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Simple Summary: The tarnished plant bug, Lygus lineolaris, is a major pest in eastern Canada strawberry fields. The objective of the present study was to evaluate the potential of two omnivorous predators of the pest: the damsel bug, Nabis americoferus, and the minute pirate bug, Orius insidiosus. The results in the laboratory showed that N. americoferus attacked all stages of the tarnished plant bug and, in the field, reduced its population for several weeks. Additionally, the impact was significant for every tested release period. Conversely, O. insidiosus only attacked smaller nymphs, and its effect was marginal. These results lead the way for an effective biological control strategy based on the use of N. americoferus against the tarnished plant bug. The tarnished plant bug, Lygus lineolaris, is a major strawberry pest. Only marginally effective control methods exist to manage this pest. Various predators attack L. lineolaris, but their potential is overlooked. In this study, we explore the potential of two omnivorous predators of the tarnished plant bug: the damsel bug, Nabis americoferus, and the minute pirate bug, Orius insidiosus. Firstly, the predation rate of these predators was measured in laboratory tests. Secondly, their potential release rates and release periods were determined in the field using strawberry plants. The results show that N. americoferus feeds on all nymphal stages and adults of the tarnished plant bug, while O. insidiosus attacks only smaller nymphs (up to the N2 stage). In the field, all tested densities of N. americoferus (0.25, 0.5, and 0.75 individual/plant) reduced the population of the tarnished plant bug for several weeks compared with the control treatment, but the effect of O. insidiosus alone was marginal. Additionally, for all the release periods tested, Nabis americoferus was efficient in reducing the pest population. These results demonstrate the potential of N. americoferus to control the tarnished plant bug in strawberry fields. We discuss the possible application of these results for establishing an effective and economically viable biological control strategy. [ABSTRACT FROM AUTHOR]

The effectiveness of predators in suppressing prey populations is known to be influenced by the predator-prey release ratio. The efficacy of Neoseiulus cucumeris (Oudemans) against Frankliniella occidentalis (Pergand) in the presence or absence of Tetranychus urticae Koch and Phytoseiulus persimilis Athias-Henriot on rose plants was evaluated in the present study. The decrease of F. occidentalis populations was compared at the six predator:prey ratios of 1:2, 1:5, 1:10, 1:20, 1:50, and 1:100 in the laboratory, and at the three release rates of 20, 40, and 100 predators per m2 in microcosm conditions. The plants without predators were considered as controls. All treatments with the release of N. cucumeris resulted in a significant decrease in F. occidentalis larval population compared to the control. The most suppression (84.5%) of F. occidentalis larvae was observed in the release rate of 100 adults of N. cucumeris per m2 in 30 days after the release of the predator. Predator ratios of 1:2 and 1:5 of N. cucumeris: F. occidentalis resulted in a 94.6 and 93.4% decrease in F. occidentalis larvae after 24 hours, respectively. The presence of T. urticae (as a competitor herbivore) and P. persimilis had no effect on the efficiency of N. cucumeris in the suppression of F. occidentalis. The dense webs of T. urticae decreased the efficiency of N. cucumeris at predator:prey ratios of 1:5 and 1:10 more than1:2. This study showed that the release of 100 adults of N. cucumeris per m2 would be sufficient to control F. occidentalis larvae on rose plants. Moreover, we demonstrated that higher release rates of N.cucumeris are needed when T. urticae's dense webs are present. [ABSTRACT FROM AUTHOR]

Abstract Background Typhlodromus setubali Dosse (Acari: Phytoseiidae) is an indigenous predatory mite in Morocco. This study aimed to evaluate its efficacy, through 3 release rates on 2 apple varieties, namely Skarlet and Golden delicious, with different initial densities of the European red spider mite, Panonychus ulmi Koch (Acari: Tetranychidae). Results The efficacy of the predator was significantly influenced by the initial P. ulmi density. Furthermore, the release rate of 50 individuals/tree did not provide effective control of P. ulmi. When it was released at 100 and 200 individuals per tree, T. setubali maintained the P. ulmi population below the economic threshold of 5 motile stages per leaf. Conclusions When the initial P. ulmi density is above the economic threshold, the lower release rate of T. setubali must be applied with high frequency or conciliated with a selective miticide treatment at a suitable dose for a successful biological control program. Further field-based studies are needed for perfect conclusions.

