Daniel Bernardi

Efficacy of indigenous entomopathogenic nematodes (Rhabditida: Heterorhabditidae, Steinernematidae), from Rio Grande do Sul Brazil, against Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) in peach orchards.

Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD(90) of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm(2), respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm(2) of either nematode. In the field, H. bacteriophora RS88 and S. riobravae RS59 sprayed individually over natural and artificially infested fruit (250IJs/cm(2)) resulted in A. fraterculus larval mortality of 51.3%, 28.1% and 20%, 24.3%, respectively. There was no significant difference in A. fraterculus pupal mortality sprayed with an aqueous suspension of either nematode; however, when using infected insect cadavers, H. bacteriophora RS88 was more efficient than S. riobrave RS59. Our results showed that H. bacteriophora RS88 was more virulent to insect larvae, with an efficient host search inside the infested fruit and control of pupae in the soil after being applied by aqueous suspension or infected cadavers.

Biology and fertility life table of the green aphid Chaetosiphon fragaefolli on strawberry cultivars.

Abstract Our objective was to study the biology and develop a fertility life table for the aphid Chaetosiphon fragaefolli (Cockerell) (Hemiptera: Aphididae) on leaves of strawberry, Fragaria × ananassa, Duchesne ex Rozier (Rosales: Rosaceae), of the cultivars Albion, Aromas, Camarosa, Camino Real, Diamante, Earlibrite, and Saborosa. This study was conducted under controlled conditions: 25 ± 1 °C, 70 ± 10% RH, and 12:12 L:D . Arenas were set up consisting of leaves inside Petri dishes containing 3% agar. Female aphids obtained after the last nymphal ecdysis were individually placed in arenas for 24 hours. The following biological parameters were evaluated: duration and survival of the nymph stage and of the life cycle (nymph-nymph), daily and total fecundity, and adult longevity. The aphids completed their biological cycle on all of the cultivars. The shortest durations (in days) of the nymphal stage were on the cultivars Camino Real and Camarosa (8.67 and 8.74 days, respectively), and the longest was on Aromas (11.12 days). The lowest survival was on cultivar Aromas (51%) and the highest on Saborosa (96%). When the time to development to the adult stage was compared, the aphids developed fastest (14.63 days) and survival was highest (96%) on cultivar Saborosa. Aphids reared on cultivar Aromas leaves had the longest pre—reproductive period (8.74 days), the greatest longevity (26.88 days), and the longest duration of the life cycle (19.76 days). Based on the fertility life table, cultivars Camarosa and Saborosa were the most favorable for development of C. fragaefolli, while Albion and Aromas were the most inadequate for aphid development.

Resistência de genótipos de milho para cultivo em várzeas subtropicais à lagarta-do-cartucho Spodoptera frugiperda

Spodoptera frugiperda e uma das pragas com elevado potencial para causar perdas economicas na cultura do milho, no ecossistema de varzeas subtropicais. Com o objetivo de identificar fontes de resistencia, foi avaliado, em laboratorio, o desenvolvimento de S. frugiperda em nove genotipos de milho. Cem lagartas recem-eclodidas foram individualizadas em tubos de vidro, contendo porcoes de folhas de milho, mantidos a temperatura de 25±1°C, umidade relativa de 70±10% e fotofase de 14h. Avaliaram-se a duracao e a viabilidade das fases de larva e pupa, o peso de larvas e de pupas e a mortalidade larval. Dentre os genotipos avaliados, destacaram-se o BRS Missoes-B e o BR 111 VI Sel. Dent C, os quais afetaram, respectivamente, o desenvolvimento da fase de larva e de pupa.

Activity of eight strains of entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae) against five stored product pests.

Stored product pests are responsible for losses that can amount 10% during cereal storage in the world. Aiming to find an alternative method to the chemicals used for the stored-product pests, eight strains of entomopathogenic nematodes (EPNs) were tested against five species of stored product pests. The bioassays were conducted in microtubes containing paper, inoculated with EPNs and insect diet. All the insect species were susceptible to the EPNs strains. Anagasta kuehniella and Tenebrio molitor larvae and Acanthoscelides obtectus adults were highly sensitive to the higher doses with most species and/or strains of EPNs. Adults of Sitophilus oryzae and Sitophilus zeamais were relatively less sensitive to all EPNs. Therefore, EPNs show as potential control agents for stored products pests in prophylactic applications in warehouses.

Coleópteros coletados com armadilhas luminosas e etanólicas em plantio de Eucalyptus spp. no Sul do Rio Grande do Sul

The objective of this study was to collect, identify and study population fluctuation of Coleoptera species in a forest of Eucalyptus spp., on a farm in the municipality of Pinheiro Machado, Rio Grande do Sul State. Insects were collected with light traps and ethanol traps, once every fifteen days, in the period of February 2006 to October 2007. The insects, after selection procedures, were identified based on entomological collections and specialized literature. A total of 6172 individuals were collected and distributed among 40 families and 249 species, of which 130 were identified at the species level and 119 at the family level, representing 4498 and 1674 of total individuals collected, respectively. Cyclocephala sp. 1, Cyclocephala sp. 2, Dyscinetus sp. 1, Euetheola humilis (Scarabaeidae) and Neoclytus curvatus (Cerambycidae) were the most abundant species, representing 49.28% of the individuals identified in genus and/or species. Scarabaeidae presented the highest number of individuals (2588), distributed in 37 species. The families Cerambycidae (47) and Scolytidae (40) presented the largest number of species. Individuals of Coleoptera were trapped at all collections but the largest number of individuals was trapped in December 2006 and March 2007.

