Fitness, acceptance and olfactory responses of Trichogramma pretiosum on eggs of Spodoptera frugiperda fed with Cry1Ac soybean Natália ALV

Spodoptera frugiperda (Smith) (Lepidoptera Noctuidae) is naturally tolerant to MON 87701 × MON 89788 soybean that expresses the Cry1Ac protein from Bacillus thuringiensis (Bt). Therefore, there are reports of outbreaks of this pest in fields where this technology has been cultivated. To support an environmental risk assessment, it is important to investigate the impacts of this technology on non-target organisms like the parasitoids of the genus Trichogramma, which can be used to manage this pest. In this study, we accessed: (i) the biology of a field population of S. frugiperda on MON 87701 × MON 89788 soybean; (ii) the impacts of the eggs produced by S. frugiperda fed with this soybean on the fitness and acceptance of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera Trichogrammatidae); and, (iii) the olfactory responses of this parasitoid to the volatiles of Bt and non-Bt soybean plants oviposited by S. frugiperda. The results of the biology of a field population of S. frugiperda when fed with Bt and non-Bt soybeans showed a similar total survival and cycle duration. No significant effects of the Bt soybean plants were observed in the life table parameters of S. frugiperda. Fitness and oviposition preference of T. pretiosum on eggs of S. frugiperda that fed with Bt and non-Bt soybeans were not different. Furthermore, the olfactory responses of this parasitoid to volatiles emitted by oviposited Bt and non-Bt soybeans were similar. These results suggest that there are no direct and indirect effects of S. frugiperda eggs fed with Bt soybean on the parasitoid fitness and acceptance, and also that T. pretiosum do not distinguish between Bt and non-Bt soybean plants oviposited by this pest. Therefore, this technology showed no adverse effects on T. pretiosum, which can help mitigate S. frugiperda outbreaks within an integrated pest management context

Diachasmimorpha longicaudata (Hymenoptera: Braconidae) tem um ínstar preferencial para parasitar Tephritidae (Diptera)?

Diachasmimorpha longicaudata (Ashmead, 1905) is a koinobiont parasitoid of Tephritidae larvae, the third instar larvae of which is considered preferential, but it is able to parasitize other larval stages and compete with native parasitoids. This study investigated the preference and parasitism capacity of D. longicaudata in larvae of different instar of Anastrepha fraterculus (Wiedemann, 1830) (AF) and Ceratitis capitata (Wiedemann, 1824) (CC). The experiments were carried out under laboratory conditions, one instar being offered at a time in parasitism units, with the following choices among the hosts: 25 AF larvae and 25 CC larvae (first, second and third instar were evaluated). The other test was a multiple-choice in relation to the instar, for larvae of the same host species, with three parasitism units being offered, with 15 larvae of each instar. The mean number of formed pupae, emerged parasitoids, parasitized pupae, unviable pupae and sex ratio were evaluated. In the first bioassay, the mean number of emerged parasitoids and parasitized pupae in the AF host were significantly higher in treatments with first and second instar larvae. For CC there was no difference between the instars tested. In the second bioassay, the mean value of emerged parasitoids and parasitized pupae, was higher in second and third instar larvae for CC, and for AF was in second instar larvae. The sex ratio was biased for males in all treatments in both bioassays. The results show that D. longicaudata can parasitize and be successful in all available larval instars, being able to compete with parasitoids of any instar.Diachasmimorpha longicaudata (Hymenoptera: Braconidae) tem um ínstar preferencial para parasitar Tephritidae (Diptera)? Diachasmimorpha longicaudata (Ashmead, 1905) é um parasitoide coinobionte de larvas de Tephritidae sendo que o terceiro ínstar larval é tido como o preferencial, mas pode parasitar outros estágios larvais e competir com os parasitoides nativos. Este estudo investigou a preferência e capacidade de parasitismo de D. longicaudata em larvas de diferentes ínstares de Anastrepha fraterculus (Wiedemann, 1830) (AF) e Ceratitis capitata (Wiedemann, 1824) (CC). Os experimentos foram realizados em condições laboratoriais, sendo oferecido um ínstar por vez em unidades de parasitismo, havendo escolha entre os hospedeiros: 25 larvas de AF e 25 larvas de CC (foram avaliadas larvas de primeiro, segundo e terceiro ínstar). O outro teste foi de múltipla escolha em relação ao ínstar, para larvas da mesma espécie hospedeira, sendo oferecidas três unidades de parasitismo, com 15 larvas de cada ínstar. Avaliou-se o número médio de pupários formados, parasitoides emergidos, pupários parasitados, pupas inviáveis e razão sexual. No primeiro bioensaio o número médio de parasitoides emergidos e pupários parasitados no hospedeiro AF foram significativamente superiores nos tratamentos com larvas de primeiro e segundo ínstar. Para CC não houve diferença entre os ínstares testados. No segundo bioensaio, o valor médio de parasitoides emergidos e de pupas parasitadas foi maior nas larvas de segundo e terceiro ínstar para CC, e para AF nas larvas de segundo ínstar. A razão sexual foi desviada para machos em todos os tratamentos, nos dois bioensaios. Os resultados demostram que D. longicaudata pode parasitar e ter sucesso em qualquer ínstar larval disponível, podendo competir com parasitoides de qualquer ínstar

