Responses of Insect Pests and Plant Diseases to Changing and Variable Climate: A Review

Paramu L. Mafongoya,Augustine Gubba,Rumbidzai D. Katsaruware-Chapoto

doi:10.5539/jas.v9n12p160

Abstract

Natural and anthropogenic factors have resulted in altered environmental conditions that influence changes in abundance and diversity of insect pests. Global climate change projections focus on crop yields and adaptation strategies to declining yields and ignore the likely impact of a changing climate on insect pests and plant diseases. In this research paper, we review the effects of climate variables namely temperature, carbon dioxide (CO2), precipitation and extreme weather events on insect pests and plant diseases incidence. Elevated temperatures, CO2 and extreme weather events have been shown to alter the distribution, reproductive potential, the incidence and abundance of plant insects and diseases in temperate regions because of the dependence of insects and diseases on environmental conditions. There is limited information on the influence of temperature and carbon dioxide as well as their interaction on the incidence and severity of insect pests, bacterial and viral diseases in the tropical regions. Information on the influence of altered precipitation patterns is also limited but could be of importance in insect distribution studies in a changing climate. Some tropical insects pests are most likely to suffer from extreme heat, resulting in death and hence pest extinction. Future research should focus on the interaction of elevated temperature and CO2, determine the influence of supra optimal summer temperatures, temperature variability, precipitation variability and the corresponding viral and bacterial diseases.

Highlights

Human activities and natural factors have led to rapid and extreme increases in atmospheric gases such as carbon dioxide, methane, chlorofluorocarbons and other greenhouse gases (IPCC, 2013)
In a study that was conducted in Zimbabwe, using the Generalized Linear Models (GLM) on coffee white stem borer (Monochamus leuconotus P.), it was predicted that the area suitable for the insect will increase in Chimanimani district by up to 200% by 2080 (Kutywayo et al, 2013)
CO2 and extreme weather events such as floods and storms have an effect on fecundity, development, survival, distribution as well as incidence of insect pests and diseases in a changing climate

Summary

Introduction

Human activities and natural factors have led to rapid and extreme increases in atmospheric gases such as carbon dioxide, methane, chlorofluorocarbons and other greenhouse gases (IPCC, 2013). The increase in frequency and intensity of extreme weather events, changes in moisture conditions, temperature rises and elevated carbon dioxide concentrations are expected to magnify pest pressure on agricultural systems through various ways (Johnson et al, 2013). Extreme weather events (dry and wet conditions) are key factors in triggering endemic and emerging insect pest outbreaks (Anderson et al, 2004). Increased frequency of extreme weather which is expected to occur with climate change and variability is set to increase the agricultural pest burden. There is, a risk that future crop yields might be overestimated if the impacts of insect pests and plant disease epidemics are not taken into consideration (West et al, 2015). This review will, examine the impact of each of the climate change variable in more detail

The Impact of Elevated Temperature on the Biology of Insect Pest and Diseases

Effect of Elevated Carbon Dioxide on Insect Pests and Diseases

Effect of Extreme Weather Events on Insect Pests and Diseases

Findings

Conclusion