COMPARATIVE INCIDENCE AND ABUNDANCE OF APHIDS AND THEIR ASSOCIATED PREDATORS ON CANOLA IN PAKISTAN.

Aphids are the utmost common and predominant pest of oilseed brassica crops which caused 70-80% of losses in yield. So, a study was conducted to check the comparative incidence and abundance of canola aphids, Brevicoryne brassicae, Lipaphis erysimi and Myzus persicae. Results revealed that the incidence of all aphids appeared on the leaves and the inflorescences in 3^rd week of January and 2^nd week of February and continued till the harvesting of Faisal Canola variety. The per leaf peak population of L. erysimi, B. brassicae and M. persicae (17.66, 12.59 and 8.49, respectively) and per inflorescence (3.82, 2.93 and 2.19, respectively) was recorded. The highest mean population ranges 60.45-70.90/leaf and 8.24- 8.94/inflorescence were observed from 08-February to 01-March and 08-February to 05- March, respectively. The temperature range of 17.67-23.33°C was suitable for the development of aphids. Predator species, Chrysoperla carnea, Coccinella undecimpunctata, and Coccinella septempunctata were recorded while the population of aphids was adequately established on the canola variety. The population of all predators increased as an increase in the population and decreased as the population of aphids decline. The present study will be helpful to take precautionary measures for the management of canola aphids when reached at economic injury level (5 aphids/leaf) on canola crop. [ABSTRACT FROM AUTHOR]