<div>Backgound: The black ladybird beetle, Stethorus sp. is a generalist predator whose larvae and adult prey on all developmental stages of the two-spotted red spider mite, Tetranychus urticae Koch. In order to develop a bological control program of T. urticae in the Mekong Delta of Vietnam , the predaotry efficacy of Stethorus sp. on T. urticae had been investigated. 
 
Methods: The investigation was conducted under the laboratory and net-house conditions at the College of Agriculture, Can Tho University. 
 
Result: Under laboratory conditions, fourth instar larvae exhibited the highest predation rate, while second instar larvae showed the lowest. Second instar larvae consumed an average of 65.63 eggs, 26.13 larvae, or 22.38 adults per day. In contrast, fourth instar larvae consumed 183.63 eggs, 88.63 larvae, or 73.63 adults per day. Adult female beetles consumed 149.38 eggs, 75.63 larvae, or 46.5 adults per day, while adult males showed lower consumption rates of 88 eggs, 62.25 larvae, or 36.13 adults per day. Under net house conditions, one pair of black ladybird beetles provided optimal control of the two-spotted red spider mites at a density of 56 mites per plant, with a control efficacy of 97.07 percent at 5 days post-release. At a red spider mite density of 168 individuals per plant, 4 and 6 pairs of black ladybird beetles demonstrated superior control efficacy of 93.02 percent and 99.54 percent respectively at 5 days post-release. 
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Predatory Efficacy of the Black Ladybird Beetle, Stethorus sp. against the Two-spotted Red Spider Mite, Tetranychus urticae Koch on Rose Plants

Background: Investigation of predatory traits, which are mostly unexplored, such as prey consumption, reproduction rate and searching propensity, could offer crucial information for the selection of creative control agents.&nbsp; 
 
Methods: In this study, two sets of experiments were carried out, the first set of which was intended to assess the effectiveness of the search and the second set for the functional response.&nbsp; 
 
Result: The intake of T. urticae by S. pauperculus, Oligota sp. and A. longispinosus dramatically increased as predator density increased from one to eight, according to research on searching efficiency. However, when predator number increased, prey consumption per predator declined. The amount of prey consumed by the larvae did not increase despite the prey density quadrupling. Prey consumption by predators increased as prey density increased, while prey consumption as a percentage dropped as prey density increased, according to a functional response. When the number of prey increased from 50 to 800, the area where predators were discovered reduced.

Assessment of Searching Efficiency and Functional Response of Acarophagous Species against Red Spider Mite, Tetranychus urticae Koch (Acari: Tetranychidae)