Controle de plantas daninhas em cultivos orgânicos de soja por meio de descarga elétrica

Dois experimentos foram instalados em semeadura direta, em área de cultivo orgânico de soja, no município de São Miguel do Iguaçu, Paraná (PR), com o objetivo de avaliar o controle de plantas daninhas na cultura da soja (BRS 232) por meio de descarga elétrica. O delineamento experimental foi blocos casualizados, com quatro repetições. No experimento 1, fixou-se a voltagem de 4400V e,no experimento 2, de 6800V. Em ambos os experimentos,os tratamentos consistiram das variações de rotação do motor do trator (i) 2200rpm (rotações por minutos); (ii) 2000rpm;(iii)1600rpm e as testemunhas(iv) capinada e (v) sem capina. O equipamento utilizado para aplicação dos tratamentos foi o Eletroherb (Sayyou do Brasil). As plantas daninhas existentes na área experimental foram o amendoim-bravo (Euphorbia heterophylla), a corda de-viola (Ipomoea spp.), a guanxuma (Sida spp.), o capim-marmelada(Brachiaria plantaginea) e o capim-colchão (Digitaria spp.). O emprego de descarga elétrica é eficiente no controle das plantas daninhas da cultura da soja. A rotação 2200rpm proporcionou o melhor controle e, consequentemente, a maior produtividade da soja

Bagging to protect calla lily flowers against stingless bee (Trigona spinipes)

Stingless bee Trigona spinipes (Hymenoptera: Apidae) is an important pest of calla lily, Zantedeschia aethiopica (L.), damaging flowers, especially the spadix. The aim was to identify the most efficient packaging for bagging calla lily inflorescences, aiming to protect against the attack of stingless bee and to maintain postharvest quality. The experiment was carried out in a calla lily plantation cultivated in soil under 50% shading screen. Treatments consisted in bagging calla lily flowers with: 1) brown kraft paper bag, 2) non-woven fabric (NWF) bag; 3) transparent plastic bag, 4) transparent micro-perforated plastic bag and 5) control (without bagging). The experimental design was completely randomized with 25 replicates and one inflorescence per plot. Inflorescences received treatments when they presented definitive color, but still with completely closed spathe. Seven days after bagging, inflorescences were collected and evaluated for damages caused by insects in the field and the postharvest characteristics. Postharvest quality evaluations of inflorescences were performed for 12 days, observing expansion of the spathe in length and width, stem weight and visual quality expressed by the number of days that remained in each class. The bagging of calla lily inflorescences was efficient in the control of stingless bee, regardless of packaging used, because under these conditions, no inflorescence presented damage. In control, 84% of damaged inflorescences were observed. Differences in postharvest characteristics were observed and inflorescences remained for longer periods in the process of spathe opening, which is characterized by the measurement of their length and width, when packed. Among packages, NWF allowed longer spathe length at the 6th day of evaluation, larger width at 7th day of evaluation and less fresh mass loss at the end of the experiment (8%). In control, reduction of spathe measurements from the first day of evaluation and loss of 11% of fresh mass were observed. It was concluded that NWF is an efficient packaging to protect calla lily against the attack of stingless bee without compromising the postharvest quality of inflorescences

Bees (Hymenoptera: Apidae) present in the flowers of the balsa wood Ochroma lagopus Swartz, 1788 - doi: 10.4025/actascibiolsci.v32i4.7103

The flower of balsa wood holds about 10 to 15 mL of nectar, which helps attracting pollinating agents, since the genus Ochroma is incapable of self-fertilization. However, a high mortality of bees is observed in these flowers. The present study investigated the frequency and constancy of mortality of the individuals of the family Apidae that fed on nectar from the balsa wood. Data was gathered from June to August 2008, in Lavras – Minas Gerais State, Brazil. In addition, the survival of the Africanized bees that fed on the nectar of this flower was compared to those that fed on 50% aqueous solution of honey. Forty flowers were analyzed, and 949 individuals of the orders Hymenoptera (98.1%), Hemiptera (0.95%), Coleoptera (0.74%) and Diptera (0.21%) were collected. Most Hymenoptera individuals were bees of the genera Partamona and Trigona (677 individuals), which were considered of constant occurrence. Flowers producing up to 16.7 nectar mL were found. The nectar diet contained 16.44% of total sugar, and resulted in low survival of the bees in laboratory (31.32 ± 2.37 hours), compared to a diet of 50% aqueous solution of honey (112.32 ± 2.03 hours).The flower of balsa wood holds about 10 to 15 mL of nectar, which helps attracting pollinating agents, since the genus Ochroma is incapable of self-fertilization. However, a high mortality of bees is observed in these flowers. The present study investigated the frequency and constancy of mortality of the individuals of the family Apidae that fed on nectar from the balsa wood. Data was gathered from June to August 2008, in Lavras – Minas Gerais State, Brazil. In addition, the survival of the Africanized bees that fed on the nectar of this flower was compared to those that fed on 50% aqueous solution of honey. Forty flowers were analyzed, and 949 individuals of the orders Hymenoptera (98.1%), Hemiptera (0.95%), Coleoptera (0.74%) and Diptera (0.21%) were collected. Most Hymenoptera individuals were bees of the genera Partamona and Trigona (677 individuals), which were considered of constant occurrence. Flowers producing up to 16.7 nectar mL were found. The nectar diet contained 16.44% of total sugar, and resulted in low survival of the bees in laboratory (31.32 ± 2.37 hours), compared to a diet of 50% aqueous solution of honey (112.32 ± 2.03 hours)