Pó-de-basalto no desenvolvimento de plantas de alface e na dinâmica populacional de insetos

The aim of this work was to evaluate effect of the application of basalt powders from three different origins via soil (incorporation) and aerial (spraying) application in the performance of lettuce plants and in the population dynamics of phytophagous insects, respectively. Lettuce seedlings cv. Veronica at 8 days after emergence were transplanted to raised beds after the incorporation of the basalt powders. The effects on plant development were evaluated 50 days after transplantation and the parameters assessed were: plant height, growth of root system, dry mass, insertion diameter, volume of the root system and chlorophyll and carotenoid contents. Insect population dynamics was performed after the application of 100 g of basalt powder diluted in two liters of water (2 L ha) through four sprayings with intervals of 10 days between each. Sampling was performed daily and the insects collected were separated and identified. There was a significant increase in the variables plant height, growth of root system and dry mass in the treatments with the incorporation of basalt powder in the soil when compared to the control treatment. There was also a significant increase of 36% and 20% in the chlorophyll and carotenoid contents in lettuce leaves, respectively. There was no significant difference in the volume of the root system and insertion diameter between the treatments. The aerial spraying on lettuce plants with different basalt powders directly influenced the insect population dynamics with a significant decrease in the number of insects collected in all treatments.

Importance of Sugar for the Development of Diatraea saccharalis (Lepidoptera: Crambidae) on Artificial Diet

To obtain insects with biological characteristics similar to those of wild insects, this study evaluated the development of Diatraea saccharalis (Fabricius) reared on artificial diet containing different sugar concentrations. First-instar caterpillars were fed seven artificial diets containing 0, 6.56, 13.13, 26.26, 52.52, 105.04, and 210.08 g of sugar per liter of diet. We evaluated the duration and viability of developmental stages, weight of pupae, fecundity and longevity of generations F1, F2, F4, F6, and F8. The artificial diet containing 26.26 and 52.52 g of sugar per liter provided the greatest viability of insects (above 75%) for the egg-adult period for eight consecutive generations, and was higher (P < 0.05) than other treatments, where viability was lower than 50%. Based on the fertility life table in F8 generation, the highest reproductive rates (Ro) were obtained in insects fed the artificial diet containing 26.26 (Ro = 126.39) and 52.52 g of sugar (Ro = 147.31). Conversely, insects to other diets presented the highest values of biological cycle duration (T = 55 d) and reductions of 50 and 90% on intrinsic rate of increase (rm = 0.0063, 0.079, 0.077, and 0.064) and finite rate of increase (λ = 1.001, 1.082, 1.081, and 1.006), respectively. We conclude that sugar is essential for the development of D. saccharalis and that amounts of 26.26 and 52.52 g per liter of diet are suitable for the rearing and multiplication of insects in laboratory.

Pathogenicity of Metarhizium anisopliae isolates on Nezara viridula and Dichelops melacanthus in wheat crop

Arq. Inst. Biol., v.84, 1-8, e0032016, 2017 RESUMO: Os percevejos Nezaraviridula (Linnaeus) e o Dichelops melacanthus (Dallas) são considerados os principais insetos-pragas na cultura do trigo no Brasil. A utilização do fungo entomopatogênico Metarhiziumanisopliae (Metschnikoff) pode ser uma alternativa para o manejo destes insetos na cultura. O objetivo do trabalho foi verificar a patogenicidade de diferentes isolados de M.anisopliae sobre adultos de N. viridula ou D. melacanthus em condições de laboratório e casa de vegetação. Em laboratório, os isolados 05RA, 11RA, 08RA e 02RA provenientes de adultos de N. viridula ou D. melacanthus, infestados a campo pelo fungo M. anisopliae, apresentaram elevada patogenicidade (100% de mortalidade) de ambas as espécies em bioensaio de aplicação tópica 8 dias após aplicação (DAA). Entretanto, o isolado 08RA apresentou a maior patogenicidade em um menor intervalo de tempo para N. viridula (Tempo Médio “TM” = 2,8 dias) e D. melacanthus (TM = 4,0 dias) em relação aos demais isolados. Em casa de vegetação, o isolado 08RA proporcionou mortalidade de 44,9% (N. viridula) e 35,7% (D. melacanthus) no mesmo período de avaliação. Contudo, aos 14 DAA, a mortalidade foi de 100% para ambas as espécies, com valores de TM de 8 dias e 10 dias para N. viridula e D. melacanthus, respectivamente. O fungo M. anisopliae constitui uma alternativa promissora de controle de adultos de N. viridula ou D. melacanthus na cultura do trigo.

Besouros cerambycidae associados a Eucalyptus spp. no município de Pinheiro Machado, RS

The objective of this study was to collect, identify and carry out a faunistic characterization of Cerambycidae occurring in a forest of Eucalyptus spp., on Sao Manoel farm, in the municipality of Pinheiro Machado, RS. In the period from February 2006 to October 2007, collections of insects were performed every 15 days, with three ethanol traps. After selection procedures, the Cerambycidae were identified based on entomological collections and specialized literature. We collected 692 insects, distributed among 29 genera and 40 species. The most abundant species were Acanthoderes jaspidea , Chlorida costata , Compsocerus barbicornis , Eburodacrys sp., Eurysthea hirta , Neoclytus curvatus and Nyssodrysina lignaria , which represented 81.17% of the total individuals. Cerambycidae were collected during practically the entire sampling period, but the largest number at a single collection occurred in the month of December. Several species demonstrate potential for damaging Eucalyptus spp., of which Neoclytus curvatus deserves the most attention, because it represented almost half of the insects collected.