The tarnished plant bug, Lygus lineolaris, is a major strawberry pest. Only marginally effective control methods exist to manage this pest. Various predators attack L. lineolaris, but their potential is overlooked. In this study, we explore the potential of two omnivorous predators of the tarnished plant bug: the damsel bug, Nabis americoferus, and the minute pirate bug, Orius insidiosus. Firstly, the predation rate of these predators was measured in laboratory tests. Secondly, their potential release rates and release periods were determined in the field using strawberry plants. The results show that N. americoferus feeds on all nymphal stages and adults of the tarnished plant bug, while O. insidiosus attacks only smaller nymphs (up to the N2 stage). In the field, all tested densities of N. americoferus (0.25, 0.5, and 0.75 individual/plant) reduced the population of the tarnished plant bug for several weeks compared with the control treatment, but the effect of O. insidiosus alone was marginal. Additionally, for all the release periods tested, Nabis americoferus was efficient in reducing the pest population. These results demonstrate the potential of N. americoferus to control the tarnished plant bug in strawberry fields. We discuss the possible application of these results for establishing an effective and economically viable biological control strategy.

Background: Typhlodromus setubali Dosse (Acari: Phytoseiidae) is an indigenous predatory mite in Morocco. This study aimed to evaluate its efficacy, through 3 release rates on 2 apple varieties, namely Skarlet and Golden delicious, with different initial densities of the European red spider mite, Panonychus ulmi Koch (Acari: Tetranychidae). Results: The efficacy of the predator was significantly influenced by the initial P. ulmi density. Furthermore, the release rate of 50 individuals/tree did not provide effective control of P. ulmi. When it was released at 100 and 200 individuals per tree, T. setubali maintained the P. ulmi population below the economic threshold of 5 motile stages per leaf. Conclusions: When the initial P. ulmi density is above the economic threshold, the lower release rate of T. setubali must be applied with high frequency or conciliated with a selective miticide treatment at a suitable dose for a successful biological control program. Further field-based studies are needed for perfect conclusions. [ABSTRACT FROM AUTHOR]

Spider mites lead to significant damage in the areas where apple is produced. Chemical control is generally preferred in the control of spider mites and other pests in Turkey. Today, many negative aspects of chemical control have turned up. Spider mites have a lot of natural enemies and knowing their activities is important. Neoseiulus californicus (McGregor, 1954) (Acari: Phytoseiidae) is a predator species which is used to control against spider mites. In this study, activities and release ratio of predator N. californicus that is control against spider mites in apple orchards are determined. For this purpose, two different experiments were established in two different apple orchards in Çavundur village and Alcıklar neighborhood in Şarkikaraağaç district of Isparta province. The study was established according to random trial parcels. 25, 50 or 100 predatory mites (NC) were released per tree in parcels. No application has been used for control. In the orchards located in Çavundur village where N. californicus has been relased, control, 25, 50 and 100 NC/tree in 63rd day, 10.31, 2.58, 1.96, 1.69 spider mite moving stages (ms)/leaf and 8.09, 1.11, 0.66 and 1.16 egg/leaf have been found. In Alcıklar neighborhood, control, 25, 50 and 100 NC/tree release 63rd day 4.53, 1.02, 0.49, and 0.49 ms/leaf and in the same order 3.11, 0.67, 0.36 and 0.31 egg/leaf has been detected. Finally, As a result, red spider populations were suppressed at different times compared to the control in all treatments. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Meyrick) is a key insect pest of tomato crop causing major economic losses worldwide. Biological control using Trichogramma parasitoids is considered a promising, eco-friendly management tactic of this pest. We performed inundative releases of Trichogramma cacoeciae (Marchal) (Hymenoptera: Trichogrammatidae) against T. absoluta in Takelsa (northeastern Tunisia). Three weekly releases of either (i) 10, 20 or 30 Trichogramma per plant in protected (greenhouse) tomato crops or (ii) 20 or 40 Trichogramma per plant in open field tomatoes were evaluated for their effectiveness. Results indicated that 20 Trichogramma per plant was the most effective release rate in significantly decreasing the pest's life stage densities. Parasitism rates were significantly higher on apical tomato leaves (estimated at 58.6% for the rate 20 Trichogramma per plant in greenhouses and at about 56% for the rate 40 Trichogramma per plant in open field) compared to those observed on middle leaves (24.6% and 45.26% for rate 2 respectively under greenhouse and open field conditions). Furthermore, the overall number of T. absolua eggs and larvae was significantly reduced after releases of Trichogramma parasitoids. These results clearly indicate that T. cacoeciae could be a promising biocontrol agent of T. absoluta in the largest tomato-producing area in Tunisia. [ABSTRACT FROM AUTHOR]