Bees (Hymenoptera: Apidae) present in the flowers of the balsa wood Ochroma lagopus Swartz, 1788 = Abelhas (Hymenoptera: Apidae) associadas às flores do pau-de-balsa Ochroma lagopus Swartz, 1788

The flower of balsa wood holds about 10 to 15 mL of nectar, which helps attracting pollinating agents, since the genus Ochroma is incapable of self-fertilization. However, a high mortality of bees is observed in these flowers. The present study investigated the frequency and constancy of mortality of the individuals of the familyApidae that fed on nectar from the balsa wood. Data was gathered from June to August 2008, in Lavras – Minas Gerais State, Brazil. In addition, the survival of the Africanized bees that fed on the nectar of this flower was compared to those that fed on 50% aqueous solution of honey. Forty flowers were analyzed, and 949 individuals of the orders Hymenoptera (98.1%), Hemiptera (0.95%), Coleoptera (0.74%) and Diptera (0.21%) were collected. Most Hymenoptera individuals were bees of the genera Partamona and Trigona (677 individuals), which were considered of constant occurrence. Flowers producing up to 16.7 nectar mL were found. The nectar diet contained 16.44% of total sugar, and resulted in low survival of the bees in laboratory (31.32 . 2.37 hours), compared to a diet of 50% aqueous solution of honey (112.32 .2.03 hours).A flor do pau-de-balsa produz cerca de 10 a 15 mL de néctar, útil na atração de polinizadores, uma vez que o gênero Ochroma é incapaz de fazer autofecundação. É observada intensa mortalidade de abelhas em suas flores. Objetivou-se realizar o levantamento da frequência e constância de mortalidade de indivíduos da família Apidae, sendo os dados levantados no período de junho a agosto de 2008 em Lavras, MinasGerais, Brasil. Além disso, avaliou-se a sobrevivência de abelhas africanizadas alimentadas com o néctar desta flor quando comparados com aquelas alimentadas com solução aquosa de mel a 50%. Foram analisadas 40 flores e coletados 949 indivíduos das Ordens: Hymenoptera (98,1%), Hemiptera (0,95%), Coleoptera (0,74%) e Diptera (0,21%). Dentre os himenópteros os mais frequentes foram dos gêneros Partamona e Trigona com 677 indivíduos, sendo estes considerados de incidência constante. Observaram-se flores com até 16,7 mL de néctar. O néctar apresentou 16,44% de açúcares totais e baixa sobrevivência das abelhas em laboratório (31,32 . 2,37h) quando comparadas com a dieta à base de mel (112,32 . 2,03h)

Inversão da sacarose utilizando ácido cítrico e suco de limão para preparo de dieta energética de Apis mellifera Linnaeus, 1758 Inversion of the sucrose using citric acid and lemon juice for preparing energetic diet of Apis mellifera Linnaeus, 1758

