Stored-product Moths Research Articles

Exploring the efficacy of pyrethroid incorporated nets for the control of stored product moth species: immediate and delayed effects on Ephestia kuehniella and Plodia interpunctella (Lepidoptera: Pyralidae).

Insect pests pose a significant threat to stored commodities, necessitating the exploration of alternative pest management strategies. Long-lasting insecticide-incorporated nets (LLINs) have emerged as a promising tool, offering selectivity and reduced ecological impact compared to conventional chemical approaches. However, their efficacy against Ephestia kuehniella Zeller and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), cosmopolitan stored product moth species, has remained underexplored. This study investigated the immediate and delayed effects of 2 commercial pyrethroid-incorporated nets, Carifend (0.34% α-cypermethrin) and D-Terrence (0.4% deltamethrin), on the adult and larval stages. Both LLINs demonstrated high efficacy in controlling E. kuehniella and P. interpunctella, with mortality rates reaching up to 100% depending on exposure and post-exposure durations. Particularly, rapid knockdown was observed with D-Terrence net inducing 100% of adults in P. interpunctella after 30 min exposure. LLINs achieved almost 100% immediate mortality rate against adults after just 1 day of exposure. In addition, immediate rates of affected individuals reached as high as 81% and 91% in E. kuehniella and P. interpunctella larvae, respectively, following just 5 h of exposure to the D-Terrence. Different responses were observed between the adult and larval stages, with larvae exhibiting higher tolerance and potential for recovery from the affected phase after short exposures. There were increasing mortality rates after greater exposure to LLIN. Findings highlight the potential of LLINs as a pest management tool in storage facilities against these important stored product moths. Understanding the responses between life stages and the significance of delayed effects is crucial for optimizing LLIN deployment strategies.

The effect of plant pesticide Tondxir against the stored product Moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae)

T Many plant extracts could be considered natural, effective methods for controlling insect pests instead of synthetic chemicals. The current examination was designed to assess the mortality percentages of the plant-based pesticide Tondxir on the date moth Ephestia cautella. A series of experiments were carried out in the laboratory to evaluate the pesticide Tondxir's effectiveness in controlling the second and fifth larval stages and the adults of t he date moth. The highest percentage of mortality rates for the second larval stage reached 100% after 5 days at a concentration of 3 ml/liter. However, the mortality rates of the fifth stage and the adult of E. cautella reached 42.14% and 17.50% after two weeks of treatment. A direct relationship was found between the increase in mortality rates with increasing pesticide concentration. The highest percentage of mortality was increased in the fifth larval stage of E. cautella, and they reached 42.14% at the third concentration, compared with the rest of the concentrations. The lowest mortality rate was for the concentration (1ml/liter), as the mortality rate reached (26.07) after 14 days of treatment.

Effects of pyroligneous acid on life history and physiology of two pyralid pests of stored products

Natural products derived from plant materials, such as wood vinegar (pyroligneous acid; PA), have shown toxicity to insects in previous studies; however, the impact of this substance on physiology and life history of stored product insects is unknown. Thus, the current study aimed to determine the effects of PA on two prominent stored product moths, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). LC50/24h values of PA were determined for both species and first instar larvae were fed on an artificial diet containing LC50 concentrations of PA for their entire life cycle. Final instar larvae were selected for biochemical analysis while life history parameters were assayed in female adults that emerged from treated larvae. In both species, significantly lower activities of digestive enzymes (α-amylase, protease, and lipase) and detoxifying enzymes (carboxylesterase, monooxygenase cytochrome P450, and glutathione S-transferase) were observed in treated larvae relative to untreated larvae. In contrast, antioxidant enzyme activities (superoxide dismutase, phenoloxidase, and ascorbate peroxidase) were significantly elevated in treated larvae compare to controls in both species. Moreover, larvae of both species tended to have lower levels of energy reserves, such as proteins, lipids, and carbohydrates, and adults exhibited reduced longevity, fecundity, and oviposition periods in comparison to untreated larvae. Finally, GC-MS analysis of the PA used for this study demonstrated that phenolic compounds and organic acids were the largest constituents. These results indicate that consumption of PA leads to the induction of to the antioxidant system, the inhibition of detoxification and digestion enzyme activities as well as reduced levels of energy reserves. Cumulatively, these effects resulted in reduced longevity and fecundity compared to control insects. This study expands our knowledge of the impacts of PA on physiology and life history for two prominent pests of stored products.

