Stored Product Protection Research Articles

Comparative analysis of the repellency activity of single compounds and the synthetic blends of semiochemicals from Aframomum melegueta (R.schum) and Dennittia tripetala (Bak.F) against Rhizopertha dominica in Calabar, Nigeria

Bioassay experiments were carried out in Calabar to compare the repellency activity of single compounds and the synthetic blends of Semiochemicals extracted from Afromomum melegueta and Dennittia tripetala. The aim of the experiment was to determine the efficacy of single compounds and the synthetic blends in suppressing the reproductive potential and adult emergence of Rhizopertha dominica, (Fabricius), a primary pest of stored cassava pellets and cereal grains in Sub-Saharan Africa. Insect culture of the adult R. dominica was set up in the laboratory at Federal College of Education Obudu to obtain fresh insects for the bioassay experiments. Dried seeds of A. melegueta (R. Schum) and D. tripetala (Baker f.) Schatz were procured from the main market in Obudu for the purpose of the research work. 100g each of the dried fruits of the spice plants were pounded separately with the laboratory pestle and mortar for the extraction of the essential oils (EOs). The oils extracted were tested for toxicity and reproductive potential deterrence against R. dominica. The chemical constituents of the essential oils were isolated, identified and tested against R. dominica. Synthetic blends of individual compounds were prepared based on their natural ratios and were also tested for toxicity and reproductive potential deterrence against the insect pests in the laboratory. The result showed that both the single compounds and the synthetic blends were toxic and repellent to the insect pest, and could significantly suppress the reproductive potential thereby inhibiting the emergence of adult insect. However, synthetic blends exhibited a stronger efficacy in their toxicity against the pest thereby providing a broad spectrum of insecticidal bioactivity against R. dominica than the single compounds. This action of the synthetic blends of extracts from the spice plants demonstrated their potential for development in stored products protection especially at the small scale resource poor farmer’s level in Nigeria.

An evaluation of the efficacy of extracts from Xylopia aethiopica and Dennittia tripetala in controlling Dermestes maculatus(degeer) an insect pest of dry stored fish in Calabar, Nigeria

Laboratory bioassays were conducted in Obudu, Nigeria to evaluate the efficacy of extracts from X.aethiopica and D.tripetala in controlling D.maculatus a primary pest of dry stored fish in sub-saharan Africa. Adult population of D. maculatus was obtained in the laboratory at the Federal college of Education Obudu, to obtain fresh insects for the experimental work. Dried fruits of X.aethiopica (Dunal) and dried seeds of D.tripetala (Bak.f.) were procured from a local market in Obudu for the purpose of the work. 100g each of the spice plants were pounded separately using laboratory pestle and mortar for the extraction of essential oils (EOS). The essential oils extracted were tested for repellence and toxicity against D.maculatus at 10µl per EO in a 4-way Olfactometer. Minitab 15 statistical soft ware was used for the analysis of data. Results indicated that the essential oils (EOS) and their constituent individual compounds were significantly (p<0.05) repellent and toxic to D.maculatus with X.aethiopica more repellent and more toxic to the insect than D.tripelala. The two oils were also observed to inhibit the activities of microbes that usually cause and accelerate delaying in stored fish. This action of the essential oils of the two spice plants and their chemical constituent demonstrated their potentials for development in stored products protection, especially at the small scale resource poor farmer’s level in Nigeria.

Nanoemulsions of Chamomile and Cumin Essential Oils: As an Alternative Bio-rational Control Approach against the Red Flour Beetle, Tribolium castaneum

Essential oil (EO) nanoemulsion is a new approach to formulate and convey insecticides and to minimize some of the common shortcomings associated with the conventional formulations of synthetic insecticides and also of essential oils. The aim of the present was to develop an oil-in-water (O/W) nanoemulsion of the essential oils of chamomile (Matricaria chamomilla L.) and cumin (Cuminum cyminum L.), and assess their lethal and sublethal toxicity to the red flour beetle Tribolium castaneum (Hersbt). The nanoemulsions of EO were characterized by droplet sizes of 341.4 and 387.1 nm for the chamomile and cumin, respectively. The polydispersivity (PDI), viscosity (cP), zeta potential (mV) and conductivity (mS/cm) of the nanoemulsions were also characterized. The cumin nanoemulsion exhibited higher lethal toxicity to the flour beetle, besides of compromising the insect weight gain while impairing their food consumption and conversion rate in sublethal exposure. Cumin EO nanoemulstion also sparked anti-feeding activity, reduced progeny production and prevented grain weight loss by the red flour beetle indicating its potential for stored product protection.

