No description available.

Avaliou-se o efeito isolado e associado de pós de origem vegetal e de genótipos de feijoeiro sobre o comportamento, biologia e danos de Zabrotes subfasciatus (Boh.) e Acanthoscelides obtectus (Say). Inicialmente, foi avaliado o efeito dos pós obtidos de 18 plantas sobre a atratividade e mortalidade dos adultos, e oviposição. A seguir, foi testado o efeito de 12 genótipos de feijoeiro incluindo materiais melhorados contendo arcelina (Arc1, Arc2, Arc3 e Arc4) e sem essa proteína (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 e Goiano Precoce) sobre a oviposição (com e sem chance de escolha) e biologia dos insetos. Com base nestes resultados, foram selecionados, para cada espécie de inseto, quatro genótipos (três resistentes e um suscetível) e quatro pós vegetais, para os quais foi avaliado o efeito associado sobre a atratividade e mortalidade dos adultos, preferência para oviposição, biologia e danos causados pelos insetos. Concluiu-se que: a) os pós obtidos da parte aérea de Chenopodium ambrosioides (erva-de-santa-maria), f. (forma) 1 e f.2; de folhas de Eucalyptus citriodora (eucalipto cheiroso), de Mentha pulegium (poejo) e de Ruta graveolens (arruda), e de cascas de frutos de Citrus reticulata (laranja cv. Murcote) são repelentes aos adultos das duas pragas; b) os pós obtidos de folhas de Ocimum basilicum (alfavaca) e de O. minimum (manjericão) são repelentes apenas para Z. subfasciatus, enquanto os pós de cascas de frutos de Citrus sinensis (laranja cv. Pêra) e de frutos de Lafoensia glyptocarpa (mirindiba) apresentam efeito repelente apenas em relação a A. obtectus; c) o pó de folhas de L. glyptocarpa apresenta atratividade a Z. subfasciatus; d) os pós de C. ambrosioides (f.2), M. pulegium, O. basilicum e R. graveolens apresentam efeito altamente tóxico aos adultos de Z. subfasciatus, causando 100% de mortalidade e impedindo a oviposição; e) em relação a A. obtectus, há total mortalidade de adultos e ausência de oviposição, com o uso de pós de C. ambrosioides (f.2) e de folhas de Coriandrum sativum (coentro); f) em teste sem chance de escolha, o genótipo Arc3 é menos ovipositado por Z. subfasciatus que 'IAC Carioca Pyatã' e 'IAC Bico de Ouro', enquanto, em relação a A. obtectus os materiais são igualmente preferidos para oviposição; g) os materiais contendo arcelina (Arc1, 2, 3 e 4) apresentam resistência do tipo não-preferência para alimentação e/ou antibiose a Z. subfasciatus, alongando o período de desenvolvimento (ovo-adulto) e reduzindo o peso dos adultos, a longevidade e a fecundidade; h) em relação a A. obtectus, a resistência do tipo não-preferência para alimentação e/ou antibiose só ocorre com o Arc1, genótipo em que há alongamento do período de desenvolvimento e menor peso dos adultos; i) 'Goiano Precoce' é o material mais adequado ao desenvolvimento dos dois insetos; j) com o emprego associado de pós vegetais e genótipos resistentes de feijoeiro, ocorre apenas efeito aditivo (e não sinérgico) das duas técnicas de controle para ambas as espécies de insetos; k) o peso consumido de grãos de feijão por Z. subfasciatus e A. obtectus não é afetado pelos pós inseticidas; esse peso, entretanto, é menor nos genótipos contendo arcelina para os dois insetos. / It was evaluated the isolated and associated effects of powders from different vegetal and bean genotypes on the behaviour, biology and damage of Zabrotes subfasciatus (Boh.) and Acanthoscelides obtectus (Say). Initially, it was evaluated the effect of powders of 18 plants on the attractivity and mortality of the adults, and oviposition. Then, the effect of 12 bean genotypes was tested including materials with arcelin (Arc1, Arc2,Arc3 and Arc4) and without this protein (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 and Goiano Precoce) on the oviposition (free-choice and no-choice tests) and biology of the insects. Based on these results, four genotypes (three resistant and one susceptible) and four powders were selected for each insect species. It was evaluated the associated effect on the attractivity and mortality of the adults, preference for oviposition, biology and damage caused by the insects. It was concluded that: powders of the aerial part from Chenopodium ambrosioides f. (form) 1 and f.2; leaves from Eucalyptus citriodora, from Mentha