Changes in biochemical contents and survival rates of two stored product moths under different thermal regimes

Plodia interpunctella (Hübner) and Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) are two destructive pests of stored products. Survival and physiological changes of last instar larvae were investigated under different thermal regimes [i.e. control (optimal temperature), cold-acclimation (CA), fluctuating-acclimation (FA) and rapid cold-hardiness (RCH)]. Our results indicate a relationship between supercooling points, carbohydrate contents, enzyme activities and survival rates of the larvae under different thermal regimes. Glycogen content was greatest for control and RCH regimes whereas the greatest trehalose level was recorded for the CA regime. The supercooling points of control larvae of P. interpunctella and E. ceratoniae were − 14 and − 10 °C, respectively, and decreased to − 16 and − 18 °C under the CA regime. Thermal regimes had no significant effect on the survival of the larvae after 24 h exposure at 0 °C, but when larvae exposed to − 5 °C for 24 h, the highest and lowest survival rates were recorded in the CA and RCH regimes, respectively. Protein phosphatases 1 and cAMP-dependent protein kinase (AMPK) were found to have the highest enzyme activity. The activity of AMPK varied between different thermal regimes and was greatest under the CA regime. CA considerably increased lower lethal times of the larvae compared with the control regime. RCH showed the highest impact on lower lethal temperature limits of the larvae. Our results indicated a characteristic enhancement of the survival rates of the larvae of P. interpunctella and E. ceratoniae under the CA regime. This enhancement is likely related to elevated contents of low molecular weight carbohydrates under the CA regime.

Host-preference and parasitic capacity of new candidates of Trichogramma species (Hym.:Trichogrammatidae) against some stored product moths

The host-preference and parasitic capacity of some local Trichogramma spp. (T. bourarachae, T. cordubensis, T. euproctidis and T. cacociae) towards four species of stored product moth eggs were investigated in order to select new candidate species for use in mass rearing and biological control against moths in storages. The efficacy of the Trichogramma spp. was compared with T. evanescens, the common wasp used commercially for biological control. Experiments were carried out by offering a single parasitoid female to eggs of the Indianmeal moth Plodia interpunctella (Hubner), the Mediterranean flour moth Ephestia kuehniella Zeller, the warehouse moth E. elutella (Hubner), and the almond moth, Cadra cautella (Walker) in choice and no-choice assays. Two different choice experiments were used to certify the same conclusion in both methods. The bioassay for host-preference of Trichogramma was carried out by offering a single early female wasp the choice between equal numbers of host eggs on square cards “Petri dish tests “and/or strip cards “strip card tests”. In Petri dish tests, E.kuehniella was a highly acceptable host species for T. bourarachae, T. euproctidis, and T. cacociae wasps while E.elutella and C.cautella eggs were more acceptable for T. evanescens and T.cordubensis, respectively. In strip card tests, E.kuehniella eggs were highly acceptable for T.bourarachae, T.cacociae and T.evanescens. Eggs of E.elutella and C.cautella were more acceptable for T.euproctidis andT. cordubensis, respectively. Significant differences were found among the parasitic capacity of the tested Trichogramma spp.: T. borarachae showed a good parasitic potential against S.cerealella and E. kuehniella; T.evanescens and T. cacociae against S.cerealella; T. cordubensis against S.cerealella and P. interpunctella and T. euproctidis against P. interpunctella. All tested wasps had a propensity to superparasitize the host eggs. T. cordubensis, T. euproctidis and T. borarachae showed promise for further investigation into selecting new biological control agents against some stored product lepidopterous pests.