Residual efficacy of spinosad and spinetoram on traditional and new improved rice varieties on the mortality of Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

Residual effects of insecticides sprayed on grains play a remarkable role in stored product protection. Over decades, the residual impact of many insecticides has been investigated. However, the negative outcomes of those neurotoxic insecticides on the biotic and abiotic environment project the requirement of seeking for alternatives. Spinosad, a bacterial formulation, has been tested for its residual efficacy on different storage and food processing facilities but the effects vary with the commodity type. Moreover, a more recent and related compound spinetoram possesses little information about its residual efficacy on traditional and new improved rice varieties maintained under storage conditions. Therefore, the objective of this research was to determine the residual efficacy of spinosad and spinetoram applied on traditional and new improved rice varieties found in Sri Lanka on the mortality of Rhyzopertha dominica over different durations of storage. Label rate of spinosad, spinetoram or distilled water (diluent/control) was sprayed on traditional/new improved rice varieties followed by kept in storage for 0–5 months. Every month a bioassay was conducted by introducing R. dominica adults to the treated grains. Mortality of R. dominica adults was determined at 3 and 10 days following introduction. In general, the adult mortality at 10 days following introduction was higher than 3 days. At 5 months following spraying, the maximum residual efficacy of spinosad was shown by Kaluheeneti, Red Basmathi, Red Nadu and Suwandel whereas the same effect of spinetoram was observed in Kaluheeneti and Suwandel. Overall, spinetoram demonstrates better residual efficacy than spinosad over 5-month storage period for the rice varieties tested.

Effects of benzothiazole on survival for reduced reproduction and development in Tribolium castaneum Herbst (Coleoptera: Tenebrionidae).

The red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), is an important stored-product pest that is distributed worldwide and has developed resistance to many insecticides. Identifying novel and effective alternative insecticides is important for the control of T. castaneum. The volatile compound benzothiazole has been identified as having great acute toxic activity against T. castaneum. However, a comprehensive evaluation of a new insecticide should include both direct toxic effects and sublethal effects. The aim of this study was therefore to evaluate the effects of benzothiazole on the development and reproduction of T. castaneum. Exposure of fourth-instar larvae to lethal and sublethal concentrations of benzothiazole (LC10 , LC30 and LC50 ) significantly decreased pupation rates, food intake and growth rates in T. castaneum. Larval duration was significantly reduced by approximately 1 day in the LC30 and LC50 treatment groups. The LC50 benzothiazole caused a significant decrease in the weight of pupae and adults, fecundity and egg hatchability. Increased and decreased nutrient (carbohydrate and lipid) contents were observed in surviving larvae and pupae, respectively. The LC30 and LC50 treatments caused the down-regulation of five growth-positive regulated genes (PI3K, AKT, CyclinE, S6K1 and S6K2) and the up-regulation of two growth-negative regulated genes (4EBP and FOXO). Benzothiazole presented adverse effects on the development and reproduction of T. castaneum, further supporting benzothiazole as a highly active compound in stored-product protection. © 2020 Society of Chemical Industry.

Real-time PCR for identification of five species of Cryptolestes based on COI barcode region

Cryptolestes(Coleoptera: Laemophloeidae) are economically important pests, which damage stored products in granaries and mills. Because it is difficult to distinguish Cryptolestes species morphologically, we develop here a high sensitivity real-time PCR method for distinguishing five species of Cryptolestes (C. ferrugineus, C. pusillus, C. turcicus, C. pusilloides and C. capensis). The lower limit of DNA concentration required for species identification is 0.1 ng/μl for C. ferruginues and C. pusilloides, and 0.01 ng/μl for C. pusillus, C. turcicus, and C. capensis. This method successfully determined species assignments for previously unidentified Cryptolestes spp. Collected from the field and will facilitate Cryptolestes identification in the field of plant quarantine and stored product protection.

Mating Attributes Relating to Parasitization and Productivity in Habrobracon hebetor (Hymenoptera: Braconidae) Rearing on Host Indian Meal Moth (Lepidoptera: Pyralidae).

The mating attributes in relating to parasitism and progeny production capacity of the parasitoid Habrobracon hebetor Say, using Plodia interpunctella (Hübner) as a host, were investigated in laboratory studies. The results indicated that 100% of the host larvae were parasitized by different individuals of H. hebetor females that were mated by the same male. Mating duration did not differ significantly among different successive matings with different females and had no effect on the rate of parasitism. In general, pairs that had their copulation early after emergence exhibited the maximum rate of parasitism as compared to delayed intervals. Moreover, the age of the H. hebetor females had no effect on the percentage of parasitism. The maximum parasitism percentage was recorded for the H. hebetor individuals that had been developed from the age group of the 6-d-old adults. The male: female ratios did not differ significantly among the female age groups. The percentage of parasitism clearly indicated a decrease with the increase of the male: female ratio. Overall, the results of the present work can be further utilized in mass rearing and release of H. hebetor in biological control programs in stored product protection.

Efficacy of phosphine fumigation for different life stages of Trogoderma inclusum and Dermestes maculatus (Coleoptera: Dermestidae)

Despite the importance of dermestid beetles as targets for stored product protection, including the protection of museum artifacts and animal-based products, there are only a few published reports regarding their susceptibility to phosphine fumigation, in contrast with other major stored product insect species. In the current study, we evaluated phosphine against all life stages of Trogoderma inclusum LeConte, the larger cabinet beetle, and Dermestes maculatus (DeGeer), the hide beetle. There were two series of laboratory bioassays; in the first series the concentrations were 0 (control), 50, 100, 200 and 600 ppm, and in the second series the concentrations were 0 (control), 50, 150, 300, 400, 500 and 600 ppm. Both series were carried out on a 5-day insect exposure protocol. The results for both species clearly indicated that eggs were by far the least susceptible life stage, followed by pupae, while most adults and larvae were killed at the 50-ppm concentration. Concentrations between 300 and 400 ppm could be utilized to provide 100% mortality for both species and all life stages. To our knowledge, our results are the first that have provided data regarding efficacy of phosphine for the control of T. inclusum and D. maculatus. Resource managers can utilize our results to more efficiently target these dermestids with specific concentrations of phosphine, depending on the target life stage.

Biocontrol potential of entomopathogenic nematode species against Tribolium confusum (Jac.) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae) under laboratory conditions

Grain commodities, like cereals and legumes, are subject to insect infestation during postharvest processing and storage. Public concerns about the potential risks that derive from the consumption of pesticide-treated commodities have created interest for the development and integration in stored product protection of alternative, ecologically safe methods for the disinfestation of stored commodities. The present study was conducted to evaluate the biocontrol potential of four entomopathogenic nematodes (EPNs): Steinernema pakistanense (LM-07), S. bifurcatum (LM-30), S. affinae (GB-14), and S. cholashanense (GB-22) against adult beetles of Tribolium confusum (Jac.) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae) under laboratory conditions. Suspensions of nematodes were applied at three different concentrations, 50, 100, and 150 IJs/beetle in 1 ml of distilled water at three different temperatures, 20, 25, and 30 °C. Mortality was recorded after 3 days of application. The concentration of 150 IJs/beetle achieved a maximum mortality of 100% for S. pakistanense at 30 °C. The same concentrations revealed that all four species of EPN were able to cause mortal effects depended on temperature and concentrations. S. pakistanense (LM-07) and S. bifurcatum (LM-30) were the most effective at 150 IJs/beetle at 30 °C and S. affinae (GB-14) and S. cholashanense (GB-22) at the same concentration at 20 °C.