Respuestas de Anastrepha fraterculus (Diptera: Tephritidae) a plaguicidas utilizados en la producción orgánica de frutas

The South American fruit fly, Anastrepha fraterculus (Diptera: Tephritidae), is an economically important pest of fruit production in Southern Brazil. In organically managed orchards the species has traditionally been controlled with oils, plant extracts, and solutions such as pyroligneous extract and lime sulfur. The objectives of this study were to examine the possible deterrent effect of pesticides with the highest electroantennographic bioactivity on fruit flies and to assess their effects on the viability of pupae in treated fruits. Antennae were exposed to pyroligneous extract (BioPirol7M®, 0.4%), lime sulfur solution (SulFertilizantes, 1%), neem (Organic Neem®, 0.5%), and rotenone (Rotenat®, 0.6%), taking into account fly sex, age and reproductive status. Pupal viability was assessed for larvae reared in papaya (Carica papaya var. Calyman) and guava (Psidium guajava var. Paluma) fruits treated with the pesticides that generated the strongest electrophysiological responses. The bioactivity of A. fraterculus antennae was highest when stimulated with pyroligneous extract and lime sulfur solution, for young and mated flies. Neither substance inhibited oviposition and larval development in treated fruits, a result that has important implications for A. fraterculus management in organic systemsLa mosca sudamericana, Anastrepha fraterculus (Diptera: Tephritidae), es una plaga de importancia económica en la producción de frutas en el sur de Brasil. En huertos bajo manejo orgánico la especie se controla tradicionalmente con aceites, extractos vegetales y soluciones como el extracto piroleñoso y sulfuro de cal. Los objetivos de este estudio fueron evaluar el posible efecto disuasivo de los plaguicidas que presentan la más alta bioactividad electroantenográficas en moscas de la fruta y evaluar sus efectos sobre la viabilidad de las pupas en frutas tratadas. Las antenas fueron expuestas al extracto piroleñoso (BioPirol 7M®, 0,4%), solución de sulfuro de cal (SulFertilizantes, 1%), Nim (Organic Neem®; 0,5%) y rotenona (Rotenat®, 0,6%), teniendo en cuenta el sexo de la mosca, la edad y el estado reproductivo. La viabilidad de las pupas fue evaluada en larvas criadas en frutas de papaya (Carica papaya var. Calyman) y guayaba (Psidium guajava var. Paluma) tratadas con los plaguicidas que generaron las respuestas electrofisiológicas más fuertes. La bioactividad de las antenas de A. fraterculus fue mayor cuando fueron estimuladas con extracto piroleñoso y la solución de sulfuro de cal, para moscas jóvenes y apareadas. Ninguna de estas sustancias inhibió la oviposición y el desarrollo de las larvas en los frutos tratados, un resultado que tiene implicaciones importantes en el manejo de A. fraterculus en sistemas orgánico

Efeito do consórcio couve e manjericão no controle biológico conservativo de pulgões