pulegium and from Ruta graveolens, and rinds of fruits from Citrus reticulata (cv. Murcote) are repellents to the adults of the two pests; b) powders of leaves from Ocimum basilicum and O. minimum are repellent only for Z. subfasciatus, while powders of rinds of fruits from Citrus sinensis (cv. Pêra) and fruits from Lafoensia glyptocarpa shows repellent effect only on A. obtectus; c) powder of leaves from L. glyptocarpa shows attractivity on Z. subfasciatus; d) powders from C. ambrosioides (f.2), M. pulegium, O. basilicum and R. graveolens show high toxicity on adults of Z. subfasciatus, causing 100% mortality and inhibiting the oviposition; e) in relation to A. obtectus, total mortality of adults and no oviposition is observed with the use of powders from C. ambrosioides (f.2) and leaves from Coriandrum sativum; f) in no-choice test, Arc3 was less oviposited by Z. subfasciatus than IAC Carioca Pyatã and IAC Bico de Ouro, while in relation to A. obtectus the materials are equally preferred for oviposition; g) the materials with arcelin (Arc1, 2, 3 and 4) show non-preference resistance for feeding and/or antibiose to the Z. subfasciatus, prolonging the time for insect development (egg-adult) and reducing the adult weight, longevity and fecundity; h) in relation to A. obtectus, non-preference resistance for feeding and/or antibiose only occurs with Arc1, genotype that prolongs the development period and reduces the adult weight; i) Goiano Precoce is the most suitable material for the development of both insects; j) with the association of vegeta powders and resistant bean genotypes, only additive effect (and not syhngistic) is observed with the two control tactics for both insect species; k) the weight of consumed bean grains for Z. subfasciatus and A. obtectus was not affected by insecticide powders; however the weight, however, was lower in the genotypes with arcelin for both insects.

The boll weevil (Anthonomus grandis grandis Boheman) is currently under eradication in the U.S. The eradication program is implemented by means of area-wide applications of malathion ULV. Frequent applications of this insecticide result in high mortality of many beneficial insects, and a greater risk of secondary pest outbreaks. Notable among the latter are the outbreaks of beet armyworm (Spodoptera exigua H?bner) and cotton aphid (Aphis gossypii Glover) in the Lower Rio Grande Valley in 1995. The present study (i) compared densities of beneficial and pest insect and spider populations between cotton fields in eradication and non-eradication areas; (ii) evaluated the use of beneficial cotton arthropod population densities as indicators of pest damage risks from cotton aphid, beet armyworm, bollworm (Helicoverpa zea Boddie), and other worms (Estigmene acrea Drury, Pseudoplusia includens Walker, and Trichoplusia ni H?bner); and (iii) evaluated the effects of malathion ULV on the red imported fire ant (Solenopsis invicta Buren) a key arthropod predator in cotton agroecosystems. Studies were conducted in central Texas, in the vicinities of College Station and Dallas, during 2002 and 2003. Results showed that a majority of cotton predators were negatively impacted by malathion ULV applications. However, convergent lady beetle (Hippodamia convergens Gu?rin-M?neville) densities were greater in active eradication fields than inactive fields. Stepwise regression analyses identified densities of lacewing (Chrysoperla carnea Stephens) larvae and lady beetle larvae (H. convergens, Coleomegilla maculata De Geer, Harmonia axyridis Pallas, and Coccinella septempunctata L.) as predictors of cotton aphid density, and density of total spiders as predictors of bollworm density. Predictors of beet armyworm or other worm densities could not be determined. This study demonstrated malathion ULV was highly toxic to fire ants, and could repel ants from treated surfaces. Malathion ULV reduced the number of foraging fire ants in the cotton canopy for three weeks and reduced fire ant predation of beet armyworm eggs. Predictors of secondary pest densities have been suggested which, if utilized, may help to prevent the occurrence of secondary pest outbreaks under boll weevil eradication. Validation of these predictors should be preformed before implementing them into an eradication program.