Host-preference and parasitic capacity of five Trichogramma species (Hym.: Trichogrammatidae) against some stored product moth pests: Poster

Host-preference and parasitic capacity of five Trichogramma species (Hym.: Trichogrammatidae) against some stored product moth pests: Poster

Expression of cry1Ab gene from a novel Bacillus thuringiensis strain SY49-1 active on pest insects.

In this study, the cry1Ab gene of previously characterized and Lepidoptera-, Diptera-, and Coleoptera-active Bacillus thuringiensis SY49-1 strain was cloned, expressed and individually tested on Ephestia kuehniella (Lepidoptera: Pyralidae) and Plodia interpunctella (Lepidoptera: Pyralidae) larvae. pET-cry1Ab plasmids were constructed by ligating the cry1Ab into pET28a (+) expression vector. Constructed plasmids were transferred to an Escherichia coli BL21 (DE3) strain rendered competent with CaCl2. Isopropyl β-d-1-thiogalactopyranoside was used to induce the expression of cry1Ab in E. coli BL21(DE3), and consequently, ∼130 kDa of Cry1Ab was obtained. Bioassay results indicated that recombinant Cry1Ab at a dose of 1000 μg g−1 caused 40% and 64% mortality on P. interpunctella and E. kuehniella larvae, respectively. However, the mortality rates of Bt SY49-1 strains’ spore–crystal mixture at the same dose were observed to be 70% on P. interpunctella and 90% on E. kuehniella larvae. The results indicated that cry1Ab may be considered as a good candidate in transgenic crop production and as an alternative biocontrol agent in controlling stored product moths.

Potential of Hymenopteran larval and egg parasitoids to control stored-product beetle and moth infestation in jute bags.

The control of stored-product moths in bagged commodities is difficult because the developmental stages of the moths are protected by the bagging material from control measures such as the application of contact insecticides. Studies were carried out to assess the ability of Hymenopteran parasitoids to locate their hosts inside jute bags in the laboratory. The ability of different parasitoids to penetrate jute bags containing rice was investigated in a controlled climate chamber. Few Habrobracon hebetor (Say) (Hymenoptera: Braconidae) passed through the jute material while a high percentage of Lariophagus distinguendus (Förster), Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae) and Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) were able to enter the Petri-dishes. Significantly more L. distinguendus and T. elegans entered compared to H. hebetor. There was significant difference in the mean percentage parasitoids invading depending on species. Head capsules and/or thorax widths were measured in order to determine whether the opening in the jute material would be large enough for entry of the parasitoids. These morphometric data differed depending on parasitoid species and sex. The parasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae) did not enter the bags, but located host larvae inside the jute bags and parasitized rice moths Corcyra cephalonica larvae by stinging through the jute material. Venturia canescens significantly reduced the number of C. cephalonica adults emerging from the bagged rice; therefore, it could be released in storage rooms containing bagged rice for biological control of C. cephalonica. The use of parasitoids to suppress stored-product insect pests in bagged commodities could become a valuable supplement to the use of synthetic pesticides.

Effect of seed extracts of five indigenous plants against the stored product Moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae)

Studies on the control of Ephestia cautella with oil of Capsicum frutescens, Anacardium occidentale, Monodora tenuifolia, Xylopia aethiopica, and Ricinus communis were carried out in the laboratory at ambient temperature of 28 ± 2 °C and relative humidity of 78 ± 5%.The extracts were studied at 0.5 ml and 1.0 ml dosages against the egg, larvae, and adult of E. cautella. Results showed that oil of A. occidentale was more effective than other extracts as it effects up to 76.65 and 90.00% adult mortality of the moth at 0.5 and 1.0 ml, respectively. In addition, only the oil of A. occidentale and C. frutescens was able to effect more than 50% larvae mortality within 96 h of exposure at 1.0 ml dosage. However, R. communis showed the greatest effect on hatchability of E. cautella eggs but its effect was not significantly (p > 0.05) different from that of A. occidentale and C. frutescens oil. Moreover, only the oils of C. frutescens, A. occidentale, and R. communis were able to prevent the adult emergence of the moth but their effect was not significantly (p > 0.05) different from other oils. Therefore, due to the effectiveness of these oil extracts on different life stages of E. cautella, they could be recommended for the management of this insect pest. Moreover, to achieve more effective control over this moth, oil of A. occidentale could be used since it appeared to be most effective and consistence in its action against different life stages of the moth.

