Entomology Commons^™

Interactions Between Phaedrotoma Scabriventris Nixon (Hymenoptera: Braconidae) And Diglyphus Isaea Walker (Hymenoptera: Eulophidae), Parasitoids Of Liriomyza Huidobrensis (Blanchard) (Diptera: Agromyzidae), K. S. Akutse, J. Van Den Berg, N. K. Maniania, K. K.M. Fiaboe, S. Ekesi

All Peer-Reviewed Publications

Liriomyza leafminer flies represent a serious threat to horticultural production in East Africa. Total field parasitism rates recorded in Kenya are below 5%, with the indigenous ectoparasitoid Diglyphus isaea Walker being one of the key parasitoid species. The International Centre of Insect Physiology and Ecology (. icipe), in collaboration with the International Potato Centre (CIP), imported into Kenya the endoparasitoid Phaedrotoma scabriventris Nixon to improve natural control of leafminers. The objective of this study was to investigate the interactions between D. isaea and P. scabriventris when used together for the biological control of Liriomyza species. These interactions were studied under …

Integrated Multiple-Tactic Management Of The Redbanded Stink Bug On Soybeans In Louisiana, Miyanda Nzala Moonga

LSU Doctoral Dissertations

Stink bugs (Hemiptera: Pentatomidae) are major pests of soybeans in Louisiana and heavy infestations often lead to economic losses. The stink bug species complex has changed in the past decade with the prevalence of the invasive redbanded stink bug, Piezodorus guildinii (Westwood), which causes greater damage than other stink bug species. Moreover, control of the redbanded stink bug has been faced with challenges because it is less sensitive to recommended insecticides. Therefore, studies were conducted to evaluate different control options for P. guildinii. Among the studies conducted was the current status of egg parasitoids of stink bugs in Louisiana. Telenomus …

Research In Biological Control Of The Formosan Subterranean Termite, Cai Wang

LSU Doctoral Dissertations

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a worldwide distributed pest of wooden structures and living plants that causes huge economic losses. Compared to chemical pesticides, biological control may provide a more environmentally friendly and persistent method for the control of C. formosanus. In this research, a series of studies were conducted to understand the termite-pathogen interaction and to develop a feasible biological control strategy. In the first part of the research, the toxicity of Bt toxins expressed by genetically modified maize to termites was tested. Plant tissues or extracts of three commercially planted Bt maize and two non-Bt …

Dna Barcoding Distinguishes Pest Species Of The Black Fly Genus Cnephia (Diptera: Simuliidae), I. M. Confitti, K. P. Pruess, A. Cywinska, T. O. Powers, D. C. Currie

Department of Entomology: Faculty Publications

Accurate species identification is essential for cost-effective pest control strategies. We tested the utility of COI barcodes for identifying members of the black fly genus Cnephia Enderlein (Diptera: Simuliidae). Our efforts focus on four Nearctic Cnephia species—Cnephia dacotensis (Dyar & Shannon), Cnephia eremities Shewell, Cnephia ornithophilia (Davies, Peterson & Wood), and Cnephia pecuarum (Riley)—the latter two being current or potential targets of biological control programs. We also analyzed one Palearctic species, Cnephia pallipes (Fries). Although Cnephia adults can be identified anatomically to species, control programs target the larval stage, which is difficult or impossible to distinguish morphologically. By using …

Life History Comparison Of Two Green Lacewing Species Chrysoperla Johnsoni And Chrysoperla Carnea (Neuroptera: Chrysopidae), Kaushalya G. Amarasekare, Peter W. Shearer

Agricultural and Environmental Sciences Faculty Research

We investigated the life histories of two green lacewing species, Chrysoperla johnsoni Henry, Wells, and Pupedis from western North America, and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) from western Europe in the laboratory. There were both similarities and differences in their life history characteristics. C. johnsoni exhibited a significantly longer developmental time for egg, first instar, and pupal stage than C. carnea. C. carnea exhibited a significantly shorter egg to adult developmental time than C. johnsoni. Except for the pupal stage, the survival of all other life history stages was not species-specific. All C. carnea pupae were able to develop …

The Life History Of Larinus Minutus, A Biological Control Agent Of Invasive Knapweeds, And Its Dispersal From Release Sites In Arkansas, Adam M. Alford