Nesidiocoris tenuis Reuter (Het.: Miridae) is widely used as a biological control agent of whiteflies and other pests in greenhouse-grown tomatoes. It is typically released augmentatively some weeks after transplanting and needs several weeks to establish. Releasing N. tenuis prior to transplanting could accelerate its establishment. However, timing for releases could affect biological control and require changes in release rates of the predator. Because N. tenuis is also phytophagous it must be released at a rate which provides the best equilibrium between adequate biological control of Bemisia tabaci Genn. and acceptable injury to the crop. The objective of this study was therefore to evaluate different release rates for releasing N. tenuis prior to transplanting for maximizing control capacity and minimizing injury to crop. The study was carried out in two subsequent trials in which different release rates were evaluated under a worst case scenario of rapid immigration of the pest into a tomato greenhouse. In the first experiment (winter experiment), four treatments were compared: (1) B. tabaci (0 N. tenuis/plant), (2) B. tabaci + 0.5 N. tenuis/plant, (3) B. tabaci + 1 N. tenuis/plant and (4) B. tabaci + 2 N. tenuis/plant. In the second experiment (summer experiment), the treatments were: (1) B. tabaci (0 N. tenuis/plant), (2) B. tabaci + 0.5 N. tenuis/plant and (3) B. tabaci + 1 N. tenuis/plant. All the evaluated rates significantly reduced the population of whitefly and gave adequate control of the pest. However, only 0.5 N. tenuis/plant did not increase crop damage compared to the treatment with no N. tenuis. [ABSTRACT FROM AUTHOR]

Bemisia tabaci Genn. (Hemiptera: Aleyrodidae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are major pests in greenhouse grown cucumber crops. Recently, Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) was shown an effective biological control agent of both pests. Hence, perhaps both pests can be controlled simultaneously by this predator. However, with simultaneous infestation of both pests, synergistic effects, or interference could affect biological control and perhaps require changes in release rates of the predator. Thus, the aim of the present study was to evaluate different release rates of A. swirskii to control both pests under a worst case scenario of rapid immigration into a cucumber greenhouse. Two experiments were conducted, one simulating the influx of whiteflies alone (whitefly experiment) and the other immigration of whiteflies and thrips together (whitefly plus thrips experiment). Three treatments were compared in the whitefly experiment: (1) B. tabaci alone, (2) B. tabaci + 25 A. swirskii m and (3) B. tabaci + 75 A. swirskii m. The high release rate was more effective than the low rate in controlling B. tabaci alone. The high rate was subsequently tested against B. tabaci and F. occidentalis for the whitefly and thrips experiment in which five treatments were compared: (1) B. tabaci alone, (2) F. occidentalis alone, (3) B. tabaci + 75 A. swirskii m, (4) F. occidentalis + 75 A. swirskii m and (5) B. tabaci + F. occidentalis + 75 A. swirskii m. This rate of A. swirskii controlled whiteflies and thrips either alone or together. Therefore, 75 A. swirskii m should be an adequate rate for controlling both pests either alone or simultaneously in cucumber greenhouses. [ABSTRACT FROM AUTHOR]

Releases of Spalangia cameroni Perkins (Hymenoptera: Pteromalidae) were conducted every second week from mid-April and up to October 2001, on four organic dairy cattle farms in Denmark to test the efficacy of this wasp as a biological control agent against house flies and stable flies. Season-long parasitism of sentinel house fly pupae averaged 32.7 and 35.8%, in two release farms versus 8.4 and 9.8%, in two control farms. Compared with the controls, the mean density of house flies and stable flies per animal was distinctly suppressed due to S. cameroni releases in the period August–September of normal peak abundance of flies. A positive correlation between temperature and parasitism was found; suggesting that temperature partially explains the discrepancy observed between an apparent suppression of flies and a relatively low overall percentage of parasitism. Expressed as a percentage of the total number of adult parasitoids recovered from the four dairies, S. cameroni was most abundant (80.5–93.1%). From early summer and onwards Muscidifurax raptor Girault and Sanders (4.0–6.0%) occurred frequently along with Spalangia nigripes Curtis (0.8–8.5%), Pachycrepoideus vindemiae (Rondani) (<5.0%), and Phygadeuon fumator Gravenhorst (Hymenoptera: Ichneumonidae) (0.3–6.9%). Based on the results, the cost of fly control achieved using S. cameroni and the future prospects for biological control of flies, are discussed. [Copyright &y& Elsevier]