Summary of commercially available pheromones of common stored-product beetles

Introduction Since the explosion of pheromone identification and synthetic production of the 1960's, pheromone utilization has become a valuable technique for monitoring and control of insect infestations (Cork, 2004) Pheromones are collectively grouped into one family of specific chemical signals designated as semiochemicals. Specific pheromones in this category are synthetically created, placed in traps that are in turn used for population tracking, stages of development and mating disruption of common stored- product pest beetles. These insects have the dexterity to infest processed foods, whole grains such as barley, rye, corn, oat and rice. Trapping and monitoring through pheromone usage can assist in reducing the amount of insecticide used by pest-control managers, only spraying when insects surpass certain levels or when they enter a vulnerable stage. Many stored-product pest beetles produce pheromones that can be classified as long-chain carbon compounds, predominately consisting of acids, aldehydes, acetates and esters. Many of these pheromones are unsaturated and consist of one or more double bonds that can be oriented into an E or Z conformation creating one or more isomers. Pheromones produced by stored-product beetles are generally more complex when compared with pheromones produced by stored-product moths. As a result of this complexity, stored-product beetle pheromones contain a degree of chirality creating additional isomers. The chemistry used for producing these compounds is more involved but can be easily reproduced and contains highly stable intermediates leading to the commercial availability of these particular pheromones. 2. Commercially available pheomones for stored-product The majority of pheromones range anywhere from 7-18 carbons in length producing carbon-chained compounds. Pheromones vary by functional group (i.e., acid, aldehyde, acetate, ester), double bond position and the configuration of the double bond (E or Z). Some of these pheromones are also branched containing methyl groups at various positions on the compound. These methyl groups create chirality in the compound depending upon how they are oriented on the molecule (R or S configuration). These factors are attractant determining for a variety of different beetles. Small changes in double bond placement and orientation of double bond or methyl group substituents may prevent attraction. The same holds true for alterations of functional groups. Through the use of organic syntheses, coupling of smaller organic compounds and the manipulation of long chain carbon compounds, these particular beetle pheromones can be made commercially available.

Conscent PE mating disruption system is an effective alternative to methyl bromide for the control of stored product moths.

Stored-product moths, Plodia interpunctella, Ephestia kuehniella, Ephestia cautella, Ephestia elutella are a serious threat to stored-food commodities. These moths are mostly controled using chemical insecticides. Recently, the residual effects of synthetic insecticide have become a serious concern to consumers. Therefore, an alternative measure is being sought. The object of the present study was to induce mating disruption and subsequently a reduction of the population of the aforementioned storage moths. Conscent PE, a steady release solid dispenser emits pheromone component Z-9, E-12- Tetradecadien-1-yl acetate. This dispenser was tested consecutively for five years in a real life situation in the United Kingdom. This mating-disruption system is specifically designed for use in enclosed spaces leading to an increase of pheromone concentration in the air. Solid dispensers containing 100 mg of sex pheromone Z-9, E-12-Tetradecadien-1-yl acetate were applied every 8 meters in a food factory. Complete absence of the pest was achieved after 12 month of continuous application. Pheromone traps showed zero captures and three monthly biological assessment indicated the absence of any breeding. There was also a dramatic decline in reported customer complaints and the twice yearly fumigations with methyl bromide were deemed unnecessary. The dispensers were found to be effective for up to 13 weeks.

