RESUMO. Avaliou-se a eficiência dos extratos etanólicos e hexânicos de graviola e pinha (EEG, EHG, EEP e EHP) sobre Aphis gossypii (Hemiptera: Aphididae) e seu inimigo natural Eriopis connexa (Coleoptera: Coccinellidae), com testes de contato, efeito residual e ingestão. As CL50 e CL99 estimadas para A. gossypii foram respectivamente, 0,39 e 5,47% para (EEP); 0,23 e 1,19% para (EEG); 0,47 e 4,39% para (EHP); 0,42 e 6,38% para (EHG). Na ação por contato, o EEG a 0,23% foi inócuo, o EHG a 0,42% foi levemente nocivo; para adultos apenas o EEP (5,47%), foi classificado como levemente nocivo e os demais tratamentos como inócuos, inclusive para o efeito residual. Quanto à seletividade por ingestão, as CL50 do EEG e EHG não interferiram na taxa de sobrevivência dos predadores, mas o EEP (0,39 e 5,47%) reduziu a zero essa taxa em menos de 7 dias, assemelhando-se ao tratamento químico Decis®. Os extratos reduziram o consumo de ovos da presa alternativa, diminuindo a capacidade predatória e, com isso, diminuiu na oviposição, afetando a fecundidade do predador e a viabilidade dos ovos. O EEG na concentração de 0,23% foi eficiente no controle de A. gossypii, e seletivo ao inimigo natural E. connexa, não interferindo na taxa de sobrevivência destes.

ABSTRACT. The effects of ethanolic and hexanic extracts of soursop and sugar apple (EES, EHS, EESA and EHSA, respectively) on Aphis gossypii (Hemiptera: Aphididae) and its natural enemy Eriopis connexa (Coleoptera: Coccinellidae) by contact exposure, residual effect and ingestion tests were evaluated. The estimated LC50 and LC99 values for A. gossypii were 0.39% and 5.47% for (EESA); 0.23% and 1.19% for (EES); 0.47% and 4.39% for (EHSA); and 0.42% and 6.38% for (EHS), respectively. Considering contact exposure, EES at 0.23% was innocuous, and EHS at 0.42% was slightly harmful; for adult ladybugs, only EESA (5.47%) was classified as slightly harmful, with the other treatments classified as harmless. The results were similar for the residual effect. For selectivity in ingestion tests, EES and EHS at the LC50 did not affect the survival rate of the predator, but EESA (0.39% and 5.47% for the LC50 and LC99, respectively) reduced the survival rate to zero in less than 7 days, resembling chemical treatment with Decis®. Extracts applied to the eggs of an alternative prey reduced the consumption of eggs and therefore the predatory capacity of the ladybug, which led to a decrease in oviposition, egg viability and ultimately a reduction in predator fecundity. EES at a concentration of 0.23% was effective in the control of A. gossypii and was selective and did not affect the survival rate of the its natural enemy E. connexa.

Se evaluó la eficiencia de varios extractos vegetales como controladores de la garrapata Rhipicephalus (Boophilus) microplus en condiciones de laboratorio. Hembras ingurgitadas se recolectaron de bovinos y se aislaron en cajas de petri. Se emplearon extractos orgánicos alcohólicos al 1% (p/v) de semillas de Annona muricata (Annonaceae), flores de Syzygium malaccensis (Myrtaceae), hojas de Cymbopogon citratus (Poaceae), hojas de Azadirachta indica (Meliaceae) y extracto hexánico de semillas de A. indica. El testigo consistió en hembras sin tratar y tratadas con agua destilada y esterilizada y dimetilsulfóxido (DMSO) a una concentración de 1%. El extracto de semillas de A. muricata mostró tener mayor poder acaricida, con 100% de eficiencia, seguido de los extractos de flores de S. malaccensis (75% y 57,25%) y semillas de A. indica (65% y 38,50%). Hubo 100% en la reducción de la eclosión de las larvas nacidas a partir de hembras tratadas con extracto de semillas de A. muricata.

The efficacy of various plant extracts in the control of Rhipicephalus (Boophilus) microplus was evaluated in the laboratory. Engorged females were collected from cattle and were isolated in Petri dishes. Organic alcoholic extracts at 1% (weight/volume) were used from seeds of Annona muricata (Annonaceae), flowers of Syzygium malaccensis (Myrtaceae), leaves of Cymbopogon citratus (Poaceae), leaves of Azadirachta indica (Meliaceae) and hexane extract 1% (weight/volume) of A. indica seeds. The control groups consisted of females either untreated or treated with distilled and sterile water and dimethylsulfoxide (DMSO) at a concentration of 1%. The extract of A. muricata seeds showed the highest acaricide power, with 100% efficacy, followed by flower extracts of S. malaccensis (75% and 57.25%) and seeds of A. indica (65% and 38.50%). There was a 100% reduction in the eclosion of larvae from eggs of females treated with the seed extract of A. muricata.

