Life-History and Behavior of the Diamondback Moth Plutella xylostella on Brassicaceae Cultivars over Multiple Generations

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a cosmopolitan pest that causes leaf-area reduction in Brassicaceae plants. DBM populations have significant genetic variability that manifests in different feeding preferences and reproductive behaviors across generations. We evaluated the influence of Brassicaceae cultivars on biological and behavioral parameters across 18 generations of DBM populations that were separated and held on three varieties of Brassicaceae: Brassica oleracea var. acephala (kale), Brassica oleracea var. italica (broccoli), and Brassica oleracea var. capitata (cabbage). P, F6, F12, and F18 generations were evaluated, and biological aspects of young adulthood and fertility parameters of adults held on each host plant were examined over multiple generations. Additionally, larvae and adults were subjected to dual-choice and multiple-choice (feeding and oviposition) between cultivars, over generations. The results indicated that larvae of P. xylostella consumed greater quantities of kale and broccoli cultivars, on average (4.05 cm2), than cabbage (2.7 cm2). The number of eggs per female in F18 generation was 1.95 and 2.17 times higher than those in the parental (P) generation, when reared on kale and cabbage. The population reared exclusively on kale had higher net population growth rate (R0), intrinsic rate (rm), finite rate (λ) and generation time (T) than that reared on broccoli and cabbage. Last generations evaluated, the larval stage reared on cabbage showed feeding preference (F18) and oviposition preference (F12 and F18) for cabbage. Thus, we note the existence of learning, characterized as pre-imaginal conditioning to cabbage cultivars, over various DBM generations

Open Access at Embrapa: brief history, recent advances and challenges

The paper aims to report on the main initiatives developed by the Brazilian Agricultural Research Corporation (Embrapa) on open access to scientific and technological information, as well as initiating the organization and availability of research data. For this purpose, a history is made, starting in 2008, when the Company, through an internal project, consolidated several actions in the scope of information management, especially the publication of its open access repositories (Alice and Infoteca-e). Next, more recent initiatives are described, such as the Open Access scenario developed within the framework of a strategic institutional project on data, information and knowledge governance, initiated in 2015 and finalized in 2017, which presented a series of guidelines to be observed on the theme by the managers and the community of Embrapa with the purpose of aligning it with the international trends

Efeito do espaçamento e de Bacillus thuringiensis Berliner sobre Alabama argillacea (Hübner), Aphis gossypii Glover e inimigos naturais no algodoeiro

Some insects are important pests in cotton crops and can cause serious yield losses. Among them we can relate Alabama argillacea (cotton leafworm) and Aphis gossypii (cotton aphid), demanding, often, the use of control measures. This study aimed to evaluate the toxicity of Bacillus thuringiensis (Dipel®) to cotton leafworm and analyze its effect on the occurrence of this pest and the cotton aphid in cotton grown under two system of row spacing, in two places in the State of Mato Grosso, Brazil, as well as in some natural enemies. The toxicity was evaluated using doses of 0.30, 0.50, 0.75 and 1.00 L/ha, considering large cotton leafworm larvae (>1.5 cm) and small ones (<1.5 cm) in a laboratory bioassay. The effect of the biopesticide on A.argillacea and A. gossypii was compared in cotton grown in row spacing of 0.90m (conventional) and 0.45m (reduced). The results indicate that: Dipel® has good efficiency for control A. argillacea caterplillars and is selective for A. gossypii, causing a significant increase in cotton yield; 0.45m row spacing promotes a decrease in density of larvae of A. argillacea and A.gossypii, and yield is similar in both spacing, 0.90 and 0.45m, and bigger in treated areas.Alguns insetos são importantes pragas na cultura algodoeira, podendo provocar sérias perdas na produção, dentre eles pode-se citar Alabama argillacea e Aphis gossypii, os quais exigem, não raras vezes, a utilização de medidas de controle. Esse trabalho teve como objetivo avaliar a toxicidade de Bacillus thuringiensis Berliner var. kurstaki (Bt - Dipel®) para A. argillacea; avaliar seu efeito sobre A. argillacea e A. gossypii em algodoeiro cultivado em dois esquemas de espaçamento, e em alguns inimigos naturais na cultura. A toxicidade de Bt foi avaliada testandose as doses de 0,30; 0,50; 0,75 e 1,00 L/ha sobre lagartas grandes (> 1,5 cm) e pequenas (< 1,5 cm). O efeito do bioinseticida sobre A. argillacea e A. gossypii foi estudado em algodoeiro DeltaOpal cultivado nos espaçamentos entrelinhas de 0,90m (convencional) e 0,45m (reduzido), em duas localidades do Estado de Mato Grosso, Brasil. O Bt foi eficiente no controle de lagartas pequenas e grandes de A. argillacea, provocando aumento significativo na produtividade do algodoeiro quando em comparação com a testemunha, não afetando outros artrópodes; o espaçamento 0,45m promoveu diminuição na densidade de lagartas de A. argillacea e de A. gossypii, quando em comparação com o espaçamento de 0,90m; e a produtividade do algodoeiro foi semelhante nos espaçamentos de 0,90 e 0,45m, e maior nas áreas tratadas