Behavioural effects of pheromone-based control system, ExosexTM SPTab, on male Indianmeal moth, Plodia interpunctella

We report on laboratory studies to examine behavioural effects of a new pheromone-based control system for stored product moths, Exosex™ SPTab auto-confusion, on virgin male Plodia interpunctella. The SPTab comprises a compressed electrostatic powder tablet, containing the female sex pheromone (Z,E)-9,12-Tetradecadienyl acetate; designed to be an attractive source to males and disrupt the mate finding ability of several stored moth pest species. Our aims were to examine the effects of SPTab contact on male ability to locate females and to be attractive sources to other males. Observations of behavioural effects were made in a moth flight tunnel. Virgin male P. interpunctella were treated on SPTabs weathered from 1-8 weeks. After treatment, males were either immediately released downwind of calling females in the upwind section of the flight tunnel, or caged individually for 1 to 48 h before release. The ability of treated males to act as false lures for other males was measured by treating males on different age SPTabs as before, caging them and then placing them upwind of untreated males. In all studies males were scored on making source contact. Males treated on the SPTab and immediately released downwind of calling females showed a 96.7% reduction in their ability to contact the females. Males held for 48 h before release still showed a significant reduction in source contact compared to untreated controls. Treated males tested after 3 h, were as attractive as calling females with >75% of flights resulting in source contact. Significant reduction in female source contact was still evident when males were treated on SPTab weathered for 4 weeks. Males treated on SPTabs weathered for up to 8 weeks were significantly attractive to untreated males, and equal to calling females. The results indicate that contact with SPTab significantly reduces the ability of male P. interpunctella to locate females for up to two days. These males could increase the confusion effect by becoming competitive attractive point sources for other males. The Exosex SPTab has novel methods of causing mating disruption. Keywords : Mating disruption, Plodia interpunctella , Exosex SPTab, Sex pheromone, Flight tunnel.

Efficacy of pheromone-based control system, Exosex™ SPTab, against moth pests in European food processing facilities

The Exosex™ SPTab auto-confusion system is a novel pheromone-based method for control of stored product moth pests in both food and tobacco processing and storage facilities. The method uses a femaleproduced sex pheromone, (Z,E)-9,12-tetradecadienyl acetate, combined with a patented electrostatic powder delivery system known as Entostat™ to disrupt mating and interrupt the lifecycle of several important moth pests: Plodia interpunctella, Ephestia kuehniella, Ephestia cautella and Ephestia elutella . Male moths are attracted to a compressed tablet of the powder, which contains the sex pheromone. The powder releases pheromone at a slow enough rate to attract males to make contact with the tablet. The powder adheres to the moth cuticle via electrostatic attraction and the moth leaves the tablet coated in female sex pheromone. Flight tunnel studies have shown that this disrupts their ability to locate female moths and they become attractive sources for other males. Here we will present findings from full scale, long term trials that were conducted under real conditions at commercial food processing facilities across Europe. Populations of target moth species were monitored alongside deployment of the SPTab system and compared with untreated control areas and historical data from the test areas in the years prior to deployment. In all cases populations were reduced compared to the same area in the previous year and compared to untreated control areas under local pest control practices. The SPTab auto-confusion system could offer the opportunity to actively reduce the use of pesticides and its use as an integrated pest management tool within the food and tobacco processing and storage industry is discussed. Keywords : Mating disruption, Plodia interpunctella, Ephestia kuehniella , SPTab, Sex pheromone.

Detection of the cry1 gene in Bacillus thuringiensis isolates from agricultural fields and their bioactivity against two stored product moth larvae

Sixty Bacillus spp. isolates were obtained from different agricultural fields in Kayseri province using selective media. Total DNA was isolated and analyzed by PCR using cry1 general primers. Of the 60 tested isolates, 17 carried the cry1 gene. B. thuringiensis subsp. kurstaki and all other isolates exhibited approximately 19-kb plasmid bands. In addition to the 270-bp band, the standard strain and isolate I47 yielded 180-bp PCR products. The isolates and standard strain were toxic to Ephestia kuehniella Zeller and Plodia interpunctella Hubner larvae. Insecticidal activity of isolates I36, I37, and I40 against Ephestia kuehniella was higher than that of the standard strain when 10^6 spore-crystals mL^{-1} was used. LC_{99} values for isolates I36, I37, and I40 were 6.46, 6.28, and 6.24 for E. kuehniella, respectively, and these isolates were also effective against Plodia interpunctella larvae. LC_{99} values for isolates I36 and I40 were 6.69 and 5.07 for P. interpunctella, respectively. The results clearly show that isolates I36, I37, and I40 were effective at lower doses, as compared to the others.

