Perception and the Characteristics of the Response of Honey Bees,Paper Wasps,and Red Wood Ants to a Low-Frequency Electric Field

Bees, wasps, and ants have no specialized receptors for the perception of an electric field. An appropriate response to naturally occurring electric fields in bees and ants is associated with atmospheric exposure, amplified by the approach of the front of a thunderstorm. The primary transducers of mechanoreceptors that respond to displacement are related to the perception of low-frequency electric fields of high intensity by insects. The non-specific mechanism of perception of electric fields is based on irritation by induced currents that flow in the locations of their contact with each other and/or conductive surfaces. The frequency dependence of the electric field sensitivity is determined mainly by the magnitude of the current induced by it and the intensity of its contact action. The magnitude of the current induced in the outer part of the insect body is non-linearly related to the frequency of the electric field. The region with the highest sensitivity to electric fields is close to 500 Hz, which is consistent with the maximum magnitude of the induced current. At the same time, the threshold of the sensitivity to an electric field in wasps is approximately 0.04 kV/m, while in bees it is 0.45 kV/m. Ants react to the action of an electric field of 7–10 kV/m by slowing their movement. Magnetic fields and ionization, which accompany the generation of an electric field whose intensity reaches 15–20 kV/m, do not stimulate changes in the behavior of insects.

     

Radio-frequency exposure of the yellow fever mosquito (A. aegypti) from 2 to 240 GHz

Fifth generation networks (5G) will be associated with a partial shift to higher carrier frequencies, including wavelengths comparable in size to insects. This may lead to higher absorption of radio frequency (RF) electromagnetic fields (EMF) by insects and could cause dielectric heating. The yellow fever mosquito (Aedes aegypti), a vector for diseases such as yellow and dengue fever, favors warm climates. Being exposed to higher frequency RF EMFs causing possible dielectric heating, could have an influence on behavior, physiology and morphology, and could be a possible factor for introduction of the species in regions where the yellow fever mosquito normally does not appear. In this study, the influence of far field RF exposure on A. aegypti was examined between 2 and 240 GHz. Using Finite Difference Time Domain (FDTD) simulations, the distribution of the electric field in and around the insect and the absorbed RF power were found for six different mosquito models (three male, three female). The 3D models were created from micro-CT scans of real mosquitoes. The dielectric properties used in the simulation were measured from a mixture of homogenized A. aegypti. For a given incident RF power, the absorption increases with increasing frequency between 2 and 90 GHz with a maximum between 90 and 240 GHz. The absorption was maximal in the region where the wavelength matches the size of the mosquito. For a same incident field strength, the power absorption by the mosquito is 16 times higher at 60 GHz than at 6 GHz. The higher absorption of RF power by future technologies can result in dielectric heating and potentially influence the biology of this mosquito.     

Review of in vivo static and ELF electric fields studies performed at Gazi Biophysics Department

In vivo effects of Static Electric and ELF Magnetic and Electric fields have been carried out for more than 20 years in the Bioelectromagnetic Laboratory at the Biophysics Department of the Medical Faculty of Gazi University. In this article, the results of in vivo ELF Electric field studies are presented as a review. Static and 50 Hz ELF (Extremely Low Frequency) Electric (E) fields effects on free radical synthesis, antioxidant enzyme level, and collagen synthesis were analyzed on tissues of guinea pigs, such as brain, liver, lung, kidney, spleen, testis, and plasma. Animals were exposed to static and ELF electric fields with intensities ranging from 0.3 kV/m to 1.9 kV/m in vertical and horizontal directions. Exposure periods were 1, 3, 5, 7, and 10 days. Electric fields were generated from a specially designed parallel plate capacitor system. The results indicate that the effects of electric fields on the tissues studied depend significantly on the type and magnitude of electric field and exposure period.     

Retardation of embryogenesis by extremely low frequency 60 Hz electromagnetic fields

Fertilized Medaka fish eggs were used to determine if electromagnetic fields, designed to simulate those beneath a high voltage power line, have biological effects on vertebrate embryo development. The newly fertilized eggs were exposed to a 60 Hz electrical field of 300 mA/m2 current density, a 60 Hz magnetic field of 1.0 gauss RMS, or to the combined electric plus magnetic fields for 48 hours. No gross abnormalities were observed in any of the embryos as they developed, but significant development delays were seen in those embryos exposed to either the magnetic or to the combined electromagnetic fields; delays were not seen in the embryos exposed to the electrical field. Thus, a 60 Hz magnetic field like that encountered in a man made powerline environment was shown to retard development of fish embryos.     