Relationship between predation by Podisus nigrispinus and developmental phase and density of its prey, Plutella xylostella

This study evaluated the predation by Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) at various densities of larvae and pupae of the pest Plutella xylostella (L.) (Lepidoptera: Plutellidae). We tested predator behavior of female P. nigrispinus at six experimental densities (1, 5, 10, 15, 20, or 25 prey items in a 1-l transparent plastic container, replicated 15 times for each density) of both the fourth instar and pupae of P. xylostella. The number of prey consumed was monitored every 15 min for 12 h and was subsequently monitored at 24 h. Podisus nigrispinus females were weighed before and after the experiments to determine the effect of different densities of prey on their weight gain. Female predators had a Type-II functional response, with attack rate estimated at 1.387 and 0.260 and a handling time of 0.091 and 0.183 h-1 for larvae and pupae, respectively. Podisus nigrispinus consumed on average 10.9 larvae or 5.5 pupae in 24 h. Despite the similarity of the response type, P. nigrispinus preferred to feed on larvae, rather than on pupae.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Quality of the Exotic Parasitoid Cotesia flavipes (Hymenoptera: Braconidae) Does Not Show Deleterious Effects after Inbreeding for 10 Generations.

Although the parasitoid Cotesia flavipes (Cameron) has proven effective in controlling sugarcane borer Diatraea saccharalis (Fabricius) for many years, concern has arisen over the quality of individuals produced at large scales. The parasitoid has been reared in laboratories in Brazil for more than 40 years, with no new introductions of new populations during that period. Since the quality of the parasitoids was not verified at the time of the species' introduction in Brazil, we do not know if there has been any reduction in quality so far. However, it is possible to determine whether the parasitoid could reduce in quality in future generations. Thus, the objective of this research was to assess the quality of these insects over 10 generations and look for evidence of any loss in quality. We used two populations: one from a biofactory that has been maintained in the laboratory for over 40 years, and an inbred laboratory population. Both were bred, and compared for 10 generations. We wanted to determine what happened to the quality of the parasitoid after 10 generations in an extreme inbreeding situation. To assure inbreeding, newly emerged females were forced to mate with a sibling. Individual females were then allowed to parasitize larvae of D. saccharalis. We performed evaluations for each generation until the tenth generation, and recorded the sex ratio, percentage emergence, number of offspring/females, and longevity of both males and females. Results of the measurements of biological characteristics demonstrated random significant differences between populations; best results were obtained intermittently for both the biofactory population and the inbred population. No significant differences across generations for the same population were observed. Thus, rearing of a C. flavipes population subjected to inbreeding for 10 generations was not sufficient to reveal any deleterious effects of inbreeding

Effect of Egg Rearing Temperature and Storage Time on the Biological Characteristics of the Predatory Stink Bug Podisus nigrispinus (Hemiptera: Pentatomidae)

In this study, we investigated the effect of egg rearing temperature and storage time on biological characteristics of the predatory stink bug Podisus nigrispinus (Dallas). In a preliminary experiment, eggs were incubated at 5, 10, 15, and 20 degrees C to examine the effect of rearing temperature on egg development. From this, we found that 15 degrees C was the optimal temperature for egg storage. To examine the effect of storage period on biological characteristics, eggs were stored at 15 +/- 1 degrees C for 0 (control), 1, 5, 9, 13, or 17 d, and then maintained at 25 degrees C, allowing us to determine the effect of storage period on incubation period and egg viability. Once nymphs reached the second instar, they were kept in individual petri dishes, and we examined the effect of storage period on stadial length, nymphal viability, and weight of fifth-instar nymphs. Finally, when the nymphs reached the adult phase, we measured the effect of storage period on adult longevity, neonate adult weight, fecundity, and egg hatching success. Our results showed that the storage of eggs at 15 +/- 1 degrees C for periods of up to 17 d did not significantly affect most of the biological characteristics analyzed.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Fonte proteica na criação de Diatraea saccharalis e seu reflexo na produção e no controle de qualidade de Cotesia flavipes Protein source in Diatraea saccharalis diet and its impact on production and quality control of Cotesia flavipes

