POPULATION DENSITY OF THE MAIN MEALYBUG SPECIES ATTACKING MANGO TREES AND THEIR ASSOCIATED PREDATORY INSECTS AT MANSOURA REGION

Abstract

The present studies were carried out in the experimental farm belonging to the Faculty of Agriculture, Mansoura University to evaluate the population density of the main mealybug species attacking mango trees (Mangifera indica L.), and their the seasonal activity of the main associated predatory insects. Also the interaction between these insect pests and their associated predatory insects in two successive years 2013/14 and 2014/15. The highest peak of Icerya aegyptiaca was recorded in the first week of November 2013 (67 indiv.) during the first year and in the fourth week of September 2015 (59 indiv.) during the second year. Icerya seychellarum recorded the highest peak in the third week of November 2013 during the first year and in the first week of November 2014 in the second year and represented by 496 and 516 indiv., respectively. While, the highest peak of Planococcus citri was found in the third week of July 2014 (156 indiv.) and in the fourth week of September 2015 (281 indiv.) during the two successive years, respectively. Moreover, the obtained results showed that Macnollicoccus hirsutus had the highest peak in the fourth week of August 2014 (191 indiv.) during the first year and in the second week of August 2015 (227 indiv.) in the second year. The highest peak of Rodolia cardinalis in the first week of November 2013 and represented by 84 and 93 indiv. for the two successive years 2013/14 and 2014/15, respectively. Chrysoperla carnea had the highest peak in the second week of August 2014 (37 indiv.) in the first year and in the end of the second year (43 indiv.). While, the highest peak of Nephus includens was found in the second week of August 2014 (22 indiv.) and in the second week of September 2015 (29 indiv.) for the two successive years, respectively. Meanwhile, the highest peak of Scymnus coccivora showed in the second week of August 2014 and 2015 for the two successive years and represented by 29 and 25 indiv., respectively. The highest average number of the main predatory insects were recorded in autumn and summer seasons and were coincided with the highest average number of the mealybug species during the two successive years 2013/14 and 2014/15. A highly positive significant effect were recorded between the highest abundant of the mealybug species as I. seychellarum and P. citri and the highest abundant predatory insects as R. cardinalis and C. carnea during the two successive years.