Hesperus Adults Research Articles

Dispersal and distribution of a generalist predator in habitats with multiple food resources

The ability to locate suitable food resources affects fitness in animals. Therefore, movements are necessary to optimize foraging in habitats where food is distributed in patches of different qualities. The aim of this work was to investigate the dispersal and distribution of females and males of the omnivorous mirid D. hesperus in mesocosms composed by food patches of different values in terms of fitness. In agreement with the Marginal Value Theorem (MVT) and the Ideal Free Distribution (IFD), individuals were expected to aggregate in the highest quality patches. Besides, the proportion of individuals in patches was predicted to be proportional to fitness, and interference among individuals was expected to rise as the density of individuals increased. Emigration rates were predicted to be higher for low- than for high-quality patches, while the opposite was predicted for immigration. Three types of habitats each with different combinations of food resources were tested: (1) habitat including patches of tomato plants with no-prey, and patches infested with either mite or whitefly; (2) with no-prey and whitefly; (3) with no-prey and mites. Each type of habitat was set up in a tomato greenhouse compartment and replicated four times. Individuals were tracked by mark-recapture methods using luminous paintings. The number of females and males in whitefly patches was significantly higher than in mite and no-prey patches, but a significant interaction sex*habitat and sex*patch was found. In habitats with only one type of prey, D. hesperus adults fitted the IFD, while in mixed prey habitats their distribution diverged from IFD. Interference was found to be significant, with female fitness decreasing as their density increased. Emigration rates were significantly lower for whitefly patches with a significant interaction patch*sex; the opposite was found for immigration. This research shows that it is unlikely that D. hesperus forage according to the omniscient principle of IFD and MVT; in contrast, it strongly suggests that it uses some simple rules to make decisions about inter-patch movement, and emigration from habitats and patches.

Role of Lygus hesperus (Hemiptera: Miridae) Adult Feeding on Deformation of Blackberry Fruits

Role of <i>Lygus hesperus</i> (Hemiptera: Miridae) Adult Feeding on Deformation of Blackberry Fruits

Flight Potential of Western Tarnished Plant Bug (Hemiptera: Miridae).

The western tarnished plant bug, Lygus hesperus Knight, is an economically important pest of several agricultural crops in the western United States. It is an increasing threat to potato, Solanum tuberosum L. (Solanales: Solanaceae), in the diverse landscape of the Columbia Basin of Oregon and Washington. In this study, flight mills were used to investigate the flight capacity of L. hesperus with the aim of better understand its dispersive characteristics in the agricultural landscape. Explicitly, we investigated the effects of biological factors such as generation, gender, and body weight on the flight potential of adult L. hesperus adults collected from field populations during spring and summer of 2019 and 2020. The study flight parameters assessed were distance, activity, velocity, and diel periodicity. In 24-h flight mill assays, a clear dichotomy pattern was found in sum flown distance for adults that travelled 1 km or shorter and adults that travelled greater than 1 km. Individuals from the summer population flew farther and more actively than those from the overwintered population. Female L. hesperus flew farther and were more active compared to males. Adult body weight before the flight was directly proportional to flight distance and number of flights, but not with velocity. Overwintered L. hesperus adults lost a higher percentage of their pre-flight body weight compared to summer adults over the course of the study. To the best of our knowledge, this is the first study that demonstrated that L. hesperus summer adult population has the flight ability to disperse greater distance in the agricultural landscape than overwintered population.

Biological control of silverleaf whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) using predatory bugs, Dicyphus hesperus (Hemiptera: Miridae) and Orius insidiosus (Hemiptera: Anthocoridae)

The silverleaf whitefly (SLW), Bemisia tabaci, is an exotic pest that causes sporadic crop damage in Canadian greenhouses, mainly on tomatoes. Its plant feeding is responsible for both direct damage as well as the transmission of plant viruses. Interestingly, omnivorous predators, which are used as biological control agents for multiple whitefly species, can establish on greenhouse crops even before the pest has established, using alternative food resources and host plants to support the predator. However, the efficiency of such indigenous omnivorous biological agents in the suppression of high density and intense SLW infestations remains unknown. This research aimed to assess the potential of two indigenous omnivorous biological agents, Dicyphus hesperus and Orius insidiosus to control SLW infestations and their effects on tomato plant health and yield at both early stages of the crop cycle, and at high pest densities. This study showed that populations of B. tabaci are able to grow rapidly. However, neither of the introduced densities of B. tabaci nor the infestation time had a significant effect on the incidence of tomato irregular ripening disorder (TIR) and yield. Our results also show that the introduction of three or five D. hesperus adults per cage reduces the number of B. tabaci larvae and pseudo-nymphs, while O. insidiosus did not significantly reduce SLW populations. Our results suggest that D. hesperus could control high levels of SWL and at an early stage in the cropping cycle.