Conservative biological control seeks to preserve beneficial organisms as the natural enemies of pests through habitat management. These studies aimed to measure the potential of basil (Ocimum basilicum L.) in the biological control of aphids in green cabbage (Brassica oleraceae L. var. acephala); and to evaluate the influence of the intercropping on green cabbage productivity. In an organic commercial crop of green cabbage in Águas Claras, RS, basil was used as an associated border (BB) and contrasted with plants in beds with no border (WB). We compared Aphididae density and parasitism, in the spring/summer seasons of 2016 and autumn/winter of 2017. Brevicoryne brassicae L. and Myzus persicae Sulzer (Hemiptera, Aphididae) were recorded in the green cabbage, in 2016. A mean of 13.8 ± 8.72 aphids/leaf was recorded in the WB, significantly higher than in the BB, 3.4 ± 1.83 (Tukey 5% p = 0.00002). In the 2017 season, this difference was not significant at 10.3 ± 12.73 (WB) and 6.9 ± 11.34 (BB). The mean of parasitized aphids was 2.8 ± 2.84 in WB and 9.9 ± 2.87 BB (p = 0.0041) in the spring crop and 2.9 ± 4.10 (WB) and 14.25 ± 7.3 (BB) in the winter (p = 0.0039). The association of green cabbage and basil had an area equivalence index (AEI) in 2016 = 1.07 and 2017 = 0.99 indicating that basil did not affect green cabbage yield.O controle biológico conservativo busca preservar organismos benéficos como os inimigosnaturais de pragas através do manejo do habitat explorando a diversificação vegetal. Este trabalho objetivou mensurar o potencial do manjericão (Ocimum basilicum L.) no controle biológico de afídeos em couve (Brassica oleraceaeL. var. acephala) e avaliara influência do consórcio na produtividade da couve. Em um plantio comercial orgânico de couve em Águas Claras, RS, o manjericão foi utilizado como bordadura em consórcio (CB) sendo contrastado com plantas em canteiros sem bordadura (SB). Foi comparada a densidade de Aphididae e o parasitismo, nas safras de primavera/verão de 2016 e outono/inverno de 2017. Foram registrados os afídeos Brevicoryne brassicaeL. e Myzus persicae Sulzerna couve, obtendo-se, em 2016 uma média 13,8 ± 8,72afídeos/folha no SB significativamente maior que no CB, 3,4 ± 1,83 (Tukey 5% p= 0,00002). Em 2017 essa diferença não foi significativa, 10,3 ± 12,73 (SB) e 6,9 ± 11,34 (CB). A média de afídeos parasitados foi de 2,8 ± 2,84 no SB e 9,9 ± 2,87 CB (p=0,0041) na safra de primavera e 2,9 ± 4,10 (SB) e 14,3 ± 7,30 (CB) na de inverno (p=0,0039). A presença do manjericão não afetou a produtividade da couve, sendo que o canteiro com o consórcio couve e manjericão apresentou índice de equivalência de área (IEA) em 2016 = 1,07 e em 2017 = 0,99

Padrão de movimento dos adultos de Spartocera dentiventris (Berg), (Hemiptera: Coreidae) em um cultivo experimental de Nicotiana tabacum L. (Solanaceae)

In the present work we investigated the movement pattern of Spartocera (=Corecoris) dentiventris (Berg) (Hemiptera: Coreidae) adults through the mark-release-recapture method in an experimen- tal tobacco crop (Nicotiana tabacum L., Solanaceae) in Porto Alegre, RS, Brazil. We marked 217 specimens from August 1999 to April 2000. Females moved 2.94 ± 0.198 times and males 1.46 ± 0.171 times among host plants. The number of movements per capture was 0.53 ± 0.03 for females and 0.54 ± 0.06 for males. Newly recruited adults took 12.75 ± 0.919 days to leave their original plant, females moved 9.87 ± 0.711 m and males 9.16 ± 1.29 m in this first movement. We estimate that females move an average of 26.22 m and males 13.89 m during their permanence in the area.O padrão de movimentação dos adultos de Spartocera (=Corecoris) dentiventris (Berg) (Hemiptera: Coreidae) foi investigado por meio do método de marcação e recaptura, em cultivo experimental de fumo (Nicotiana tabacum L., Solanaceae) em Porto Alegre, RS, Brasil. Foram marcados 217 indivíduos no período de agosto de 1999 a abril de 2000; as fêmeas movimentaram-se 2,94 ± 0,198 vezes e os machos, 1,46 ± 0,171 vez entre as plantas hospedeiras. O número de movimentos registrados por recaptura foi de 0,53 ± 0,03 para fêmeas e de 0,54 ± 0,06 para machos. Os adultos recém-recrutados levaram 12,75 ± 0,91 dias para dispersar de sua planta de origem; as fêmeas percorreram 9,87 ± 0,711 m e os machos, 9,16 ± 1,29 m nesse primeiro movimento. Estima-se que as fêmeas percorram du- rante sua permanência na área uma média de 26,22 m, e os machos, 13,89 m

