Climate Change Impacts and Forecasts of Oil Palm Leaf Miner Populations

Abstract

Agricultural production is very sensitive to climate change, and it suffers from periodic outbreaks of insect pests which cause considerable losses especially in the humid and sub-humid tropics which severely constrain the productivity potential of global agriculture under changing climate conditions. The oil palm leaf miner is a major pest of the oil palm. Mathematical relationships between the leaf miner insect stages and weather factors were developed for pest predictions and forecasting. Decadal variation in air temperature was characterized by wide differences between 1961 – 1970 and 2001 – 2010. The assessment of the sensitivity of leaf miner to variability in weather and climate conditions is important in view of evidence that show expansion of pest ranges as a result of climate variability impacts. The study has established an upward increase in temperature, attributed to climate change, with a concomitant increase in leaf miner abundance between 1980 and 2010. Larvae showed an increasing trend for the observed period. When this observation was correlated with the weather (temperature, rainfall, and relative humidity) during these periods, it could be inferred that there was proliferation as a result of weather changes. This was different from the decreasing trend observed during the 1976 – 1980 period. Pupae showed a decreasing trend for the observed period. Adults showed an increasing trend for the observed period. It could be inferred that adults were proliferating due to temperature increases and rainfall decreases. An incremental increase in temperature could help explain fluctuations in insect pest populations within and between years. Thus climatic conditions greatly influenced seasonal leaf miner populations. The climate forecast up to 2050 indicates an upward trend in temperature and a downward trend in rainfall and relative humidity. This followed the climate trend between 1961 and 2010. This study contributes to the understanding of the insect pest-weather relationship in broad agricultural and food security terms. A major advantage is the potential for limiting the spread of outbreaks through timely control of early pest infestations.