IPM guidelines as fundament for sustainability in plant protection: The case for stored product protection: Poster

IPM guidelines as fundament for sustainability in plant protection: The case for stored product protection: Poster

Web-based phosphine fumigation monitoring with active sensor validation confirms lethality in stored grains:

The predominant measurement technologies for fumigation gases over the past 60 years include colorimetric tubes, photoionization detectors, and electrochemical sensors. Their limitations and inaccuracies are well documented. Spectros Instruments has shown non-dispersive infrared monitoring (NDIR) to be a superior analytical tool for the practical measurement of fumigation gases as shown in Table 1. Any compliant fumigation monitor must be accurate, reliable and affordable. Stored Product Protection has additional requirements in remote regions such as Central China and Western Australia. In these cases, the value of real time access via the internet to fumigation data collected with NDIR Technology from a remote location adds heretofore unknown benefits. Allocation of manpower and materials resources are optimized by access to information about fumigant gas levels in grain storages via the internet. Data is automatically transferred to a central database that can be accessed in real-time from any location with internet access. Intelligent monitors with built-in diagnostics tracking barometric pressure, temperature, sample flows and detector voltages are described. This data collection, data warehousing and reporting platform maintains measurement traceability to certified compliance with secure, encrypted electronic notebook format. Knowing REAL phosphine concentrations allows informed decisions to be made to achieve required CxT and avoid situations leading to target pest phosphine resistance.

Sustained effective use of phosphine in stored product protection in India: Role of UPL Limited: Presentation

Sustained effective use of phosphine in stored product protection in India: Role of UPL Limited: Presentation

Efficacy of Beauveria bassiana in combination with an electrostatically charged dust for the control of major stored-product beetle species on concrete

Laboratory bioassays were carried out to determine the insecticidal efficacy of a Beauveria bassiana formulation (Bb38, Exosect Ltd, UK), which is based on the combined use of the fungus with the electrostatically charged dust Entostat. The efficacy of Bb38 was conducted on concrete surfaces against adults of the lesser grain borer, Rhyzopertha dominica, the rice weevil, Sitophilus oryzae, the confused flour beetle, Tribolium confusum and the rusty grain beetle, Cryptolestes ferrugineus, in two series of bioassays. In the first series, adults of the above species were exposed on concrete surfaces treated with Bb38 and mortality was recorded after 7 and 14 days of exposure (immediate mortality). These tests were carried out in all combinations of two temperatures, i.e. 25 and 30° C and two levels of relative humidity (r.h.), i.e. 55 and 75%. In the second series of bioassays, adults of the above species were exposed to Bb38 for 7 days, and after this interval, the surviving individuals were transferred in untreated concrete, where mortality was recorded again 7 and 14 days later (delayed mortality). From the species tested, R. dominica was by far the most susceptible, given that mortality reached 100% in almost all temperatures and r.h. levels. From the other species, S. oryzae and C. ferrugineus were moderately susceptible, while Bb38 was less effective for T. confusum. In the second series, immediate mortality for R. dominica was much higher than that of the other species. Moreover, delayed mortality of R. dominica reached 100% in contrast with the other species, where delayed mortality was low. Based on the results of the present work, we found that the insecticidal effect of Bb38 is not affected much by temperature and r.h., for the vast majority of the species and conditions tested. Moreover, in some cases, there was some post-exposure delayed activity of the formulation. This is one of the few studies that examine commercial formulations of fungal-based insecticides against stored product insects, which are expected to provide solutions in stored product protection, where traditional insecticides cannot be applied, as in the case of organic products.

Essential Oils in Stored Product Insect Pest Control

Among botanical extracts used as insecticides, essential oils (EOs) are promising alternatives to chemical insecticides. EOs are synthesized by plants, and they play a key role in plant signaling processes including also attractiveness toward pollinators and beneficial insects. Plant species producing essential oils (over 17,000 species) are called aromatic plants and are distributed worldwide. Our review aims to evaluate research studies published in the last 15 years concerning the use of EOs in stored product protection. More than 50% of the retrieved manuscripts have been published by authors from Eastern countries (Iran, China, India, and Pakistan), investigating different aspects related to insect pest management (exposure route, effect on the target pest, and mode of action). Coleoptera was the most studied insect order (85.41%) followed by Lepidoptera (11.49%), whereas few studies targeted new emerging pests (e.g., Psocoptera). Almost all the trials were carried out under laboratory conditions, while no experiments were conducted under real operating conditions. Future research studies concerning the use of EOs as insecticides should focus on the development of insecticide formulations which could be successfully applied to different production realities.

