RESUMO

The objective of this work was to evaluate the effects of synthetic insecticides used in the cotton crop on eggs and third-instar larvae of the ladybeetle Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae). The products used in g a.i. L-1 of water were triflumuron 0.048 (Certero 480 SC), spinosad 0.24 (Tracer 480 SC), chlorfenapyr 1.2 (Pirate 240 SC), chlothianidin 0.33 (Focus 500 WP) and imidacloprid 0.33 + -cyfluthrin 0.042 (Connect 100 + 12.5 SC). Distilled water was used as a control. Both eggs and larvae were distributed in Petri dishes and treated with the insecticides by spraying in a Potter's tower. A fully randomized experimental design, with five replications and six treatments consisting of five pesticides and one control was used. Each plot consisted of ten eggs or third-instar larvae. The embryonic period and viability of the treated eggs; survival and duration of third-instar larvae; survival and duration of larval and pupal stages of development; sexual ratio, and the total number of eggs laid by the surviving mated females from treated eggs and third-instar larvae were evaluated. The tests were carried out at 25 ± 2º C, RH 60 ± 10% and 12h-photophase. Triflumuron 0.048 was innocuous to the predator's eggs and slightly harmful to third-instar larvae. Spinosad 0.24 was slightly harmful to eggs and third-instar larvae, whereas chlofernapyr 1.2, chlothianidin 0.33 and imidacloprid 0.33 + -cyfluthrin 0.042 were harmful to eggs and third-instar larvae of C. sanguinea.

Objetivou-se avaliar a seletividade fisiológica de inseticidas utilizados em algodoeiro para ovos e larvas de terceiro instar de Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae). Os produtos utilizados em g i.a. L-1 de água foram triflumurom 0,048 (Certero 480 SC), espinosade 0,24 (Tracer 480 SC), clorfenapir 1,2 (Pirate 240 SC), clotianidina 0,33 (Focus 500 PM) e imidaclopride 0,33 + -ciflutrina 0,042 (Connect 100 + 12,5 SC). Utilizou-se água destilada como tratamento testemunha. Tanto ovos quanto larvas foram distribuídos em placas de Petri e tratados com os inseticidas por meio de pulverização em torre de Potter. O delineamento experimental utilizado foi o inteiramente ao acaso, com cinco repetições e seis tratamentos constituídos pelos cinco inseticidas e pela testemunha, sendo que cada parcela foi composta por dez ovos ou dez larvas de terceiro instar. Avaliaram-se o período embrionário e a viabilidade de ovos tratados; sobrevivência e duração de larvas de terceiro instar; sobrevivência e duração dos estágios de desenvolvimento larval e pupal, razão sexual e o total de ovos colocados pelas fêmeas provenientes de ovos e larvas de terceiro instar tratados. Os bioensaios foram conduzidos a 25 ± 2º C, UR 60 ± 10% e fotofase de 12h. O inseticida triflumurom 0,048 foi seletivo a ovos do predador e levemente nocivo a larvas de terceiro instar. Espinosade 0,24 foi levemente nocivo a ovos e larvas de terceiro instar, e clorfenapir 1,2; clotianidina 0,33 e imidaclopride 0,33 + -ciflutrina 0,042 foram prejudiciais a ovos e larvas de terceiro instar de C. sanguinea.

RESUMO

This study aimed to evaluate the quality of the aphid Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.) as hosts for the parasitoid Diaeretiella rapae (McIntosh). Parasitization by D. rapae was higher on M. persicae than on L. erysimi and B. brassicae. The time of development of D. rapae from egg to mummy or egg to adult male or female were shorter on M. persicae than on L. erysimi and B. brassicae. Moreover, D. rapae showed no significant differences in the emergence rate, sex ratio and longevity when reared on the three aphid species. Myzus persicae was the largest aphid host, with B. brassicae and L. erysimi being of intermediate and of small size, respectively. Diaeretiella rapae reared on M. persicae was larger than when reared on L. erysimi and B. brassicae, and females of D. rapae were significantly larger than males on M. persicae, but males of D. rapae were larger than females when reared on L. erysimi. No difference in size was detected between males and females in parasitoids reared on B. brassicae. Among the aphid species studied, M. persicae was found to be the most suitable to D. rapae.

Assuntos

Assuntos

RESUMO

ABSTRACT Identifying pesticides that are selective in regard to natural enemies is critical to good practice of integrated pest management. This study was aimed to evaluate the selectivity of the following pesticides (in g a.i. L-1 of water) in regard to the predator Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae): triflumuron (Certero SC 480 0.048), spinosad (Tracer 480 SC 0.24), chlorfenapyr (Pirate SC 240 1.2), clothianidin (Focus 500 PM 0.33), beta-cyfluthrin + imidacloprid (Connect 100/12, SC 5 0.33 / 0.042), and distilled water as a control treatment. The products were sprayed on C. sanguinea pupae and adults using a Potters tower; the pupas were kept singly until they became adults, when couples were made. For adults, the couples were made after the application of the products. The bioassays were realized at 25 ± 2º C, RU 60 ± 10% and photophase of 12h. Evaluations were made of the duration, survival and sexual rate of directly treated pupae; survival and reproductive parameters of directly treated adults; survival and duration of the larval and pupal development stages, sexual ratio and reproductive parameters of adults developed from pupae and of directly treated adults. Triflumuron and spinosad were innocuous to the C. sanguinea pupae, and slightly prejudicial to the adults of the predator as well to its phases and generations following development. Chlorfenapyr, chlothianidin and imidacloprid/ß-cyfluthrin were toxic to C. sanguinea pupae and adults.