Reproductive Development of Lygus hesperus (Hemiptera: Miridae) Adults Under Constant and Variable Temperatures.

As water for agriculture becomes less available in the semi-arid western United States, alternative irrigation strategies such as deficit irrigation may be necessary for continued crop production. Alternative irrigation practices in cotton (Gossypium spp. [Malvales: Valvaceae]) can result in episodic drought stress that alters temperature profiles within the crop canopy. These altered temperatures may influence populations of important pests such as Lygus hesperus Knight. Field studies often associate lower population densities of L. hesperus with limited irrigation. Recent studies of the thermal ecology of L. hesperus egg and nymphal development have demonstrated only subtle effects of the high, variable temperatures typical of moderate drought stress in cotton. However, influences of these conditions on L. hesperus adult reproductive development have not been studied. The reproductive development of L. hesperus adults was examined under constant (±0.2°C) and variable (±8°C) regimes at a low (15°C), moderate (22°C), and high (29°C) daily mean temperatures. No developmental differences were demonstrated between temperature regimes under moderate or high temperatures. At the low temperature, only the times to the occurrence of eggs, filled medial accessory glands, and filling seminal vesicles were shorter under variable regime, compared with the constant temperature. These results suggest that temporary, episodic increases in crop canopy temperatures caused by moderate drought stress are unlikely to impact L. hesperus population growth, and may only promote short-term displacement of adults into adjacent crops with preferable conditions.

Impact of Lygus hesperus (Hemiptera: Miridae) Feeding and Oviposition on Lettuce

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is an important insect pest of lettuce, Lactuca sativa L. in the central coast region of California. However, little is documented on the injury symptoms relative to levels of L. hesperus infestation on lettuce. Experiments were conducted in which lettuce plants were exposed to 0, 1, 3, 5, and 10 L. hesperus adults for 2 and 7 days. The major injury symptom observed was lesions on the midrib of the leaves, and under low to moderate infestation (e.g., one to five adults per plant) after 2 days of exposure these lesions were not significantly different from the insect-free control. Under heavy infestation (e.g., 10 adults per plant), however, lesions developed rather quickly after 2 days of exposure. The number of lesions was positively associated with numbers of feeding sites and eggs. When heavy infestation lasted for a week, most of the plants died. At low to moderate infestation, more lesions developed compared with the insect-free control. After a weeklong exposure, an increase in number of lesions was negatively associated with plant height. The results emphasize the need for regular scouting to facilitate immediate management decisions and actions to reduce losses from L. hesperus feeding and oviposition injury in lettuce.

Characterization of Lygus hesperus (Hemiptera: Miridae) Feeding and Oviposition Injury on Celery Seedlings

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), can be a serious pest of celery, Apium graveolens dulce (Mill.) Pers. in the Central Coast region of California. Little is known about injury symptoms caused by L. hesperus adults on celery. When celery seedlings were exposed to L. hesperus adults, their crown area was found destroyed with necrotic dead tissue. Destroyed crowns of dead seedlings were observed when seedlings were exposed to five or more L. hesperus adults for ≥24 h but was not observed on seedlings exposed ≤12 h. In addition, elongated lesions were noticed on the celery petiole and were significantly greater when exposed to five or more L. hesperus adults for as little as 4 h. Number of elongated lesion injuries and number of eggs recovered from elongated lesions was correlated (r = 0.66; P &lt; 0.001). Data provide key diagnostic symptoms of L. hesperus feeding and ovipositional injury on celery seedlings. Also, this study expands our understandings on the effects of L. hesperus adult density and duration of exposure which reinforces the need for regular scouting, and immediate management decisions and action to reduce losses from L. hesperus injury in both celery seedlings and mature plants in greenhouse and field settings, respectively Accepted for publication 27 April 2016. Published 4 May 2016.

