Effects of Bt Corn and Egg Density on Western Corn Rootworm (Coleoptera: Chrysomelidae) Adult Emergence and Estimation of Effective Bt Dose.

Since 2003, rootworm-protected transgenic corn has been commercially deployed in the United States as a principal method of control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Durability of this technology depends partly on larval mortality ("dose") exerted by the traits, but density-dependent mortality can confound calculations of dose. Research reported here examined the effects of density-dependent mortality on adult emergence and estimates of trait dose. At sites in Illinois and Indiana, western corn rootworm eggs were infested at four densities on non-Bt corn and at a single density on corn hybrids with transgenic events MON 88017 (VT Triple PRO), DAS-59122-7 (Herculex Insect Protection), and MON 88017 × DAS-59122-7 (SmartStax corn). Beetles were collected weekly in large emergence cages. Density-dependent mortality and the effect of Bt traits were examined using percent survival from egg to adult, sex ratio, and beetle mass. Beetle emergence from Bt treatments was very low, and percent survival from non-Bt treatments was greatest at the lowest egg density (410 eggs per row-meter). Therefore, emergence from the lowest infestation density on non-Bt corn was used to estimate the effective dose of the Bt treatments. Sex ratio and beetle mass were unaffected by density-dependent effects and were not consistently affected by Bt traits. Dose was estimated at 97.4-99.3% for MON 88017, 98.8-99.9% for DAS-59122-7, and 99.7-100.0% for MON 88017 × DAS-59122-7. This study confirms the need to account for density-dependent mortality when estimating dose of corn rootworm protection events even at relatively low egg infestation densities.

Efficacy of pyramided Bt proteins Cry1F, Cry1A.105, and cry2Ab2 expressed in Smartstax corn hybrids against lepidopteran insect pests in the northern United States.

Commercial field corn (Zea mays L.) hybrids transformed to express some or all of the lepidopteran insect-resistant traits present in SmartStax corn hybrids were evaluated for insecticidal efficacy against a wide range oflepidopteran corn pests common to the northern United States, during 2008 to 2011 at locations in 15 states. SmartStax hybrids contain a pyramid of two Bacillus thuringiensis (Bt) derived events for lepidopteran control: event TC1507 expressing Cry1F protein and MON 89034 expressing CrylA.105 + Cry2Ab2. These studies focused on characterization of the relative efficacy of each event when expressed alone or in combination, and compared with non-Bt hybrid. Corn hybrids containing pyramided insecticidal proteins Cry1F + Cry1A.105 + Cry2Ab2 (SmartStax) consistently showed reduced plant feeding damage by a wide range of lepidopteran larvae compared with single event and non-Bt hybrids. Corn hybrids expressing TC1507 or MON 89034 as single or pyramided events were consistently efficacious against Ostrinia nubilalis (Hübner). SmartStax hybrids had less injury from Agrotis ipsilon (Hufnagel) and Striacosta albicosta (Smith) than corn hybrids containing only event MON 89034 but were not more efficacious than single event TC1507 hybrids. Corn hybrids with event MON 89034 provided better control of Helicoverpa zea (Boddie), than event TC1507 alone. Spodoptera frugiperda (J.E. Smith) efficacy was higher for hybrids with pyramid events and single events compared with the non-Bt hybrids. The spectra of activity of events TC1507 and MON 89034 differed. The combination of TC1507 + MON 89034 provided redundant control of some pests where the spectra overlapped and thereby are expected to confer a resistance management benefit.

Evaluation of corn hybrids expressing Cry34Ab1/Cry35Ab1 and Cry3BbL against the western corn rootworm (Coleoptera: Chrysomelidae).

