Alci Enimar Loeck

Monitoramento de agrotóxicos em dois mananciais hídricos no sul do Brasil

The objective of this study was to evaluate and to monitor the presence of pesticides in the waters of the Sao Goncalo channel and the Piratini river located in the southern region of the State of Rio Grande do Sul. During the rice growing season, water samples were collected five times, three samples from the river Piratini and four from the Sao Goncalo canal. The methodology used for the analysis of residues of quinclorac, carbofuran and clomazone was the High Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD) and for residues of the pesticides fipronil and betacyfluthrin, the Gas Chromatography with Electron Capture Detection (GC-ECD) was used. Results show that from sowing to harvesting the quantity of pesticide residues in water decreased. It was also observed that, at the lowest point (Laranjal), a greater number of analyses contaminated with residues was detected (11 samples with some type of pesticide). Insecticide carbofuran and herbicide quinclorac were pesticides that presented residues more frequently (16 and 15 times, respectively). Clomazone and fipronil were present in each of the 7 samples with residues and betacyfluthrin was not detected at any site.

Epigeic ants (Hymenoptera: Formicidae) in vineyards and grassland areas in the Campanha region, state of Rio Grande do Sul, Brazil

In order to characterize the epigeic myrmecofauna in fields and vineyards in the physiographic region of Campanha, located in the Pampa biome, state of Rio Grande do Sul, inventories were conducted on three farms. On each farm, samples were collected in three environments: the rows in the vineyards, the spaces between rows in the vineyards, and the adjacent areas, with vegetation similar to that which preceded the establishment of crops. In each environment, 20 points were sampled using pitfall traps. We collected 72 species distributed among 24 genera and seven subfamilies. The study provides the first inventory of the ant fauna in the region, contributing with new records for the state of Rio Grande do Sul and for Brazil. It is hoped that this inventory will stimulate further studies on the biodiversity of this biome that is still poorly known.

Crescimento do fungo simbionte de formigas cortadeiras do gênero Acromyrmex em meios de cultura com diferentes extratos

The cutter ants show preference for some vegetable species, which are constantly defoliated, while others are not attacked, although they are abundant and located close to the nest. The ants of the goods Atta and Acromyrmex cut plants and they transport pieces to the anthills. The vegetable material is used for the cultivation of the mushroom Leucoagaricus gongylophorus, mushroom from of which theyfeed. Several works using extracts of plants have been accomplished to evaluate the effect on the development of the mushroom symbiont. The objective of this work was to evaluate the influence of added culture means of different extracts on the growth of the L. gongylophorus mushroom. Where mushrooms of the species Acromyrmex ambiguus, Acromyrmex crassispinus, Acromyrmex heyeri and Acromyrmex lundi were inoculated in the means Nutritious Agar and BDA, both added of molasses and extracts of Lolium multiflorum Lam., Typha angustifolia L. and ant (Atta sexdens piriventris). The Pagnocca medium was used as pattern. The plates were maintained in cameras acclimatized to the temperature of 25 + 1°C and 24 hours of darkness, for a period of 49 days. The fungal growth was evaluated with base in the diameter of the colony, which was accomplished with weekly intervals, totalizing seven evaluations. Also the dry weight was evaluated from the mushroom to the 53 days. The results showed that the mushroom cultivated by different species of ants has differentiated growth in culture means with different extracts.

Controle de Sitophilus zeamais Mots., 1855 (Coleoptera: Curculionidae) com inseticidas empregados em frutíferas temperadas

The maize weevil Sitophilus zeamais Mots. has frequently occurred in temperate fruits in the field, damaging peaches in Pelotas, RS, apples in Fraiburgo, SC and grapes in Serra Gaucha, RS, Brazil. This work evaluated in laboratory, the effect of deltamethrine (Decis 25 CE, 40mL 100L-1), dimetoate (Dimetoato CE 150mL 100L-1), thrichlorphon (Dipterex 500 SNAqC 300mL 100L-1), phosmet (Imidan 500 PM, 200g 100L-1), fenthion (Lebaycid 500 CE 100mL 100L-1), chlorpiriphos (Lorsban 480 BR, 150mL 100L-1), malathion (Malation 1000, 200mL 100L-1), carbaryl (Sevin 480 SC, 360mL 100L-1), fenitrothion (Sumithion 500 CE, 150mL 100L-1) and methidathion (Supracid 400 CE, 100mL 100L-1) commonly used in temperate fruit pest control and the new insecticides thiamethoxam (Actara 250 WG, 15 e 30g 100L-1), emamectin benzoate (Proclaim 5 SG, 10 e 20g 100L-1), imidacloprid (Provado 200 SC, 30 e 60mL 100L-1), spinosad (Tracer 480 CE, 10 e 20mL 100L-1) and etofenprox (Trebon 100 SC, 100 e 150mL 100L-1). Experiments were conducted treating apple fruits with an insecticide solution per 10 seconds (residual contact) and offered to adults of S. zeamais sp, and by spraying compounds directly on adults (direct contact). The insecticides trichlorfon (150g 100L-1), fenthion (50g 100L-1), chlorpiriphos (72g 100L-1), malathion (200g 100L-1), methidathion (40g 100L-1) and thiamethoxam (3.75 and 7.5g 100L-1) were efficient in the control of the maize weevil by residual contact. Fenthion (50g 100L-1), chlorpiriphos (72g 100L-1), malathion (200g 100L-1), fenitrothion (75g 100L-1) and methidathion (40g 100L-1) were efficient by direct contact.