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This dissertation studies three institutions of development in the United States during the early twentieth century. The first chapter exploits a unique shift in agricultural production in the American South to analyze how the cultivation of a child labor intensive crop (cotton) impacted schooling, with a particular focus on racial differences. Since African-American children were more likely to be employed as farm laborers than white children, their educational attainment may have been more responsive to changes in cotton production. I test this prediction using newly collected county-level panel data for Georgia, a major cotton producer. The results reveal that reductions in cotton production increased the school enrollment rate of African Americans. By contrast, I find little evidence that cotton production affected the enrollment rate of whites. This suggests that the shift away from cotton production after the arrival of the boll weevil can explain a significant amount of the narrowing of the racial differential in enrollment rates. The second chapter explores how Southern school boards responded to changes in their budgetary environment. I utilize exogenous variation in state school funds generated by discontinuous budget allocation rules, and employ a differences-in-differences strategy, to investigate how the relative quality of education for African Americans changed with the level of state funding for education. Results suggest whites, rather than African Americans, bore the brunt of budget cuts, perhaps because there was little fat to trim from the budgets of African-American schools. The third chapter of this dissertation (co-authored with Carola Frydman and Eric Hilt) estimates the effect of President McKinley's assassination on corporate valuations. McKinley acted favorably toward business interests, and while in office he permitted significant merger activity. His Vice President, Theodore Roosevelt, was a well known reformer and took a stronger stance against trusts. Our analysis indicates that firms vulnerable to antitrust prosecution saw greater decreases in their valuations following the assassination. The value of railroads susceptible to antitrust litigation declined further when Roosevelt sought to apply the Sherman Act to railroads, providing further evidence that firms benefited from regulatory forbearance during McKinley's Presidency.

Avaliou-se o efeito isolado e associado de pós de origem vegetal e de genótipos de feijoeiro sobre o comportamento, biologia e danos de Zabrotes subfasciatus (Boh.) e Acanthoscelides obtectus (Say). Inicialmente, foi avaliado o efeito dos pós obtidos de 18 plantas sobre a atratividade e mortalidade dos adultos, e oviposição. A seguir, foi testado o efeito de 12 genótipos de feijoeiro incluindo materiais melhorados contendo arcelina (Arc1, Arc2, Arc3 e Arc4) e sem essa proteína (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 e Goiano Precoce) sobre a oviposição (com e sem chance de escolha) e biologia dos insetos. Com base nestes resultados, foram selecionados, para cada espécie de inseto, quatro genótipos (três resistentes e um suscetível) e quatro pós vegetais, para os quais foi avaliado o efeito associado sobre a atratividade e mortalidade dos adultos, preferência para oviposição, biologia e danos causados pelos insetos. Concluiu-se que: a) os pós obtidos da parte aérea de Chenopodium ambrosioides (erva-de-santa-maria), f. (forma) 1 e f.2; de folhas de Eucalyptus citriodora (eucalipto cheiroso), de Mentha pulegium (poejo) e de Ruta graveolens (arruda), e de cascas de frutos de Citrus reticulata (laranja cv. Murcote) são repelentes aos adultos das duas pragas; b) os pós obtidos de folhas de Ocimum basilicum (alfavaca) e de O. minimum (manjericão) são repelentes apenas para Z. subfasciatus, enquanto os pós de cascas de frutos de Citrus sinensis (laranja cv. Pêra) e de frutos de Lafoensia glyptocarpa (mirindiba) apresentam efeito repelente apenas em relação a A. obtectus; c) o pó de folhas de L. glyptocarpa apresenta atratividade a Z. subfasciatus; d) os pós de C. ambrosioides (f.2), M. pulegium, O. basilicum e R. graveolens apresentam efeito altamente tóxico aos adultos de Z. subfasciatus, causando 100% de mortalidade e impedindo a oviposição; e) em