O objetivo do trabalho foi avaliar diferentes dietas para lagartas de Diatraea saccharalis, com o intuito de obter informações sobre as características biológicas da praga e consequentemente avaliar a qualidade do parasitoide Cotesia flavipes, visando melhorar tecnicamente sua produção massal. Lagartas de 24 horas de idade foram transferidas para tubos (25 lagartas/tubo) contendo dieta artificial com levedura de cerveja e germe de trigo e outra somente com germe de trigo como fonte de proteína. Depois de aproximadamente 15 dias, as lagartas foram retiradas dos tubos e acondicionadas em placas com dieta, sendo observadas lagartas de D. saccharalis não parasitadas e parasitadas para avaliação das características biológicas de D. saccharalis e C. flavipes.nas diferentes dietas. Além da observação das características biológicas de D. saccharalis, foram realizadas medições nas lagartas de 15 dias de idade. Também, massas de pupas de C. flavipes.produzidas em biofábrica foram classificadas em três diferentes tamanhos, sendo pequenas (1,3 a 2,5 cm de comprimento), médias (2,5 a 3,5 cm de comprimento) e grandes (3,5 a 4,0 cm de comprimento). Após a emergência dos adultos foi realizado o parasitismo em lagartas de D. saccharalis, sendo observados o número de machos e fêmeas, tamanho da massa, razão sexual e número de pupas inviáveis. A dieta artificial que contém somente germe de trigo é a mais indicada para criação massal do hospedeiro D. saccharalis para produção em larga escala de C. flavipes. Massas de pupas classificadas como grandes possuem melhor qualidade em criações massais de C. flavipes.<br>The aim of this work was to evaluate different diets for Diatraea saccharalis larvae, obtaining information about the biological characteristics of the pest, and to evaluate the quality of Cotesia flavipes parasitoid, to improve mass rearing method. For the accomplishment of the experiment, 24 hour-old larvae were transferred to tubes (25 larvae/tube) containing artificial diets with yeast and wheat germ or just wheat germ as protein source. After approximately 15 days, the larvae were removed from tubes and placed in Petri dishes, being observed D. saccharalis larvae not parasitized and parasitized for evaluation of D. saccharalis and C. flavipes.biological characteristics. Biological characteristics of D. saccharalis were also evaluated in 15 day-old larvae. Pupae mass of C. flavipes.from mass rearing were classified in three different sizes separated in small (1.3 to 2.5 cm of length), moderate (2.5 to 3.5 cm of length) and large (3.5 to 4.0 cm of length) classes. After the adult emergency, the parasitism was evaluated in D. saccharalis larvae, being observed the number of males and females, size of pupae mass, sex ratio and number of unviable pupae. The artificial diet that contains wheat germ is the most suitable for D. saccharalis mass rearing and C. flavipes. Pupae mass of large size presents better quality of C. flavipes

Consumo foliar da traça-das-crucíferas em couve e brócolis tratados com sinigrina

A estimativa da área foliar, em função da sua redução causada pelo consumo por insetos filófagos, é uma metodologia básica em várias áreas da Entomologia, como, por exemplo, em estudos sobre resistência de plantas, entomologia econômica e ecologia nutricional. Um dos fatores que pode interferir na quantidade de área foliar consumida pelo fitófago é a presença de certos químicos nas folhas, como a sinigrina em brassicáceas. Dessa forma, foram aplicadas em folhas de couve e brócolis diversas concentrações de sinigrina (0,2, 0,4, 0,8, 1,6, e 3,2 mg/mL em solução a 5% de Tween20(r)), medindo-se o consumo da área foliar por lagartas de P. xylostella, o qual foi aferido pela porcentagem de redução da área, diferença de peso e escala visual de notas. Os resultados mostraram que as concentrações 0,2, 0,4 e 3,2 mg/mL de sinigrina aumentam o consumo em folhas de couve e diminuem em folhas de brócolis por lagartas de P. xylostella. As metodologias utilizadas proporcionam resultados similares, sendo as estimativas de peso fresco e nota visual mais práticas

Consumo foliar da traça-das-crucíferas em couve e brócolis tratados com sinigrina

Leaf area estimation, based on their reduction due to consumption by phytophagous insects, is a basic methodology in several areas of Entomology, for instance, in studies about plant resistance, economic entomology and nutritional ecology. One of the factors that can affect the amount of leaf area consumed by insects is the presence of certain chemicals in the leaves, such as sinigrin in Brassicaceae. Thus, several concentrations of sinigrin were applied on the leaves of cabbage and broccoli (0.2, 0.4, 0.8, 1.6, and 3.2 mg/mL in 5% Tween20(r) solution) in order to measure leaf area consumption by larvae of P. xylostella, estimated by the percentage of area reduction, weight loss and visual scale of notes. The results show that the concentrations of 0.2, 0.4 and 3.2 mg/mL of sinigrin increase larvae consumption of P. xylostella on kale leaves and decrease it on broccoli leaves. The methodologies used provide similar results, and fresh weight measurements and visual grades are more practical.A estimativa da área foliar, em função da sua redução causada pelo consumo por insetos filófagos, é uma metodologia básica em várias áreas da Entomologia, como, por exemplo, em estudos sobre resistência de plantas, entomologia econômica e ecologia nutricional. Um dos fatores que pode interferir na quantidade de área foliar consumida pelo fitófago é a presença de certos químicos nas folhas, como a sinigrina em brassicáceas. Dessa forma, foram aplicadas em folhas de couve e brócolis diversas concentrações de sinigrina (0,2, 0,4, 0,8, 1,6, e 3,2 mg/mL em solução a 5% de Tween20(r)), medindo-se o consumo da área foliar por lagartas de P. xylostella, o qual foi aferido pela porcentagem de redução da área, diferença de peso e escala visual de notas. Os resultados mostraram que as concentrações 0,2, 0,4 e 3,2 mg/mL de sinigrina aumentam o consumo em folhas de couve e diminuem em folhas de brócolis por lagartas de P. xylostella. As metodologias utilizadas proporcionam resultados similares, sendo as estimativas de peso fresco e nota visual mais práticas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES