Movement and distribution of Sitophilus zeamais adults and relationship between their density and trapping frequency in wheat bulks under different grain temperatures and moisture contents

Movement and distribution of Sitophilus zeamais adults and relationship between their trapping frequency and insect density were determined in one tonne wheat with 11.5 ± 0.2, 12.5 ± 0.1 and 13.5 ± 0.2% moisture contents (wet basis) inside cylindrical bins at 20, 25 and 30 °C. The introduced adult densities were 0.5, 1.0, and 2.0 adults/kg wheat (A/kg). Inside each bin, 15 probe traps were vertically installed in three layers. In each layer, five traps were installed at the center and half radii of the bin individually. The trapped adults were counted daily up to 7 d, and then 15 kg wheat was sampled at each trap location. The insect number in each sample was counted.The recovered adults in the top layer were less than that in the middle layer, while no significant difference between at middle and bottom layers. In each layer, adults preferred the center location at 0.5 A/kg, while this trend was unidentified at other densities. There was an autocorrelation of insect densities at adjacent locations at ≥ 1.0 A/kg, while no autocorrelation in the vertical direction. The adults had an aggregation distribution at any temperature, moisture content and adult density. The normal and Poisson model could not be used to describe the distribution of the count frequency of the adults in the samples, while the negative binomial model could describe this distribution in 18 out of 27 sampling sets at ≤ 1.0 A/kg. The trapping frequency was strongly influenced by the trapping period and increased with the increase of insect densities. The relationship between adult densities and trapping frequencies at the sampling locations had a significant difference at different grain temperatures, while no difference at different moisture contents, grain depths, and locations.     

Evaluation of sampling units and sampling plans for adults of Cryptolestes ferrugineus (Coleoptea: Laemophloeidae) in stored wheat under different temperatures, moisture contents, and adult densities

Development and evaluation of optimum size and number of sample units is required for cost-effective management of stored grain beetles. In this study, we evaluated the sampling parameters and accuracy of insect density detection and estimation, developed the optimum size and number of sample units, and conducted a feasibility study of the insect detection and density estimation. The measured insect densities in 92% of random samples were less than the introduced insect densities and 67.4 ± 10.8% of random samples did not contain adults when the introduced insect density was 0.1 A/kg (adult/kg). If the random sampling technique was used and 15% of the stored wheat bulk was sampled, 72% of determined means of insect densities of the sampling sets were lower than the introduced insect densities. Increasing the size of sample units did not improve the accuracy of the estimation of insect densities; however, it did considerably increase the probability of insect detection when insect densities were lower than 1.0 A/kg. We recommend at least 7 kg per sample unit for insect detection (especially when insect densities < 0.1 A/kg) and the optimum number of sample units with 15 kg grain per unit should be >24 for a fixed precision of 0.35 when insect densities < 0.1 A/kg. This might be a challenge for grain storage practice. Therefore, using sampling technique to estimate insect densities and detect insects at low insect densities (<0.1 A/kg) might not be practicable.     

Damage potential of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on cocoa beans: Effect of initial adult population density and post infestation storage time

The effect of different initial adult population densities of Tribolium castaneum (Herbst) at several post infestation storage times on the final adult population density, the percentage of damaged beans, the percentage of weight loss, and the weight of insect feeding residues on cocoa beans was investigated in laboratory experiments. Both factors interactively had highly significant (P < 0.01) effects on variables assessed. The highest mean final adult population density of 129.7 ± 4.6 was recorded in samples infested with the highest initial adult population density and stored for 150 d, while the least mean adult population density of 10.8 ± 0.54 was recorded on samples infested with the lowest initial adult population density in samples stored for 30 d. The highest percentage damaged cocoa beans 51.0 ± 1.21% was recorded in samples infested with the highest initial adult population density, while the least mean percentage damaged beans of 16.9 ± 1.26% was also recorded on samples infested with the lowest initial adult population density. Similar trends of means were recorded for all the remaining variables. Correlation between factors was significant and positive. Multiple and simple linear regressions analyses were also significant (P < 0.01) and all equations fitted the regression models and perfectly described the relationship between the independent and the dependent variables. Our results show that T. castaneum can impact negatively on both the quantity and quality of stored cocoa within just 30 days of infestation, with the impact increasing with increasing population density and post infestation storage time.     

Geostatistical analysis of adult Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) in wheat stored at constant temperatures

Insect monitoring and sampling programmes are used in the stored grains industry for the detection and estimation of insect pests. At the low pest densities dictated by economic and commercial requirements, the accuracy of both detection and abundance estimates can be influenced by variations in the spatial structure of pest populations over short distances. Geostatistical analysis of Rhyzopertha dominica populations in 2-dimensions showed that, in both the horizontal and vertical directions and at all temperatures examined, insect numbers were positively correlated over short (0–5 cm) distances, and negatively correlated over longer (≥10 cm) distances. Analysis in 3 dimensions showed a similar pattern, with positive correlations over short distances and negative correlations at longer distances. At 35 °C, insects were located significantly further from the grain surface than at 25 and 30 °C. Dispersion metrics showed statistically significant aggregation in all cases. This is the first research using small sample units, high sampling intensities, and a range of temperatures, to show spatial structuring of R. dominica populations over short distances. This research will have significant implications for sampling in the stored grains industry.     

Predicting Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) populations and associated grain damage in smallholder farmers’ maize stores: A machine learning approach

Prostephanus truncatus is a notorious pest of stored-maize grain and its spread throughout sub-Saharan Africa has led to increased levels of grain storage losses. The current study developed models to predict the level of P. truncatus infestation and associated damage of maize grain in smallholder farmer stores. Data were gathered from grain storage trials conducted in Hwedza and Mbire districts of Zimbabwe and correlated with weather data for each site. Insect counts of P. truncatus and other common stored grain insect pests had a strong correlation with time of year with highest recorded numbers from January to May. Correlation analysis showed insect-generated grain dust from boring and feeding activity to be the best indicator of P. truncatus presence in stores (r = 0.70), while a moderate correlation (r = 0.48) was found between P. truncatus numbers and storage insect parasitic wasps, and grain damage levels significantly correlated with the presence of Tribolium castaneum (r = 0.60). Models were developed for predicting P. truncatus infestation and grain damage using parameter selection algorithms and decision-tree machine learning algorithms with 10-fold cross-validation. The P. truncatus population size prediction model performance was weak (r = 0.43) due to the complicated sampling and detection of the pest and eight-week long period between sampling events. The grain damage prediction model had a stronger correlation coefficient (r = 0.93) and is a good estimator for in situ stored grain insect damage. The models were developed for use under southern African climatic conditions and can be improved with more input data to create more precise models for building decision-support tools for smallholder maize-based production systems.     

Effect of temperature on raw whole milk density and its potential impact on milk payment in the dairy industry

The objective of this study was to determine the effect of temperature on whole milk density measured at four different temperatures: 5, 10, 15, and 20 °C. A total of ninety-three individual milk samples were collected from morning milking of thirty-two Holstein Friesian dairy cows, of national average genetic merit, once every two weeks over a period of 4 weeks and were assessed by Fourier transform infrared spectroscopy for milk composition analysis. Density of the milk was evaluated using two different analytical methods: a portable density meter DMA35 and a standard desktop model DMA4500M (Anton Paar GmbH, UK). Milk density was analysed with a linear mixed model with the fixed effects of sampling period, temperature and analysis method; triple interaction of sampling period x analysis method x temperature; and the random effect of cow to account for repeated measures. The effect of temperature on milk density (ρ) was also evaluated including temperature (t) as covariate with linear and quadratic effects within each analytic method. The regression equation describing the curvature and density–temperature relationship for the DMA35 instrument was ρ = 1.0338−0.00017T−0.0000122T² (R² = 0.64), while it was ρ = 1.0334 + 0.000057T−0.00001T² (R² = 0.61) for DMA4500 instrument. The mean density determined with DMA4500 at 5 °C was 1.0334 g cm⁻³, with corresponding figures of 1.0330, 1.0320 and 1.0305 g cm⁻³ at 10, 15 and 20 °C, respectively. The milk density values obtained in this study at specific temperatures will help to address any bias in weight–volume calculations and thus may also improve the financial and operational control for the dairy processors in Ireland and internationally.     

