Predatory mite Amblyseius orientalis prefers egg stage and low density of Carpoglyphus lactis prey.

Amblyseius orientalis (Ehara) (Acari: Phytoseiidae) is an effective predatory mite for spider mite control on fruit trees in China. In recent decades, it has been produced massively at a commercial natural enemy producer, feeding on the storage mite Carpoglyphus lactis (L.). In the predator production process, the ratio of predatory mites to their prey was found to be critical for the population increase of A. orientalis in large-scale rearings. In this study, we investigated the predatory capacity of A. orientalis on various developmental stages of the prey C. lactis, and the effect of prey numbers on predator reproduction. The maximum predation rate of A. orientalis adults on C. lactis adults was 2.21 per day at the lowest density of five prey adults, and on C. lactis eggs it was 45.07 at the highest density of 60 prey eggs. The preference index Ci of A. orientalis on C. lactis eggs and adults was 0.4312 and - 0.9249, respectively, suggesting that A. orientalis preferred eggs to adults. Amblyseius orientalis could reproduce when it preyed on either eggs or deutonymphs of C. lactis. However, the fecundity of the predatory mites is not always proportional to the provided prey number. Higher density of prey deutonymphs resulted in lower fecundity, whereas more prey eggs resulted in higher fecundity of A. orientalis. Therefore, our study indicated that the choice of suitable density and developmental stage of prey can significantly improve A. orientalis production on a large scale.

Orius similis (Hemiptera: Anthocoridae): A Promising Candidate Predator of Spodoptera frugiperda (Lepidoptera: Noctuidae).

The bug Orius similis Zheng is a native generalist predator of insect pests in southern China. The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a notorious defoliator that is now an economically important insect pest throughout China. To investigate the ability of O. similis to control FAW, we evaluated the predatory capacity, behavior, and functional response of O. similis with respect to FAW and their olfactory response. Both females and males successfully preyed on FAW eggs and first-instar larvae but not on second-instar or older larvae. Adult O. similis only attacked and killed one egg or one larva at a time before sucking the prey, and similar predatory behavior was also observed with regard to FAW egg masses. Both female and male O. similis exhibited type II functional response when preying on FAW eggs and first-instar larvae. Maximum estimated prey consumed per day was 23.7 eggs and 26.2 larvae for adult females and 22.5 eggs and 19.6 larvae for adult males. Moreover, in a Y-tube olfactometer experiment, both female and male O. similis exhibited a significant preference for maize (Zea mays L.) seedlings damaged by FAW over clean air, healthy seedlings, FAW feces, and FAW, suggesting that seedlings damaged by FAW may releases specific volatiles attracting the predator. Collectively, the results of the study suggest that O. similis is a promising candidate for the biological control of FAW eggs and first-instar larvae, particularly given its attraction to FAW-damaged leaves, which may enable it to locate the target prey rapidly.

Efficiency of biological control for fall armyworm resistant to the protein Cry1F / Eficiência do controle biológico da lagarta-do-cartucho resistente à proteína Cry1F

Abstract Understanding the ecological and toxicological relationship between genetically modified cultivars (GM) and biological control agents is of great importance for discussions related to the compatability of GM cultivars and integrated management strategies for pest resistance. The present study evaluated the search behavior and predatory capacity of Orius insidiosus (Say) (Hemiptera: Anthocoridae) and Doru luteipes (Scudder) (Dermaptera: Forficulidae) on eggs and caterpillars of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistant or not to the protein Cry1F expressed in Bt corn. To determine the search time, a stopwatch was run until the capture of the first prey, predation capacity was evaluated by counting the prey remaining after 24 hours of infestation. The injuries of S. frugiperda in genetically modified and conventional corn in the presence and absence of predators was also evaluated. The predators were not able to distinguish between resistant and susceptible prey (eggs or caterpillars), given the predatory behaviour observed. There was no difference in searching time or predatory capacity between the predators for eggs and caterpillars of either resistant or susceptible S. frugiperda. In the presence of predators, the injury scores for resistant S. frugiperda on the Bt corn plants were lower. It was concluded that O. insidiosus and D. luteipes did not notice the presence of the protein Cry1F in the prey S. frugiperda, which may facilitate the combined use of GM corn and biological control in integrated management programs and for management of pest resistance.