Using water bottles for trapping of Indianmeal moths in stored peanuts

AbstractSticky traps baited with sex pheromone are the most common trapping devices used in monitoring of moth pests in food warehouses and food processing. However, these traps only capture males, and it is debatable whether captures of male moths can be used as spatio‐temporal indicators of hot spots of conspecific larvae (only larvae are responsible for damage to food products). Water has been documented as highly attractive to stored product moths, and here we present the first performance data on water bottles as monitoring devices. On average, water bottles caught 15 times more Indianmeal moths [Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)] than unbaited sticky traps and 74 times more moths than probe traps. We showed that hole size in water bottles had negligible effect on their trapping performance in a naturally infested peanut warehouse. Experimental evaluation of water loss over time showed that smaller holes dramatically reduced water evaporation (less frequent service required), and detergent can be added to the water to reduce moth decomposition without adversely affecting water attractiveness (trap performance). Trap captures of males and females were linearly correlated, and based on quantitative statistical analysis [Spatial Analysis by Distance IndicEs (SADIE)], we showed that weekly captures of the two sexes were spatially correlated. The applied implications of using water bottles in improved IPM of moths in food facilities are discussed.

Long‐term pheromone‐mediated mating disruption of the Mediterranean flour moth, Ephestia kuehniella, in a flourmill

AbstractSeveral studies have indicated that mating disruption (MD) successfully reduces population densities of stored product moths, for example, the Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). However, practical issues, such as finding control plots, replication, and lack of similarity between replicates, often incur problems in full‐scale investigations and often draw focus from the added results. We here present results from long‐term monitoring of E. kuehniella populations in two similar flourmills in Poland, one treated with pheromone for MD and one left untreated and used as control. Pheromone‐mediated MD was applied during 2 years. Thirty pheromone dispensers (one per 100 m3 factory volume), each releasing about 2 mg (Z,E)‐9,12‐tetradecadienyl acetate per day, were used. Pheromone‐baited traps were used to monitor the moth populations in the MD mill and in a nearby untreated mill. The reduction in trap catch during the MD treatment was about 90% or more, compared with the untreated mill or pre‐treatment periods of the MD mill. The reduction was larger during the 2nd year of MD than during the 1st year. These results contribute to the picture that MD is an effective method to control moth species infesting stored products.

Effect of MON 810 Bt transgenic maize diet on stored-product moths (Lepidoptera: Pyralidae)

The transgenic hybrid MON 810-YieldGard ® was developed to protect maize against herbivorous Lepidoptera larvae in the field. Although the hybrid kernels contained 20 times less of the Cry1Ab toxin than leaves, they had been shown to be toxic to some stored product pests, indicating a protective effect of Cry1Ab during maize storage. However, the characterization of the resistance level and benefits of the Cry1Ab kernels during their storage are still incomplete. In this study, we compared the suppressive effect of the diets obtained from the MON 810-YieldGard ® hybrid to four species of stored product moths: Ephestia kuehniella, Ephestia elutella, Cadra cautella and Plodia interpunctella. The diets originated from kernels that were obtained at two different experimental fields containing the same concentration of Cry1Ab (0.35±0.056 μg g −1), and caused 100% mortality in E. ellutella, C. cautella and P. interpunctella, and 65% mortality in E. kuehniella. The comparison of LD 50 (time when 50% individuals died) and larval relative growth rate (RGR) among the tested species revealed that P. interpunctella was the most sensitive species followed by E. elutella, C. cautella and E. kuehniella. The lowest toxic concentration of Cry1Ab in the diet of E. kuehniella larvae was determined by mixing the diets from hybrid kernels containing Cry1Ab with diets from control kernels without Cry1Ab. The mortality of E. kuehniella larvae decreased with decreasing Cry1Ab concentration, and the LD 50 (concentration when 50% individuals died) was 0.20 μg Cry1A g −1 of diet. Similarly, the larval RGR decreased with decreasing logarithmically transformed concentrations of Cry 1Ab in the diet. These results show that MON 810-YieldGard ® hybrid kernels are protected during their storage against feeding by stored product moths.