relação a A. obtectus, há total mortalidade de adultos e ausência de oviposição, com o uso de pós de C. ambrosioides (f.2) e de folhas de Coriandrum sativum (coentro); f) em teste sem chance de escolha, o genótipo Arc3 é menos ovipositado por Z. subfasciatus que 'IAC Carioca Pyatã' e 'IAC Bico de Ouro', enquanto, em relação a A. obtectus os materiais são igualmente preferidos para oviposição; g) os materiais contendo arcelina (Arc1, 2, 3 e 4) apresentam resistência do tipo não-preferência para alimentação e/ou antibiose a Z. subfasciatus, alongando o período de desenvolvimento (ovo-adulto) e reduzindo o peso dos adultos, a longevidade e a fecundidade; h) em relação a A. obtectus, a resistência do tipo não-preferência para alimentação e/ou antibiose só ocorre com o Arc1, genótipo em que há alongamento do período de desenvolvimento e menor peso dos adultos; i) 'Goiano Precoce' é o material mais adequado ao desenvolvimento dos dois insetos; j) com o emprego associado de pós vegetais e genótipos resistentes de feijoeiro, ocorre apenas efeito aditivo (e não sinérgico) das duas técnicas de controle para ambas as espécies de insetos; k) o peso consumido de grãos de feijão por Z. subfasciatus e A. obtectus não é afetado pelos pós inseticidas; esse peso, entretanto, é menor nos genótipos contendo arcelina para os dois insetos. / It was evaluated the isolated and associated effects of powders from different vegetal and bean genotypes on the behaviour, biology and damage of Zabrotes subfasciatus (Boh.) and Acanthoscelides obtectus (Say). Initially, it was evaluated the effect of powders of 18 plants on the attractivity and mortality of the adults, and oviposition. Then, the effect of 12 bean genotypes was tested including materials with arcelin (Arc1, Arc2,Arc3 and Arc4) and without this protein (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 and Goiano Precoce) on the oviposition (free-choice and no-choice tests) and biology of the insects. Based on these results, four genotypes (three resistant and one susceptible) and four powders were selected for each insect species. It was evaluated the associated effect on the attractivity and mortality of the adults, preference for oviposition, biology and damage caused by the insects. It was concluded that: powders of the aerial part from Chenopodium ambrosioides f. (form) 1 and f.2; leaves from Eucalyptus citriodora, from Mentha pulegium and from Ruta graveolens, and rinds of fruits from Citrus reticulata (cv. Murcote) are repellents to the adults of the two pests; b) powders of leaves from Ocimum basilicum and O. minimum are repellent only for Z. subfasciatus, while powders of rinds of fruits from Citrus sinensis (cv. Pêra) and fruits from Lafoensia glyptocarpa shows repellent effect only on A. obtectus; c) powder of leaves from L. glyptocarpa shows attractivity on Z. subfasciatus; d) powders from C. ambrosioides (f.2), M. pulegium, O. basilicum and R. graveolens show high toxicity on adults of Z. subfasciatus, causing 100% mortality and inhibiting the oviposition; e) in relation to A. obtectus, total mortality of adults and no oviposition is observed with the use of powders from C. ambrosioides (f.2) and leaves from Coriandrum sativum; f) in no-choice test, Arc3 was less oviposited by Z. subfasciatus than IAC Carioca Pyatã and IAC Bico de Ouro, while in relation to A. obtectus the materials are equally preferred for oviposition; g) the materials with arcelin (Arc1, 2, 3 and 4) show non-preference resistance for feeding and/or antibiose to the Z. subfasciatus, prolonging the time for insect development (egg-adult) and reducing the adult weight, longevity and fecundity; h) in relation to A. obtectus, non-preference resistance for feeding and/or antibiose only occurs with Arc1, genotype that prolongs the development period and reduces the adult weight; i) Goiano Precoce is the most suitable material for the development of both insects; j) with the association of vegeta powders and resistant bean genotypes, only additive effect (and not syhngistic) is observed with the two control tactics for both insect species; k) the weight of consumed bean grains for Z. subfasciatus and A. obtectus was not affected by insecticide powders; however the weight, however, was lower in the genotypes with arcelin for both insects.

