Prediction of Aulacaspis Tubercularis Newstead (Hemiptera: Diaspididae) Populations Using RCP Scenarios in Luxor Governorate, Egypt

The present work was carried out to study the effect of some climatic factors on the population density of the white mango scale insect, Aulacaspis Tubercularis on mango trees during three time series (2011-2040, 2041-2070 and 2071-2100) under four Representative Concentration Pathway (RCP) scenarios (2.6, 4.5, 6.0 and 8.5) as compared with the current population of the pest (average of population density for two years of 2017 and 2018) at Esna district, Luxor Governorate, Egypt. Monthly estimations of total A. tubercularis population indicated the presence of four peaks of insect abundance per year. The means of solar radiation were entirely above the optimum range for activities of nymphs, adult females and total population of A. tubercularis and solar radiation was the most effective variables in population changes by 39.31, 39.38 and 43.50% for nymphs, adult females and total population of A. tubercularis during the base year data, respectively. The percentages of explained variance (E.V.%) indicated that the combined effect of these climatic factors viz., maximum temperature, minimum temperature and solar radiation were responsible for 82.37, 77.14 and 85.59 % of the population changes of nymphs, adult females and total population of this scale insect, respectively.

The obtained results revealed the all expected values for numbers of nymphs, adult females and total population of insect during the all different time series under all different RCPs scenarios were smaller in comparison to the current population of insect. Expected total population of insect will be smaller at time series of (2071-2100) as compared with the two-time series of (2011-2040) and (2041-2070) under the scenarios of RCPs (2.6, 4.5, 6 and 8.5). Also, the time series of (2071-2100) exhibited higher percentages of decreasing of the number of nymphs, adult females and total population with averages of (70.37, 48.38 and 60.33%, respectively) as compared to the time series of 2041-2070 (63.01, 47.10 and 55.74%) and the time series of 2011-2040 (56.04, 44.58 and 50.81%, respectively). Furthermore, the RCP 2.6 scenario exhibited the highest population density of nymphs, adult females and total population A. tubercularis and the lowest decreasing percentage for population density of different stages of A. tubercularis as compared with the other RCPs during all different time series.

Keywords: RCPs, Aulacaspis Tubercularis; Seasonal activity; Climate change scenarios; Mango