José Cola Zanuncio

Desenvolvimento de Thyrinteina arnobia Stoll (Lepidoptera: Geometridae) em folhas de Eucalyptus urophylla e Psidium guajava

The development of Thyrinteina arnobia Stoll (Lepidoptera: Geometridae) caterpillars fed either on Eucalyptus urophylla or Psidium guajava (Myrtaceae) leaves was studied in laboratory. The first instar was the most critical for survival of this insect in both diets. Shortest larval period (27 days) was obtained for males on guava leaves, with the longest one for caterpillars which originated females or males with E. urophylla leaves (37 days). No insects feeding on guava leaves which originated males reached six instar while the sexual ratio with this diet was 0.6. With E. urophylla leaves, 58.3% of males presented six instars with a sexual ratio of 0.3. The width of head capsules of the caterpillars, for both sexes, was significantly different in both diets, being bigger for those fed with guava leaves, with rates of 4.3; 6.2; 10.0 and 13.0%, from the second to the fifth instar, respectively. This rate reached 28.0% in the sixth instar, corresponding to an increase of 113.0% in relation to the previous instar, indicating that individuals fed on guava leaves are stronger and more vigorous than those fed on E. urophylla. Largest width of the head capsule was associated to high viability and short duration of the larval period for individuals fed on guava leaves what suggests that this diet is more suitable for rearing this insect. T. arnobia is a native pest of guava and probably it is not adapted to feed on Eucalyptus yet.

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.

Extrato da glândula de feromônio na atração e estimulação alimentar de ninfas de Podisus nigrispinus (Dallas) e Supputius cincticeps (Stal)

Estudou-se o efeito do extrato de glândulas dorso-abdominais, produtoras de feromonio sexual de Podisus nigrispinus (Dallas) e de Supputius cincticeps (Stal) (Heteroptera: Pentatomidae), adicionadas em dieta artificial, como atrativo e estimulante alimentar para ninfas desses predadores, comparado com ninfas criadas somente em dieta artificial ou com presas alternativas. O extrato de glândulas pincelado sobre a dieta artificial, apresentou atratividade em 88% de ninfas de P. nigrispinus alimentando-se desta dieta, semelhante aquelas sobre dieta pincelada e contendo o extrato em mistura (10% v/p) (84%) e aquelas alimentadas com a presa alternativa Musca domestica L. (Diptera: Muscidae) (100%). S. cincticeps, apresentou 60 e 56% de ninfas alimentando-se sobre as mesmas dietas, o que foi menor que a percentagem de ninfas alimentando-se na presa alternativa Tenebrio molitor L. (Coleoptera: Tenebrionidae) (92%). Ninfas de P. nigrispinus e de S. cincticeps, apresentaram pesos semelhantes, com a dieta artificial sem mistura (2,7 e 1,3 mg), com extrato de glândula (2,8 e 1,6 mg), pincelada com o extrato (2,1 e 1,0 mg) e com a dieta artificial com extrato de glândula e pincelada com o mesmo (2,4 e 1,2 mg), respectivamente. No entanto, esses pesos, foram inferiores aqueles obtidos com a presa alternativa (3,1 e 3,0 mg).

Aspectos biológicos de Thyrinteina arnobia (Lep.: Geometriadae) provenientes de lagartas criadas em folhas de Eucalyptus cloeziana ou de Psidium guajava sob condições de campo

Eucalyptus plantations in Brazil may be damaged by native insects of many orders including Orthoptera, Coleoptera and Lepidoptera. These insects feed on Brazilian tree species of the family Myrtaceae to which the genus Eucalyptus belongs. The Lepidoptera Thyrinteina arnobia Stoll (Lepidoptera: Geometridae) is the most harmful defoliator of Eucalyptus in Brazil. The objective of this work was to evaluate biological aspects of T. arnobia adults originated from caterpillars fed on guava or eucalyptus plants. Adults of T. arnobia originated from caterpillars reared with eucalyptus or guava leaves presented significant differences for most biological aspects evaluated, except for duration of preoviposition and oviposition periods and sex ratio. This shows that species feeding on host plants related to eucalyptus can cause considerable damage in reforestation with species of this genus. T. arnobia insects are still undergoing an imposed adaptation process to eucalyptus plants and likely feed on these plants to escape from pressure by physical and chemical barriers of Brazilian native Myrtaceae.