Graduate Theses and Dissertations

Larinus minutus Gyllenhal, a biological control agent of invasive knapweeds, has become established in several states and provinces since initial North American introduction in 1991. In order to reduce growing spotted knapweed populations in Northwest Arkansas, Larinus minutus (a biological control agent of spotted knapweed) was released annually from 2008-2011. Little is known about the larval development of this species, although the widespread use of this insect has provided research describing detailed host range and generalized life history. The speed and extent of the spread of this weevil from release sites following introduction have not been reported. This research described …

Laboratory Bioassays To Estimate The Lethal And Sublethal Effects Of Various Insecticides And Fungicides On Deraeocoris Brevis (Hemiptera: Miridae), K. G. Amarasekare, P. W. Shearer

Agricultural and Environmental Sciences Faculty Research

This laboratory bioassay focused on lethal and sublethal effects of five insecticides (chlorantraniliprole, cyantraniliprole, spinetoram, novaluron, and lambda-cyhalothrin) and two fungicide treatments (sulfur and a mixture of copper hydroxide and mancozeb) on the predatory mired bug, Deraeocoris brevis (Uhler) (Hemiptera: Miridae) using second instars and adult males and females. Formulated pesticides were tested using concentrations that were equivalent to the high label rate (1x) (high rate) and 1/10th of that amount (0.1x) (low rate) dissolved in 378.5 liters of water. Lambda-cyhalothrin was highly toxic to D. brevis nymphs and adults at both rates, whereas both rates of novaluron were highly …

Developmental Time, Longevity, And Lifetime Fertility Of Three Introduced Parasitoids Of The Mealybug Paracoccus Marginatus (Hemiptera: Pseudococcidae), Kaushalya G. Amarasekare, Catharine M. Mannion, Nancy D. Epsky

Agricultural and Environmental Sciences Faculty Research

Developmental time, longevity, and lifetime fertility of three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff) (Hymenoptera: Encyrtidae) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied in the laboratory to understand the outcome of their recovery in field studies conducted in the United States. The developmental time of both male and female A. papayae and A. loecki was shorter than the developmental time of male and female P. mexicana. Male parasitoids of all three species had a shorter developmental time than …

Biological Control Of The Black Cutworm, Agrotis Ipsilon (Lepidoptera: Noctuidae), And Endophyte Mediated Tritrophic Interactions In Turfgrass, Andrea Jeanne Bixby-Brosi

University of Kentucky Doctoral Dissertations

Components of successful pest management programs must be complementary and not antagonistic. This project examined interactions between natural enemies of the black cutworm, Agrotis ipsilon (Hufnagel), an important turfgrass pest, and host plant resistance by endophytic grass.

Agrotis ipsilon nucleopolyhedrovirus (AgipMNPV) was examined as a bio-insecticide for controlling A. ipsilon in turfgrass. Fresh (1-week-old) AgipMNPV residues killed 76−86% of neonates hatching from eggs on golf course tees, however, residual control of implanted larvae lasted no more than a few weeks. Combinations of AgipMNPV with adjuvants, such as optical brightener and lignin, failed to accelerate or extend …

Introduction And Establishment Of Cyrtobagous Salviniae Calder And Sands (Coleoptera: Curculionidae) For The Control Of Salvinia Minima Baker (Salviniaceae), And Interspecies Interactions Possibly Limiting Successful Control In Louisiana, Katherine A. Parys

LSU Doctoral Dissertations

Common salvinia, Salvinia minima Baker, is a floating aquatic invasive macrophyte that obstructs waterways and causes problems in wetlands across Louisiana and Texas. The salvinia weevil, Cyrtobagous salviniae Calder and Sands, has been released in over 14 countries around the world for the biological control of Salvinia spp. We successfully monitored the introduction and establishment of C. salviniae on S. minima in southern Louisiana between 2006 and 2010. Cyrtobagous salviniae significantly lowered the biomass of S. minima and increased the number of terminal buds damaged but had no significant impact on pH, dissolved oxygen, conductivity, surface temperature, percent of surface …

Host Instar Susceptibility And Selection And Interspecific Competition Of Three Introduced Parasitoids Of The Mealybug Paracoccus Marginatus (Hemiptera: Pseudococcidae), Kaushalya G. Amarasekare, Catharine M. Mannion, Nancy D. Epsky

