of pesticides can be used – including alternatives to conventional chemical ones-, preventive approach offers the following comparative advantages:

• Reduced damage on crops and rangelands and therefore preservation of food security and livelihood of highly vulnerable rural communities;

Appropriately applied preventive approach allows reacting before significant increase of locust populations occur. Curative or palliative responses intervene only when there the outbreak is declared, which means already effective and much more important damage, with negative impact on food security.

• Reduced negative impact on human health and the environment

Preventive approach allows early detection of change in behaviour and increase in locust populations. This means that control operations can be carried out: a) at an early stage of locust development, both in terms of biology (hoppers instead of adults) and population dynamics (local infestations instead of a major outbreak; locust populations not yet in gregarious phase); and b) when there is no immediate threat on cropping areas. This enables to spray slow-acting pesticides (such as bio-pesticides or IGRs on hoppers, the latter being applied in barriers), which are less hazardous for human health and the environment, or of small quantities of chemical products on well-defined targets usually located in relatively remote areas, i.e. far from crops and inhabited zones. 

On the contrary, in presence of a major outbreak, the primary objective is the quick mortality of more than 80 percent of the locust populations over large infested areas in order to protect crops. This involves widespread full-cover spraying of huge quantities of chemical pesticides (fast-acting products) close to (or in) cropping areas and in the vicinity of inhabited zones. Inhabitants in the infested areas have to be aware of and adopt withholding periods for themselves, their livestock and their crops/harvests. Spraying, handling and storage of high quantities of pesticides also expose directly and for variable durations numerous workers whose health has to be monitored. Last, as chemical pesticides are not specific to locusts, non-target fauna can be affected (incl. beneficials such as bees), which also needs to be monitored.

• Reduced financial costs

Experience demonstrates that massive control operations are very expensive. Carried out during emergency contexts, i.e. during locust outbreaks and often with inadequate preparation, they imply costly measures, which are the rapid procurement of huge quantities of pesticides and equipment, massive and immediate recruitment of additional human resources  not always well-prepared or without updated knowledge, contracts for survey and control flying hours, etc. The cost of monitoring potential side-effects on human health and the environment of widespread use of high quantities of chemical pesticides has also to be added, as well as costs for mitigation, i.e. disposal of empty pesticide drums, obsolete pesticides and contaminated soils, improvement of pesticide warehouse and storage conditions for remaining pesticides, etc.

Preventive approach is a valuable solution to considerably reduce such costs. It implies long-term and streamlined locust management, that is to say an integrated strategy, which takes into account all situations and all aspects, including preparedness and contingency plans.

In other words, the locust preventive control strategy is the only sustainable solution and, for such transboundary plant pests, it also needs to be coupled with regional cooperation. 

This preventive strategy is the result of a long history of applied research carried out from the beginning of the 20^th century, with solid scientific bases and extensive field practice.

Results obtained by FAO in other geographical areas with other transboundary pests, in particular in the framework of the Programme EMPRES (Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases) – Desert Locust Component, and related experience gained, demonstrate how this approach is valuable.

• Monitoring 
• Information and forecasting
• Early warning & reaction
• Up-to-date survey/control methods and technologies
• Reducing impact on human health and environment 
• Preparedness for locust campaign, including contingency planning
• Capacity strengthening
• Regional cooperation