The carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae), is an insect pest in carrot production in Ontario. The aim of this study was to survey the egg parasitoids attacking the carrot weevil in carrot fields in Ontario, and elucidate the seasonal and chemical ecology of these natural enemies. / Field surveys were conducted during three years in commercial carrot fields in the Holland Marsh and district marshes to detect the presence of carrot weevil egg parasitoids, to determine their geographical distribution and to evaluate the effect of insecticides on the rate of emergence and the activity of parasitoid adults. Two egg parasitoids, Anaphes listronoti Huber and A. victus Huber were found. The dominant species Anaphes listronoti is gregarious, was recovered from most of the sampled fields and was distributed in all sampled marshes whereas the solitary parasitoid A. victus was only sporadically found in the Holland Marsh. These Anaphes species occurred in carrot fields from the end of April to the beginning of September and seasonal parasitism averaged 33% in commercial carrot fields and up to 79% in an untreated plot. The insecticides phosmet, diazinon and cypermethrin used in carrot production, did not affect emergence rate of parasitoid adults indicating that immature stages are protected against insecticide penetration in the host egg. However, insecticide applications decreased parasitism rates and suggest a lethal effect on parasitoid adults by direct contact and insecticide residues, although no difference was observed between treatments. / Laboratory studies were performed to determine the existence of a sexual pheromone produced by female A. listronoti using a four-arm olfactometer. An automated system of insect tracking was developed to quantify male behavior in the olfactometer. The response of males to odor emitted by virgin females less than two days of age was measured. Virgin females less than one-day-old released a long-range pheromone from 4 hours until 16 hours after the onset of the photophase. Females of one and two days of age started to emit the sexual pheromone earlier than younger females.

A somatic embryogenic system was created using material from the British Columbia Ministry of Forests and Range’s Sitka Spruce (Picea sitchensis (Bong.) Carr) breeding program for resistance to the white pine weevil (Pissodes strobi Peck.). The goal was to provide a system that could aid in understanding the phenotypic and genotypic variation that exists in these traits. Embryogenic lines were derived from controlled crosses of parental genotypes previously ranked for the abundance of three physical bark traits: sclereid cells, constitutive resin canals and traumatic resin canals. The number of filled seeds per cone from controlled pollinations was low, with a mean of 9.4 ± 6.8 (mean ± SD), compared to open-pollinated material, which had greater than 40 seeds per cone. The mean induction rate (to embryogenic cultures) was 7 %, ranging from 0 % to 56 % by cross. Of 135 genotypes, 88.1 % produced mature embryos. The number of embryos produced varied by culture. Nearly all (44 of 45) genotypes germinated, with a mean germination rate of 80 %. The overall conversion rate of somatic embryos to plants was 5.5 %. A novel method of cryopreservation that used a temperature pretreatment but did not require dimethyl sulfoxide was tested. Embryogenic cultures were recovered from 31 % of genotypes (n = 112). Genotypic and phenotypic variation were observed during each stage of the somatic embryogenic process. This project demonstrated that somatic embryogenesis and cryopreservation can be used to create a system to study phenotypic and genotypic variation in Sitka spruce. / Graduate

Thesis--Virginia Polytechnic Institute and State University. / Also available via the Internet.

