Counteraction effect between Tetranychus urticae Kochand Eotetranychus lewisi (McGregor) on strawberry
Paramjit Kaur and Frank G Zalom
The competitive interaction of Tetranychus urticae Koch and Eotetranychus lewisi (McGregor) on strawberry was studied at different temperatures (15, 20 and 25 °C). The results showed that the T. urticae was dominant on E. lewisi on strawberry. The total population emerged of T. urticae (2.33 at 15 °C; 89.00 at 20 °C; 101.00 at 25 °C) was more as compared to E. lewisi (1.67 at 15 °C; 14.67 at 20 °C; 19.67 at 25 °C) on strawberry. In contrast to strawberry, the population of E. lewisi was found to be significantly dominant on T. urticae on castor bean leaf. The population of T. urticae was 5.13, 6.07 and 1.39 times greater than E. lewisi at 25, 20 and 15 °C, respectively on strawberry. Three conclusions were made from the recorded competitive interactions between these mites: the preferred host for T. urticae is strawberry; E. lewisi can survive better than T. urticae at low temperatures if a favourable host is available, and T. urticae is dominant compared to E. lewisi on strawberry. E. lewisi completed its life cycle on strawberry leaves and it increased in abundance, so its pest status potential in strawberry cultivation was confirmed.