Temperature-Dependent Survival of Adult Lygus hesperus (Hemiptera: Miridae).

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is a key pest of many horticultural and agronomic crops in the western United States. Despite its well documented pest status, many aspects of the basic biology, including overwintering ecology, of L. hesperus are poorly understood. We examined the influence of eight constant temperatures from 10 to 35°C on survival of nondiapausing adult L. hesperus held with or without food, and the consequences of exposure to an extended period at 10°C on subsequent reproduction. Survival analyses indicated that, on average, fed insects tended to live longer than unfed insects, females lived longer than males, and the survival time decreased with increasing temperature. Nonlinear regressions indicated that median survival for insects grouped by gender and feeding status declined exponentially with increasing temperature. Survival functions for combinations of insect class (gender and feeding status) and temperature were adequately described by the respective two-parameter logistic functions. When adults were held for 9 d at 27°C with food after a 33-d period at 10°C either with or without food, no deleterious effects of prior starvation on propensity to mate or fecundity were demonstrated. These findings indicate that when temperatures are low, nondiapausing L. hesperus adults are capable of extended host-free survival with little or no impact on subsequent reproduction. Our findings suggest the current understanding of L. hesperus overwintering dynamics is incomplete. In addition, our results provide quantitative baseline information to facilitate more comprehensive investigation of the ecology of L. hesperus overwintering.

Potential Transmission of &lt;I&gt;Pantoea&lt;/I&gt; spp. and &lt;I&gt;Serratia marcescens&lt;/I&gt; (Enterobacteriales: Enterobacteriaceae) to Plants by &lt;I&gt;Lygus hesperus&lt;/I&gt; (Hemiptera: Miridae)

Lygus hesperus Knight (Hemiptera: Miridae) is a key agricultural pest in the western United States. In a recent study, proteins from Pantoea ananatis and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) were identified in diet that was stylet probed and fed on by L. hesperus adults. P. ananatis and S. marcescens are ubiquitous bacteria that infect a wide range of crops. The objective of our study was to determine whether L. hesperus transfer P. ananatis and S. marcescens to food substrates during stylet-probing activities. Sucrose (5%) was spread under parafilm and exposed to adult L. hesperus for 24 h. Diet similarly prepared but not exposed to insects was used for controls. MacConkey agar was inoculated with stylet-probed or control diets and incubated at 25 degrees C. After 24 h, bacterial colonies were observed on agar that was inoculated with stylet-probed diet, but were not observed on agar inoculated with control diet. Isolated bacterial colonies were putatively identified as either Pantoea spp. or S. marcescens using the API 20e identification kit. These results indicate that L. hesperus is capable of vectoring P. ananatis and S. marcescens.

Dispersion, Distribution, and Movement ofLygusspp. (Hemiptera: Miridae) in Trap-Cropped Organic Strawberries

Alfalfa (Medicago sativa L.) is a highly attractive plant host to Lygus spp. and is used as a trap crop in California organic strawberries to influence the dispersion and dispersal of these pests, particularly Lygus hesperus Knight. The abundance and distribution of Lygus spp. nymphs between two trap crops separated by 50 strawberry rows was analyzed in 2008 and 2010. Nymphs demonstrated a bimodal distribution in strawberries between trap crops, where nymphs were most abundant and aggregated in alfalfa, when compared with interior strawberry rows, where nymphs were less abundant. The majority of nymphs were concentrated in trap crops and nymphal densities in interior strawberry rows were well below economic thresholds. The movement of Lygus spp. from a marked alfalfa trap crop into adjacent strawberry rows or trap crops was also studied in 2008 and 2009 using a chicken egg albumin enzyme-linked immunosorbent assay mark-capture technique. The majority of marked-captured L. hesperus adults and Lygus spp. nymphs remained in alfalfa trap crops, rather than dispersing out into strawberry rows at 24 h, 48 h, and 2 wk, postprotein application. The attenuation of Lygus spp. movement in alfalfa associated with organic strawberries is a key component of successful trap cropping. A small percentage of marked adults and nymphs were captured in neighboring alfalfa trap crops, located 62 m from the point of protein application, highlighting the dispersal capacity of this key pest.

