Abstract

Experiments were carried out in the Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore during 2011 to study the biology of mealybugs viz., Paracoccus marginatus and Phenacoccus solenopsis infesting sunflower. The egg, first, second and third instar nymphal periods of P. marginatus were 6.33 ± 0.58, 4.00 ± 1.00, 3.67 ± 0.58 and 5.00 ± 1.00 days, respectively. Adult longevity of females and males were 20.33 ± 1.53 and 1.67 ± 1.15 days, respectively. Total life cycle of P. marginatus was 39.33 ± 2.53 days for females and 24.00 ± 1.73 days for males. The oviposition period was 7.33 ± 0.58 days and fecundity was 329.33 ± 20.03 eggs on sunflower seedlings. Egg period of P. solenopsis was very short with an average of 48.33 ± 7.64 minutes. Duration of first, second and third instars were 6.33 ± 1.15, 9.67 ± 0.58 and 6.00 ± 0.00 days respectively. Longevity of males was shorter by 1.33 ± 0.58 days compared to females (38.67 ± 3.06 days). Total life cycle of P. solenopsis was 60.67 ± 4.06 days for females and 30.33 ± 1.58 days for males. Oviposition period of adult female of P. solenopsis was 18.67 ± 0.58 days which was longer than for P. marginatus. Adult female of P. solenopsis recorded high fecundity with an average of 511.00 ± 131.73 eggs on sunflower seedlings.

Keywords: Sunflower, Paracoccus marginatus, Phenacoccus solenopsis, biology