Climate change and Citrus Pests

Abstract

Evidence is mounting that climatic changes in recent decades are already impacting significantly on the distribution and population dynamics of agricultural and horticultural pests. These observed changes are consistent with theoretical models developed as early as the mid-1990’s. Species are overwintering further poleward and into higher altitudes. The number of generations and population abundances are changing in sometimes complicated fashion in response to changes in temperature and soil moisture regime. These changes will challenge biosecurity policies and in-orchard pest management. They are likely to continue for the foreseeable future, though they will be non-linear, and are in the context of seasonal and inter-annual variability. This trended variability will challenge traditional heuristic pest management development models based on adaptive management. I will illustrate some of these expected impacts using examples of high profile citrus pests, including medfly and Aleurocanthus woglumi, and outline strategies and ingredients for systems to help manage citrus pests under these changing conditions. There is a large, irreducible uncertainty regarding the future rate of greenhouse gas emissions, and consequently the rate and extent of expected climate changes. This makes it impossible to accurately and precisely forecast the changes in pest management. What we can do is illustrate the types of change to expect, and robust strategies and systems to manage pests under this type of uncertain change.