Wagner de Souza Tavares

Selective effects of natural and synthetic insecticides on mortality of Spodoptera frugiperda (Lepidoptera: Noctuidae) and its predator Eriopis connexa (Coleoptera: Coccinellidae).

Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is a serious pest of corn in several American countries. It is mainly controlled with synthetic insecticides. The objectives of this study were to evaluate the effects of the natural products, neem oil and pyroligneous extract, and the synthetic insecticide, lufenuron, at 2.50mL water (0.25 %) on the mortality of 2-, 4- and 6-day-old caterpillars of S. frugiperda, and their selectivities against fourth instar larvae of Eriopis connnexa Germar (Coleoptera: Coccinellidae). Four- and 6-day-old S. frugiperda caterpillars showed higher mortality after exposure to neem oil (83.33 ± 0.83 and 89.58 ± 0.90 %, respectively) and lufenuron (95.83 ± 0.96 and 85.41 ± 0.83 %), compared to pyroligneous extract (68.75 ± 0.69 and 31.25 ± 0.31 %). The deleterious effect of pyroligneous extract was higher in 2- (83.33 ± 0.83 % mortality) and 4-day-old (68.75 ± 0.69 %) S. frugiperda caterpillars than in 6-day-old caterpillars (31.25 ± 0.31 %). Larval mortality of the predator E. connexa was lower with neem oil and pyroligneous extract (25.00 ± 0.33 %) than with lufenuron (91.66 ± 1.22 %). Neem oil is thus recommended for control of S. frugiperda because of its high toxicity, combined with its relatively low toxicity to larvae of the natural enemy E. connexa.

Deleterious activity of natural products on postures of Spodoptera frugiperda (Lepidoptera: Noctuidae) and Diatraea saccharalis (Lepidoptera: Pyralidae).

The control of Lepidoptera pests should be carried out before hatching of their caterpillars to avoid damage to the crops. The aim of this work was to assess the activity of neem (trade name: Natuneem®, producer: Base Fértil, Chapadão do Sul, Brazil) and pyroligneous extracts (trade name: Biopirol 7M®, producer: Biocarbo, Itabirito, Brazil) at 10 mL/L (1%) and 20 mL/L (2%) contents on egg masses of different ages of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) and of Diatraea saccharalis F. (Lepidoptera: Pyralidae) at Embrapa Corn and Sorghum in Sete Lagoas, Minas Gerais State, Brazil. The tests took place in an unbiased casualized design with 12 treatments and four replications. The insecticides were diluted in water, and 0.04 mL of the solution was applied to recently laid and one- and two-day-old eggs of S. frugiperda and D. saccharalis. Caterpillars hatching from recently laid egg masses of S. frugiperda was lower with 2% pyroligneous extract [(0.02 ± 0.00)%]. Recently laid eggs and one- or two-day-old eggs of D. saccharalis presented lower caterpillar hatching with 1% neem extract [(0.00 ± 0.00)%, (0.00 ± 0.00)%, and (1.00 ± 0.01)%] and 2% neem extract [(0.00 ± 0.00)%], compared to 1% pyroligneous extract [(27.30 ± 3.22)%, (28.40 ± 3.32)%, and (37.80 ± 4.14)%] and 2% pyroligneous extract [(42.20 ± 4.49)%, (48.70 ± 4.97)%, and (56.60 ± 5.52)%], respectively. Neem and pyroligneous extracts had impact on hatching of S. frugiperda and D. saccharalis caterpillars.

Phytochemistry and quantification of polyphenols in extracts of the Asteraceae weeds from Diamantina, Minas Gerais state, Brazil

Plantas daninhas Asteraceae sao ricas em substâncias quimicas com atividades biologicas e farmaceuticas. Os objetivos deste trabalho foram descrever a fitoquimica e quantificar os polifenois em extratos etanolicos de folhas de 12 especies de plantas daninhas Asteraceae coletadas em Diamantina, Minas Gerais, Brasil. A triagem de extratos de Asteraceae revelou a presenca de taninos, esteroides, triterpenos, antocianinas e flavonoides. O conteudo de fenois totais foi alto para extratos de Lychnophora ericoides (147,97 ± 2,66), Lepidaploa lilacina (141,11 ± 1,99) e Eremanthus elaeagnus (134,61 ± 7,81) e baixo em extratos de Lychnophora ramosissima (32,65 ± 0,70) e Lychnophora sp. (54,03 ± 0,73). Extratos de plantas daninhas Asteraceae de Diamantina podem ter potencial em estudos biologicos que estao a procura para pesticidas e drogas.

Rice-straw mulch reduces the green peach aphid, Myzus persicae (Hemiptera: Aphididae) populations on kale, Brassica oleracea var. acephala (Brassicaceae) plants.