Agricultural and Environmental Sciences Faculty Research

Three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff [Hymenoptera: Encyrtidae]) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied for their host instar susceptibility and sex ratio, host instar selection, and interspecific competition in the laboratory. All three parasitoids were able to develop in the second instars, third-instar females, and adult females of P. marginatus. No progeny emerged from first-instar mealybugs. The proportion of female emergence was increased with increasing host size. Parasitoids selected their host instars for oviposition when they …

Molecular Diagnosis Of A Previously Unreported Predator-Prey Association In Coffee: Karnyothrips Flavipes Jones (Thysanoptera: Phlaeothripidae) Predation On The Coffee Berry Borer, Juliana Jaramillo, Eric G. Chapman, Fernando E. Vega, James D. Harwood

All Peer-Reviewed Publications

The coffee berry borer, Hypothenemus hampei, is the most important pest of coffee throughout the world, causing losses estimated at US 500 million/year. The thrips Karnyothrips flavipes was observed for the first time feeding on immature stages of H. hampei in April 2008 from samples collected in the Kisii area of Western Kenya. Since the trophic interactions between H. hampei and K. flavipes are carried out entirely within the coffee berry, and because thrips feed by liquid ingestion, we used molecular gut-content analysis to confirm the potential role of K. flavipes as a predator of H. hampei in an organic …

Impact Of Dietary Diversification On Invasive Slugs And Biological Control With Notes On Slug Species Of Kentucky, Anna K. Thomas

University of Kentucky Master's Theses

Increasing introductions of non-native terrestrial slugs (Mollusca: Gastropoda) are a concern to North American regulatory agencies as these generalists impact the yield and reduce the aesthetic value of crop plants. Understanding how the increase in diversification in North American cropping systems affects non-native gastropods and finding effective biological control options are imperative for pest management; however, little research has been done in this area. This study tested the hypothesis that dietary diversification affects the biological control capacity of a generalist predator and allows the slug pest Deroceras reticulatum (Müller) (Stylommatophora: Agriolimacidae) to more effectively fulfill its nutritional requirements. Results showed …

Virulence Of Mexican Isolates Of Entomopathogenic Fungi (Hypocreales: Clavicipitaceae) Upon Rhipicephalus = Boophilus Microplus (Acari: Ixodidae) Larvae And The Efficacy Of Conidia Formulations To Reduce Larval Tick Density Under Field Conditions, César Andrés Ángel-Sahagún, Roberto Lezama-Gutiérrez, Jaime Molina-Ochoa, A. Pescador-Rubio, S. R. Skoda, C. Cruz-Vázquez, A. G. Lorenzoni, E. Galindo-Velasco, H. Fragoso-Sánchez, John E. Foster

Department of Entomology: Faculty Publications

The first objective was laboratory evaluation of the virulence of 53 Mexican isolates of fungi against larvae of Rhipicephalus (Boophilus) microplus. Thirty-three isolates of Metarhizium anisopliae var. anisopliae (Metschnickoff) Sorokin (Hypocreales: Clavicipitaceae) and 20 isolates of Isaria (Paecilomyces) fumosorosea (fumosoroseus) (Wize) (Eurotiales: Trichomaceae) were tested on 7-day-old larvae under laboratory conditions. Larvae were immersed in a suspension containing 10⁸ conidia/mL and the CL₅₀ values were estimated. Then, field tests were conducted to determine the efficacy of formulations of the isolate with the highest virulence. M. anisopliae (Ma 14 isolate) was formulated with four carriers: Tween, Celite, …

Fungal Entomopathogens: New Insights On Their Ecology, Fernando E. Vega, Mark S. Goettel, Meredith Blackwell, David Chandler, Mark A. Jackson, Siegfried Keller, Masanori Koike, Nguya K. Maniania, Arnulfo Monzón, Bonnie H. Ownley, Judith K. Pell, Drauzio E.N. Rangel, Helen E. Roy

All Peer-Reviewed Publications

An important mechanism for insect pest control should be the use of fungal entomopathogens. Even though these organisms have been studied for more than 100 y, their effective use in the field remains elusive. Recently, however, it has been discovered that many of these entomopathogenic fungi play additional roles in nature. They are endophytes, antagonists of plant pathogens, associates with the rhizosphere, and possibly even plant growth promoting agents. These findings indicate that the ecological role of these fungi in the environment is not fully understood and limits our ability to employ them successfully for pest management. In this paper, …