Correlations among indices of electric and magnetic field exposure in electric utility workers

Power-frequency electric and magnetic fields are known to exhibit marked temporal variation, yet in the absence of clear biological indications, the most appropriate summary indices for use in epidemiologic studies are unknown. In order to assess the statistical patterns among candidate indices, data on 4383 worker-days for magnetic fields and 2082 worker-days for electric fields collected for the Electric and Magnetic Field Project for Electric Utilities using the EMDEX meter [Bracken (1990): Palo Alto, CA: Electric Power Research Institute] were analyzed. We examined correlations at the individual and job title group levels among indices of exposure to both electric and magnetic fields, including the arithmetic mean, geometric mean, median, 20th and 90th percentiles, time above lower cutoffs of 20 V/m and 0.2 μT, and time above higher cutoffs of 100 V/m and 2.0 μT. For both electric and magnetic fields, the arithmetic mean was highly correlated with the 90th percentile; moderately correlated with the geometric mean, median, and lower and higher cutoff scores; and weakly correlated with the 20th percentile. Electric and magnetic field indices were generally weakly correlated with one another. Rank-order correlation coefficients were consistently greater than product-moment correlation coefficients. Job title group summary scores showed higher correlations among electric field indices and magnetic field indices and between electric and magnetic field indices than was found for individual worker-days, with only the 20th percentile clearly independent of the others. These results suggest that individuals' exposures are adequately characterized by a measure of central tendency for electric and magnetic fields, such as the arithmetic or geometric mean, and an indicator of a lower threshold or cutoff for each field type, such as the 20th percentile or proportion of time above 20 V/m or 0.2 μT. A single measure of central tendency for each type of field appears to be adequate when exposures are assessed at the job title level. © 1994 Wiley-Liss, Inc.     

The survival of ingested Serratia marcescens in houseflies (Musca domestica L.) after electrocution with electric fly killers

Electric fly killers (EFKs) are commonly used to control flying insects that enter food establishments. For establishment of the incidence of pathogen-bearing insects in food establishments, insect samples obtained from EFK trays could be used. The principal difficulty with this approach is that the survival time of microorganisms on or within insect corpses after electrocution is unknown. This study determined the survival of Serratia marcescens (as a representative of the enteric bacteria) within houseflies following their electrocution by a commercial EFK. S. marcescens was successfully ingested by houseflies and survived on and within the corpses after electrocution for up to 5 weeks. Maximal levels of bacteria were recovered 24 h postelectrocution. The study also demonstrates the ability of ingested S. marcescens to out-compete resident microbial flora within houseflies. The findings are intended to pave the way for further research to determine the incidence of pathogen-laden flying insects in food establishments.     

烟田中静电喷雾和电动喷雾下噻虫嗪的防效及对昆虫群落的影响

【目的】探明静电喷雾与电动喷雾对噻虫嗪防治害虫效果及烟田昆虫群落的影响,为静电喷雾在烟草上的推广应用提供理论依据。【方法】利用静电喷雾与电动喷雾法喷施0.66 g·L~(-1)25%噻虫嗪水分散粒剂,施药1、3、7 d后,测定2种方法对烟蚜与斜纹夜蛾的防治效果、在烟株与土壤中的沉积以及对昆虫群落的影响。【结果】喷施25%噻虫嗪水分散粒剂1、3、7 d后,静电喷雾对烟蚜和斜纹夜蛾的防治效果均显著高于电动喷雾的防治效果,且防治效果均随时间的推移而升高。噻虫嗪在静电喷雾处理区烟叶上的沉积量高于电动喷雾处理区烟叶上的沉积量,而在静电喷雾处理区土壤中的沉积量低于电动喷雾处理区土壤中的沉积量,且都随时间的推移而降低。静电喷雾与电动喷雾均引起烟田昆虫群落的变化,静电喷雾引起的害虫和中性昆虫的数量变化大于电动喷雾,但天敌昆虫的数量变化小于电动喷雾,且静电喷雾区烟田的物种丰富度明显高于电动喷雾区,可见静电喷雾施药对烟田昆虫群落的影响小于电动喷雾施药。静电喷雾的S_t/S_i与S_n/S_p比值明显高于电动喷雾,说明静电喷雾烟田中昆虫群落稳定性高于电动喷雾烟田中昆虫群落的稳定性。【结论】相比电动喷雾,静电喷雾能够提高噻虫嗪在烟叶上的沉积量,从而提高噻虫嗪对害虫的防治效果,同时减少噻虫嗪在土壤中的沉积量,提高噻虫嗪的生态安全性,因此,静电喷雾在烟草病虫害防治上具有较好的应用前景。     