Resumo O entendimento de relações ecológicas e toxicológicas envolvendo culturas geneticamente modificadas (GM) e agentes de controle biológico é de grande importância para discussões relativas à compatibilidade de culturas GM com estratégias de manejo integrado e manejo de resistência de pragas. Este trabalho avaliou o comportamento de busca e a capacidade predatória de Orius insidiosus (Say) (Hemiptera: Anthocoridae) e Doru luteipes (Scudder) (Dermaptera: Forficulidae) sobre ovos e lagartas de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistente ou não à proteína Cry1F expressa em milho Bt. Para determinar o tempo de busca foi utilizado um cronômetro que foi disparado até a captura da primeira presa; a capacidade de predação foi avaliada através da contagem das presas remanescentes 24 h após infestação. Também foram avaliadas as injúrias de S. frugiperda em milho transgênico e milho convencional na presença ou ausência dos predadores. Os predadores não foram capazes de distinguir entre presas (ovos ou lagartas) resistentes e suscetíveis, considerando os comportamentos predatórios avaliados. Não houve diferença no tempo de busca e capacidade predatória sobre ovos e lagartas de S. frugiperda resistente ou suscetível entre os predadores. Na presença dos predadores, as notas de injúria de S. frugiperda resistente nas plantas de milho Bt foram menores. Conclui-se que O. insidiosus e D. luteipes não percebem a presença da proteína Cry1F na presa S. frugiperda, o que pode contribuir para o uso integrado de milho GM e controle biológico em programas de manejo integrado e manejo de resistência de pragas.

Treating green pea aphids, Myzus persicae, with azadirachtin affects the predatory ability and protective enzyme activity of harlequin ladybirds, Harmonia axyridis.

As a natural enemy of green peach aphids, harlequin ladybirds, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), are also indirectly affected by azadirachtin. In this study, we evaluated the effects of ladybird exposure to azadirachtin through azadirachtin-treated aphids. About 2 mg/L azadirachtin treated aphid can deliver the azadirachtin to ladybird larvae in 12 and 24 h. And azadirachtin treatment affected the rate at which fourth instar larvae and adult ladybirds preyed on aphids. Furthermore, the antifeedant effect increased with increasing azadirachtin concentrations. Twelve hours after exposing fourth instar ladybird larvae to aphids treated with 10 mg/L azadirachtin, the antifeedant effect was 47.70%. Twelve hours after exposing adult ladybirds to aphids treated with 2 mg/L azadirachtin, the antifeedant effect was 67.49%. Forty-eight hours after exposing ladybird larvae to azadirachtin-treated aphids, their bodyweights were 8.37 ± 0.044 mg (2 mg/L azadirachtin), 3.70 ± 0.491 mg (10 mg/L azadirachtin), and 2.39 ± 0.129 mg (50 mg/L azadirachtin). Treatment with azadirachtin affected the ability of ladybirds to prey on aphids. The results indicated that the instant attack rate of ladybird larvae and adults and the daily maximum predation rate were reduced by azadirachtin treatment. Superoxide dismutase (SOD), peroxidase (POD), and peroxide (CAT) enzyme activities of ladybirds were affected after feeding on aphids treated with azadirachtin. Azadirachtin has certain antifeedant effects on ladybirds and affects the ability of ladybirds to prey on aphids and the activities of SOD, POD, and CAT enzymes, which results in inhibition of normal body development.

Efficiency of biological control for fall armyworm resistant to the protein Cry1F

Abstract Understanding the ecological and toxicological relationship between genetically modified cultivars (GM) and biological control agents is of great importance for discussions related to the compatability of GM cultivars and integrated management strategies for pest resistance. The present study evaluated the search behavior and predatory capacity of Orius insidiosus (Say) (Hemiptera: Anthocoridae) and Doru luteipes (Scudder) (Dermaptera: Forficulidae) on eggs and caterpillars of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistant or not to the protein Cry1F expressed in Bt corn. To determine the search time, a stopwatch was run until the capture of the first prey, predation capacity was evaluated by counting the prey remaining after 24 hours of infestation. The injuries of S. frugiperda in genetically modified and conventional corn in the presence and absence of predators was also evaluated. The predators were not able to distinguish between resistant and susceptible prey (eggs or caterpillars), given the predatory behaviour observed. There was no difference in searching time or predatory capacity between the predators for eggs and caterpillars of either resistant or susceptible S. frugiperda. In the presence of predators, the injury scores for resistant S. frugiperda on the Bt corn plants were lower. It was concluded that O. insidiosus and D. luteipes did not notice the presence of the protein Cry1F in the prey S. frugiperda, which may facilitate the combined use of GM corn and biological control in integrated management programs and for management of pest resistance.