Where To Sample? Ecological Implications Of Sampling Strata In Determining Abundance And Impact Of Natural Enemies Of The Coffee Berry Borer, Hypothenemus Hampei, Juliana Jaramillo, Adenirin Chabi-Olaye, Christian Borgemeister, Charles Kamonjo, Hans Michael Poehling, Fernando E. Vega

All Peer-Reviewed Publications

Several parasitoids of African origin have been introduced to coffee producing areas of the Americas and Asia as biological control agents of the coffee berry borer (CBB) Hypothenemus hampei (Coleoptera: Curculionidae). These parasitoids have become established in the field but their effect on the CBB has been limited. A two-year field study in Western Kenya has found Prorops nasuta (Hymenoptera: Bethylidae) to be the predominant parasitoid emerging from CBB-infested coffee berries collected on coffee trees or from the ground. P. nasuta comprises more than 75% of the total natural enemies collected. The density of P. nasuta was 90% higher in …

Predation And Reproductive Output Of The Ladybird Beetle Stethorus Tridens Preying On Tomato Red Spider Mite Tetranychus Evansi, Erika P.J. Britto, Manoel G.C. Gondim, Jorge B. Torres, Komi K.M. Fiaboe, Gilberto J. Moraes, Markus Knapp

All Peer-Reviewed Publications

Predatory behaviour and reproductive output of the ladybird beetle Stethorus tridens Gordon as function of the tomato red spider mite (TRSM), Tetranychus evansi Baker & Pritchard, densities was investigated in the laboratory. Adult female of S. tridens were isolated in cylindrical plastic arenas, containing a leaf disc of Solanum americanum Mill. with 5, 20, 40, 60, 80 or 100 T. evansi nymphs. The number of prey consumed and eggs laid were evaluated daily for ten consecutive days, starting at the oviposition. Oviposition of S. tridens was positively correlated with prey consumption and lower threshold prey consumption for S. tridens laying …

Ecological Traits Of A New Aphid Parasitoid, Endaphis Fugitiva (Diptera: Cecidomyiidae), And Its Potential For Biological Control Of The Banana Aphid, Pentalonia Nigronervosa (Hemiptera: Aphididae), Frédéric B. Muratori, Raymond J. Gagne, Rusell H. Messing

USDA Systematic Entomology Laboratory

Most parasitoids of aphids are small wasps belonging to the families Braconidae or Aphelinidae. However, some dipteran parasitoids are also known to use aphids as hosts. We describe and give life-history information on a new species of aphid parasitoid, Endaphis fugitiva Gagné and Muratori, found to parasitize the banana aphid, Pentalonia nigronervosa Coquerel, the vector of banana bunchy top virus. Field and laboratory observations show that fly eggs are laid on the leaves near an aphid colony, the newly hatched fly larvae search for hosts while crawling on the leaf, and then penetrate the aphid between the legs and thorax. …

Biological Control Of Marmara Gulosa Guillén And Davis In The San Joaquin Valley, Crystal A. Kirkland

Master's Theses

Peelminer, Marmara gulosa Davis and Guillén, has been reported as a sporadic pest in California and Arizona since 1998. Marmara gulosa has been a persistent pest in the San Joaquin Valley of California (USA) since 1998. Prior to 2000 the only reports of high populations of citrus peelminer were in the Coachella Valley. The larval stages of M. gulosa create serpentine mines scarring the upper epidermal layers of citrus rind, rendering it unacceptable for fresh market sale. Chemicals have failed to provide adequate control of M. gulosa; thus, the use of natural enemies is considered the best long-term option. …

Cross Mating Studies Among Five Fruit Fly Parasitoid Populations: Potential Biological Control Implications For Tephritid Pests, Maxwell K. Billah, Susan W. Kimani-Njogu, Robert A. Wharton, William A. Overholt, David D. Wilson, Millicent A. Cobblah

All Peer-Reviewed Publications

The reproductive compatibility between four different species/populations of the tephritid parasitoid Psyttalia (Walker) species from Kenya and individuals of the morphologically identical Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae) from a laboratory culture in Italy used in augmentative biological control of olive fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae) was assessed through cross mating tests using single-pair and group mating methods. Reciprocal crosses among the species resulted in the production of viable offsprings up to the second generation. In spite of the successful production of viable offspring in the laboratory, Psyttalia species are known to have specific host fruit and/or host fly preferences …