Organic mulches, like peel and rice-straw, besides other materials affect the UV and temperature, which cause a reduction in the aphid arrival. The aim was to evaluate the effect of covering the soil with straw on the populations of the green peach aphid, Myzus persicae on the kale, Brassica oleracea var. acephala plants. The first experiment evaluated the direct effect of the rice-straw mulch and the second its indirect effect on aphid immigration, testing the plant characteristics that could lead to the landing preference of this insect. The third experiment evaluated the direct effect of the mulch on the aphid population. In the second and third experiments, four plants, each in a 14 L polyethylene pot with holes at the bottom, were used in areas with and without soil mulching. These pots were changed between areas, after seven days, to evaluate the effects of this change on the arrival of the winged aphids to the plants. Each plant was covered with anti-aphid gauze and inoculated with one winged M. persicae. Winged and apterous adults of this insect were counted per plant after 15 days. The temperature increased in the mulched plots to a maximum of 21–36°C and to 18–32°C in the plots with or without soil covering, respectively. Plant growth reduced the numbers of the winged aphids landing before and after they were moved to the bare soil plots. The nutrient content was similar in plants in both the mulched and no mulched plots. The population growth of M. persicae was higher in the control than in the mulched plots. This was partially due to temperatures close to 30°C in these plots and changes in the plant physiology. The soil mulching with rice-straw decreased the M. persicae landing, increased the plot temperatures and improved the vegetative growth of the kale plants.

The introduced tree Prosopis juliflora is a serious threat to native species of the Brazilian Caatinga vegetation

Despite its economic importance in the rural context, the Prosopis juliflora tree species has already invaded millions of hectares globally (particularly rangelands), threatening native biodiversity and rural sustainability. Here we examine seedling growth (leaf area, stem diameter, plant height) and seedling mortality across five native plant species of the Caatinga vegetation in response to competition with P. juliflora. Two sowing treatments with 10 replications were adopted within a factorial 2 × 5 randomized block design. Treatments consisted of P. juliflora seeds sowed with seeds of Caesalpinia ferrea, Caesalpinia microphylla, Erythrina velutina, Mimosa bimucronata and Mimosa tenuiflora (one single native species per treatment), while seeds of native species sowed without P. juliflora were adopted as controls. Overall, our results suggest that P. juliflora can reduce seedling growth by half and cause increased seedling mortality among woody plant species. Moreover, native species exhibit different levels of susceptibility to competition with P. juliflora, particularly in terms of plant growth. Such a superior competitive ability apparently permits P. juliflora to establish monospecific stands of adult trees, locally displacing native species or limiting their recruitment. The use of less sensitive species, such as C. ferrea and M. tenuiflora, to restore native vegetation before intensive colonization by P. juliflora should be investigated as an effective approach for avoiding its continuous spread across the Caatinga region.

Palmistichus elaeisis (Hymenoptera: Eulophidae) Parasitizing Pupae of Citioica anthonilis (Lepidoptera: Saturniidae) Collected on Piptadenia gonoacantha (Fabaceae)

ABSTRACT. The moth Citioica anthonilis (Herrich-Schaeffer, [1854]) (Lepidoptera: Saturniidae: Ceratocampinae) occurs in areas of preserved forests, where it is a significant defoliator of Piptadenia gonoacantha (Martius) Macbride (Fabaceae) trees. In this study, caterpillars of fourth instar C. anthonilis were collected from the ground after falling from a P. gonoacantha tree in a herbarium and were reared in the laboratory. Pupae of C. anthonilis, the velvetbean caterpillar Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Noctuidae), and the flour beetle Tenebrio molitor Linnaeus, 1758 (Coleoptera: Tenebrionidae) were each parasitized by mated parasitoid females wasp Palmistichus elaeisis Delvare & LaSalle, 1993 (Hymenoptera: Eulophidae). Data were collected relating to the levels of parasitism and emergence rates of P. elaeisis per host pupa, and the size of the host pupae. Our results show that the fecundity of P. elaeisis was highest in C. anthonilis hosts, probably because of the greater size of these pupae, which supported the development of an increased number of parasitoids. Therefore, C. anthonilis is a suitable host for rearing P. elaeisis in the laboratory, which could be a means of rearing parasitoids for the biological control of this defoliator of P. gonoacantha and other pests in Brazil.

Organismos de solo associados à supressora de plantas daninhas Crotalaria juncea (fabaceae) e sua importância como refúgio para inimigos naturais

Organismos de solo desempenham um importante papel em cultivos orgânicos de Crotalaria juncea (Fabaceae) e estao associados com a conservacao natural do ambiente. O presente estudo teve como objetivo investigar a populacao de organismos de solo no cultivo orgânico de C. juncea, bem como sua importância como um refugio para inimigos naturais. Dalbulus maidis (Hemiptera: Cicadellidae), Diabrotica sp. (Coleoptera: Chrysomelidae), Doru luteipes (Dermaptera: Forficulidae), Gryllus assimilis (Orthoptera: Gryllidae), Lagria villosa (Coleoptera: Lagriidae), Melanotus sp. (Coleoptera: Elateridae), Meloidogyne incognita (Tylenchida: Heteroderidae), Nephila clavipes (Araneae: Nephilidae), Orius insidiosus (Hemiptera: Anthocoridae), Pheidole sp. (Hymenoptera: Myrmicidae), Phyllophaga sp. (Coleoptera: Scarabeidae), Procornitermes sp. (Isoptera: Termitidae), Solenopsis sp. (Hymenoptera: Formicidae) e Utetheisa ornatrix (Lepidoptera: Arctiidae) foram identificados em C. juncea. Os organismos que foram encontrados durante um periodo de tres meses em 144 trincheiras em C. juncea foram as especies de pragas (84,47%) e inimigos naturais (15,53%). Inimigos naturais tiveram uma media de 11,89 individuos por 1,08 m3 de solo cultivado com C. juncea. A abundância de organismos na fase de vagem (5,49%) de C. juncea foi menor do que nas fases vegetativa (83,50%) e floracao (11,01%). Plantas de C. juncea podem ser usadas como parte de um sistema de cultivo para o Manejo Integrado de Pragas.