Three dimensional temporal and spatial distribution of adult Oryzaephilus surinamensis and Sitophilus oryzae in stored wheat under different temperatures,moisture contents,and adult densities

Three dimensional temporal and spatial distributions of adult Oryzaephilus surinamensis at densities of 0.1, 1.0, and 5.0 adults/kg wheat (referred to as A/kg) and adult Sitophilus oryzae at densities of 1.0, 5.0, and 10.0 A/kg were determined in bins filled with 1.5 t wheat having 11.0 ± 0.8, 13.0 ± 0.6, or 15.0 ± 0.5% moisture content at 20 ± 1, 25 ± 1 or 30 ± 1 °C. At each of the five sampled locations, wheat was separated into three 15 kg vertical layers and the number of adults in each layer was counted.Less than 30% of adult O. surinamensis were recovered in the top layer, while more than 80% of adult S. oryzae were recovered in the top layer. Adults of O. surinamensis preferred the center locations in each layer and adults of S. oryzae preferred the top layer. Densities of both species at adjacent locations in the horizontal direction were autocorrelated with each other. The temporal continuous property might not exist for the adults of O. surinamensis but exists for the adults of S. oryzae. Even though both species had aggregated and clumped distribution at any temperature, moisture content and adult density, adults of O. surinamensis had a more homogeneous distribution than S. oryzae. These characterized patterns of distribution of adult insects could be used to effectively estimate their density inside stored grain-bins.     

Evaluation of dosimeter tubes for monitoring phosphine fumigations

Within integrated pest management options, fumigation of stored products is one method to help control post-harvest insect infestations in our food and agricultural products. Fumigant gas concentration monitoring is important to confirm that the treatment was adequate to achieve the desired insect control, but monitoring can be relatively expensive and labor intensive. This study evaluated how accurately dosimeter tubes could monitor phosphine fumigation treatments. The dosimeter tube is designed to continuously react with phosphine gas during the fumigation period and yields a measurement in terms of concentration 1 time product or CT, which can be interpreted as cumulative exposure. Two models of dosimeter tubes were evaluated (high range and low range). The reference method for these trials were wireless phosphine monitoring sensors, which recorded gas concentrations at hourly intervals during an exposure, and from this a CT product was also calculated. Model LPG-1, high-range dosimeter tube, measured within ± 25% of the phosphine monitoring sensors for CT dosages less the 70,000 ppm1hr. Model LPG-2, low-range tube, tended to significantly over-estimate phosphine CT dosage by 50%–100% of the phosphine monitoring sensor references. Secondly, bioassays of fumigant efficacy were performed using susceptible and resistant adult Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), lesser grain borers, and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), red flour beetle, for estimating insect control at the varied fumigation CT treatments. For the susceptible strains, CT dosages ∼5000 ppm1hr controlled both species. However, the insect control varied from 60% to 100% for resistant adults at CT dosages of ∼20,000 ppm1hr. The dosimeter tubes function in these ranges of dosages where each insect species are controlled and the dosimeter tube model LPG-1 provides reasonable estimates of the fumigation dosage for a given treatment level.     

预测平房仓中小麦的密度分布与储藏质量模型

采用LHT-1粮食回弹模量仪测定小麦堆在不同压应力下的压缩密度,实验结果表明：当小麦(众麦1号,含水率为11.70.-18.18 %w.b.)的竖直压应力增大(0.631-221.060 kPa)压缩密度增大(740.50-853.85 kg/m₃),两者可拟合出二次关系方程。建立平房仓中小麦的密度、应力与粮层深度关系的微分方程组,用数值方法计算平房仓中小麦密度与粮层深度关系,由积分法计算出平房仓中小麦的储藏重量。模型计算结果表明：平房仓中小麦密度随着粮层深度的增加而增大,随着深度增加,密度增加率减小;在一个20米宽,40米长的平房仓中,小麦密度从表层的800 kg/m₃增加到10米深处的833.5 kg/m₃,密度增加了4.1%。在同一深处,密度随平房仓长、宽的尺寸增大而增大,增大值很小。在平房仓中同一深处,密度随含水率的增大而增大,增大值很小。小麦的摩擦角、小麦与仓壁摩擦系数几乎不影响平房仓中的密度。本模型计算了5个实仓中的小麦储藏重量,计算值与粮重实际账面数几乎一致,最大误差为2.63%。     