Effect of Azadirachta indica (Sapindales: Meliaceae) oil on Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae and adults

Azadirachta indica A. Juss. (Meliaceae) is used to control insects due to its compounds that have insecticidal, repellent, and antifeedant properties. These effects also may cause sublethal impacts on insects that reduce populations of target species. Such species can have economic importance, like Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which feeds on various plant species. Thus, the objective of this study was to evaluate the larval mortality, lethal concentration, and sublethal effects on larvae, pupae, and adults of S. frugiperda after larvae were fed on an artificial diet containing A. indica oil at different concentrations. The oil was incorporated into the artificial diet at the concentrations of 5,000, 10,000, and 15,000 ppm, plus a control group. Four replicates of 35 second instar caterpillars were made for each treatment, and observed daily until pupation and emergence. The larval survival, duration of the larval and pupal periods, pupal weight and viability, wing length, and deformation of adults were evaluated. Longevity, fertility, and fecundity also were recorded for each pairing (mating arrangement) of males and females that developed on either a diet without oil and propanone, with propanone only, and with both oil and propanone. Azadirachta indica oil in the diet reduced survival and prolonged duration of the larval and pupal periods. Pupae in the groups that contained oil weighed less, and the adults had smaller wing length than in the control group. There was no influence on pupal viability, but the number of deformed adults increased. The oil reduced fecundity and longevity, but it did not alter fertility. These results suggest that the oil may reduce the probability of this insect remaining in the environment due to its ability to decrease the offspring and longevity of this species.Azadirachta indica A. Juss. (Sapindales: Meliaceae) é usada no controle de insetos devido a seus compostos que possuem atividade inseticida, de repelência e de deterrência alimentar. Esses efeitos também podem causar impactos subletais, reduzindo as populações de espécies-alvo. Espécies essas que podem ter importância econômica, como Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) que se alimenta de várias espécies de plantas. Assim, esse estudo teve como objetivo avaliar a mortalidade larval, concentração letal e o efeito subletal em larvas, pupas e adultos de S. frugiperda cuja larva se alimentou de uma dieta contendo óleo de A. indica em diferentes concentrações. O óleo foi incorporado, com propanona, em dieta artificial em concentrações de 5.000, 10.000, e 15.000 ppm, e o grupo controle. Quatro réplicas de 35 lagartas de segundo ínstar foram feitas para cada tratamento e observadas diariamente até a pupação e a emergência. Foram avaliados a sobrevivência larval, a duração da fase larval e pupal, o peso e a viabilidade pupal, o comprimento da asa e a proporção de adultos deformados. A longevidade, fertilidade e fecundidade também foram registradas para cada combinação de machos e fêmeas que se desenvolveram em dieta sem óleo e propanona, com somente propanona ou com óleo e propanona. O óleo de Azadirachta indica na dieta reduziu a sobrevivência e retardou a fase larval e pupal. As pupas dos grupos que continham óleo pesaram menos e os adultos tiveram um menor comprimento de asa do que os do grupo controle. Não houve influência na viabilidade pupal, mas o número de adultos deformados foi aumentado. O óleo reduziu a fecundidade e a longevidade, mas não alterou a fertilidade. Esses resultados sugerem que o óleo pode reduzir a probabilidade do inseto permanecer no ambiente devido a sua habilidade de diminuir a prole e a longevidade dessa espécie

Effect of Azadirachta indica (Sapindales: Meliaceae) Oil on the Immune System of Spodoptera frugiperda (Lepidoptera: Noctuidae) Immatures