Qualidade da semente e senescencia de genotipos de soja sob dois niveis de infestacao de percevejos (Pentatomidae).

The objective of this research was to evaluate the genotypes CR-1 and CR-3, from the genetic improvement program of soybean flavor of the Federal University of Vicosa, in Vicosa, MG, Brazil, under two levels of Heteroptera infestation. The genotypes tested were CR-1, CR-3, Cristalina, Davis (susceptible genotype) and IAC-100 (resistant genotype). The genotypes CR-1, CR-3, Davis and Cristalina under low level of infestation (2.8 Heteroptera/beating) produced similar percentage of normal seeds (57%) but inferior to the genotype IAC-100 (77%). Under high level of infestation (6.42 Heteroptera/beating), the genotypes CR-1, CR-3 and Cristalina produced similar percentage of normal seeds but inferior to the genotypes Davis (43%) and IAC-100 (59%). All genotypes showed low level of leaves retention (less than 6%) when cultivated under low level of infestation by Heteroptera but under high level of infestation of these bugs, the genotypes CR-1 and IAC-100 showed smallest level of leaf retention (less than 5%) followed by Davis and CR-3 (6-20%) and Cristalina (21-40%). The genotypes CR-1, IAC-100 and Davis showed no green stem under low infestation, contrary to what was registered for CR-3 (3.6% green stem) and Cristalina (11% green stem). IAC-100, CR-1, and Davis showed the smallest percentages of plants with green stem (6.4, 10.3 and 18.3%, respectively) compared to CR-3 (64.8%) and Cristalina (77.3%).

Chrysoperla externa (Neuroptera: Chrysopidae) and Utetheisa ornatrix (Lepidoptera: Arctiidae) on organically grown Crotalaria juncea (Fabaceae)

Chrysoperla externa (Neuroptera: Chrysopidae) larvae can avoid foraging on plants of Crotalaria juncea (Fabaceae) after the issuance of floral buds, when the prey of Utetheisa ornatrix (Lepidoptera: Arctiidae) incorporate toxic pyrrolizidine alkaloids from this plant. This reduces the predation and favors increasing the number of adults and eggs of this defoliator on crops of this plant. The aim of the present paper was to evaluate some biological and ecological aspects of C. externa and U. ornatrix on the organic crop of C. juncea in the EMBRAPA Maize and Sorghum in Sete Lagoas, Minas Gerais State, Brazil. Chrysoperla externa and U. ornatrix were more abundant in the vegetative and flowering stages of C. juncea, respectively, with caterpillars of this defoliator feeding on leaves and seeds of this plant. The duration of the stages/instars, survival, lifetime fecundity, and oviposition showed that the branches of C. juncea are a suitable food for U. ornatrix. The abundance of adults and larvae of C. externa was lower in the flowering and pods stages of C. juncea, respectively, when the postures of U. ornatrix are present, probably due to the toxicity of the eggs of this prey to this predator. During these stages, C. externa may be reared with alternative hosts, and when the crops of C. juncea are scarce, an artificial diet should be used for rearing this defoliator in the laboratory for biological research and the development of biological control tactics.

EFFECT OF TEMPERATURE ON THE REPRODUCTION OF BRACON VULGARIS ASHMEAD (HYMENOPTERA: BRACONIDAE), A PARASITOID OF THE COTTON BOLL WEEVIL'

ABSTRACT: This research studied the effect of temperature on the reproduction of Bracon vulgaris Ashmead (Hymenoptera: Braconidae), an ectoparasitoid of the cotton boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae), in climatic chambers, using constant temperatures of 20, 25, and 30°C, relative air humidity of 70 ± 10% and a photophase of 14 h. Females of the parasitoid produced a greater number of eggs when exposed to 25°C (124.65 eggs) in relation to those exposed to 20 (43.40 eggs) and 30°C (49.60 eggs). The mean number of parasitized larvae per female of B. vulgaris at 25°C (71.75) was greater than at 20°C (31.40) and 30°C (25.15). The daily intrinsic rates of increase (rm) were -0.007 at 20°C, 0.07 at 25°C and 0.03 at 30°C, revealing that the temperature of 25°C produced increases of 1,100 and 133% in the value rm in relation to the temperatures of 20 and 30°C, respectively. In programs of biological control of the boll weevil using innoculative releases, adult females of B. vulgaris with approximately five (at 25 or 30°C) or 20 day old (at 20°C) should be used; when using innundative releases, adult females of B. vulgaris, with ages between 11 and 31; 9 and 29 or 3 and 14 days of age, respectively, at 20, 25, or 30°C should be used.