基于有限元方法的平房仓中小麦堆的密度分布研究

选定剑桥修正模型作为小麦堆的应力与应变关系本构方程,使用有限元方法计算平房仓中小麦堆的应变分布值,由应变值计算出平房仓中小麦堆的密度分布值。结果表明：小麦储藏在平房仓中,其堆密度分布是不均匀的。在同一含水率下,小麦平均层密度随着粮层深度的增加而增加,增加率随粮层深度的增加而减小;在同一粮层下,小麦的堆密度随距仓壁的距离减小而减小,在粮仓的拐角处小麦堆密度达到该层的最小值,当粮层深度越深,小麦堆层密度分布越不均匀;平房仓内小麦的平均堆密度随着含水率的增加而减小,平均堆密度相对于无压缩密度的增加率随含水率增加而增大;由剑桥修正模型计算出的数据拟合了平房仓中小麦平均层密度与粮层深度、含水率之间的关系方程。实仓验证得到：该模型计算的平房仓中小麦的重量与实仓内账面小麦重量的误差小于1.64%。     

A novel strategy for improving radio frequency heating uniformity of dry food products using computational modeling

This study attempted to quantify effects of dielectric properties (DPs) and densities of a surrounding container and treated food products on heating uniformity in a 6 kW, 27.12 MHz parallel plate radio frequency (RF) system. A computer simulation model was established with finite element-based commercial software, COMSOL Multiphysics®, and experiments with 1.5 kg soybean flour packed in a rectangular polystyrene container were performed to validate the developed model. Surface temperature distributions of soybean flour in three different horizontal layers were obtained with an infrared camera, and temperature–time histories at two representative locations inside the container were monitored with two optical fiber sensors. The uniformity index (UI) was used as a criterion to evaluate the RF heating uniformity within food products. Results showed that the RF heating uniformity in food samples was clearly influenced by DPs and density of the surrounding container. UI was the lowest when the surrounding container dielectric constant was in a comparable range of the sample's, with the loss factor values of surrounding container lying between 0.01–0.1% of the sample's. The optimum RF heating uniformity in food products could be achieved with a smaller density value of the surrounding container. The correlations of DPs and density between surrounding container and food products derived from the validated simulation model could provide valuable information and strategy to improve the RF heating uniformity in low moisture foods for insect or microbial control. Thus, the established strategy can further be used for developing effective industrial-scale RF treatment protocols after optimization of this process by the food industry.Industrial relevanceAlthough the most important characteristic of radio frequency (RF) treatments is fast and volumetric heating generated by dipole rotation and ionic conduction, edge over-heating is still a major problem for foods heated in rectangular containers. The validated model was used to study the effects of dielectric properties and density of sample and surrounding container on sample uniformity index. Simulated results illustrated that the RF heating uniformity could be improved when the dielectric constant and density of surrounding container and sample were in accordance with the established relationships. The established strategy may provide valuable optimized methods to ensure RF heating uniformity in industrial applications.     

Influence of thermosonication on Geobacillus stearothermophilus inactivation in skim milk

The influence of high intensity ultrasound coupled with thermoprocessing on the inactivation of Geobacillus stearothermophilus vegetative cells and spores in skim milk powder was explored using response surface methodology and two polynomial models were developed. Optimization of cell reduction (4.8 log) was found to be at 19.75% total solids (TS), 45 °C, and 30 s, while optimization of spore reduction (0.45 log) was found to be at 31.5% TS, 67.5 °C, and 17.5 s. Model verification experiments were performed using common milk powder processing conditions. Results showed the inactivation of cells and spores to be most effective before (9.2% TS, 75 °C, and 10 s) and after (50% TS, 60 °C, and 10 s) the evaporator during milk powder processing and may produce an additive effect in microbial reduction when the two locations are combined, resulting in a 5.8 log reduction for vegetative cells and 0.51 log reduction for spores.     