Sweepnet Captures of Lygus hesperus (Hemiptera: Miridae) Adult Genders and Age-Classes in Cotton

Management of the western tarnished plant bug, Lygus hesperus Knight, in cotton usually relies on population estimates obtained using the sweepnet. Recent studies indicated adult L. hesperus gender and physiological age influence feeding behavior, within-plant distribution, and injury to cotton. Whether these differences in behavior also influence capture by the sweepnet is not known. We evaluated the sweepnet for sampling L. hesperus adults of known gender and age class in Pima and Acala Upland cotton. Adults of 4 classes (females, prereproductive or reproductive; males, prereproductive or reproductive) marked with fingernail polish to prevent flight were released into assigned sample rows. Captures of marked adults declined seasonally in all experiments. In Pima cotton, the sweepnet was least effective for sampling prereproductive female L. hesperus, and most effective for collecting reproductive males. Captures of reproductive females and prereproductive males were intermediate. We suggest the influence of adult gender and age class on sweepnet captures in Pima cotton corresponds to a propensity for prereproductive adults to reside within plant terminals substantially shielded by foliage. Similar differences in Upland cotton were not observed, probably because the comparatively open structure of the Upland terminal minimized the effects of gender and age class on collection efficiency. Finally, dissection of native L. hesperus indicated an age structure dominated by reproductive maturity. Therefore, future mark-release-recapture studies of factors influencing sweepnet sampling for L. hesperus adults in cotton may maximize relevance by focusing on reproductively mature adults.

Response by Lygus hesperus (Hemiptera: Miridae) Adults to Salivary Preconditioning of Cotton Squares

Response by Lygus hesperus (Hemiptera: Miridae) Adults to Salivary Preconditioning of Cotton Squares

Salivary Proteins ofLygus hesperus(Hemiptera: Miridae)

ABSTBACTLygus hesperus Knight (Hemiptera: Miridae) causes economic damage to a wide range of crops in the western United States. While stylet-probing, L. hesperus discharge saliva consisting of lytic enzymes that facilitate extraoral digestion of host tissues. L. hesperus saliva primarily consists of polygalacturonases, α-amylases, and proteases, but salivary constituents other than these enzymes have not been documented. Improved knowledge of L. hesperus salivary proteins could lead to a better understanding of Lygus-host interactions, and aid in the development of crops that are resistant or tolerant to injury caused by Lygus spp. The objective of our study was to use mass spectrometry to identify salivary proteins of L. hesperus adults. Multiple polygalacturonases and proteases were identified from diet that was stylet-probed and fed upon by L. hesperus. Laccase, alkyl hydroperoxide reductase-like protein, glucose dehydrogenase, and xanthine dehydrogenase were identified in styletprobed diets by using mass spectrometry, and laccase activity was confirmed using a colorimetric assay. This is the first study to identify laccase, glucose dehydrogenase, and xanthine dehydrogenase from L. hesperus saliva; we propose these enzymes target plant-defense compounds. Nearly 100 proteins from the bacterial plant pathogen, Pantoea ananatis and nine proteins from Serratia spp. were identified in stylet-probed diets. These results suggest L. hesperus may vector these plant pathogens. Our study adds to the list of documented L. hesperus salivary proteins, and provides information that will be useful for the further study of L. hesperus saliva and Lygus-microbe interactions.

Injury to Cotton by Adult &lt;I&gt;Lygus hesperus&lt;/I&gt; (Hemiptera: Miridae) of Different Gender and Reproductive States

Lygus hesperus Knight (Hemiptera: Miridae) is a key pest of cotton (Gossypium spp.) in the western United States that injures floral buds (squares) and developing fruit (bolls). However, no clear relationship between Lygus population level and plant injury has been established. Age-dependent feeding activity by L. hesperus is a possible source of variation that has not been examined for its influence in studies of the impact of Lygus on cotton. Recent video-based laboratory studies indicated that feeding behaviors and trivial movement varied among L. hesperus adults of different gender and reproductive states (prereproductive; reproductive and unmated; and reproductive and mated). We compared within-plant distributions and accumulations of feeding injury to intact cotton plants corresponding to adult L. hesperus of different gender and reproductive states. Adult females, regardless of reproductive state, were observed on squares and axillary buds more often than were males. Additionally, prereproductive adults were observed on squares and axillary buds more often than were mated or unmated reproductive adults, regardless of gender. Plants that were exposed to prereproductive adults exhibited more abscised squares and more squares with injured anthers compared with plants exposed to reproductive adults. However, feeding injury did not differ by insect mating status or gender. These results are consistent with results of our previous video-based assays, and indicate adult reproductive state represents a source of variation that should be controlled in studies to evaluate Lygus-induced injury to cotton and other crop plants.

