Evaluation of The Predatory Efficiency of Orius Albidipennis Reuter for Two Prey Species Myzus Persicae (Sulzer) and Thrips Tabaci Lind. on The Carrot Plant in Laboratory

Abstract

The study aimed to investigate the effect of different densities of M.persicae and T. tabaci on the predatory ability of the predator O. albidipennis and determine the preference for one of the two prey, in addition to assessing the in vitro predator's efficiency in reducing the number of aphids on the carrot plant. The results indicated that the rates of predated adult and nymph thrips were significantly higher than that of predated aphids. The highest rate of predation for nymphs and adults thrips was 33.2 and 25 preys per day, respectively, at a density of 60prey/container, while the highest rate of predation of adults and nymphs of aphids was 19 and 13.2prey/day, respectively, at a density of 60prey/container. The food preference experiment showed that the adults of the predator O. albidipennis feed on the immature stages thrips and aphids when introduced together and have no clear preference for one of the prey. The results of evaluating the efficiency of predator adults on reducing different densities of aphids showed that the predator was effectively able to reduce the population increase of aphids when the insect densities were 10, 20 or 30 insect. however, the predator was not effective when introduced to aphids at starting density of 40, no significant difference was found due to predator presence or absence as the aphids population density were 118.4 and 135.2 insects/cage after four days, respectively.

Predation Capacity of the Banded Thrips Aeolothrips intermedius for the Biological Control of the Onion Thrips Thrips tabaci

“…In fact, Mahendran and Radhakrishnan [ 37 ] observed that the commercialized Aeolothripidae predator Franklinothrips vespiformis larvae are able to prey on 12 Scirtothrips bispinosus (a Thripidae harmful for tea plantations) adults within 24 h. In our experiment, the prey ( T. tabaci adults) were administrated sequentially (three prey every three hours) in order to keep the prey/predator rate quite constant during the experiment. However, Khamis and Jabbar [ 38 ] and El-Sheikh et al [ 39 ] observed that the number of prey ( T. tabaci adults) killed by Orius albipennis was significantly correlated with the prey density varying from 10 to 25 prey per day for prey densities from 10 to 60 per predator. This indicates that under field working conditions with higher prey densities, A. intermedius could increase its predatory efficacy and be a very effective predator for the control of T. tabaci , with predation rates in line with other predators already commercialized ( F. vespiformis , Orius sp., and predatory mites).…”