The banana weevil, Cosmopolites sordidus, is an economical pest of Musa, distributed to most areas where the crop is grown. The beetle larvae produce feeding tunnels in the pseudostem and rhizome, reducing bunch weight and causing toppling or snapping of plants. In developing an integrated pest management system for South Africa, specific aims of the study were to quantify the genetic diversity of the species around the world, investigate the population dynamics of the insect, determine the potential of semiochemical mass trapping, elucidate the efficacy of cultural and chemical control methods and establish economic thresholds for the banana weevil on Cavendish bananas in South Africa. Pest status of the insect is variable around the world, and may be influenced by genetically distinct populations of the weevil. Six populations from four countries were sampled: Australia, Costa Rica, South Africa (South Coast, North Coast and Tzaneen) and Uganda. DNA was isolated from 12 individuals per population and subjected to amplified fragment length polymorphism (AFLP) analysis. The AFLP analysis involved DNA restriction with EcoRI and PstI enzymes, ligation of adapters, and a pre-selective and five selective PCR amplifications. Empirical analysis of the AFLP fingerprints showed that, within populations, genetic diversity varied from 16-53%, with the South Coast and Tzaneen/Australian populations the least and most variable, respectively. The coefficient of gene differentiation showed that the Tzaneen population were the most differentiated from the South Coast population, while the South and North Coast populations were the most similar. All the populations showed statistically distinct marker frequencies, except for the Costa Rican and South and North Coast populations, which were similar. Based on the simple mismatch coefficient, a neighbour-joining tree showed the Australian, Ugandan and South African coastal populations produced monophyletic groups, while the South African Tzaneen population were removed from the other populations and presented an ancestral state. The population dynamics of the insect was investigated over two seasons and at three locations in the South Coast of KwaZulu-Natal. Adult activity was monitored with semiochemical (Cosmolure®) baited pitfall traps. Traps were moved monthly to a random independent location, or left in situ for the duration of the experiment. The ontogeny was determined by dissecting felled plants and toppled plants (up to 2-week-old fresh residues), and harvested plants visually classified as an early and a late rotting stage (decayed residues). Replicated, randomised block designs were used in the experiments. The adult beetles were sexed and the percentage females with eggs and the number of eggs per female were recorded. Larval head capsule widths were measured with an electronic caliper. Ambient temperature and precipitation (rainfall + irrigation) were measured on site. Weevils were active throughout the year and mainly collected in stationary traps, with a collection peak in May and high numbers in early spring and late autumn/early winter. The activity was usually a negative and a positive function of ambient temperature and corrected rainfall, respectively. Eggs per female and percentage females with eggs were reduced during winter and a positive function of ambient temperature. The beetles sampled from plant material represented an equal sex ratio, while the pheromone traps collected a female biased sex ratio during spring and autumn/early winter. The beetle had overlapping generations with a peak of adults and larvae in autumn and late summer, respectively. Adults were mainly associated with decayed residues while larvae were mostly found in freshly toppled plants. Adults were the main over-wintering stage. The earliest larval instars were usually sampled during autumn. The data suggested that the beetle is multivoltine in the study areas and provided valuable information for the optimal management of the insect pest. Semiochemical adult trapping methods were compared in field trials using a randomised block design. Pseudostem traps, pitfall traps containing a pheromone (either Cosmolure® (Pheromone A) or Cosmolure+® (Pheromone B)), and unbaited pitfall traps (control), were compared over 5 weeks during all seasons along the Southeast coast of South Africa. Pseudostem traps treated with an insecticide, and rhizome traps were included as additional treatments in autumn. In summer two treatments were also added: individual suspension of both pheromones above a pitfall trap either in combination with or without a pseudostem trap. The adult beetles were sexed, and the number of internal eggs