Can Low Release Numbers Lead To Establishment And Spread Of An Exotic Parasitoid: The Case Of The Diamondback Moth Parasitoid, Diadegma Semiclausum (Hellén), In East Africa, G. Gichini, B. Löhr, A. Rossbach, B. Nyambo, R. Gathu

All Peer-Reviewed Publications

From 2001 onwards, Diadegma semiclausum, an exotic parasitoid of the diamondback moth, was introduced and released in Kenya, Tanzania and Uganda. Contrary to common practice where thousands of parasitoids are released, we released very low numbers, 125 females in Kenya, 160 in Uganda and 350 in Tanzania. About 2 years after this single release, the establishment and natural spread of the parasitoids was assessed in all release areas. Two methods were employed: in Kenya, a grid with equidistant points in the four cardinal directions (2-50 km) with the release area in the centre was used and collections were made 27 …

Impact Of An Exotic Parasitoid On Plutella Xylostella (Lepidoptera: Plutellidae) Population Dynamics, Damage And Indigenous Natural Enemies In Kenya, B. Löhr, R. Gathu, C. Kariuki, J. Obiero, G. Gichini

All Peer-Reviewed Publications

Diadegma semiclausum (Hellén) (Hymenoptera: lchneumonidae), an exotic diamondback moth parasitoid, was released in two pilot areas (Werugha in Coast Region and Tharuni in Central Province) in Kenya. Fifteen month before release, observations on the diamondback moth, Plutella xylostella (Linnaeus), and local natural enemy population dynamics and pest damage were initiated in both areas and continued for three years after release. The P. xylostella population was bimodal with higher records during dry seasons. At Werugha, the peak population of P. xylostella was 16.8 per plant (October 2001); at Tharuni it was 12.8 (February 2002). Populations at Werugha declined from three months …

Population Ecology Of Pseudacteon Tricuspis Borgmeier (Diptera: Phoridae), An Introduced Parasitoid Of The Red Imported Fire Ant Solenopsis Invicta Buren (Hymenoptera: Formicidae) In Louisiana, Donald Charles Henne

LSU Doctoral Dissertations

Aspects of the population ecology of a parasitoid (Pseudacteon tricuspis) of the red imported fire ant (Solenopsis invicta) in Louisiana were studied. The spatio-temporal abundance patterns, dispersal, population spread, aggregation, direct mutual interference and functional response characteristics of this parasitoid were studied to address deficiencies in our knowledge about phorid flies, particularly Pseudacteon parasitoids. This endoparasitoid was discovered to manipulate host ant behavior in ways that benefit its own survival. Laboratory experiments to gain insights into behavioral and functional responses revealed that fly aggregations were density-dependent and interference was not significant when 1-3 females were simultaneously confined with hosts, although …

Phylogenetic Study Of Diadegma Species (Hymenoptera: Ichneumonidae) Inferred From Analysis Of Mitochondrial And Nuclear Dna Sequences, Barbara Wagener, Annette Reineke, Bernhard Löhr, Claus P.W. Zebitz

All Peer-Reviewed Publications

The genus Diadegma consists of a large group of parasitoid wasps with a confusing taxonomy based on morphological characters. No phylogenetic studies on this genus or any of its species have been published so far. We examined DNA variations in a 498 bp segment of the cytochrome oxidase I gene (COI) of mitochondrial DNA (mtDNA) and in the internal transcribed spacer 2 (ITS2) of ribosomal DNA (rDNA) and compared nine different Diadegma species (i.e., D. semiclausum, D. insulare, D. fenestrale, D. mollipla, D. rapi., D. leontiniae, D. chrysostictos, D. armillata, D. blackburni) from various geographical origins. Interspecific variation ranged from …

Incidence Of Larval And Pupal Parasitoids Of Lepidoptera In Uganda With Special Reference To New Associations, I. Rwomushana, S. Kyamanywa, A. J. Ngi-Song, C. O. Omwega

All Peer-Reviewed Publications

Cotesia flavipes Cameron (Hymenoptera: Braconidae) was introduced in Uganda in 1998 for the biological control of the old association cereal stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). However there is little information on whether this parasitoid will attack new association Lepidoptera, which in turn may have implications on its efficacy on Ch. partellus. This study investigated the incidence of introduced Co. flavipes on Ch. partellus, and new association lepidopteran species and associated effects on its efficacy. Parasitism levels for Co. flavipes in several locations varied between 13.7-34.8% and 1.5-18.8% on Ch. partellus and new association hosts, respectively. Implications for biological control …