Among-Sampler Variation in Sweep Net Samples of Adult Lygus hesperus (Hemiptera: Miridae) in Cotton

The sweep net is a standard sampling method for adults of the western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), in cotton (Gossypium spp.). However, factors that influence the relationship between true population levels and population estimates obtained using the sweep net are poorly documented. Improved understanding of these factors is needed for the development and application of refined treatment thresholds. Recent reports of significant among-sampler differences in sweep net-based population estimates of the adult tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), seem to preclude meaningful comparisons of population estimates collected by different samplers. We used a mark-release-recapture method and the standard sweep net to evaluate among-sampler differences in population estimates of L. hesperus adults. Adult lygus, marked with fingernail polish to facilitate identification and prevent flight, were released into 10-m sample rows on the evening before 10-sweep samples were collected the following morning. The experimental design was a randomized complete block with three replications of three treatments (sampler). Separate experiments were conducted in two plantings each of Pima (Gossypium barbadense L.) and Acala (Gossypium hirsutum L.) cotton. Collections of marked bugs from each study were evaluated for effects of sampler, sample date, and their interaction. Although differences in lygus collections were observed among sample dates in some tests, no differences were detected in the population estimates by different samplers. These results demonstrate that the sweep net technique can be sufficiently standardized to allow direct comparison of population estimates obtained by different samplers.

Efficacy of Beauveria bassiana Against Lygus hesperus (Hemiptera: Miridae) at Low Temperatures

The western tarnished plant bug, Lygus hesperus Knight, is susceptible to the naturally-occurring pathogen, Beauveria bassiana (Balsamo) Vuillemin, in the San Joaquin Valley of California. Recent research efforts have focused on selection of Beauveria strains that were effective against Lygus under the high-temperature conditions typical of the cotton (Gossypium spp.) production season. However, the most appropriate use of this pathogen may not be as a rescue treatment. Alternatively, B. bassiana may be useful to efforts to target overwintering populations of Lygus if isolates are available that are highly virulent under the low temperature conditions typical of winter and early-spring in the San Joaquin Valley. One commercially-available isolate and 4 native isolates of B. bassiana were assayed against L. hesperus adults under constant temperatures of 12.8, 18.3, and 23.9°C. Although decreasing temperatures were associated with diminished Beauveria-induced mortality of Lygus and slower development of disease symptoms, no differences in efficacy were detected among the tested isolates. Differences in the patterns of occurrence of Beauveria disease symptoms were observed among isolates at some temperatures, but those differences were not substantial. Furthermore, results at some temperatures suggested potential influences of Lygus adult age or gender on susceptibility to B. bassiana. Those effects should be further investigated. Overall, the results did not indicate that any of the tested isolates of B. bassiana were superior to the commercially-available isolate under low temperature conditions.

Stage‐specific predation on Lygus hesperus affects its population stage structure

AbstractEvidence suggests that prey can vary in their susceptibility to predation depending on their developmental stage. Stage‐dependent predation is of particular importance to integrated pest management, because it is often a particular developmental stage of a pest that causes the majority of the damage to the crop. An understanding of stage‐dependent biocontrol is therefore important for predicting the ultimate impact of herbivore populations. In this article, we addressed this issue by focusing on the stage structure of Lygus hesperus Knight (Heteroptera: Miridae) populations in cotton as related to the density of a specific generalist predator. We first demonstrated in a field experiment that Geocoris spp. adults suppressed L. hesperus eggs and/or early instars (first through third), but did not suppress fourth through fifth instars or adult L. hesperus. We then demonstrated that this stage‐specific predation translated into season‐long shifts in the stage structure of L. hesperus populations in cotton fields. Using weekly sweep counts across 21 separate cotton fields, we found a negative correlation between season‐long Geocoris spp. densities and season‐long densities of L. hesperus nymphs. In contrast, there was no such correlation between Geocoris spp. and L. hesperus adults. Taken together, these results suggest that Geocoris spp. predators influence the stage structure of L. hesperus populations in cotton, which in turn has the potential to affect patterns of cotton square damage and sampling bias when monitoring L. hesperus populations.