noted. Pheromone A proved to be the most effective of the different traps. Grouping of the pheromones resulted in a synergistic response, while combining the pseudostem did not enhance trap efficacy. The different plant material traps and the control were usually equally effective in catching weevils. Plant material traps caught greater numbers of fecund females, but pheromone traps captured a higher proportion of females. Treatment effects were much less pronounced in summer, and compared to a pseudostem trap, pitfall traps were the most efficacious during spring. Compared to conventional pseudostem trapping, Pheromone A pitfall traps should be optimally applied during spring in South Africa. Cultural control methods were investigated over 2 years at an ongoing trial in the Southern KwaZulu Natal, South Africa. Harvesting at ground level and dissection of remnants, and covering of the mat with soil and moving debris to the inter-row, were compared to a positive control that involved treatment of plants with a registered pesticide, and a negative control that involved harvesting at approximately 150 cm with no soil or sanitation amendments. Yield, weevil damage and pseudostem girth of plants were measured from August to November annually, while adult beetle densities were assessed over 4 weeks in October/November and April. Nematode samples were analysed in October/November every year. Damage parameters included the Coefficient of Infestation, the Percentage Coefficient of Infestation (PCI) at two intervals, the summed PCI value, the percentage cross sectional damage of the central cylinder (XI) and cortex, and the mean cross sectional damage percentage (X mean). A replicated block design was used in the experiment. The parameters were similar before the onset of the trial. Fruit yield and plant girth, corrected by nematode densities, were not significantly different in any treatment, nor were the nematodes controlled. Soil cover and recession of remnants was the only effective treatment, significantly reducing the Coefficient of Infestation, but not the adult density or any other damage parameter. The former showed promise as a cultural control method because it only needs to be applied seasonally and reduced the XI, the damage parameter most closely related to yield, by 14.18%. The weevil is difficult to control, and chemical control arguably provides the best opportunity to manage the pest. The efficacy of injecting bifenthrin, chlorpyrifos, fipronil, imidacloprid, oxamyl and water (control) into residual banana plants was determined. The chemicals were administered every even numbered month over 2 years at two locations in Southern KwaZulu-Natal, South Africa. Yield, weevil damage and pseudostem girth of plants felled from August to October were measured, while adult beetle densities were assessed over 4 weeks in October and April. Nematode samples were analysed in October every year. Damage parameters included were similar to that of the cultural control trial. Replicated block designs were used in the experiments. The parameters were similar before the onset of the trial. Fruit yield and plant girth, corrected by nematode densities, were not significantly increased after chemical applications, nor were the nematodes controlled. Fipronil and imidacloprid were highly effective against C. sordidus, minimising damage to the periphery, cortex and central cylinder of the rhizome and significantly reduced adult density. Fipronil caused a 95% and imidacloprid a 100% reduction in the XI. Injection of fipronil and imidacloprid provides an optimal chemical strategy in an integrated pest management programme for the banana weevil. Economic thresholds of the insect were investigated on bananas at four locations in the South Coast of KwaZulu-Natal. Yield (bunch weights) and larval damage to felled plants were measured from August to October in 2003, while adult densities were assessed over 4 weeks in October 2003. Nematode samples were collected and analysed in October 2003. Damage parameters included were similar to that of the cultural control trial. Replicated block designs were used in the experiments. The economic-injury level (EIL) for chemical and cultural control was calculated. Nematode densities did not influence the yield of plants. The XI was the best predictor of yield, but under certain conditions X mean was the most important. Chemical control showed the lowest EIL, with more than 1 and 7% damage to the central cylinder when applying fipronil and imidacloprid, respectively. The EIL for cultural control was more than 11% damage to the central cylinder. A recommendation algorithm, considering all the findings of the individual studies, is provided for IPM of the banana weevil in the South Africa. The potential use of microbial and invertebrate (especially parasitoids) biological control and semiochemical mass trapping of the weevil requires further research. Long-term research should focus on host resistance, and weevil damage to the central cylinder can serve as indicator of susceptibility of Cavendish bananas. / Thesis (PhD (Entomology))--University of Pretoria, 2008. / Zoology and Entomology / unrestricted