Growth of symbiont fungi of some higher attine ants in mineral medium

Bioassays were conducted to verify the possibility of culturing the symbiont fungus of some higher attine in mineral medium and finding out the optimum pH value for their satisfactory mycelial growth. Three organic media and one mineral medium were inoculated with isolates from Atta sexdens piriventris and Acromyrmex heyeri. In mineral medium different values of pH (4.0, 5.0, 6.0 and 7.0) were tested with isolates from A. laevigata and A. laticeps. The behavior of isolates (colony diameter) was different in the mineral medium. However, even the one which grew the least of all provided enough mycelial for RAPD analysis. The best range of pH for fungal growth in mineral medium was between 4.0 and 5.0

ADEQUAÇÃO DE UMA DIETA ARTIFICIAL PARA OS BIÓTIPOS "MILHO" E "ARROZ" DE SPODOPTERA FRUGIPERDA (LEPIDOPTERA: NOCTUIDAE) ( 1 )

Spodoptera frugiperda is considered one of the main pest in corn and irrigated rice (fall armyworm) crops, causing high leaf losses. The objective of this study was to obtain an appropriate artificial diet to rear the biotypes “corn” and “rice” of S. frugiperda in laboratory. The insects were collected in areas cultivated with corn and irrigated rice in the meadow ecosystem and the identification was accomplished by the analysis of the DNA genomic. The development of the two biotypes was accompanied on Greene’s diet and the same diet modified to 25 ± 1oC, UR of 70 10% and fotofase of 14 hours. The study was accomplished with 150 larvae by diet individualized in glass tubes containing artificial diet. At emergency 20 couples were individualized and fed with aqueous solution of honey to 10%. The Greene diet made possible better development of the two biotypes, providing larger development speed, larger weight of larvae in the maximum development, weight of pupas and total fecundity, besides higher values of the net reproductive rates, intrinsic and finite rates of increase.

Aspectos biológicos de Argyrotaenia sphaleropa (Meyrick 1909)(Lepidoptera: Tortricidae) em Dietas Artificiais com Diferentes Fontes Proteicas

Biology aspects of Argyrotaenia sphaleropa Meyrick fed on artificial diets with different protein sources were studied: D1-white bean, wheat germ, soybean protein and casein; D2-common bean and yeast and D3-common bean, yeast and wheat germ, evaluating the duration and viability of all developmental stages (egg, larval, prepupa and pupa) and of the total cycle (egg-adult), sex ratio, pupa weight, fecundity, longevity and life table of fertility. Tests were conducted in the laboratory at 25±1°C, 65±10% RH and 14h of photophase. Duration of the egg stage was 6.6 days on all diets. The longest duration of larval and prepupal stages on D1 and pupal stages on D2, resulting in a longer duration of the total cycle on these two diets (30,9 and 30,8 days). The total viability was higher than 62% on all diets, and there was no statistical difference among the treatments. The number of instars was four or five on all treatments. The lowest fecundity was observed in D1. Based on the fertility life table, D3 was the most suitable diet for rearing A. sphaleropa, due to the lowest development time (T), the highest finite increasing rate (l), and total viability exceeding 75%.

Oxicenus maxwelli (Keifer) (Acari: Eriophyidae) danificando a cultura da oliveira, Olea europaea L., no Estado do Rio Grande do Sul

O micro acaro da oliveira Oxicenus maxwelli (Keifer, 1939) foi identificado em pomares de oliveira nos municipios de Santana do Livramento, Bage, Candiota, Pelotas e Rio Grande, RS, nos meses de novembro de 2010 a fevereiro de 2011. A especie foi encontrada nas faces superior e inferior de folhas jovens, em flores e brotos, onde causa deformacoes, queda de folhas e flores, diminuicao da fotossintese e superbrotacao, prejudicando a producao da planta e a comercializacao dos frutos deformados. Este e o primeiro registro da especie atacando a oliveira no Estado do Rio Grande do Sul.

Consumo foliar de cultivares de arroz irrigado por Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Mean foliage consumption by fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) was measured, for each sex and instar, in laboratory conditions, on rice leaves of cultivars BR-IRGA 410 and Embrapa 6-CHUI. No significant difference of total leaf consumption was observed among caterpillars that developed males or females. Differences were observed among instars with the seventh one being responsible for the higher total consumption. Duration of larval stage was not different for males and females on both cultivars but significant differences were observed in the duration of different instars, independently of sex. The seventh instar was the longest and represented the higher daily consumption. Average daily consumption was similar to male and females in the instars tested, in both cultivars, and increased considerably after the fifth instar.

Biology of Fopius arisanus (Hymenoptera: Braconidae) in Two Species of Fruit Flies.

Fopius arisanus (Sonan, 1932) (Hymenoptera: Braconidae) is an egg–larval parasitoid used in control programs of Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann). In Brazil, C. capitata and Anastrepha fraterculus (Wiedemann) are considered the main tephritid pests of exotic and indigenous fruits. The objective of this study was to study the biology of F. arisanus in C. capitata and A. fraterculus. Eggs of the two fruit fly species were used to determine the parasitism rate, number of offspring, emergence rate, sex ratio, adult weight and longevity of male and female F. arisanus. These biological parameters were used to develop a fertility life table. We observed higher parasitism and emergence rates of adults, a shorter duration of the egg–adult period and a sex ratio biased to females when F. arisanus was reared in eggs of C. capitata than in those of A. fraterculus. However, adults of F. arisanus from eggs of A. fraterculus were heavier and had greater longevity than those obtained from C. capitata eggs. The fertility life table showed better biological and reproductive performance for F. arisanus reared in eggs of C. capitata, although eggs of A. fraterculus also provided positive values for population increase.