Resumo O entendimento de relações ecológicas e toxicológicas envolvendo culturas geneticamente modificadas (GM) e agentes de controle biológico é de grande importância para discussões relativas à compatibilidade de culturas GM com estratégias de manejo integrado e manejo de resistência de pragas. Este trabalho avaliou o comportamento de busca e a capacidade predatória de Orius insidiosus (Say) (Hemiptera: Anthocoridae) e Doru luteipes (Scudder) (Dermaptera: Forficulidae) sobre ovos e lagartas de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistente ou não à proteína Cry1F expressa em milho Bt. Para determinar o tempo de busca foi utilizado um cronômetro que foi disparado até a captura da primeira presa; a capacidade de predação foi avaliada através da contagem das presas remanescentes 24 h após infestação. Também foram avaliadas as injúrias de S. frugiperda em milho transgênico e milho convencional na presença ou ausência dos predadores. Os predadores não foram capazes de distinguir entre presas (ovos ou lagartas) resistentes e suscetíveis, considerando os comportamentos predatórios avaliados. Não houve diferença no tempo de busca e capacidade predatória sobre ovos e lagartas de S. frugiperda resistente ou suscetível entre os predadores. Na presença dos predadores, as notas de injúria de S. frugiperda resistente nas plantas de milho Bt foram menores. Conclui-se que O. insidiosus e D. luteipes não percebem a presença da proteína Cry1F na presa S. frugiperda, o que pode contribuir para o uso integrado de milho GM e controle biológico em programas de manejo integrado e manejo de resistência de pragas.

Laboratory evaluation of Mesocyclops aspericornis as a biocontrol agent of Aedes aegypti.

Mesocyclops aspericornis abounds in village ponds. Hence, the predatory capacity of M. aspericorniswas considered for use as a biological control agent for Aedes aegypti mosquitoes. In laboratoryexperiments, M. aspericornis consumed 33–50 mosquitoe larvae within 24-hours time period. M.aspericornis preyed upon only the first instar larvae of Ae. aegypti within a few seconds after theirintroduction. It started feeding on the tail portion first and ended with the head capsule. The meanvalue (triplicate) showed that the predatory capacity was 45.76 against the control 1.2. M. aspericornisprefers only the first instar mosquitoe larvae and feeds on them voraciously. When the Aedes larvaeattained the second instar stage, M. aspericornis attacked and killed them.

Evaluación de Macrocyclops albidus (J.) para el control larval de Aedes aegypti (L.) bajo condiciones de laboratorio en Cuba / Evaluation of Macrocyclops albidus (J.) for the Aedes aegypti (L.) larval control under laboratory conditions in Cuba

Se realizaron colectas en 4 localidades del país, con el propósito de evaluar la capacidad depredadora de copépodos ciclópodos sobre larvas de Aedes aegypt (L.), los especimenes fueron identificados como Macrocyclops albidus (J.) (Copepoda: Cyclopoida). Bajo condiciones de laboratorio, se evaluó la capacidad depredadora de un copépodo al cabo de 24 h sobre 50 larvas recién eclosionadas en placas de Petri; también se probaron diferentes densidades de copépodos (25, 50, 100) ante 300 larvas, en recipientes plásticos. Ma. albidus demostró ser un depredador activo de larvas de Ae. aegypti, con una media de depredación de 23,51 a las 24 h. La densidad de 25 copépodos por recipiente resultó insuficiente para lograr un buen control con altas densidades larvarias (media de supervivencia larvaria= 20,9), con 50 copépodos se logró una reducción significativa de larvas (media= 7) y mediante la prueba Duncan (p< 0,01) se demostró que la cantidad de 100 copépodos fue suficiente para depredar la casi totalidad de las larvas con una media= 1,4. Se recomendaron estudios posteriores para evaluar la eficacia de los copépodos como agentes de control biológico en condiciones naturales.

With the purpose of evaluating the predatory capacity of cyclopoid copepods on larvae of Aedes aegypti (L.), collections were made in four localities of the country. The specimens were identified as Macrocyclops albidus (J.) (Copepoda: Cyclopoida). Under laboratory conditions, the predatory capacity of a copepod was evaluated after 24 hours on 50 larvae newly hatched in Petri´s plates. Different copepods densities were also tested (25, 50, 100) on 300 larvae in plastic recipients. Ma. albidus showed to be an active predator of Ae. aegypti larvae with a predatory mean of 23.51 at 24 hours. The density of 25 copepods for recipient was insufficient to achieve a good control with high larvae densities (mean larvae survival = 20.9). A significant reduction of larvae was achieved (survival mean = 7) with 50 copepods by Duncan´s test (p <0.01). It was demonstrated that 100 copepods was enough to depredate almost the totality of the larvae with a mean = 1.4. Further studies were recommended to evaluate the effectiveness of the copepods as agents of biological control under natural conditions.