RESUMO Identificar pesticidas seletivos a inimigos naturais é fundamental para a boa prática do Manejo Integrado de Pragas. Este estudo objetivou avaliar a seletividade dos seguintes agroquímicos (em g i.a. L-1 de água) sobre o predador Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae): triflumurom (Certero 480 SC 0,048), espinosade (Tracer 480 SC 0,24), clorfenapir (Pirate 240 SC 1,2), clotianidina (Focus 500 PM 0,33), imidaclopride+ß-ciflutrina (Connect 100/12,5 SC 0,33/0,042), e água destilada como tratamento testemunha. As pulverizações dos produtos foram realizadas em pupas e adultos de C. sanguinea por meio de torre de Potter; as pupas permaneceram individualizadas até a emergência dos adultos quando foram formados casais. Para os adultos tratados, os casais foram formados logo após as aplicações dos produtos. Os bioensaios foram conduzidos a 25 ± 2º C, UR 60 ± 10% e fotofase de 12h. Avaliou-se a duração, sobrevivência e razão sexual de pupas diretamente tratadas; sobrevivência e parâmetros reprodutivos de adultos diretamente tratados; sobrevivência e duração dos estádios de desenvolvimento larval e pupal, razão sexual e parâmetros reprodutivos de adultos provenientes de pupas e adultos diretamente tratados. Os inseticidas triflumuron e espinosade foram seletivos às pupas de C. sanguinea, levemente nocivos aos adultos do predador, assim como às suas fases e gerações subsequentes de desenvolvimento. Clorfenapir, clotianidina e imidaclopride+ß-ciflutrina foram tóxicos a pupas e adultos de C. sanguinea.

RESUMO

ABSTRACT The neem plant (Azadirachta indica A. Juss) possesses insecticide properties and has been used widely as an alternative in the control of a number of pest arthropods. As the aphids Brevicoryne brassicae (Linnaeus, 1758) and Myzus persicae (Sulzer, 1776) are important pests in the cultivation of kale, the present study was aimed to evaluate the efficiency of the extract of neem oil for the control of these insects. Ten adult aphids were put into Petri dishes 5 cm in diameter, containing leaf disk of kale on an agar gel layer. The insects were given the substances by means of a hand sprayer at the concentrations of 0.25%; 0.50%; 0.75%; 1.0% and 2.0%. As positive controls, 0.028% imidacloprid was utilized, while the negative control was only distilled water. The Petri dishes were maintained in an climatic chamber at 25 ± 2º C, relative humidity of 70 ± 10% and 12-hour photophase. The evaluations of mortality of the aphids and of the number of surviving nymphs from the treated adults were carried out at 1h, 6h, 12h, 24h, 48h and 72h after spraying of the compounds on the insects. Neem oil at all the tested concentrations is efficient in the control of B. brassicae, but for M. persicae it is toxic only at the concentrations of 1% and 2%.

RESUMO A planta de Nim (Azadirachta indica A. Juss) possui propriedades inseticidas e vem sendo amplamente utilizada como alternativa no controle de muitos artrópodes-praga. Sendo os pulgões Brevicoryne brassicae (Linnaeus, 1758) e Myzus persicae (Sulzer, 1776) pragas importantes para a cultura da couve-manteiga, avaliou-se neste trabalho a eficiência do extrato de óleo de Nim para o controle desses insetos. Dez pulgões adultos foram colocados em placas de Petri de 5 cm de diâmetro, contendo discos foliares de couve sobre uma camada de ágar-gel. Os insetos receberam as substâncias por meio de pulverizador manual, nas concentrações de 0,25%; 0,5%; 0,75%; 1,0% e 2,0%. Como testemunha positiva, utilizou-se imidaclopride 0,028% e negativa, apenas água destilada. As placas de Petri foram mantidas em câmara climatizada a 25 ± 2º C, umidade relativa de 70 ± 10% e fotofase de 12 horas. As avaliações da mortalidade dos pulgões e do número de ninfas sobreviventes oriundas de adultos tratados foram realizadas a 1h, 6h, 12h, 24h, 48h e 72h, após a pulverização dos compostos sobre os insetos. O óleo de Nim em todas as concentrações testadas foi eficiente no controle de B. brassicae, e para M. persicae somente nas concentrações de 1% e 2%.