Made available in DSpace on 2016-03-07T19:20:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-10-01. Added 1 bitstream(s) on 2016-03-07T19:24:06Z : No. of bitstreams: 1 000858038.pdf: 2029297 bytes, checksum: 32eca951c39a9154e19ceffc8c5311f5 (MD5) / O bicudo-do-algodoeiro, Anthonomus grandis, é a principal praga da cotonicultura mundial e o conhecimento de sua bioecologia e distribuição na cultura é indispensável para realizar amostragens e determinar o momento adequado de seu controle. O objetivo deste trabalho foi estudar a dinâmica populacional, a distribuição vertical e espacial de A. grandis, bem como elaborar um plano de amostragem sequencial para essa praga. Os experimentos foram conduzidos nos anos agrícolas 2012/13 e 2013/14, na Estação Experimental da Fundação MS, em Maracaju, MS, em um campo de 10.000 m2, subdividido em 100 parcelas de 10 x 10 m. A cultivar utilizada foi FM 993, semeada com 80 cm de espaçamento entrelinha. Para a condução da cultura foram utilizados fungicidas, herbicidas e o regulador de crescimento, exceto inseticidas. Semanalmente foram avaliadas cinco plantas por parcela e registrou-se o número de botões florais com orifícios de alimentação, oviposição e de adultos de A. grandis em cada estrato das plantas (terço superior, médio e inferior). Para o estudo da dispersão da praga na área, foram utilizados os índices: razão variância/média, índice de Morisita, Coeficiente de Green e expoente k da distribuição Binomial Negativa. Para estudo dos modelos probabilísticos que descrevem a distribuição espacial dos insetos, foram testados os ajustes às distribuições de Poisson e Binomial Negativa. O plano de amostragem sequencial foi elaborado com base no Teste Sequencial da Razão da Máxima Verossimilhança, e foi utilizado o nível de controle de 10% dos botões florais atacados (alimentação + oviposição) e o nível de segurança de 5% de botões florais atacados (alimentação + oviposição). O valor do erro tipo I e do erro tipo II utilizado foi 0,05, o mais indicado para estudos com insetos. A distribuição espacial dos botões florais utilizados para alimentação e para oviposição foi de forma agregada até... / The cotton boll weevil Anthonomus grandis is the main pest of cotton crop worldwide, and the knowledge of its bioecology and distribution is essential to carry out sampling and determine the right time of your control. The main purpose of this study was to evaluate the population dynamics, vertical and spatial distribution of A. grandis and prepare a sequential sampling plan for this pest. The experiments were conducted in two seasons, 2012/13 and 2013/14, at the Experimental Station of the Foundation MS, in Maracaju, MS, in a field of 10,000 m2, divided into 100 plots of 10 x 10 m. The cultivar used was FM 993, seeded 80 cm rows apart. For the crop development were used fungicides, herbicides and growth regulators, except insecticides. Five plants per plot were weekly evaluated and recorded the number of flower buds with feeding and oviposition punctures, and adults of A. grandis in each part of five plants (upper, middle and lower). To dispersion study of A. grandis in the area, the following indexes were used: variance/mean ration, Morisita index, Green coefficient and k exponent of negative binomial distribution. To study the probabilistic models that describes the spatial distribution of insects, adjustments to Poisson and Negative Binomial distributions were tested. The sequential sampling plan was based on Maximum Likelihood Reason Sequential Test, and used the threshold level of 10% of attacked flower buds (feeding + oviposition) and the security level of 5% of attacked flower buds (feeding + oviposition). The values of type I and type II errors used was 0.05, the most suitable for insect studies. The spatial distribution of flower buds with feeding and oviposition was aggregate up to 85 DAE, with best fit to the Negative Binomial distribution, and as of this date was random, with best fit to the Poisson distribution. Adults of A. grandis are randomly distributed in the area, with best fit to Poisson distribution throughout ...