Comparative Genetic Studies Of Native And Introduced Coccinellidae In North America, Elliot S. Krafsur, John J. Obrycki, James D. Harwood

Entomology Faculty Publications

During the past four decades, several species of aphidophagous Coccinellidae became established in North America, including Coccinella septempunctata, Harmonia axyridis, Hippodamia variegata, and Propylea quatuordecimpunctata. After their establishment, unknown circumstances favoured a rapid increase in population densities and distribution of H. axyridis and C. septempunctata at localities hundreds and thousands of kilometers from their release sites. Propylea quatuordecimpunctata and Hippodamia variegata have spread more slowly after becoming established in northeastern North America. Comparative studies based upon allozyme variation in these four introduced species and in six native North American species of ladybird beetles revealed …

Quantifying Aphid Predation Rates Of Generalist Predators In The Field, James D. Harwood, John J. Obrycki

Entomology Faculty Publications

The community of predators within agroecosystems has the potential to restrict aphid populations, especially early in the season before exponential increases in density and prior to the arrival of specialist natural enemies. Although direct observations of predation, laboratory feeding trials and manipulative field studies have been used to estimate levels of biological control exerted by different species (or potentially negative interactions between them), it is often difficult to extrapolate results to naturally occurring interactions in the field.

Over 100 investigations have utilized gut-content analysis to estimate aphid predation rates by predators. Throughout the last century, gut dissection, which enables the …

Tritrophic Interaction Of Parasitoid Lysiphlebus Testaceipes (Hymenoptera: Aphidiidae), Greenbug, Schizaphis Graminum (Homoptera: Aphididae), And Greenbug-Resistant Sorghum Hybrids, Mahmut Dogramaci, Z. B. Mayo, Robert J. Wright, John C. Reese

Department of Entomology: Faculty Publications

Interactions of the parasitoid Lysiphlebus testaceipes (Cresson) and the greenbug, Schizaphis graminum (Rondani), on greenbug-resistant ‘Cargill 607E’ (antibiosis), ‘Cargill 797’ (primarily tolerance), and -susceptible ‘Golden Harvest 510B’ sorghum, Sorghum bicolor (L.) Moench, were tested using three levels of biotype I greenbug infestation. The parasitoid infestation rate was 0.5 female and 1.0 male L. testaceipes per plant. For all three greenbug infestation levels, the parasitoid brought the greenbug under control (i.e., prevented the greenbugs from killing the plants) on both resistant hybrids, but it did not prevent heavy leaf damage at the higher greenbug infestation rates. At the low greenbug infestation …

Evaluation Of Beauveria Bassiana And Host Plant Resistance For The Management Of Rice Stink Bug In Rice Agro-Ecosystem, Dilipkumar Thakorbhai Patel

LSU Master's Theses

Isolates of Beauveria bassiana (Balsamo) Vuillemin were tested for biological control of rice stink bug, Oebalus pugnax (Fab.), in the laboratory, in small-plot field experiments compared with conventional insecticides, and in a large-plot experiment to determine the spread and persistence of the fungus. The soil-derived isolate LRC28 was more virulent to O. pugnax adults than the rice stink bug-derived isolate RSB in a laboratory experiment. The fungal isolates did not differ from one another in reducing insect numbers or in infecting rice stink bugs in the small-plot experiments. A single application of B. bassiana reduced rice stink bug nymphs on …

Impact Of Ceutorhynchus Litura Feeding On Root Carbohydrate Levels In Canada Thistle (Cirsium Arvense), Gary L. Hein, Robert G. Wilson

Department of Entomology: Faculty Publications

Canada thistle is a serious perennial weed found throughout the northern regions of the United States and Canada. The weevil, Ceutorhynchus litura (F.), was first released in Canada in 1965 as a potential biological control agent for Canada thistle; however, its impact as a control agent has been sporadic. The objective of this study was to characterize C. litura impacts on the carbohydrate profile in Canada thistle roots through the growing season and to evaluate the potential for this biological control agent in causing stress to Canada thistle. Field plots, infested with C. litura, were established and extensively sampled …