Insect pest densities across site-specific management zones of irrigated corn in northeastern Colorado

The ability to manage insect pests in a site-specific manner is hindered by the costs and time required to describe pest densities and distributions. The purpose of this study was to determine whether insect pest distributions are related to site-specific management zones (SSMZs). Site-specific management zones, as described in this study, delineate fields into three zones of similar yield potential: high, medium, and low productivity. If insect densities vary across SSMZs, it is possible that management decisions could be made at the SSMZ level instead of treating the whole field. This research was conducted during summers 2001 and 2002 on cooperators' farms in northeastern Colorado. Surveys were conducted within corn, Zea mays L., fields, so that densities of three common insect pests of Colorado corn could be compared across SSMZ. The three insect pests were western corn rootworm, Diabrotica virgifera virgifera LeConte; European corn borer, Ostrinia nubilalis (HiAbner); and western bean cutworm, Richia albicosta (Smith). D. v. virgifera larvae and adults were most common in the high-productivity SSMZ. O. nubilalis larval abundance was similar at three fields, whereas in a fourth field the larvae were most common in the high-productivity SSMZ. In one field that contained substantial numbers of R. albicosta, egg abundance was similar across SSMZs, whereas larvae were most common in the high-productivity SSMZ. Site-specific management zones seemed to correlate well with the abundance of some insect pests and might prove useful for managing insects in a site-specific manner.     

微生物对昆虫行为的影响研究进展

在漫长的进化过程中,微生物与昆虫形成了多种形式的互作关系.微生物的广泛分布为与昆虫接触并影响昆虫的行为提供了背景条件.为了深入探究微生物影响昆虫行为的现象和机制,本文综述了微生物影响昆虫行为方面的研究进展.微生物通过产生可被昆虫识别的化学信号物质、参与昆虫或寄主植物信息化合物的合成等方式可影响昆虫对其寄主的定位和选择....     

EPG即时显示软件Realdisplay的开发和利用

研究和开发在刺吸式植食性昆虫取食行为研究中,刺吸电位技术（EPG）的一种新的应用软件Realdisplay。该软件可任意选择EPG信号采集频率和显示的通道数,也可以在同一屏幕上同时以不同的信号采焦频率即时清晰地显示1个通道的EPG信号,使研究者能准确地了解和控制昆虫的即时行为细节。此外,该软件存储的EPG信息为实验过程中每一时刻的电热值,因而后续分析和统计极为方便。因此,Realdisplay强化了EPG技术的功能,拓宽了EPG技术的应用领域。为研究刺吸式植食性昆虫的取食行为细节,昆虫与病毒、宿主植物的关系提供了有力的工具。     

Astylus atromaculatus (Coleoptera: Melyridae): abundance and role in pollen dispersal in Bt and non-Bt cotton in South Africa

In South Africa, modified Bt (Cry1 Ac) cotton cultivars and organic ones coexist. This raises the question of the risk of dissemination of genetically modified (GM) pollen to non-GM crops by visiting insects. We inventoried the flower-visiting insects in Bt and non-Bt cotton fields of the South African Highveld region and investigated their role in pollen dispersal. Their diversity and abundance varied slightly among sites, with Astylus atromaculatus as the predominant insect on both Bt and non-Bt cotton flowers. The other major flower-visiting species were Apis mellifera and solitary Apidae. No differences were found in the abundance of each taxum between Bt and non-Bt cotton except for Scoliidae and Nitidulidae, which were scarce overall (<0.5%) but more abundant on the non-Bt flowers in the central area of the field at one site. The pollen load on A. atromaculatus was as high as on Apis mellifera. Cage tests showed that A. atromaculatus can pollinate female cotton plants by transferring pollen from male donor plants. In the field, the flight range of this insect was generally short (25 m), but it can occasionally reach up to 200 m or even more. This study therefore highlights that A. atromaculatus, commonly regarded as a pest, could be an unexpected but efficient pollinator. Because its population density can be high, this species could mediate unwanted cotton pollen flow when distances between coexiting fields are not sufficient.     