Do anthropogenic transports facilitate stored-product pest moth dispersal? A molecular approach

Stored-product moths cause large economic damage in food processing industries and storage facilities. Control of indoor pests is currently dealt with locally, and control strategies seldom include different mills or cooperative industries in joint efforts to reduce infestations. In colder climates where conditions hinder flight dispersal of stored-product moths, we hypothesize that human transport between mills will facilitate dispersal. Albeit considered intuitive, this hypothesis has so far never been tested. Male moths from three mills (populations) in southern Sweden and Denmark were collected and by using amplified fragment length polymorphism (AFLP) pair-wise F(st) values were calculated. Cluster (population) origins of the genotypes were computed by using a model-based method, structure. The results suggest that known transportation of flour between two mills generate genetically more similar populations of the economically important stored-product moth, Ephestia kuehniella (Zell.) (Lepidoptera; Pyralidae), compared to the third mill, with another distribution area, but situated geographically in between the other mills. The structure model placed the sampled genotypes to belong to either two or five original populations, with a higher probability of two original populations. The third mill was consistently different from the other two mills independent of the models' calculated number of populations. Although the study was restricted to three mills and one transportation route, it highlights the possibility that transportation of food products promotes genetic mixing (i.e. dispersal) of insect pest populations. Including cooperating mills in control (or monitor) strategy schemes against stored-product pest insects would therefore be a more effective action, rather than to treat each mill separately.

The effects of temperature on flight initiation in a range of moths, beetles and parasitoids associated with stored products

The effects of temperature on flight initiation in a range of stored-product pests and their parasitoids have been studied in laboratory flight chambers. Tests were conducted between 10 and 32.5 °C at intervals of 2.5 °C. The minimum temperatures for flight initiation in the stored-product moths Ephestia kuehniella, E. elutella and Plodia interpunctella were in the range 12.5–15 °C. For the stored-grain beetles, minimum temperatures for flight initiation varied from 17.5 °C for Ahasverus advena and Typhaea stercorea, 20 °C for Rhyzopertha dominica, 25 °C for Tribolium castaneum, to 27.5 °C for Sitophilus oryzae. The minimum temperature for flight initiation in the hymenopteran parasitoids, Anisopteromalus calandrae and Lariophagus distinguendus, was 17.5 °C. Flight is discussed as a factor in sustainable pest management strategies for storage insects; its importance in the spread of infestation and the likely success of physical and biological control methods is highlighted.

Potential of Cleisthopholis patens Elliot as a maize protectant against the stored product moth, Plodia Interpunctella (Hubner) (Lepidoptera; Pyralidae)

The root bark powder, stem bark powder and leaves powder of Cleisthopholis patens were tested for their insecticidal activity as a stored product protectant at four different concentrations (0.5, 1.0, 2.0 and 3.0 g) on the moth, Plodia interpunctella, at ambient tropical storage conditions of temperature and relative humidity. Moth mortality, egg hatchability, adult emergence were used as indices of insecticidal activity. The result obtained shows that the root bark powder was effective at 1.0, 2.0 and 3.0 g/20 g of the maize evoking 100% adult moth mortality within 72 h of application. The stem bark powder of C. patens at 1.0, 2.0 and 3.0 g/20 g of the maize produced 78 – 100% moth mortality within 72 h of treatment. But the stem bark powder caused 100% adult moth mortality of P. interpunctella at 3.0 g/20 g maize in 96 h post-treatment. The leaf powder was moderately effective against the adult moth at 3.0 g/20 g of the maize grain in evoking 70 – 80% adult mortality within 96 h of treatment. The root and stem bark powder inhibited development of egg to adult at all the concentrations evaluated and therefore prevented adult emergence. However, 2 – 11% adult emergence of P. interpunctella was obtained in the maize grain treated with the leaf powder.