The insect immune system includes several mechanisms responsible for defending against pathogens, parasites, and parasitoids. Some botanical insecticides, such as Azadirachta indica oil, cause changes in the immune system of various insect species. Spodoptera frugiperda is an important agricultural pest; thus, knowledge about the effect of neem oil on the immune system of this species can assist in its management. This study aimed to evaluate the effect of A. indica oil on the immune system of S. frugiperda. Caterpillars (2–3 mg) were placed individually in containers (50 ml) with approximately 10 g of diet, containing 125, 250, and 500 ppm of neem oil with propanone; the control group received only the propanone diet. In four experiments, the total number of hemocytes, the phagocytic activity, the activity of lysozyme-like enzymes, and phenoloxidase activity were measured in caterpillars at the end of the sixth instar. The total number of hemocytes in insects exposed to neem oil was 21% lower than in the control group. The percentage of cells that phagocyted the latex beads was similar among the caterpillars that ingested the different concentrations. The mean diameter of cell lysis halos was reduced only at concentrations of 125 and 250 ppm. Absorbance did not differ between treatments. Knowing that this oil reduces the number of circulation cells and the activity of lysozyme-like enzymes is of great importance to design control strategies, once the neem oil could be added to other biological agents for mortality reducing the chances of this insect surviving in the environment.O sistema imune nos insetos inclui uma série de mecanismos que são responsáveis por defendê-lo frente a patógenos, parasitos e parasitoides. Alguns inseticidas vegetais, como o óleo de Azadirachta indica, causam alterações no sistema imune de várias espécies de insetos. Spodoptera frugiperda é uma importante praga agrícola, assim, o conhecimento sobre o efeito do óleo de nim no sistema imune dessa espécie pode auxiliar no manejo deste inseto. Este estudo objetivou avaliar o efeito do óleo de A. indica sobre o sistema imune de S. frugiperda. Lagartas com 2 a 3 mg foram colocadas, individualmente, em frascos (50 ml) com aproximadamente 10 g de dieta, contendo 125, 250 e 500 ppm de óleo de nim com propanona, além do grupo controle que recebeu a dieta apenas com propanona. Em quatro experimentos foram avaliados, em lagartas no final do sexto ínstar, o número total de hemócitos, a atividade fagocítica, a atividade das enzimas tipo lisozima e da atividade da fenoloxidase. Constatou-se uma redução de 21% do número total de hemócitos naqueles insetos expostos ao óleo de nim em relação ao grupo controle. A porcentagem das células que fagocitaram as esferas de látex foi semelhante entre as lagartas que ingeriram as diferentes concentrações. O diâmetro médio dos halos de lise celular foi reduzido somente nas concentrações de 125 e 250 ppm. A absorbância não diferiu entre os tratamentos. Saber que esse óleo reduz o número de células circulantes e a atividade de enzimas tipo lisozima é de grande importância para traçar estratégias de controle, uma vez que o óleo de nim pode ser adicionado a outros agentes biológicos de mortalidade, reduzindo as chances desse inseto sobreviver no ambiente

Intra and interspecific competition between Diachasmimorpha longicaudata (Hymenoptera Braconidae) and Aganaspis pelleranoi (Hymenoptera Figitidae)

Braconidae and Figitidae parasitoids are important agents of pest population regulation in natural and agricultural systems, with species used in applicate biological control programs of fruit flies (Diptera Tephritidae). However, many aspects of the interactions of parasitoids with their heterospecific and conspecific are poorly understood. Thus, the interspecific competition between the par- asitoids Diachasmimorpha longicaudata (Ashmead) (DL) (Hymenoptera Braconidae) and Aganaspis pelleranoi (Brethes) (AP) (Hymenoptera Figitidae), was studied using Anastrepha fraterculus (Wiedemann) (Diptera Tephritidae) as host. Host larvae were offered to only one parasitoid on a single occasion or on two occasions, or even to two parasitoid species, alternating the offering sequence. Thus, six exposure regimes were completed: AP (host exposed for 4 hours); DL (host exposed for 40 minutes); AP-AP (host exposed to AP for 4 hours and then to a conspecific for an additional further 4 hours); DL-DL (host exposed to DL for 40 minutes and then to a conspecific for an additional 40 minutes); AP-DL (host exposed to AP for 4 hours and then to DL for 40 minutes); and DL-AP (host exposed to DL for 40 minutes and then exposed to AP for 4 hours). The mean number of parasitized pupae, emerged parasitoids, oviposition scars per host (larvae) and sex ratio of parasitoids were compared between the different exposure regimes. The mean of parasitized pupae and emerged parasitoids was higher in the DL-DL and DL-AP treatments. The mean number of oviposition scars per host was correlated positively with the mean number of parasitoid offspring and the emerged females in treatments AP, DL, AP-AP, DL-DL for both species, and DL-AP only to D. longicaudata. When the hosts were exposed only once to the parasitoids, the sex ratio was male biased (AP and DL treatments); but when exposed twice, the treatments spawned offspring female biased, except for D. longicaudata at AP-DL treatment. Irrespective of the parasitism order, D. longicaudata suppress the emergence of A. pelleranoi