Comparative Biology of Carmine Spider Mite, Tetranychus Cinnabarinus Boisduval (Prostigmata: Tetranychidae) Infesting Marigold

The biology of carmine spider mite, Tetranychus cinnabiranus (Boisd.) on marigold worked out under laboratory conditions at 21 and 27°C, and 50 and 60% RH at Solan, Himachal Pradesh during August 2002 to June 2003. The results revealed that both sexes have three developmental stages (larva, protonymph and deutonymph) interrupted in between with a quiescent stage. The incubation period varied from 4.78±0.16 to 6.00±0.13 days during August to June and hatching percentage of eggs was maximum (80.97%) during April to June. The number of eggs laid by a single female varied from 48.7±1.67 to 57.70±1.34. The mean larval period was minimum during August to October (1.26±0.02 days) and maximum during mid February to April (1.56±0.04) days). There were two nymphal instars viz., protonymph and deutonymph and mean duration their varied from 1.49±0.03 to 2.36±0.07 and 1.56±0.04 to 2.72±0.06 days, respectively. The longevity of male and female varied from 11.20±0.25 to 14.50±0.37 and 15.20±0.25 to 19.45±0.39 days, respectively. The pre-oviposition, oviposition and post-oviposition periods varied from 1.50±0.17 to 2.35±0.12, 4.60±0.16 to 6.10±0.21 and 9.10±0.26 to 12.5±0.35 days, respectively. The sex ratio of male to female was found to be 1: 4.31, 1: 5.95 and 1: 5.5. The entire life span of male and female was 24.12±0.33 and 29.07±0.28 days during August to October, 29±0.36 and 33.59±0.40 days during mid February to April, and 20.5±0.25 and 24.46±0.30 days during April to June.