Bemisia tabaci (Hemiptera: Aleyrodidae) biótipo B é uma das mais limitantes pragas do tomateiro no mundo. A produção do tomateiro é altamente dependente de inseticidas, ocasionando problemas ao produtor, consumidor e ambiente. Uma alternativa promissora para redução dos efeitos maléficos ocasionados pelo uso indiscriminado de inseticidas sintéticos são os inseticidas de origem botânica. Este trabalho objetivou avaliar o efeito de extratos aquosos a 3% (p/v) de diferentes estruturas de treze espécies botânicas no comportamento dos insetos adultos de B. tabaci biótipo B bem como sua atividade inseticida sobre ovos, ninfas e adultos do inseto em tomate. A água destilada foi utilizada como controle negativo e o inseticida tiametoxam (18 g/100 L de água) como controle positivo. O extrato à base de folhas de Toona ciliata foi o mais eficiente nos testes em que foram avaliados o efeito dos extratos sobre o comportamento da mosca-branca, diminuindo o número de insetos adultos e ovos em folíolos de tomateiro. O extrato de folhas de Piper aduncum apresentou o maior efeito ovicida (78,00% de ninfas não eclodidas), no entanto foi pouco efetivo sobre ninfas e adultos. Os extratos de folhas de Trichilia pallida, Trichilia casaretti e Toona ciliata apresentaram os maiores índices de controle (67,9; 60,3; 55,1%, respectivamente). Para adultos, T. pallida foi o mais eficiente (72,8%). Com base nos resultados, a aplicação dos extratos de T. pallida, T. ciliata e T. casaretti mostra-se promissora no manejo de infestações de B. tabaci biótipo B em tomateiro.

Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B is one of the most limiting pests of tomato crops in the world. Tomato yield is currently dependent on the use of pesticides, which are problematic to farmers, consumers and the environment. A promising alternative to reduce the harmful effects caused by the indiscriminated use of synthetic insecticides is the use of insecticides of botanical origin. This study aimed to evaluate the effect of 3% (w/v) aqueous extracts from different structures of thirteen botanical species on the behavior of B. tabaci biotype B adults, as well as insecticidal activity of such aqueous extracts on B. tabaci eggs, nymphs, and adults infesting tomato plants. A distilled water solution was used as a negative control, and thiamethoxam insecticide (18 g/100 L of water) as a positive control. Leaf extract of Toona ciliata was observed to have the most efficient inhibitory effect in tests of extracts on whitefly behavior. Furthermore, the use of leaf extract of Toona ciliata led to the most drastic reduction in the number of adults and eggs on tomato leaflets. Leaf extract of Piper aduncum led to the greatest observed ovicidal effect (78.00% of non-hatched nymphs); however it was not effective against nymphs and adults. The leaf extracts of Trichilia pallida, Trichilia casaretti, and Toona ciliata showed the highest control indexes (67.9, 60.3, and 55.1%, respectively). For adults mortality, T. pallida was the most effective (72.8%). Our results indicate that application of extracts of T. pallida, T. ciliata, and T. casaretti are promising strategies to manage B. tabaci biotype B on tomato.

Se evaluó la actividad larvicida del "matico" neotropical Piper tuberculatum. Los compuestos secundarios fueron extraídos de hojas, tallos y espigas maduras (con frutos y semillas) de plantas silvestres y de plantas in vitro de P. tuberculatum. Fue evaluada la toxicidad aguda de extractos de espigas maduras con frutos y semillas y de plantas in vitro de P. tuberculatum sobre el "cogollero" Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) mediante bioen-sayos de contacto. Solamente extractos Diclorometano:metanol (CH2Cl2:MeOH) (2:1) y etanólicos (EtOH) de espigas maduras y el extracto CH2Cl2:MeOH (2:1) de plantas in vitro mostraron niveles significativos de mortalidad. Los extractos CH2Cl2:MeOH (2:1) y EtOH de espigas maduras causaron 90% de mortalidad cuando dosis de 0,1850 mg/µL se aplicaron sobre S. frugiperda en 24 y 48 h de exposición, respectivamente. El extracto CH2Cl2:MeOH (2:1) de plantas in vitro causó 95% de mortalidad cuando dosis de 0,1850 mg/µL también se aplicaron en 48 h de exposición. Los mejores resultados para las espigas maduras fueron: CL50 0,001 mg/µL con EtOH y 0,007 mg/µL con CH2Cl2:MeOH (2:1) y CL90 0,027 mg/µL con EtOH y 0,103 mg/µL con CH2Cl2:MeOH (2:1); y en el caso de las plantas in vitro, solamente el extracto CH2Cl2:MeOH (2:1) fue: CL50 0,003 mg/µL y CL90 0,060 mg/µL. Se discute el valor potencial de los extractos de P. tuberculatum como un eficiente insecticida sobre S. frugiperda.