Hyperchiria incisa incisa (Lepidoptera: Saturniidae) on Plants of Clitoria fairchildiana in ViÇOsa, Minas Gerais State, Brazil

ABSTRACT. Clitoria fairchildiana Howard (Fabaceae) is a rustic and rapidly growing species with a broad leafy crown. This species naturally occurs in secondary forest of the Amazon region. In Brazil, this plant is also used in landscaping of streets, squares, roads and parking lots. This study identified a lepidopteran defoliator of C. fairchildiana at the Federal University of Viçosa in Viçosa, Minas Gerais State, Brazil. This species was identified as Hyperchiria incisa incisa Walker, 1855 (Lepidoptera: Saturniidae: Hemileucinae). Larvae of this insect are yellowish-brown at early instars and pale green in the last ones with its body almost completely covered with stinging spines at all stages. Hyperchiria incisa incisa should be included in pest monitoring programs of C. fairchildiana.

LIFE HISTORY NOTES ON THE SAWFLY HAPLOSTEGUS NIGRICRUS CONDE (HYMENOPTERA: PERGIDAE) ON PSIDIUM GUAJAVA (MYRTACEAE) IN MINAS GERAIS STATE, BRAZIL

Abstract The life history of Haplostegus nigricrus Conde (Hymenoptera: Pergidae), a leaf-feeding sawfly of Psidium guajava L. (Myrtaceae), was studied in Viçosa, Minas Gerais State, Brazil. The life history and morphology are compared with those of Haplostegus epimelas Konow (Hymenoptera: Pergidae), another species that feeds on guava leaves. Haplostegus nigricrus females oviposit in the midrib of guava, and larvae feed on the leaves. Late-instar larvae drop to the ground and construct a cell for pupation. Cocoons are made individually with soil particles and other substrate. Three occurrence peaks of female adults were observed for H. nigricrus and two for H. epimelas. No males of H. nigricrus were found. The importance of this study to the knowledge of South American Pergidae is discussed. Abstract Resumo.—A história de vida de Haplostegus nigricrus Conde (Hymenoptera: Pergidae), um Symphyta desfolhador de Psidium guajava L. (Myrtaceae), foi estudada em Viçosa, Estado de Minas Gerais, Brasil. A história de vida e a morfologia desse inseto são comparadas com as de Haplostegus epimelas Konow (Hymenoptera: Pergidae), outra espécie de Symphyta que se alimenta de folhas de goiabeira. Larvas de H. nigricrus alimentam-se das folhas de goiabeira e as fêmeas ovipositam em sua nervura principal. Larvas de ultimo estádio descem até o chão onde constroem uma célula para empupar. Os casulos são confeccionados individualmente com partículas de solo e outros substratos. Três picos de ocorrência para fêmeas adultas foram observados para H. nigricrus e dois para H. epimelas. Machos de H. nigricrus não foram capturados. A importância desse estudo para o conhecimento dos Pergidae Sul-Americanos é discutida.

Multivariate approach to quantitative analysis of Aphis gossypii Glover (Hemiptera: Aphididae) and their natural enemy populations at different cotton spacings

The relationship between pests and natural enemies using multivariate analysis on cotton in different spacing has not been documented yet. Using multivariate approaches is possible to optimize strategies to control Aphis gossypii at different crop spacings because the possibility of a better use of the aphid sampling strategies as well as the conservation and release of its natural enemies. The aims of the study were (i) to characterize the temporal abundance data of aphids and its natural enemies using principal components, (ii) to analyze the degree of correlation between the insects and between groups of variables (pests and natural enemies), (iii) to identify the main natural enemies responsible for regulating A. gossypii populations, and (iv) to investigate the similarities in arthropod occurrence patterns at different spacings of cotton crops over two seasons. High correlations in the occurrence of Scymnus rubicundus with aphids are shown through principal component analysis and through the important role the species plays in canonical correlation analysis. Clustering the presence of apterous aphids matches the pattern verified for Chrysoperla externa at the three different spacings between rows. Our results indicate that S. rubicundus is the main candidate to regulate the aphid populations in all spacings studied.