Population fluctuation of Gyropsylla spegazziniana (Lizer y Trelles) (Hemiptera: Psyllidae) in two cropping systems of Ilex paraguariensis A. St.-Hil. (Aquifoliaceae).

The psyllid Gyropsylla spegazziniana is a key pest of maté crop in Southern Brazil, and its incidence has increased as a result of the extensive monoculture cropping system. The objective of this research was to compare the occurrence and population fluctuation of G. spegazziniana in native and high tree density cropping systems. The experiment was carried out in the county of São Mateus do Sul, state of Paraná, Brazil. The number of galls per tree and the natural enemies were counted and two types of yellow traps were used to collect the psyllids. The population of G. spegazziniana was noticeably higher in the high density area. The population peak occurred from November to January, when high temperatures were recorded. Larvae of predatory Syrphidae (Diptera) were observed in more than 70% of the galls.A ampola-da-erva-mate, Gyropsylla spegazziniana, é uma das pragas-chave da cultura da erva-mate no Sul do Brasil, cuja ocorrência tem aumentado em função do monocultivo extensivo. O objetivo desta pesquisa foi comparar a ocorrência e flutuação populacional de G. spegazziniana em sistemas de cultivo de erva-mate nativo e adensado. O experimento foi realizado no município de São Mateus do Sul, estado do Paraná, Brasil. A amostragem dos insetos foi feita usando-se dois tipos de armadilhas amarelas e por inspeção das plantas, contando-se o número de ampolas e de inimigos naturais. As populações de G. spegazziniana foram mais elevadas na área adensada, com o pico populacional de novembro a janeiro, quando foram registradas as temperaturas mais altas do período. A presença de larvas de Syrphidae (Diptera), predadoras de ninfas de G. spegazziniana, foi registrada em mais de 70% das ampolas

Tabelas de vida e de fertilidade de Pineus boerneri Annand (Hemiptera: Adelgidae) em Pinus spp. (Pinaceae).

Parâmetros biológicos de Pineus boerneri foram avaliados em laboratório em mudas de Pinus taeda e Pinus elliottii. As ninfas foram acompanhadas durante seu desenvolvimento. O período total do ciclo de vida não diferiu significativamente nas duas espécies, respectivamente 69 dias em P. taeda e 65 em P. elliottii. O mesmo ocorreu com a fecundidade média, com 40 ovos/fêmea em P. taeda e 53 em P. elliottii. Porém, considerando a fecundidade média diária, houve diferença significativa com 1,3 ovos/fêmea/dia em P. taeda e 1,8 ovos/fêmea/dia em P. elliottii. A taxa de mortalidade ninfal foi mais alta em P. taeda (50%) do que em P. elliottii (28%). Esse padrão refletiu-se na esperança de vida que foi maior em P. elliottii no estágio ninfal, mas semelhante no estágio adulto nas duas plantas hospedeiras. A capacidade inata da espécie para aumentar em número e a razão finita de aumento foram semelhantes, indicando a mesma capacidade reprodutiva nos dois hospedeiros. A taxa líquida de reprodução foi significativamente maior em P. elliottii (23,8 ovos/fêmea) que em P. taeda (15,4). As maiores taxas de sobrevivência ninfal e reprodutiva em P. elliottii evidenciam que esta planta é mais propícia para o desenvolvimento de P. boerneri. Biological parameters of Pineus boerneri were evaluated in laboratory using seedlings of Pinus taeda and Pinus elliottii. The nymphs were observed along their development. The total life cycle was not significantly different on P. taeda and P. elliottii, being, respectively, 69 and 65 days. The same trend was observed for mean fecundity, being about 40 eggs/female on P. taeda and 53 on P. elliottii. However, when daily mean fecundity was considered, the difference was significant, being 1.3 eggs/female/day on P. taeda and 1.8 on P. elliottii. The nymphal mortality was greater on P. taeda (50%) than on P. elliottii (28%). These results reflected on life expectancy which was higher on P. elliottii for the nymphal stage, but for the adult stage there was no significant difference between both host plants. The intrinsic rate of natural increase and the finite rate of increase were similar, indicating that P. boerneri shows the same reproductive capacity on both hosts, despite the net reproductive rate being much greater on P. elliottii (23.8 eggs/female) than on P. taeda (15.4). The highest nymphal survival and reproductive rates on P. elliottii indicate that this host plant is more suitable for the development of P. boerneri