Mortality and movement of Cryptolestes ferrugineus and Rhyzopertha dominica in response to cooling in 300-kg grain bulks

We examined the effect of low temperatures on insect population density and mortality of adult and immature stages of Cryptolestes ferrugineus and Rhyzopertha dominica in three barrels holding 300 kg of wheat each. Barrels were infested with 2 insects/species/kg and left to develop at 30 °C for 5 months. Temperature of the grain mass before cooling was 38 °C in the centre to a low of 28 °C on the periphery. On 11 February the building door was opened to allow for cooling of the grain. During the 3 weeks of cooling, temperatures in the centre reached as low as −5 °C. Segregated (11 segments) grain trier samples were collected from three locations in each barrel, from February until March 2013 (6 dates), sieved, and the number of live and dead adults counted. Sieved grain was held for 5 weeks 30 °C and emerged adults counted to give an estimation of immature stages within the grain at the time of sampling. Rhyzopertha dominica adults were found mainly in the top 40 cm of the barrel, and there was little movement to the centre as the grain mass cooled. The initial distribution of C. ferrugineus adults was more complex; in two barrels adults were mostly in the centre of the grain mass, while in the other barrel, more adults were found on the periphery. When the grain mass cooled, C. ferrugineus adults in all barrels were found mostly in the centre. On day 0, the average number of live adults of C. ferrugineus and R. dominica were 232 ± 56 and 414 ± 48 insects/100 g, respectively. Rhyzopertha dominica adults were more susceptible to low temperatures than C. ferrugineus. The density of immatures of C. ferrugineus and R. dominica were similar at 0 d, there was a decline over the 21 d, but there was some survival at day 21.     

Structure and physical stability of hybrid model systems containing pork meat and superworm (Zophobas morio larvae): The influence of heating regime and insect: meat ratio

Hybrid model systems, containing pork shoulder meat and Zophobas morio larvae in different insect:meat ratios, were subjected to isothermal heating at 70 or 80 °C to investigate how this would affect the rheological behavior, water holding properties and textural properties of these model systems. Meat and insect model systems were also studied for comparison. Rheological and textural characteristics were significantly higher in meat model systems compared to insect and hybrid model systems. Furthermore, insect:meat ratio had little to no effect on the studied attributes of the hybrid model systems. It was also demonstrated that heating the hybrid model systems at 80 °C resulted in similar viscoelastic and water holding properties compared to meat model systems heated at 70 °C. However, even when heated at this higher temperature, the maximum force measured during penetration of the hybrid model systems was still approximately 3 times lower compared to meat model systems.Industrial relevanceThis study investigated the effect of insect:meat ratio and heating temperature on structure formation and water holding in hybrid model systems. The results offer important insights with regard to the composition and processing of hybrid meat products. They indicate that similar viscoelastic and water holding properties compared to meat products may be obtained by applying higher heating temperatures. However, results showed that obtaining the desired texture may pose an important challenge when developing hybrid meat products.     

Insect population dynamics in commercial grain elevators

Data were collected in 1998-2002 from wheat stored in commercial grain elevators in south-central Kansas. Bins at these elevators had concrete walls and were typically 6-9 m in diameter and 30-35 m tall. A vacuum-probe sampler was used to collect grain samples in the top 12 m of the wheat in each bin. The primary insect species found in the wheat samples were: Cryptolestes ferrugineus, Rhyzopertha dominica, and Tribolium castaneum. In the top 3.7 m of grain, R. dominica, C. ferrugineus, T. castaneum and Sitophilus oryzae made up 44, 36, 19 and 1% of the insects found in the samples, respectively. From 3.8 to 12.2 m, R. dominica, C. ferrugineus, T. castaneum and S. oryzae were present at 84, 8, 8, and 1%, respectively. The most prevalent species also changed over time. In June, the start of wheat harvesting and storage in Kansas, insect density was low in the bins. At this time, C. ferrugineus was the most common insect, and it was found mostly in the top grain sample (0-1.2 m). In September through November, C. ferrugineus and R. dominica were at similar densities; however, from February to March, R. dominica was more common.Generally, insect density was greatest at the top and decreased with grain depth. Very few insects were found in samples collected from greater than 12 m (most of the bins contained grain to depths of 24-36 m). Insect density for all species increased rapidly from June through October. During this period less than 20% of the bins had economically significant insect densities (>2 insects/kg). From October until February, the average insect density remained fairly constant but it was greatly reduced in April, May, and June. Bins that had insect densities >2 insects/kg tended to be located adjacent to other heavily infested bins.     