Combined effects of the entomopathogenic fungus, Paecilomyces fumosoroseus Apopka-97, and the generalist predator, Dicyphus hesperus, on whitefly populations

The effects of intraguild interactions between Dicyphus hesperus Knight (Hemiptera: Miridae) and Paecilomyces fumosoroseus Apopka-97 (PFR-97TM) (Wize) Brown and Smith (Ascomycota: Hypocreales) on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) populations were investigated in tomato greenhouse microcosms. Conditions were established in which interference or synergy would most likely occur; namely, a high number of available whiteflies were combined with large numbers of both D. hesperus and PFR-97TM. We measured live whitefly density in a factorial repeated measures experiment where plants were provided or withheld releases of D. hesperus and/or applications of PFR-97TM for 6 weeks. Releases of D. hesperus were made at a rate of 10 adults/plant during the first and third week and PFR-97TM suspensions were applied with a backpack sprayer at a rate of 18 × 107, 1.3 × 107 and 1.2 × 107 viable blastospores/ml during the first, third and fourth week, respectively. Results revealed a non-significant interaction effect between D. hesperus and PFR-97TM, indicating that their actions were independent. Individual whitefly reductions of 48% and 35% were achieved by PFR-97TM and D. hesperus, respectively. Collectively, the natural enemies reduced whitefly densities by 62% relative to the controls. The density of D. hesperus adults was unaffected by multiple applications of PFR-97TM. These results suggest that the combination of generalist entomopathogenic fungi and generalist predators has the potential to cause increased pest mortality despite evidence of minimal interference.

Intraguild predation by the generalist predator Dicyphus hesperus on the parasitoid Encarsia formosa

Predation was measured in the laboratory by Dicyphus hesperus females on patches of greenhouse whitefly (Trialeurodes vaporariorum) pupae. The patches contained different proportions of unparasitized pupae and those parastisized as nymphs by Encarsia formosa. Dicyphus hesperus fed readily on parasitized pupae and the number of parasitized pupae consumed increased with the proportion available indicating a capacity for intraguild predation. However, D. hesperus females did not display a preference for feeding on parasitized pupae versus unparasitized pupae. Dicyphus hesperus adults were released at three densities into greenhouse enclosures containing tomato plants harbouring greenhouse whitefly and immature E. formosa. Numbers of killed and parasitized whitefly nymphs and pupae and the total number of healthy whitefly were compared among Dicyphus density treatments. On upper leaves, the amount of predation on whitefly nymphs was higher at the highest predator density than at the lower density or in enclosures where D. hesperus was not released. On lower leaves, the number of parasitized pupae was lowest with the highest predator density indicating a negative effect of intraguild predation by D. hesperus on E. formosa. Despite this, Dicyphus density did not affect the density of whitefly in the presence of E. formosa. The results are discussed as they relate to concurrent use of D. hesperus and E. formosa for regulation of greenhouse whitefly populations.

Biological and molecular characteristics of Beauveria bassiana isolates from California Lygus hesperus (Hemiptera: Miridae) populations

Abstract Lygus hesperus is an important pest of many crops grown in the Western US. In addition, other species of Lygus cause damage in other parts of the world. To date, no selective pesticide exists for the control of Lygus spp. and broad spectrum pesticides that also kill natural enemies may lead to secondary pests. Entomopathogenic fungi may offer an alternative to chemical pesticides. Isolates of Beauveria bassiana collected from San Joaquin Valley of California (SJV) L. hesperus populations were screened for their ability to grow at high temperatures and for their ability to infect and kill L. hesperus adults and nymphs under laboratory conditions. No isolate grew at 37 or 35 °C but most isolates were able to grow at 32 °C. In addition, one L. hesperus isolate was more efficacious at higher doses than the commercial isolate. Microsatellite markers were used to determine that selected isolates could be distinguished from other isolates. Preliminary information suggested 82 SJV isolates of B. bassiana were closely related to each other but distantly related to the commercial isolate.