Emergence of Palmistichus elaeisis (Hymenoptera: Eulophidae) from Pupae of Thagona tibialis (Lepidoptera: Lymantriidae) Collected in the Medicinal Plant Terminalia catappa (Combretaceae)

ABSTRACT: The biological control of pests is an alternative to chemical control in plant crops used in folk medicine. The bark and the roots of tropical almond Terminalia catappa L. (Combretaceae) are indicated for dysentery, bile and gastric fevers and intestinal parasites; the leaves are used to treat colic and hemorrhoids; the unripe fruit is an astringent, the ripe fruit is a laxative, and its oil is used as an emulsifier for soothing the chest. Palmistichus spp. (Hymenoptera: Eulophidae), gregarious endoparasitoids, were little known until the publication of the first revision of this group in 1993. Fifty-four individuals of Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae) were collected after emerging from a pupa of Thagona tibialis Walker, 1855 (Lepidoptera: Lymantriidae) when their caterpillars defoliated a tree of T. catappa at the campus of the Federal University of Viçosa (UFV) in Viçosa, Minas Gerais State, Brazil. The parasitoid individuals were identified by the Department of Biology of the Lund University in Sölvegatan, Lund, Sweden. The present study includes a new host, pupae of T. tibialis associated to T. catappa, for P. elaeisis in Brazil.

Mortality of Anticarsia gemmatalis (Lepidoptera: Noctuidae) Caterpillars Post Exposure to a Commercial Neem (Azadirachta indica, Meliaceae) Oil Formulation

Abstract The velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is the most important defoliator of soybean (Glycine max L. Merrill, Fabaceae) crops in Brazil. Early-instar caterpillars of this pest are the main target of control. The objective of this work was to evaluate the toxicity of a commercial product, Bioneem® [neem oil (Azadirachta indica A. Juss., Meliaceae)], sprayed on A. gemmatalis caterpillars. Bioneem® was sprayed on soybean plants and 3 h later specific branches were enclosed by organza bags in a greenhouse with third-instar A. gemmatalis caterpillars. Ten replications with 80 caterpillars were used per treatment. The mortalities of A. gemmatalis caterpillars (mean 3rd to 6th instars) was 3.17, 7.18, 5.00, 11.25, 16.74, and 18.15%, whereas the respective mortalities of the pupae obtained from treated the caterpillars were 20.57, 22.79, 29.64, 39.16, 51.50, and 59.17%. The viabilities until the pre-pupal stage were 76.26, 70.03, 65.36, 49.59, 31.76, and 22.68% with 2.5, 5, 10, 15, 20, and 25% of the neem oil, respectively. The larval stage of this pest (3rd instar to pre-pupa) lasted longer in the 20% neem oil treatment than at the other rates, but its longevity was not affected. Anticarsia gemmatalis pupae presented developmental interruptions and anomalies at all concentrations of neem oil. The commercial product Bioneem® (neem oil) can therefore be used as a suitable alternative to synthetic insecticides to control A. gemmatalis.

Biological and Ecological Consequences of Diolcogaster sp. (Hymenoptera: Braconidae) Parasitizing Agaraea minuta (Lepidoptera: Arctiidae) and the Effects on Two Costus (Costaceae) Plant Species in Brazil

ABSTRACT Costus spicatus (Jacq.) Sw. and Costus spiralis (Jacq.) Roscoe var. spiralis (Costaceae) are economically important plants due to their pharmacological and medicinal properties and ornamental value. These plants are natives from the Brazilian Atlantic Rainforest and are fed upon by Agaraea minuta Schaus, 1892 (Lepidoptera: Arctiidae). This study describes the damage done by A. minuta on C. spicatus and C. spiralis and the biological and ecological aspects of parasitism of A. minuta by Diolcogaster sp. (Hymenoptera: Braconidae). Twenty stems of C. spicatus and C. spiralis with 100 last-instar caterpillars of A. minuta, were collected per plant in each of 2 years. The stem heights (F, P > 0.05), leaf lengths (F, P > 0.05), leaf widths (F, P > 0.05) and the number of leaves per stem (F, P > 0.05) of both plant species; number of pupae obtained from caterpillars of A. minuta (F, P > 0.05), adult emergence of this defoliator (F, P > 0.05) and of Diolcogaster sp. (F, P > 0.05) were similar during the 2 study periods. Agaraea minuta fed on C. spicatus and C. spiralis, and Diolcogaster sp. was shown to be a parasitoid suppressor of populations of this defoliator.