Pressure- and Temperature-Dependent Density Change of Juices During Concentration

Density of seven fruit juices (melon, plum, peach, black currants, cherry-plum, pear, and tangerine) have been measured at temperatures from 283 to 403 K and at pressures from 0.1 to 10 MPa for the concentrations of soluble solids from 10.7 to 70°Brix. Measurements were made with a hydrostatic weighing technique. The uncertainty of the density measurements was estimated to be less than 0.075%. The effect of temperature, pressure, and concentration on the fruit juice density was studied. The applicability and predictive capability of the various models for the density of fruit juices were studied. Various polynomials, power, exponential, logarithmic, and their combinations correlation models were used to represent the combined effect of temperature and concentration on the density. Models which represent the density of juice relative to pure water density were considered.     

Temporal dynamics and response to fogging or fumigation of stored-product Coleoptera in a grain processing facility

Stored-product Coleoptera were monitored continuously over 22 months using pitfall traps at an operating food mill and adjacent warehouse in Kansas. Mill management practiced conventional pest management, including monthly crack and crevice applications of a residual insecticide and semi-annual fumigation with methyl bromide in the mill, and application of dichlorvos+pyrethrin (commonly called fogging) in the warehouse. The dynamic temporal changes in insect captures and effect of the global interventions on insect captures were analyzed. Data show that more Trogoderma variabile individuals were captured in the warehouse than any other species, but Tribolium castaneum was captured with greater frequency. Trogoderma variabile captures inside the warehouse tended to mirror outside captures suggesting immigration from the outside. The food mill was infested year round with T. castaneum but developed substantial populations of Typhaea stercorea during the warm months from May through October. Stored-product insects were nearly always captured during the first trapping interval following methyl bromide or dichlorvos+pyrethrin applications, but it was not clear if the insects were surviving inside the structure or if they were rapidly recolonizing after treatment. Population increases immediately following fumigation or fogging occurred only in fungus-feeding species in late spring or summer. The most successful fumigation was conducted late in the autumn when environmental conditions prevented insect activity outside. Information contained in this study provides data that could be used to improve insect management programs for milling and processing facilities.     

Stability of anthocyanins and ascorbic acid in sonicated strawberry juice during storage

The stability of anthocyanins and ascorbic acid in sonicated strawberry juice during storage was investigated. Strawberry juice was sonicated at varying acoustic energy densities (AEDs) ranging from 0.33 to 0.81 W/mL and treatment times of 0–10 min. The degradation kinetics of sonicated samples followed first-order kinetics. Degradation rate constants were linearly correlated with AED (R ² > 0.91). Selected samples were stored for 10 days at 4 and 20 °C. A second-order polynomial model was employed to investigate the effects of storage time and processing variables. During storage higher loses were observed at a storage temperature of 20 °C compared to 4 °C. Predictive models developed for anthocyanins and ascorbic acid content were highly significant (P < 0.0001) and closely correlated to the experimental data (R ² > 0.91). Degradation mechanisms for anthocyanins and ascorbic acid due to sonication and storage are proposed.     

Plodia interpunctella and Trogoderma variabile larval penetration and invasion of untreated and methoprene-treated foil packaging

Packaged food products inside retail stores and food warehouses are susceptible to infestation by stored-product insects. The insect growth regulator methoprene can be impregnated onto packaging materials to help limit stored-product insect population development and prevent infestations. The objectives of this study were to determine the effect of methoprene-treated foil packaging on egg hatchability and the penetration and invasion ability of the warehouse beetle, Trogoderma variabile Ballion, and the Indian meal moth Plodia interpunctella (Hübner). Twenty-five eggs of each species were added to Petri dishes containing untreated packaging or packaging containing 0.1, 0.25, and 0.5% of the active ingredient methoprene. Petri dishes were held for 7 d in an environmental chamber at 27 °C and 60% r.h. to determine percent hatchability of eggs. Additionally, 6 cm by 8 cm food packages were created from untreated and methoprene-treated packaging and placed into 0.18-L vials. First or third instars of each species were introduced into vials containing diet or no diet, to determine penetration ability after 21 and 42 d. In a separate experiment, packages were pierced with pinholes, and first instar T. variable or P. interpunctella were introduced and observed after 21 and 42 d for package invasion. The foil packaging had no significant effect on egg hatchability of either species. T. variabile were unable to penetrate or invade any foil packages. P. interpunctella invaded all packages containing pinholes. The methoprene-treated packaging reduced adult emergence of P. interpunctella and caused pupal and adult deformations in T. variabile. Methoprene-treated packaging presents a valuable option for food manufacturers to prevent insect infestations and maintain integrity of packaged food products.