Predicting the impact of climate change on regional and seasonal abundance of the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) using temperature-driven phenology model linked to GIS

The mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a highly invasive and polyphagous pest of global incidence. The fundamental hypothesis of the present study was that the temperature variations due to global climate change may affect seriously the future distribution and abundance of P. solenopsis, which might further aggravate the crop yield losses. We employed a temperature-based phenology model of P. solenopsis in a geographic information system for mapping population growth potentials of P. solenopsis. The three risk indices viz., establishment risk index, generation index and activity index were computed using interpolated temperature data from worldclim database for current (2000) and future (2050) climatic conditions. The daily minimum and maximum temperature data from four selected weather stations in India were used for analysing within-year variation of pest population. A linear relationship was established between the activity indices and yield losses at various locations reported in literatures for predicting the future trend of yield loss due to climate change. The results revealed that, under current temperature conditions P. solenopsis can complete >4.0 generations per year on ∼80% of the global cotton production areas. Economic losses are likely to occur in areas where at least 8.0 generations can develop in a year; under current climate ∼40% areas fall under this category. The increased geographical suitability at higher latitudes in cotton production areas, additional 2.0 generations per year, and 4.0 fold increase of population abundance of P. solenopsis are expected in tropical and sub-tropical cotton areas of Brazil, South Africa, Pakistan and India due to predicted climate change. Analysis of within year population increase at various selected locations in India revealed that, P. solenopsis attained maximum potential population increase during the major cotton growing season (May–June to October–November). On the other hand, the innate ability of P. solenopsis population to increase reduced considerably during off season and cooler winter months. The increased pest activity of P. solenopsis due to climate change may intensify the losses in cotton yield, with forecasted losses in India to increase from existing losses of million US$ 1217.10 to future losses of million US$ 1764.85 by the year 2050. Here, we illustrate the possible impact of climate change on future P. solenopsis exacerbation based on temperature-driven population studies, which will help in undertaking agro-ecoregion specific management strategies.