Insect quality control: synchronized sex,mating system,and biological rhythm

The sterile insect technique (SIT) is a method of eradicating insects by releasing mass-reared sterilized males into fields to reduce the hatchability of eggs laid by wild females that have mated with the sterile males. SIT requires mass-production of the target insect, and maintenance of the quality of the mass-reared insects. The most important factor is successful mating between wild females and sterile males because SIT depends on their synchronized copulation. Therefore, understanding the mating systems and fertilization processes of target insects is prerequisite. Insect behavior often has circadian rhythms that are controlled by a biological clock. However, very few studies of relationships between sterile insect quality and circadian rhythm have been performed compared with the amount of research on the mating ability of target insects. The timing of male copulation attempts with receptivity of females is key to successful mating between released males and wild females. Therefore, we should focus on the mechanisms controlling the timing of mating in target insects. On the other hand, in biological control projects, precise timing of the release of natural enemies to attack pest species is required because behavior of pests and control agents are affected by their circadian rhythms. Involving both chronobiologists and applied entomologists might produce novel ideas for sterile insect quality control by synchronized sex between mass-reared and wild flies, and for biological control agent quality by matching timing in activity between predator activity and prey behavior. Control of the biological clocks in sterile insects or biological control agents is required for advanced quality control of rearing insects.     

Insect pollination enhances seed yield, quality, and market value in oilseed rape

The relationships between landscape intensification, the abundance and diversity of pollinating insects, and their contributions to crop yield, quality, and market value are poorly studied, despite observed declines in wild and domesticated pollinators. Abundance and species richness of pollinating insects were estimated in ten fields of spring oilseed rape, Brassica napus var. SW Stratos?, located along a gradient of landscape compositions ranging from simple landscapes dominated by arable land to heterogeneous landscapes with extensive cover of semi-natural habitats. In each field, we assessed the contribution of wind and insect pollination to seed yield, seed quality (individual seed weight and oil and chlorophyll contents), and market value in a block experiment with four replicates and two treatments: (1) all flowers were accessible to insects, self and wind pollination, and (2) flowers enclosed in tulle net bags (mesh: 1 × 1 mm) were accessible only to wind and self pollination. Complex landscapes enhanced the overall abundance of wild insects as well as the abundance and species richness of hoverflies. This did not translate to a higher yield, probably due to consistent pollination by honey bees across all fields. However, the pollination experiment showed that insects increased seed weight per plant by 18% and market value by 20%. Seed quality was enhanced by insect pollination, rendering heavier seeds as well as higher oil and lower chlorophyll contents, clearly showing that insect pollination is required to reach high seed yield and quality in oilseed rape. Our study demonstrates considerable and previously underestimated contributions from pollinating insects to both the yield and the market value of oilseed rape.     

转RRM2基因棉田昆虫群落多样性及其时序动态

为了评价新型转基因棉花在长江生态区对棉田生态环境安全性的影响, 2013-2015年作者以新型转RRM2基因棉花(Gossypium hirsutum)为材料, 以其亲本‘中棉所12’为对照, 在安徽省沿江棉区系统研究了转基因棉田昆虫群落、害虫亚群落和天敌亚群落的结构与组成、个体数量、群落特征参数及其季节性动态变化。结果表明: 转RRM2基因棉田的主要类群组成、优势类群与非转基因棉田没有差异, 但在2013年转RRM2基因棉田棉蚜个体数量显著高于非转基因棉田, 叶螨类、棉铃虫和其他鳞翅目的个体数量显著低于非转基因棉田, 在其他年份没有显著差异; 其他类群的个体数量在两类棉田间没有显著差异。在棉田害虫发生量大的年份, 转RRM2基因棉田的昆虫群落个体数量较非转基因棉田增加, 物种丰富度较非转基因棉田减少, 但差异不显著, 而两类棉田年度间均差异显著。转RRM2基因棉田昆虫群落和害虫亚群落的全生育期多样性指数、均匀度指数和优势集中性指数与非转基因棉田没有显著差异; 其天敌亚群落的三个指数在2013年与非转基因棉田差异显著, 其他年份没有显著差异; 两类棉田年度间差异均不显著。转RRM2基因棉田昆虫群落、害虫亚群落和天敌亚群落个体数量、群落特征参数的时序动态与非转基因棉田较一致, 具季节性波动; 在群落个体数量高峰期, 群落多样性指数和均匀度指数处于低谷, 而优势集中性指数则相反; 昆虫群落、害虫亚群落的季节波动明显, 天敌亚群落的季节性变化较平缓。因此, 转RRM2基因棉花对棉田昆虫群落的结构与组成、群落特征参数及其时序动态没有显著影响, 但在气候适宜年份, 转RRM2基因棉田的害虫发生量可能增大。     