The larvicidal activity of the neotropical "matico" Piper tuberculatum was evaluated. The secondary compounds were extracted of leaves, stems and mature spikes with fruits and seeds from wild plants and in vitro plants of Piper tuberculatum. The acute toxicities to the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), of extracts of spikes with fruits and seeds and in vitro plants of P. tuberculatum were evaluated by means of contact bioassays. Only CH2Cl2:MeOH (2:1) and EtOH extracts of mature spikes and CH2Cl2:MeOH (2:1) extract from in vitro plants showed significant levels of larval mortality. The CH2Cl2:MeOH (2:1) and EtOH extracts of mature spikes caused 90% mortality when doses of 0.1850 mg/µL were applied to the S. frugiperda in 24 and 48 h of exposure, respectively. The CH2Cl2:MeOH (2:1) extract from in vitro plants caused 95% mortality when doses of 0.1850 mg/mg/µL were too applied in 48 h of exposure. The mature spikes test best results were: LD50 0.001 mg/µL with EtOH and 0.007 mg/mg/µL with CH2Cl2:MeOH (2:1) and LD90 0.027 mg/µL with EtOH and 0.103 mg/µL with CH2Cl2MeOH (2:1); and, in the case of in vitro plants, only CH2Cl2:MeOH (2:1) extract was: LD50 0.003 mg/µL and LD90 0.060 mg/µL. The potential value of extracts derived from P. tuberculatum as efficient insecticides against S. frugiperda is discussed.

The biocid action of DCM:MeOH (2:1), EtOH and aqueous extracts of leaves, stems and mature spikes (with fruits and seeds) of field plants and DCM:MeOH (2:1) extract of in vitro plants of Piper tuberculatum on III larval stage of Diatraea saccharalis was evaluated. The method was by inoculating the previously eluted extract with distillate water as topic applications on the larval mesothorax. Only DCM:MeOH and EtOH extracts of mature spikes and DCM:MeOH extract of in vitro plants showed significant levels of larval mortality. The corresponding highest toxic effect was (a) for mature spikes respect to in vitro plants and (b) EtOH extract respect to DCM:MeOH extract, according to the results showed for the lethal concentration to 50% (LC50) and 90% (LC90), in 72 hours of exposure. Thus, in the case of mature spikes was: LC50 0,11 mg/mL with EtOH and 0,16 mg/mL with DCM:MeOH) and LC90 (0,35 mg/mL with EtOH and 0,55 mg/mL with DCM:MeOH); and, in the case of in vitro plants, only with DCM:MeOH extract, was: LC50 0,39 mg/mL and LC90 2,62 mg/mL. The results of probit values-mortality lines showed the same tendency.

En el presente trabajo evaluamos la acción biocida sobre larvas del III estadío de Diatraea saccharalis, usando extractos acuoso, diclorometano-metanol (DCM:MeOH, 2:1) y alcohólico (EtOH, 96%) de hojas, tallos y espigas maduras (con frutos y semillas) de Piper tuberculatum, en larvas del III estadío. El método de inoculación del extracto, previamente eluido con agua destilada, fue de aplicación tópica en el mesotorax de las larvas. Solamente los extractos DCM:MeOH y EtOH de espigas maduras y extracto DCM:MeOH de plantas in vitro mostraron niveles significativos de mortalidad larval. El mayor efecto tóxico correspondió a extractos de espigas maduras respecto a plantas in vitro y a extracto EtOH respecto a extracto DCM:MeOH, tal como lo expresan los resultados de las concentraciones letales a 50% (CL50) y 90% (CL90), en 72 h de exposición. Así tenemos que en el caso de espigas maduras fue: CL50 (0,11 mg/mL con EtOH y 0,16 mg/mL con DCM:MeOH) y CL90 (0,35 mg/mL con EtOH y 0,55 mg/mL con DCM:MeOH); en el caso de plantas in vitro, unicamente con DCM:MeOH, fue: CL50 0,39 mg/mL y CL90 2,62 mg/mL. Los resultados de las rectas valores probitos-mortalidad expresaron la misma tendencia.