The effects of apholate on diapausing and nondiapausing alfalfa weevil, Hypera postica (Gyllenhal), were studied. Different stages, sexes, and ages of the weevil were treated with aqueous-apholate solution. Adult topical application and larval and adult dipping methods were used in the experiment. Both showed the effectiveness of sterilization, and caused high mortality to the treated insects. Adult dipping was an acceptable method of treatment. The best age for treatment seemed to be reproductively mature virgin adults. Egg viability was similar to the check when only the females were treated with apholate. When only males or when both sexes were treated the egg viability was decreased depending on the apholate concentration used. The most effective apholate concentration for sterilizing male alfalfa weevils ranged from 0.5 to 1.0%. A gradual increase in egg viability occurred starting about the 3rd week after treatment. Dissection of the immature adults showed that gonadal development was delayed by apholate. The reproductive organs of apholate-treated mature adults were reduced in size. The treated males do not compete sexually on an equal basis with the normal males, although considerable mixing of sperm occurred during the mating of female weevils with the apholate-treated and -untreated males. / M.S.

Laboratory studies and field observations were conducted to ascertain the development of the female sex organs of the alfalfa weevil during aestivation, to study the role of this aestivation on sexual development, and to investigate the factors responsible for this interaction. Measurements of female sex organs were made in dissected weevils at monthly intervals to observe each of the developmental stages of sexual maturation. Results of this sexual development as it progressed after adult emergence, were presented by means of tables, graphs, and a series of photographs. The importance of not confusing old and new weevils was recognized in this work, since their behavioral patters differ in many respects. The nature and physiology of the aestivation of this weevil was discussed and evidence was presented to support the author's suggestion that this aestivation is a "true diapause." It was demonstrated in this paper that diapause synchronized the sexual growth of the alfalfa weevil to the seasonal changes of the year for species adaptation and survival. / Master of Science

The qualitative and quantitative aspects of mating behavior, the stimulus for locating and mating, and the effects of varying temperatures on mating behavior and oviposition were studied in the laboratory. Postdiapausing weevils, collected in April, and nondiapausing weevils, reared in the laboratory, were utilized. In both groups, the males aggressively mounted the females from any angle or position with little or no indication of prior courtship. In petri dishes at 75 ± 3° F, both groups spent about 59% of their total time in mating behavior. Mounted time spent in actual copulation (aedeagus inserted) was 47% for nondiapausing pairs and 74% for postdiapausing pairs. This difference in behavior was probably caused by the younger, nondiapausing females which often prevented copulation by tucking the genital opening under the elytra. Males, when given a choice between virgin and non-virgin females, mated with non~virgins in a ratio of 7:1. Nondiapausing pairs mounted fewer times .for longer durations per mounting than the postdiapausing. Crowding by other weevils appeared to reduce mating efficiency, but not mating initiation. Sight was found to play a role in attracting weevils to each other over distances of.a few inches. No evidence of sound production was discovered, nor was there found to be a pheromone serving as a sex attractant. Since males mounted other males as well as other species of curculionids, there is apparently rto mechanism for recognition of sex or species. Higher temperatures resulted in a greater number of mountings of shorter duration. At lower temperatures, pairs mounted fewer times and riot infrequently copulated for as long as 12 hours. The number of ovipositing females and the average number of eggs per female increased with the temperature. / Master of Science