Studies were conducted across nine U.S. states, over 5 yr, to characterize the efficacy of transgenic corn (Zea mays L.) hybrids producing insecticidal proteins derived from Bacillus thuringiensis (Bt) for control of western corn rootworm, Diabrotica virgifera virgifera Le Conte. Hybrids tested had the same genetic background, contained one of two single events (DAS-59122-7 expressing Cry34Ab1/Cry35Ab1 or MON 88017 expressing Cry3Bb1) or a pyramid consisting of both rootworm-active events (SmartStax traits) and were compared with a non-Bt near isoline. Frequency analyses of root feeding data showed that hybrids containing both events sustained less root damage (0-3 node injury scale) than hybrids containing either event alone. The levels of root protection provided by MON 88017 and DAS-59122-7 were not different from each other. Efficacy was also evaluated based on consistency of protection, based on the proportion of plants with root ratings of either < or = 0.25 or < 1.00 on the node injury scale. The combination of two modes of action in SmartStax provided greater product consistency over a single mode of action at the 0.25 level and all hybrids producing Bt proteins provided equally high consistency at the 1.00 level. Overall these data show single and multiple mode of action hybrids provided high, consistent protection over the past 5 yr across the trial geography; however, pyramiding the rootworm Bt events provided greater and more consistent root protection. These findings also support that pyramided traits like SmartStax (Cry3Bb1 + Cry34Ab1/Cry35Ab1) remain a viable strategy for delaying resistance to either trait.

Relationship of trait, Type A behavior, and physical fitness variables to cardiovascular reactivity and coronary heart disease risk potential.

PURPOSE: This research investigated the effects of individual characteristics on cardiovascular reactivity, and in turn on the potential for developing coronary heart disease. DESIGN: Path analysis was performed using LISREL, a structural equation modeling program providing maximum likelihood estimators and goodness-of-fit measures. SETTING: Data were collected during a health assessment program, from participants attending a Department of Defense senior service school. SUBJECTS: Participants were 134 senior-ranking male military and civilian employee volunteers, representing approximately 84% of all students in training. MEASURES: Five individual characteristics, four measures of cardiovascular reactivity, and one coronary heart disease risk potential variable were investigated. These included Physical Fitness, Type A behavior, Trait Anger and Trait Anxiety, Diastolic and Systolic Blood Pressure measures, and Coronary Heart Disease Risk. RESULTS: Significant path coefficients (critical ratios > 2) indicated that the mean diastolic blood pressure under a video stress condition was predictive of increased potential of developing coronary heart disease (.51), while hard driving Type A behavior was a cardiovascular reactivity antecedent associated with an increase in coronary heart disease risk directly (.14) and indirectly (.39). Physical fitness, on the other hand, had a positive affect in that increased fitness was related to lower cardiovascular reactivity when participants were stressed (-.58). CONCLUSIONS: Physical fitness is indirectly beneficial in reducing coronary heart disease risk potential by reducing an individual's diastolic blood pressure response, while scoring high as a Type A Hard Driving personality increases cardiovascular reactivity and coronary heart disease risk. This study is limited to middle-aged males who were generally healthy and displayed concern for their health.

Job and personal factors related to job stress and risk of developing coronary artery disease.

Results indicated that job stress is affected by physical stressors, role conflict, quantitative workload, job boredom, and whether one has an external locus of control. Coronary artery disease potential, as measured by the cholesterol ratio, was affected by sex, height-weight index, and smoking.

Dental stress model and assessment questionnaire.

This article presented a new dental stress model, which is based upon "perceived" (psychological) stresses. The model consists of antecedents of stress (stressors) and the resulting job and life stresses which produce psychologic and physiologic stress responses and behavioral consequences. From the proposed model, a stress evaluation questionnaire was constructed to help dental personnel diagnose excessive stressors in their own lifestyles.

Factors predictive of stress, organizational effectiveness, and coronary heart disease potential.

Research to predict stress, organizational effectiveness, and potential for developing coronary heart disease (CHD) is presented based on two samples (n = 357 and n = 225). Results indicate that perceived stress is predicted by a combination of individual and job related characteristics. The data suggest that stress, in turn, affects individual and organizational health and effectiveness, by causing increases in cold/flu episodes, somatic symptoms, while decreasing job satisfaction. In addition, stress has an indirect effect on job performance and absenteeism. Models for predicting the ratio of total serum cholesterol divided by HDL cholesterol as an indicator of coronary heart disease potential are provided and a CHD screening model is proposed.