STUDY ON SOME BIOLOGICAL ASPECTS OF CITRUS MEALYBUG Planococcus citri Risso (Hemiptera :Pseudococcidae )IN LABORATORY.

Abstract

The lab. Studies on the biological aspects of mealybug Planococcus citri found that the female nymphal stage develops through three instars. The first is a wandering and called crawlers . This instar covered with wax after 2-3 days from feeding .In this instar it is hard to distinguish between male and female. The average of body length and width of this instar were 0.5 mm and 0.21 mm, respectively .It was also found that the growth period of the first instar was 5 days at 25±2 oC and 65 ±5% RH. The second nymphal instar was found the average ofbody length and width were 0.87 and 0.47 mm ,respectively ,while the average of growth period reached to 5.5 days. The body of 2nd instar is surrounded by waxy appendages , equal in length except the posterior pair was longer than the others . The 3rd nymphal instar is bigger than the second .The average of body length and width were 1.39 mm and 0.84 mm respectively,while the average of growth period reached to 5.5 days . The male nymphal stage passes through four nymphal instars .The wing buds could be seen at the second instar .The color of 2nd instar is brownish grey.This period of growth starts to sercted waxes filegment around the body. The length and width of the body averaged 0.82 mm and 0.36 mm,respectively ,and the average of growth period reached to 4.5 days. The average length and width of the body of the 3rd male nymphal instar were 0.98 mm and 0.30 mm ,respectively ,while the average period of this instar was 5.5 days. The 4th male nymphal instar, which is reddish brown in color with incomplete black wings .The average of length and width of the body were 1.11 mm and 0.36 mm ,respectively.while the average of growth period of this instar reached to 4.5 days. Adult male has apair of wings in the mesothorax and the average of length and width of the body were 1.13 mm and 0.24 mm ,respectively. The body length and width of adult female were 2.52 mm and 1.65 mm in average. . The female lay 431.31 eggs under the condition of 25 ± 2 oC and 65 ±5 RH .The average of length and width of egg were 0.31 mm and 0.18 mm,respectively .