Em época de escassez de néctar, pode-se fornecer ao enxame uma suplementação alimentar utilizando "açúcar invertido" que é obtido pela hidrólise da sacarose em meio ácido por aquecimento, formando uma mistura de glicose e frutose. O ácido normalmente utilizado em tal reação é o ácido cítrico, no entanto, diante da dificuldade de pequenos produtores apícolas em obterem tal produto comercialmente, uma alternativa seria substituí-lo pela utilização de suco de limões. Sendo assim, o objetivo deste trabalho foi quantificar a inversão da sacarose em dietas para operárias de Apis mellifera, empregando-se o ácido cítrico e sucos de limões. Prepararam-se 21 soluções aquosas de açúcar cristal na proporção de 100 g/100 mL, colocando-se em cada uma 1,0; 2,0; 3,0; 5,0; 10,0; 15,0 ou 20,0 mL de suco dos limões Galego [Citrus aurantifolia (C.) Swingle], Tahiti [Citrus latifolia Tanaka] ou Cravo [Citrus limonia (L.) Osbeck]. Além dessas, outras seis soluções aquosas de açúcar na mesma proporção foram preparadas adicionando-se 0,1; 0,16; 0,3; 0,5 e 0,7 g de ácido cítrico e uma para testemunha. Quantificou-se a inversão pelo método de Somogyi-Nelson. Para o limão Cravo foi encontrada a menor porcentagem de inversão. Em relação a adição de ácido cítrico, constatou-se que ao colocar 0,1 g, a inversão foi estimada em 12,2% enquanto que, com a adição de 0,16 g, a inversão seria de 18,8%. A quantidade máxima de ácido cítrico a ser adicionada foi estimada em 0,18 g adotando como critério o pH médio de 3,3 dos méis de abelhas africanizadas. Para os sucos dos limões Galego, Tahiti e Cravo, quando utilizados como substitutos do ácido cítrico, estimou-se a quantidade máxima a ser adicionada sendo igual a 2,1; 3,6 e 5,3 mL, respectivamente, para cada 100 g de açúcar em 100 mL de água, para o pH fixado em 3,3. Considerando-se a inversão e o pH, o suco do limão Tahiti forneceu melhores resultados.<br>In times of nectar shortage, food supplementation using "inverted sugar" obtained by sucrose hydrolysis in an acid environment by heating can be supplied to the hive, forming a glucose and fructose mixture. The acid usually used in such a reaction is the citric acid, however, due to the difficulty that small producers have to obtain the product commercially, an alternative would be to replace it with lemon juice. The objective of this work was to quantify the inversion of sucrose present in Apis mellifera worker diets by employing commercial citric acid and lemon juice. A total of 21 aqueous solutions of granulated sugar at the proportion of 100 g/100 mL were prepared, placing in each one 1.0; 2.0; 3.0; 5.0; 10.0; 15.0 or 20.0 mL of the juices of the Galego [Citrus aurantifolia (C.) Swingle], Tahiti [Citrus latifolia Tanaka] or Cravo [Citrus limonia (L.) Osbeck] lemon varieties. In addition to those, six other aqueous sucrose solutions were prepared by adding 0.0 (control); 0.16; 0.3; 0.5 and 0.7 g citric acid. Sucrose inversion was quantified by using the Somogyi-Nelson method. For the Cravo lemon, the lowest inversion rate was found. Regarding the addition of citric acid, it was estimated that in placing 0.1 g, the inversion was of 12.2% while with 0.16 g, an inversion of 18.8% sucrose present in the solution. The maximum amount of citric acid to be added was estimated to be 0.18 g, adopting as a criterion the mean pH of 3.3 in Africanized bee honey. If Galego, Tahiti and Cravo lemon juices are used as replacements for the citric acid, the maximum added amount should be 2.1, 3.6 and 5.3 mL, respectively, for each 100 g sugar/100 mL water, at fixed pH of 3.3. Considering the inversion rate and pH level recommended for the use of citric acid, Tahiti lemon juice provides better results

Eficiência do Bacillus thuringiensis var. kurstaki (Berliner, 1915) no controle da traça da cera Galleria mellonella (Linnaeus, 1758) (Lepidoptera: Pyralidae) Efficiency of Bacillus thuringiensis var. kurstaki (Berliner, 1915) for control of the greater wax moth Galleria mellonella (Linnaeus, 1758) (Lepidoptera: Pyralidae)

Objetivou-se avaliar a eficiência do Bacillus thuringiensis var. kurstaki (Berliner) no controle de Galleria mellonella (Linnaeus). Os experimentos foram realizados no Laboratório de Biologia de Insetos do Departamento de Entomologia da Universidade Federal de Lavras - UFLA, Lavras, MG, a 28±2ºC, UR 70±10% e fotofase de 12 horas. Aplicou-se formulação comercial de B. thuringiensis var. kurstaki por meio de pulverização, imersão dos favos e também foi incorporada à dieta artificial fornecida às lagartas de terceiro ínstar da traça da cera. A aplicação do produto fitossanitário por meio da pulverização dos favos mostrou-se eficiente no controle de lagartas, atingindo níveis iguais ou superiores a 85% de mortalidade quando foram utilizados 5 g/100 mL de água. Na aplicação por imersão dos favos, todas as dosagens testadas foram eficientes atingindo até 100% de mortalidade. Adicionada à dieta artificial, a concentração com maior porcentagem de mortalidade foi de 10g/60g de dieta. Sintomas de infecção pelo B. thuringiensis foram identificados nas lagartas e o isolamento da bactéria, por meio de uma cultura de Bacillus, comprovou a causa da morte desses insetos em todas as dosagens da formulação comercial do B. thuringiensis var. kurstaki utilizadas.<br>This research aim at evaluating the efficiency of Bacillus thruringiensis var. kurstaki (Berliner) in the control of Galleria mellonella (Linnaeus).The experiments were conducted in the Insect Biology Laboratory of the Entomology Department of the Universidade Federal de Lavras - UFLA, Lavras, MG, Brazil, at 28±2ºC, RH 70±10% and 12-hour photophase. Commercial formulation of B. thuringiensis. var. kurstaki was applied through spraying, comb soaking and also incorporated into the artificial diet fed to third instar caterpillars of the greater wax moth. Application of B. thuringiensis var. kurstaki through the spraying of the combs was efficient for control, reaching levels equal or larger than 85% of mortality when 5 g/100 mL of water were utilized. In the application by soaking of the combs all the dosages tested were efficient reaching up to 100% of mortality. Added to the artificial diet, the concentration with the greatest percentage of mortality was of 10 g/60 g of diet. Symptoms of infection by B. thruringiensis were identified both in the caterpillars and the isolation of the bacterium through a culture of Bacillus, proved to be the responsible of mortality of those insects at all the dosages of commercial formulation of B. thuringiensis var. kurstaki utilized