RESUMEN. El nopalOpuntia ficus-indica se cultiva con diversos propósitos en el mundo, mientras que en México, principal productor y consumidor mundial, particularmente se consume como verdura (nopalitos). La producción de nopalitos se ubica, principalmente, en los alrededores de la Ciudad de México donde las cochinillas silvestres Dactylopius spp. son de los insectos más nocivos para el cultivo. El control químico es el método de más uso por los productores, aunque el control biológico podría ser útil para un manejo integrado de plagas. No obstante, los estudios taxonómicos sobre las especies de cochinilla y sus enemigos naturales en México no son abundantes. En esta investigación se planteó conocer las especies presentes de Dactylopius y sus enemigos naturales en Tlalnepantla, Morelos, una de las áreas de mayor producción de nopalitos en México. Se seleccionaron 30 sitios distribuidos en esta región y se establecieron cinco sitios para monitoreo de enemigos naturales cada dos semanas durante un año. La única especie de cochinilla silvestre del nopal que se encontró correspondió a Dactylopius opuntiae (Cockerell), los enemigos naturales en orden de abundancia fueron Leucopis bellula, Sympherobius barberi, Laetilia coccidivora, Hyperaspis trifurcata, Salpingogaster cochenillivorus, Sympherobius angustus y Chilocorus cacti. Se proporcionan descripciones de biología de los enemigos naturales en campo y laboratorio. Diversos factores relacionados con el manejo del cultivo tuvieron un efecto sobre las poblaciones de D. opuntiae y sus enemigos naturales.

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Spodoptera frugiperda (Smith) is the main maize pest in America and was recently detected as an invasive pest in some countries in Asia and Africa. Among its natural enemies presented in Mexico, Trichogramma pretiosum Riley is the only egg parasitoid used in Integrated Pest Management (IPM) programs regardless of its effectiveness. A search for natural enemies of S. frugiperda was then carried out to determine whether this parasitoid has been established, and to detect native egg parasitoids or predators associated with this pest. The sentinel technique (egg masses) was used, and then placed in maize and sorghum fields in the state of Guanajuato, Mexico. Trichogramma atopovirilia Oatman and Platner, an egg parasitoid, and Chelonus insularis Cresson egg-larva parasitoid were recovered from field surveys. Among the natural enemies that preyed on eggs of S. frugiperda, we found mites of the genus Balaustium, and Dermaptera of the genus Doru, both species in great abundance. Laboratory tests were performed to compare the potential parasitism of T. atopovirilia against T. pretiosum. T. atopovirilia obtained 70.14% parasitism while T. pretiosum, 29.23%. In field cages, three doses of the parasitoids were tested. Total parasitism did not exceed 8% in any of the two species, but T. atopovirilia parasitized a greater number of hosts using two and three parasitoids per pest egg. Then, the use of Trichogramma species needs to be reevaluated in biological control programs against S. frugiperda.

The synergistic mortality and improved fungal performance observed here support the hypothesis that combinations of low insecticide doses and entomopathogenic fungi can enhance integrated pest management programs and reduce the environmental impact of insecticides. Antagonism shows that some particular combinations and application sequences may produce disadvantages in pest control. © 2018 Society of Chemical Industry.

Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is one of the most economically important pests of potato, tomato, and peppers in Central America, Mexico, the United States, and New Zealand. Its control is based on the use of insecticides; however, recently, the potential of the eulophid parasitoid Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) for population regulation has been studied. Because T. triozae is likely to be exposed to insecticides on crops, the objective of this study was to explore the compatibility of eight insecticides with this parasitoid. The toxicity and residual activity (persistence) of spirotetramat, spiromesifen, beta-cyfluthrin, pymetrozine, azadirachtin, imidacloprid, abamectin, and spinosad against T. triozae adults were assessed using a method based on the residual contact activity of each insecticide on tomato leaf discs collected from treated plants growing under greenhouse conditions. All eight insecticides were toxic to T. triozae. Following the classification of the International Organization of Biological Control, the most toxic were abamectin and spinosad, which could be placed in toxicity categories 3 and 4, respectively. The least toxic were azadirachtin, pymetrozine, spirotetramat, spiromesifen, imidacloprid, and beta-cyfluthrin, which could be placed in toxicity category 2. In terms of persistence, by day 5, 6, 9, 11, 13, 24, and 41 after application, spirotetramat, azadirachtin, spiromesifen, pymetrozine, imidacloprid, beta-cyfluthrin, abamectin, and spinosad could be considered harmless, that is, placed in toxicity category 1 (<25% mortality of adults). The toxicity and residual activity of some of these insecticides allow them to be considered within integrated pest management programs that include T. triozae.

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