O objetivo deste trabalho foi avaliar os efeitos dos extratos etanólicos de Aspidosperma pyrifolium sobre lagartas da traça-das-crucíferas (Plutella xylostella). Os extratos etanólicos da casca do caule, do fruto e da raiz de A. pyrifolium foram obtidos pelos métodos fitoquímicos clássicos, e as subfrações resultantes foram testadas contra P. xylostella, nas dosagens 4 e 5 mg L-1. O extrato bruto etanólico da casca do caule foi mais letal. A subfração aquosa rica em alcalóides, derivada do extrato da casca do caule, causou 100% de mortalidade larval a 4 mg L-1. A atividade inseticida foi associada à presença dos alcalóides monoterpenóides indólicos aspidofractinina, 15-demetoxipirifolina e N-formilaspidofractinin. Estes alcalóides apresentaram excelente propriedade inseticida contra P. xylostella.

The objective of this work was to assess the effects of Aspidosperma pyrifolium ethanol extracts on cabbage moth (Plutella xylostella) larvae. The ethanol extracts of the stem bark, fruits and roots of A. pyrifolium were obtained by classical phytochemical methods, and the resulting subfractions were tested on P. xylostella, using 4 and 5 mg L-1. The crude ethanol extract of the stem bark was more lethal. The alkaloid-rich aqueous subfraction derived from the stem bark extract caused 100% larval mortality at 4 mg L-1. Insecticidal activity was associated with the presence of the monoterpenoid indole alkaloids aspidofractinine, 15-demethoxypyrifoline, and N-formylaspidofractinine. These alkaloids presented excellent insecticidal properties against P. xylostella.

Estudou-se o efeito tóxico do extrato metanólico da amêndoa da semente de nim, obtido pelo aparelho de Soxhlet, na mortalidade de ovos e lagartas de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). Para constatação do efeito ovicida, ovos com 24 horas da oviposição foram contados e pulverizados com extrato nas concentrações 1000; 500; 250; 125 e 62,5 mg L-1. As testemunhas foram pulverizadas com água e metanol. O experimento foi mantido, em laboratório, a 25 ± 2°C; UR de 50 ± 10% e fotofase de 12 h. O período de incubação, para todos os tratamentos inclusive as testemunhas, foi em média de quatro dias, sendo que o extrato não afetou a viabilidade dos ovos, embora os valores tenham variado de 51,7% a 80,6%. Lagartas recém-eclodidas foram colocadas em tubos contendo um folíolo de tomateiro, previamente imerso em extrato, nas concentrações de 2000; 4000; 6000 e 8000 mg L-1 e acondicionados na câmara climatizada à 27 ± 1°C; UR: 65 ± 10% e fotofase: 12 h. Aos quatro dias, causaram mortalidade de 82, 68, 94,7 e 100%, respectivamente, sendo que, ao sexto dia, todas as concentrações tinham causado 100% de mortalidade da fase larval. As testemunhas tratadas com água e com metanol apresentaram mortalidade de 4% e 8%, respectivamente.

A methanolic extract from neem seed kernels, obtained using the Soxhlet apparatus was used to study the mortality of eggs and larvae of Tuta absoluta (Lepidoptera: Gelechiidae) and to evaluate of the ovicidal effect. Eggs 24 hours after oviposition were counted and sprayed with the extract at the concentrations of 1000, 500, 250, 125 and 62.5 mg L-1. Controls were sprayed with water and methanol. The experiment was conducted in laboratory conditions at 25±2°C; UR 50±10% and 12 h of photophase. Incubation period for all treatments, including controls, was four days on the average. The extract did not affect the viability of eggs, although the values varied between of 51.7% the 80.6%. Larvae recently hatched from eggs were placed in glass tubes containing a tomato leaflet previously immersed for five seconds into the extract, at concentrations of 2000, 4000, 6000 and 8000 mg L-1 and conditioned on BOD at 27±1°C; 65±10% RH and 12 hours of light. By the fourth day after treatment the extract caused mortalities of 82, 68, 94.7 and 100%, respectively. By the sixth day, all concentrations caused 100% mortality of the larvae. The controls with water and methanol presented mortalities of 4 and 8%, respectively.