The Survival of Ingested <Emphasis Type="Italic">Serratia marcescens</Emphasis> in Houseflies (<Emphasis Type="Italic">Musca domestica</Emphasis> L.) After Electrocution with Electric Fly Killers

Electric fly killers (EFKs) are commonly used to control flying insects that enter food establishments. For establishment of the incidence of pathogen-bearing insects in food establishments, insect samples obtained from EFK trays could be used. The principal difficulty with this approach is that the survival time of microorganisms on or within insect corpses after electrocution is unknown. This study determined the survival of Serratia marcescens (as a representative of the enteric bacteria) within houseflies following their electrocution by a commercial EFK. S. marcescens was successfully ingested by houseflies and survived on and within the corpses after electrocution for up to 5 weeks. Maximal levels of bacteria were recovered 24 h postelectrocution. The study also demonstrates the ability of ingested S. marcescens to out-compete resident microbial flora within houseflies. The findings are intended to pave the way for further research to determine the incidence of pathogen-laden flying insects in food establishments. Received: 30 April 2002 / Accepted: 3 July 2002     

Electric birefringence of polytetrafluoroethylene particles in agarose gels

Electric birefringence studies of strongly elongated, rod-like particles of polytetrafluoroethylene (PTFE) in agarose gels show that the negative effect observed by semi-diluted aqueous suspensions at low frequencies and at low electric field strengths (the so called "anomaly') disappears. The absolute value of the low frequency effect increases 3-4 times and the amplitude of modulation decreases faster compared to that of the suspensions. This together with decreased decay relaxation times in gels make the possibilty that the PTFE particles orientation in gels is not due to dipolar but to electrophoretic orientation mechanism quite probable. Similar change in the orientation mechanism could be expected also for suspensions of higher concentrations. The further elucidation of the orientation mechanism using fractions with lower polydispersity, broader ranges of experimental conditions (particle concentration, ionic strength and composition, electric field strengths, frequencies, etc.) could be interest for several fields: colloid electro-optics and especially that of concentrated colloids, pulsed field gel electrophoresis of DNA (and especially its sinusoidal biased field variant) and of nucleoprotein complexes and for the gel research.     

Suction trap catches of airborne insects in relation to convection in the lower atmosphere

Over the last 25 years, since the classic work of Johnson CG. (London: Methuen, 1969) there have been a number of reviews on weather and the movement of insects in the air. These reflect increased field research by entomologists and meteorologists, particularly with the advent of remote-sensing techniques. There is, however, a gap in the literature relating to the influence of convective structures in the atmosphere on insect movement on the small scale (within and between fields). Such papers that have been published on insects and convection tend to report associations with large-scale convective structures (often several hundred kilometres in extent) and generally treat the insects as inert ‘particles’. Conversely, the relatively well-researched subject of insect movement on the small scale tends not to discuss possible convective influences, even though these might have been present. This paper presents the results of a field investigation of the spatial and temporal distributions of insects arriving in a suction trap sampling at a height of 12.2 m over arable land in southern England. It was found that the majority of insects caught were non-randomly distributed in time. The association of such clumps with the passage of convective structures through the atmosphere is discussed.     

Measurement of magnetically induced electric fields in conductive media near a 60 Hz current-carrying wire.

