Should Grain Elevator Managers Adopt Integrated Pest Management?

Insect infestation during storage and processing causes millions of dollars of wheat damage annually in the United States. Insect infestation reduces wheat storing processing profit as well as consumer confidence in wheat food products. Meanwhile, increased concerns about insecticide use have increase interest in Integrated Pest Management (IPM) strategies. This research compares the costs of IPM and chemical-based approaches to insect control to determine why most elevator managers have not adopted IPM practices.Agribusiness,

Distribution of psocids (Psocoptera) in temperature gradients in stored wheat

Psocids have become important pests of stored products during the last two decades, but little is known about their behavior or ecology. We examined distribution of Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae), Liposcelis entomophila (Enderlein), and Liposcelis paeta (Pearman), three of the main psocid pests of stored grain throughout the grain growing regions of the world, in temperature gradients of 20°-24°C, 20°-30°C, and 20°-42°C in small bulks of wheat to determine their ecological preferences. Psocids consistently preferred the warmest regions of the gradients, except in the 20-42°C gradients. Over 80 and 78% of psocids moved to the warmest region of the grain in the 20°-24° and 20°-30° gradients, respectively. Liposcelis bostrychophila females and both sexes of L. paeta preferred the warmer region of the grain in the 20°-42° gradient, while densities of L. entomophila males were higher in more moderate temperature regions of the grain and densities of L. entomophila females were evenly split between the warm and hot regions of the grain. Temperatures can be below 20°C during much of the storage season for grains, so the current results help to explain why psocids move to warmer regions of the grain which occur toward the center of the grain mass as grain temperatures cool in the fall. This may allow psocid populations to continue to grow during the colder months

Personality Traits, Job Search and the Gender Wage Gap

This paper introduces the Big Five personality traits along with other covariates in a job search, matching and bargaining model and investigates how education and personality traits affect job search behavior and labor market outcomes. It develops and e

Personality traits, intra-household allocation and the gender wage gap

© 2017 Elsevier B.V. A model of how personality traits affect household time and resource allocation decisions and wages is developed and estimated. In the model, households choose between two behavioral modes: cooperative or noncooperative. Spouses receive wage offers and allocate time to supplying labor market hours and to producing a public good. Personality traits, measured by the so-called Big Five traits, can affect household bargaining weights and wage offers. Model parameters are estimated by Simulated Method of Moments using the Household Income and Labor Dynamics in Australia (HILDA) data. Personality traits are found to be important determinants of household bargaining weights and of wage offers and to have substantial implications for understanding the sources of gender wage disparities

Structural heat treatments against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae): effect of flour depth, life stage and floor.

The effect of high temperatures (50-60°C) and two levels of sanitation (~0.5 and 43 g of flour), on mortality of eggs, young larvae, old larvae, pupae, and adults of the red flour beetle, Tribolium castaneum, were evaluated during heat treatment of a pilot flour mill at Kansas State University. The mill was heated once during 13-14 May 2009 and once during 25-26 August 2009. Each of the heat treatments lasted 24 h. Bioassay boxes, with life stages of T. castaneum and temperature sensors confined in small compartments, were placed in 25 locations across all five mill floors. Temperature data showed that the mean time to 50°C based on the two treatments ranged from 10.39 to 17.18 h, and the mean time above 50°C ranged from 6.01 to 13.63 h. The mean maximum temperatures attained ranged from 50.7 to 61.4°C. In general, temperatures were lower in compartments with 43 g of flour when compared with compartments with 0.5 g of flour. Temperatures were also lower on the first floor than on the remaining floors. In box bioassays, essentially none of the life stages survived the 24 h heat treatment (99-100% mortality), except on the first floor. The survival of insects, especially on the first floor, is related to how quickly temperatures reached 50°C and how long temperatures were held between 50 and 60°C, and the maximum temperatures attained at a given location. There were only small differences in mortality between the two levels of sanitation. These results show that heat treatment of flour mills can control all life stages of T. castaneum in 24 h. Keywords: Tribolium castaneum, Heat treatment, Sanitation, Life stages, Methyl bromide alternative

Detection of Stored-Grain Insect Infestation in Wheat Transported in Railroad Hopper-Cars