Orientador: Antonio Carlos Busoli / Coorientador: Marcos Gino Fernandes / Banca: José Carlos Barbosa / Banca: Raphael de Campos Castilho / Banca: Marcos Doniseti Michelotto / Banca: Crébio José Ávila / Resumo: O bicudo-do-algodoeiro, Anthonomus grandis, é a principal praga da cotonicultura mundial e o conhecimento de sua bioecologia e distribuição na cultura é indispensável para realizar amostragens e determinar o momento adequado de seu controle. O objetivo deste trabalho foi estudar a dinâmica populacional, a distribuição vertical e espacial de A. grandis, bem como elaborar um plano de amostragem sequencial para essa praga. Os experimentos foram conduzidos nos anos agrícolas 2012/13 e 2013/14, na Estação Experimental da Fundação MS, em Maracaju, MS, em um campo de 10.000 m2, subdividido em 100 parcelas de 10 x 10 m. A cultivar utilizada foi FM 993, semeada com 80 cm de espaçamento entrelinha. Para a condução da cultura foram utilizados fungicidas, herbicidas e o regulador de crescimento, exceto inseticidas. Semanalmente foram avaliadas cinco plantas por parcela e registrou-se o número de botões florais com orifícios de alimentação, oviposição e de adultos de A. grandis em cada estrato das plantas (terço superior, médio e inferior). Para o estudo da dispersão da praga na área, foram utilizados os índices: razão variância/média, índice de Morisita, Coeficiente de Green e expoente k da distribuição Binomial Negativa. Para estudo dos modelos probabilísticos que descrevem a distribuição espacial dos insetos, foram testados os ajustes às distribuições de Poisson e Binomial Negativa. O plano de amostragem sequencial foi elaborado com base no Teste Sequencial da Razão da Máxima Verossimilhança, e foi utilizado o nível de controle de 10% dos botões florais atacados (alimentação + oviposição) e o nível de segurança de 5% de botões florais atacados (alimentação + oviposição). O valor do erro tipo I e do erro tipo II utilizado foi 0,05, o mais indicado para estudos com insetos. A distribuição espacial dos botões florais utilizados para alimentação e para oviposição foi de forma agregada até... / Abstract: The cotton boll weevil Anthonomus grandis is the main pest of cotton crop worldwide, and the knowledge of its bioecology and distribution is essential to carry out sampling and determine the right time of your control. The main purpose of this study was to evaluate the population dynamics, vertical and spatial distribution of A. grandis and prepare a sequential sampling plan for this pest. The experiments were conducted in two seasons, 2012/13 and 2013/14, at the Experimental Station of the Foundation MS, in Maracaju, MS, in a field of 10,000 m2, divided into 100 plots of 10 x 10 m. The cultivar used was FM 993, seeded 80 cm rows apart. For the crop development were used fungicides, herbicides and growth regulators, except insecticides. Five plants per plot were weekly evaluated and recorded the number of flower buds with feeding and oviposition punctures, and adults of A. grandis in each part of five plants (upper, middle and lower). To dispersion study of A. grandis in the area, the following indexes were used: variance/mean ration, Morisita index, Green coefficient and k exponent of negative binomial distribution. To study the probabilistic models that describes the spatial distribution of insects, adjustments to Poisson and Negative Binomial distributions were tested. The sequential sampling plan was based on Maximum Likelihood Reason Sequential Test, and used the threshold level of 10% of attacked flower buds (feeding + oviposition) and the security level of 5% of attacked flower buds (feeding + oviposition). The values of type I and type II errors used was 0.05, the most suitable for insect studies. The spatial distribution of flower buds with feeding and oviposition was aggregate up to 85 DAE, with best fit to the Negative Binomial distribution, and as of this date was random, with best fit to the Poisson distribution. Adults of A. grandis are randomly distributed in the area, with best fit to Poisson distribution throughout ... / Doutor

No description available.

The alfalfa weevil, Hypera postica (Gyllenhal), was first found in the United States in Salt Lake City, Utah, during 1904 (Titus, 1910b). It spread form this point of original introduction and partially infested Cache Valley by 1912 (Titus, 1913). The alfalfa weevil has become one of the more important insect problems currently affecting American agriculture. Recently, this problem has attracted national attention because of the development of resistance to insecticides by the alfalfa weevil, the outlawing of certain pesticides for use on forage crops and the rapid spread of the alfalfa weevil to new areas. With this increased attention, many discrepancies have appeared in different reports of the alfalfa weevil's biology. The results of studies in the eastern United States often do not agree with those of studies which were made in Utah and vicinity during the early part of this century. In order to investigate the discrepancies or differences, and to determine the behavior patterns of the alfalfa weevil in Cache Valley, this study was undertaken. It was conducted from June, 1965 to August, 1966. The main topics investigated were the adult alfalfa weevil's flight activities, reproduction, daily field activities, seasonal history including diapause, and respiration under controlled conditions.

No description available.