EFICÁCIA DE TERRA DE DIATOMÁCEA E TEMPERATURA PARA O CONTROLE DO GORGULHO-DO-MILHO EM MILHO ARMAZENADO

Treatment with diatomaceous earth (DE) is an efficient insect control technique in integrated pest management programs of stored grain. Its main advantages are: low toxicity to mammals and long lasting efficacy. The objective of this research was to evaluate the efficacy of DE under different doses and temperatures to control Sitophilus zeamais in stored maize. In vials with 100 g of clean and dry corn kernels, 30 non-sexed 7-14 day-old adults of S. zeamais were submitted to the following treatments in three replicates: DE (Keepdry®) at 500, 750 and 1000 mg kg-1, at 15, 25 and 30 °C. The mortality was evaluated from the 1st to the 28th day. After this period, the adults were removed and the progeny was kept until the 56th day, when the insects were counted and the grain moisture content evaluated. The effect of temperature on S. zeamais mortality was significant for the three DE doses. The 750 and 1000 mg kg-1 doses caused the highest mortality at 25 °C and 30 °C, but with no significant difference between them. The progeny development was significantly higher in the control compared to the treatments with DE; there was no significant difference in the number of progeny among the three DE doses at any of the temperatures studied. The results support the use of DE as an effective grain protectant against S. zeamais in stored corn.O tratamento com Terra de Diatomácea (TD) é uma técnica eficiente para o controle de insetos em programa de manejo integrado de grãos armazenados. Suas principais vantagens são: baixa toxicidade para mamíferos e períodos de eficácia mais longos. O objetivo deste trabalho foi avaliar a eficácia de TD em diferentes doses e temperaturas para o controle de Sitophilus zeamais em milho armazenado. Em frascos com 100 g de milho limpo e seco, foram colocados 30 adultos de S. zeamais não sexados de 7 a 14 dias de idade, e submetidos aos seguintes tratamentos com três repetições: TD (Keepdry®) a 500, 750 e 1000 mg kg-1, mantidos a 15, 25 e 30 °C. A mortalidade foi avaliada entre o 1° e o 28° dia. Após este período, os adultos foram removidos e a progênie mantida até o 56° dia quando foi contado o número de insetos e avaliado o teor de umidade dos grãos. O efeito da temperatura na mortalidade S. zeamais foi significativo para as três doses de TD. As doses de 750 e 1000 mg kg-1 proporcionaram a maior mortalidade a 25 °C e 30 °C, mas sem diferenças significativas entre elas. O desenvolvimento da progênie foi altamente significativo no controle comparado ao grão tratado com TD; não foi constatada diferença significativa na progênie entre as três doses de TD nas temperaturas estudadas. Os resultados suportam o uso de TD como um protetor eficiente para o controle de S. zeamais em milho armazenado

FORRAGEAMENTO DA ABELHA AFRICANIZADA NA FLORADA DA BRACATINGA

O experimento foi desenvolvido no Município de Mandirituba, Paraná, com o objetivo de avaliar o forrageamento das operárias de Apis mellifera L. em inflorescências de Bracatinga. As operárias foram coletadas com rede entomológica, entre 10h e 16h, em oito dias ensolarados, no período de 5 a 28 de agosto de 2001. As abelhas capturadas foram imediatamente anestesiadas para que o conteúdo do papo fosse avaliado com refratômetro manual para medir a concentração de sólidos solúveis totais (açúcares) no néctar. Em média, 27,02 ± 9,88% das operárias forrageavam néctar e pólen ao mesmo tempo, com o pico de abelhas portando néctar às 15h e de pólen às 13h. Diferenças estatísticas foram observadas na concentração de açúcares no néctar entre as horas do dia que variou de 18,5% a 36,8%, com o pico às 13h. A concentração de açúcares no néctar apresentou uma correlação positiva direta e moderada com a temperatura; foi inversamente correlacionada com a umidade relativa no ar; e não apresentou correlação significativa com a luminosidade.This experiment was conducted in Municipality of Mandirituba, Paraná, to assess the foraging behavior of Apis mellifera L. workers on Bracatinga flowers. The worker bees were collected using an insect net from 10h to 16h, during eight sunny days, from August 5 to 28, 2001. The bees were immediately anesthetized and the crop content was evaluated using a manual refractometer to measure the total soluble sugar in the nectar. On average 27.02 ± 9.88% of the bees presented nectar and pollen simultaneously, with the peak of bees carrying nectar at 3 p.m. and pollen at 1 p.m. Statistical differences were observed on nectar sugar concentration amongst hours of the day varying from 18.5% to 36.8%, with the peak at 1 p.m. The sugar concentration in the nectar was moderate and directly correlated to temperature; inversely correlated to relative humidity; and was not correlated to luminosity

INFESTAÇÃO E DANOS DE Cinara atlantica RELACIONADOS COM O ESTADO NUTRICIONAL E HÍDRICO EM MUDAS DE Pinus taeda L.

