Influence of Varying Temperature on Life Stages of Chrysoperla carnea (Stephens) under Laboratory Conditions

Abstract

A laboratory study was conducted to evaluate the influence of different temperatures on life stages of Chrysoperla carnea (Stephens) on frozen eggs of Sitotroga crealella. The study was conducted under laboratory conditions at | department of Plant Protection, SAU, Tandojam Sindh, Pakistan during 2013-14. The result revealed that the maximum hatching 88 % of eggs was recorded at 28 ºC followed by 25, 31, 22, 34 and 37 ºC. The highest mortality (dx) was recorded in first instar at 34 ºC followed by at 22, 31, 37, 25 and 28 ºC, whereas, minimum (dx) was recorded in third instar and pupal stages as well. The highest and lowest apparent mortality (100qx) was observed in the first instar and egg stages at 37 ºC. The data further depicted that the highest survival fraction (Sx) was recorded as (0.98) in second instar, third instar and pupa at 28 ºC, whereas, the lowest (Sx) was observed as (0.13) in the first instar at 37 ºC. The maximum indispensable mortality (IM) was 42 in egg stage at 37 ºC and lowest 1.0 in pupal stage at all temperature regimes. The number of the surviving at the beginning of the stage (lx) was highest 39 adults emerged at 28 ºC followed by 31, 24, 20 and 5 adults emerged at 25, 31, 22 and 34 ºC, respectively. On the other hand, minimum total generation mortality (K) was recorded as 0.11 at 28 ºC followed by 0.21, 0.32, 0.40, and 1.00 at 25, 31, 22 and 34 ºC, respectively. The minimum duration from egg to adult emergence was 12.0 days at 34 ºC and maximum 23.5 days at 22 ºC. There was significant difference between the duration and treatments (P<0.05). It is concluded that the maximum mortality was recorded at 37 ºC in egg and first instar stages, no any stage was survived after second instar. The temperature ranges from 25 to 31 ºC have been proved suitable for the development of C. carnea.. However, 1st and 2nd instar survived for short period at 37 ºC only.