A biological and integrated control program for Carduus thistles was developed using the biological control agents Rhinocyllus conicus Froelich and Ceuthorhynchidius horridus (Panzer) and the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D). Field studies on the development of Ceuthorhynchidius horridus (Panzer) on Carduus thistles in Virginia between 1975-1978 showed that the weevil has one generation annually. Oviposition occurred from mid-December until early April, and larvae occurred in rosettes from late December through late May. Teneral adults, which appeared in mid-May through June, underwent an aestival diapause during most of July through September. Adult reappearance in late September coincided with an increase in feeding. Although adult feeding marks, teneral adults and first and third instar larvae were easily found in the field, detection of eggs, second instars or overwintering adults was difficult and time consuming. Acute and chronic effects of spring application of 2,4-D (LVA) on adult C. horridus were examined. LC₅₀ values for males (70.2 kg/ha) and females (61.4 kg/ha) corresponded to 41.7 and 36.6 times, respectively, the recommended application rate of 1.68 kg/ha. Treatment with 1.68 kg/ha did not affect adult survival, but increased dosages (16.8-147.8 kg/ha) caused significantly greater mortality. Adult vitality, measured by number of feeding marks/weevil and weight change/time, was unaffected by the herbicide. Field application of herbicides did not prevent survival, reproduction, or population increase of C. horridus. Herbicidal effect on larval R. conicus was studied by examining the mortality, emergence rates and weights of weevils developing from plants treated with 2,4-D (LVA). Infested heads, obtained by caging ovipositing R. conicus on primary heads of musk thistle (Carduus nutans L.) (resembles C. thoermeri Weinmann), were treated with 2,4-D at 1.68 kg/ha 0-3 weeks after oviposition. Blooms treated immediately following oviposition failed to support larval development beyond the second instar. Developmental times and weights of weevils that emerged from blooms sprayed at 1, 2, and 3 weeks were not significantly different from controls. Plants sprayed up to 2 weeks after oviposition (late-bud to early-bloom) did not produce viable seeds. Treatments at 3 weeks after oviposition (full-bloom) allowed 10% germination of seeds not damaged by R. conicus in primary heads, and plants survived to produce additional heads. Acute and chronic effects of the herbicide 2,4-D on adult R. conicus were also examined. LC₅₀ values for adults prior to over-wintering (males 78.6 kg/ha; females 61.0 kg/ha) were lower than those for overwintered weevils (males 117.1 kg/ha; females 126.6 kg/ha), but were still at least 40 times the recommended application rate of 1.68 kg/ha. Survival was not significantly affected by direct application of 2,4-D at 1.68 kg/ha plus sticker or by exposure to herbicide sprays and residue while on musk thistle rosettes. Mean egg production/ovipositing female/3 day period was not significantly different (range = 5.44 - 7.60), regardless of the 2,4-D dosage applied (range = 0.0 - 147.84 kg/ha); all ovipositing weevils produced viable eggs. Field treatment with up to 2.24 kg/ha of 2,4-D resulted in death of host plants, but did not prevent survival or reproduction of R. conicus populations. / Ph. D.

The purpose of this investigation was to test three insecticides on all the life stages of the alfalfa weevil. The objectives were to obtain information on the toxicity of certain insecticides on the alfalfa weevil in the laboratory, to establish standard susceptibility curves of the life stages of the alfalfa weevil to the insecticides tested, to establish a basis for insect resistance, to compare the speed of action of certain classes of insecticides and to observe the effects of certain insecticides on molting, feeding and other processes that may be affected. Dibrom, heptachlor epoxide, and Indian were tested against various life stages of the alfalfa weevil. These three insecticides were chosen because of the differences in their chemistry and activity. Dibrom, a volatile organophosphate, could be expected to act fast but have relatively limited residual life.Heptachlor epoxide as a cyclodiene compound should have exhibited the characteristic latent period of from two to six hours before symptoms of its activity appeared. The residual activity should be great. Indian, a more stable organophosphate than Dibrom, would be expected to be somewhat intermediate between the other two in speed of action and residual activity. Each insecticide was impregnated in filter paper at the dosage of 100 micrograms per square centimeter of filter paper surface. The insects were introduced on to the filter paper for continuous exposure to the insecticide residue. Mortality and certain other effects were recorded according to time of exposure. In general, responses of the alfalfa weevil to the three insecticides were comparable. One insecticide may have been quicker acting than the other two against a particular life stage, but the differences in the effects of the insecticides were not great. In every case, the three insecticides inhibited feeding, molting, or maturation to another life stage. / Master of Science