The response of Cinara atlantica population to the nutritional status of recently planted seedlings of P. taeda was evaluated on field, in Três Barras city in the state of Santa Catarina, and to water stress in greenhouse, in Colombo city, Paraná state. In the greenhouse, 4 treatments were tested with 30 plants each treatment: non-stressed seedlings (at 60% of field capacity) and the stressed ones (at only 30% of field capacity), with and without insects. Each plant was infested with 10 nymphs of 3rd and 4th instars. Weekly, the number of aphids was counted, the height and diameter of the plants were measured, the nutritional status of the needles were analyzed and the volume of water applied accordingly. It was observed that the recently-planted seedlings were less attractive to C. atlantica because of their low N content condition caused by planting stress. The infestation of the water stressed plants in the greenhouse was the double of the population on the non-stressed plants. Plant height increased directly proportional to the aphid infestation and the impact of the insects was equivalent to that resulting from the water stress. The infested seedlings also presented an increasing in diameter, but there was no influence of water stress.Foi avaliada a resposta de populações de Cinara atlantica ao estado nutricional de mudas de Pinus taeda L., em condições de campo no município de Três Barras (SC), e ao estresse hídrico, em casa de vegetação em Colombo (PR). Em casa de vegetação, foram avaliados 4 tratamentos com 30 mudas cada: plantas não-estressadas (com 60% da capacidade de campo) e estressadas (com 30% da capacidade de campo), ambos com e sem insetos. Cada planta foi infestada com 10 ninfas de 3º e 4º instar. Semanalmente, era contado o número de afídeos, medidos a altura e o diâmetro de todas as plantas e acrescentado o volume de água correspondente. Em campo, foram plantadas 60 plantas, das quais, quinzenalmente, 15 plantas eram arrancadas ao acaso, contando-se o número de afídeos por planta e analisando-se o estado nutricional, durante dois meses. Constatou-se que o aumento do teor de nitrogênio nas mudas de P. taeda correlaciona-se diretamente com o aumento no número de insetos. As mudas com estresse hídrico apresentaram maiores teores de nitrogênio e incidência de pulgões. Em casa de vegetação, as plantas apresentaram menor crescimento em altura na presença de insetos, com ou sem estresse hídrico. As mudas infestadas apresentaram maior crescimento em diâmetro, independentemente do estresse hídrico, no tempo observado e condições do estudo

Pineus boerneri Annand, 1928 (Hemiptera, Adelgidae) - a new species to Brazil: morphology of eggs, nymphs and adults

Pineus boerneri Annand, 1928 (Hemiptera, Adelgidae) _ a new species to Brazil: morphology of eggs, nymphs and adults. Pineus boerneri represents the first Adelgidae species recorded in Brazil. This aphid species forms extensive colonies on branches and trunk of Pinus spp., with apterous oviparous females, eggs and nymphs covered with white wax. The aim of this research is to study the morphology of eggs, nymphs, and adults to provide useful data for species identification in order to solve taxonomic issues. The study was based on morphometric data and optical and scanning electron microscopy images. First instar nymphs are active and can be easily distinguished from the others by their elongate minute yellowish body; well developed legs bearing a pair of sensorial setae at the apex of the second tarsomere; and antenna with three segments with a large rhinarium and distinct apical setae on the last segment. From the second to the fourth instar, nymphs are sessile, with round red body; they loose the third antennal segment and its sensorial structures, as well as the setae on the second tarsomere. The oviparous female is reddish-brown, with round body with about 0.76 mm diameter; legs reduced; antennae one-segmented; ovipositor distinct; numerous wax glands are present, mainly on the head. Accurate characterization of the species and distinction of the nymphal instars of P. boerneri were made possible by canonical analysis of morphometric data and morphological characters

Combination of diatomaceous earth and powder deltamethrin for insect control in stored corn

The use of diatomaceous earth (DE) is a very efficient insect control measure in stored grain IPM due to its low cost, easy application, reduction of active ingredient residues, lower environmental contamination and operator safety. The objective of this research was to evaluate the efficacy of different dosages of DE mixed with powder deltamethrin for controlling Sitophilus zeamais in stored corn. Samples of 100 g of clean and dry corn, in three replicates, were submitted to the following treatments: DE (Keepdry®), at the dosages of 500, 750 and 1000 g/t; powder deltamethrin (K-Obiol®) at 0,5 g a.i. /t and 1,0 g a.i. /t; and combinations of the lowest and highest DE dosages with the two dosages of deltamethrin. Thirty adults of S. zeamais were placed in each vial with the treated grains and kept in environment chambers at 25ºC. Mortality was evaluated from the 1st to the 28th day. In the treatments mixing DE with deltamethrin or deltamethrin alone, the mortalyti was registered since the first day. In the treatments using only DE, the first dead insects were recorded after the 3rd day, especially in the highest dosages. After the 7th day, however, there was no statistical difference among all treatments, except for the lowest dosage of DE which reached a satisfactory control level only by the 14th day. It was concluded that treatments using DE combined with low dosages of powder deltamethrin represent an efficient control measure against S. zeamais in stored corn because insect mortality is faster than in treatments using DE alone and residues of active ingredients are much lower than using the insecticide in high dosages