Electric fields induced in a conductive body by the magnetic field of a current-carrying wire were analyzed theoretically and experimentally to assess the dosimetric importance of highly nonuniform, field-exposure conditions. Experimentation revealed that a 60-Hz magnetic field was inversely proportional to the radius of a wire bundle carrying 100 A within a 0.5-m2 test area. A miniaturized electric field probe was used to measure the electric fields induced in 5-cm-deep, saline-filled models. In the theoretical analysis, numerical estimates of induced fields were made by a spreadsheet method. The theoretical calculations and the measured values of induced electric fields were generally in good agreement. The induced fields were in a plane perpendicular to a vertically incident magnetic field; the maximally induced fields were in areas nearest the wire bundle. The strength of the induced field increased with model size: from 96 microV/cm in a 10 x 10 cm model to 176 microV/cm in a 40 x 40 cm model. The strength of the field induced in a 20 x 20 cm model decreased with increasing model-to-wire spacing: from 132 microV/cm for a 1-cm spacing (2-mT maximum, incident field) to 50 microV/cm for a 6-cm spacing (0.33-mT maximum). The results indicate that increases in local values of nonuniformly incident fields produce relatively small increases in induced electric fields. This finding may be important in dosimetric consideration of circumstances, such as use of electric blankets, in which fields of low average strength are accompanied by intense local fields.     

Ion channel clustering enhances weak electric field detection by neutrophils: apparent roles of SKF96365-sensitive cation channels and myeloperoxidase trafficking in cellular responses

We have tested Galvanovskis and Sandblom’s prediction that ion channel clustering enhances weak electric field detection by cells as well as how the elicited signals couple to metabolic alterations. Electric field application was timed to coincide with certain known intracellular chemical oscillators (phase-matched conditions). Polarized, but not spherical, neutrophils labeled with anti-K_v1.3, FL-DHP, and anti-TRP1, but not anti-T-type Ca²⁺ channels, displayed clusters at the lamellipodium. Resonance energy transfer experiments showed that these channel pairs were in close proximity. Dose-field sensitivity studies of channel blockers suggested that K⁺ and Ca²⁺ channels participate in field detection, as judged by enhanced oscillatory NAD(P)H amplitudes. Further studies suggested that K⁺ channel blockers act by reducing the neutrophil’s membrane potential. Mibefradil and SKF93635, which block T-type Ca²⁺ channels and SOCs, respectively, affected field detection at appropriate doses. Microfluorometry and high-speed imaging of indo-1-labeled neutrophils was used to examine Ca²⁺ signaling. Electric fields enhanced Ca²⁺ spike amplitude and triggered formation of a second traveling Ca²⁺ wave. Mibefradil blocked Ca²⁺ spikes and waves. Although 10 μM SKF96365 mimicked mibefradil, 7 μM SKF96365 specifically inhibited electric field-induced Ca²⁺ signals, suggesting that one SKF96365-senstive site is influenced by electric fields. Although cells remained morphologically polarized, ion channel clusters at the lamellipodium and electric field sensitivity were inhibited by methyl-β-cyclodextrin. As a result of phase-matched electric field application in the presence of ion channel clusters, myeloperoxidase (MPO) was found to traffic to the cell surface. As MPO participates in high amplitude metabolic oscillations, this suggests a link between the signaling apparatus and metabolic changes. Furthermore, electric field effects could be blocked by MPO inhibition or removal while certain electric field effects were mimicked by the addition of MPO to untreated cells. Therefore, channel clustering plays an important role in electric field detection and downstream responses of morphologically polarized neutrophils. In addition to providing new mechanistic insights concerning electric field interactions with cells, our work suggests novel methods to remotely manipulate physiological pathways.     

Areawide models comparing synchronous versus asynchronous treatments for control of dispersing insect pests

Integrated pest management (IPM) has the goal of combining several control methods that reduce populations of pest insects and their damage to tolerable levels and thereby reduce the use of costly pesticides that may harm the environment. Insect populations can be monitored during the season to determine when the densities exceed an economic threshold that requires treatment, often as an insecticide application. We developed a simulation model where insect populations varied in exponential growth in fields and dispersed to adjacent fields each day of a season. The first model monitored populations of individual fields in a grid of fields and treated any field with insecticide if it exceeded a threshold population (asynchronous model) as done in traditional IPM. The second model treated the entire grid of fields with insecticide when the average population of all fields exceeded the threshold (synchronous model). We found that the synchronous model at all growth and dispersal rates tested had average field populations during a season that were significantly lower and required fewer treatments than the asynchronous method. Parameters such as percentage of fallow fields, number of fields, and treatment threshold had little affect on relative differences between the two models. The simulations indicate that cooperation among growers in areawide monitoring of fields to obtain an average population estimate for use in treatment thresholds would result in significantly less insect damage and fewer insecticide treatments. The synchronous method is more efficient because population refugia are precluded from which dispersal could reintroduce insects.