Levels of insect infestation, insect spatial distribution, and the relationship between the number of insect-damaged kernels (IDK) and the number of insects present in grain samples in three-hopper railcars transporting wheat from country elevators to a mill were studied. Six of eight sampled railcars were infested with more than two species of insects. The most abundant species collected were the lesser grain borer, Rhyzopertha dominica (F.), and rusty grain beetle, Cryptolestes ferrugineus (Stephens), with the larval stage of the two species being the most prevalent (\u3e90%). The spatial distributions of these two species within the grain mass were typically clumped in railcar compartments containing\u3e0.4 insect/2.75-kg sample of wheat, and these foci of high-infestation levels varied in compartments within the railcars and among the sampled railcars. There were no significant correlations between IDK and insect density for any of the different stage-specific insect populations that were collected in the grain samples. Mean numbers of immatures and IDK differed among railcars and compartments within railcars, but not among grain depths. Number of insects in the first discharge sample was not correlated with mean numbers of insects in the entire compartment. This indicates that each compartment of a railcar should be sampled to determine level of insect infestation but that sampling at different depths within a compartment is less important

Freezing for control of stored-product psocids

A series of studies was conducted by exposing young and old eggs, nymphs, and adults of the psocids Liposcelis bostrychophila (Badonnel), L. paeta (Pearman), L. decolor (Pearman), and L. entomophila (Enderlein) to -18°C for various time intervals. Survival was assessed as initial and final, at different times depending on the life stage. Young eggs of L. bostrychophila were the most tolerant life stage of any of the species, with scattered survival out to 120 h of exposure to -18°C. Eggs were the most tolerant life stage for each species, requiring 24, 12, and 2 h of exposure for complete kill of L. paeta, L. decolor, and L. entomophila, respectively. Nymphs and adults of all species were far more susceptible than eggs, with no final survival after two hours of exposure. Results show the extreme variation between different psocid life stages and species to cold temperatures, and provide guidelines for using cold as a control strategy for psocids. Our results show that 24 h at -18°C is sufficient to kill all life stages of the psocid species tested, except for young L. bostrychophila eggs which will require at least 128 h of exposure at -18°C for complete mortality

Effectiveness of flameless catalytic infrared radiation against life stages of three stored-product insect species in stored wheat

A bench top flameless catalytic infrared emitter was evaluated in the laboratory to disinfest wheat containing different life stages (ages) of the lesser grain borer, Rhyzopertha dominica; rice weevil, Sitophilus oryzae; and red flour beetle, Tribolium castaneum. The emitter produces infrared in the 3 to 7 um range. A noncontact infrared thermometer obtained real-time grain temperatures during exposures of uninfested and infested wheat containing various life stages of the three insect species. The grain temperatures attained were influenced by wheat quantity, distance from the emitter, and exposure time, which in turn influenced effectiveness against various life stages of the three species. In general, higher grain temperatures were attained in 113.5 g of wheat as opposed to 227.0 g, at 8.0 cm from the emitter surface rather than at 12.7 cm, and during a 60-sec exposure compared to a 45-sec exposure. Logistic regression indicated the probability of death of various life stages of R.  dominica, S. oryzae, and T. castaneum was temperature-dependent. About 99 to 100% mortality of all life stages of the three species occurred when the mean wheat temperatures were in the range of 108 to 114°C. The promising results show flameless catalytic infrared technology to be a viable option for disinfestation of stored wheat, provided such high temperatures do not affect grain quality.Keywords: Infrared radiation, Stored-product insects, Non-chemical method, Efficacy assessmen

Detection of Stored-Grain Insect Infestation in Wheat Transported in Railroad Hopper-Cars

Levels of insect infestation, insect spatial distribution, and the relationship between the number of insect-damaged kernels (IDK) and the number of insects present in grain samples in three-hopper railcars transporting wheat from country elevators to a mill were studied. Six of eight sampled railcars were infested with more than two species of insects. The most abundant species collected were the lesser grain borer, Rhyzopertha dominica (F.), and rusty grain beetle, Cryptolestes ferrugineus (Stephens), with the larval stage of the two species being the most prevalent (\u3e90%). The spatial distributions of these two species within the grain mass were typically clumped in railcar compartments containing\u3e0.4 insect/2.75-kg sample of wheat, and these foci of high-infestation levels varied in compartments within the railcars and among the sampled railcars. There were no significant correlations between IDK and insect density for any of the different stage-specific insect populations that were collected in the grain samples. Mean numbers of immatures and IDK differed among railcars and compartments within railcars, but not among grain depths. Number of insects in the first discharge sample was not correlated with mean numbers of insects in the entire compartment. This indicates that each compartment of a railcar should be sampled to determine level of insect infestation but that sampling at different depths within a compartment is less important