Stop the brain drain – Why we need stored-product protection research for food safety:

In the history of human development, stored-product protection (SPP) is probably older than the invention of agriculture because even what was hunted and gathered needed to be stored to provide food for the bad days. One may think that the human race had enough time to find out everything that could be found out on SPP. But this is not the case. SPP problems often require a solution custom-made for the given product or storage situation, climate, socio-economic background, etc. Modern SPP research in the Americas, Asia, Europe, or Oceania was often started as a result of World War I or II, when hunger was an issue. But, with the absence of hunger, we witness another scary development: SPP research is dying out, institutions are closed down, e.g., CSL UK 2009, SGRL Australia 2009, DPIL Denmark 2010, INRA France 2015. Yes, research costs money. But, do we take into account that climate change may already have led to increased numbers of conflicts and increased mobility? That a lack of food safety can tear apart all advances of civilization and culture in the brink of a moment? Why are there no calls for SPP research under Horizon 2020? What happened to the Millenium Goal to cut down hunger by 50%? The FAO states that one third of our grains are lost between harvest and consumption. It is high time to improve food storages and SPP methods using all knowledge and technology available in order to reduce losses, it is high time to support international SPP research!

Food Safety and Global Challenges to Stored Product Protection – A WFP Perspective: Presentation

Food Safety and Global Challenges to Stored Product Protection – A WFP Perspective: Presentation

Synergistic repellent activity of hot and cool thermal-sense compounds against two stored product insect pests

Abstract The repellent activities of one hot thermal-sense compound, vanillyl butyl ether (VBE), and two cool thermal-sense compounds, menthoxypropanediol (MPD) and (−)-isopulegol (IPG), against two stored product insects, Tribolium confusum and Liposcelis bostrychophila, were investigated. Such thermal-sense compounds affect mammals through transient receptor potential (TRP) channels, and both types of agonists (VBE and menthol) exhibited mutually inhibitory effects on mammalian TRPV1 and TRPM8 channels. Each compound exhibited repellent activity against both T. confusum and L. bostrychophila in a dose-dependent manner. Furthermore, synergistic effects were observed between VBE and MPD or IPG. The composition of TRP channels is different between mammals and insects. These results suggest that the use of thermal-sense compounds might serve as an alternative to essential oils in stored products protection.

EFFICACY OF NINE CROATIAN INERT DUSTS AGAINST RICE WEEVIL SITOPHILUS ORYZAE L. (COLEOPTERA: CURCULIONIDAE) ON WHEAT

Laboratory bioassay was carried out to study the insecticidal effect of 9 Croatian inert dusts against Sitophilus oryzae (L.) and to test their influence on bulk density of treated wheat. In order to compare effectiveness of Croatian inert dust samples, a standard USA diatomaceous earth (DE) Celatom® Mn 51, registered as an insecticide for stored-products protection, was used. Wheat kernels with approximately 13% moisture content were treated with inert dusts at doses 300, 400, 500 and 600 ppm and mortality of S. oryzae adults was assessed after 7 and 14 days and progeny after 49 days. The most effective Croatian inert dust samples were D-02B, D-01 and MA-4 with the LD90 values of 359.6, 447.2 and 458.7 ppm, respectively. In addition, effective dose that reduced F1 progeny in half was lower in regard to the other tested samples including the standard DE Mn 51, with the ED50 values 71.9, 54.6 and 137.6 ppm, respectively. According to the XRF analytical results, the highest amount of biogenic silica (BSi) was found in samples D-02B, D-01 and MA-4 (45.98, 35.09 and 21.28%, respectively). Paleontological data analysis confirmed diatoms species in only 5 samples of Croatian inert dusts (D-01, D-02B, PD-1, MA-4 and JU-1). All tested inert dusts affected reduction in bulk density of treated wheat at the LD90 concentrations, from 4.4 (D-02B) to 5.6 (JU-1) kg hL-1. More effective inert dusts at lower doses equally reduced bulk density as less effective inert dusts at much higher doses.

Biological Traits of Cadra cautella (Lepidoptera: Pyralidae) Reared on Khodari Date Fruits Under Different Temperature Regimes.

The almond moth, Cadra cautella (Walker) (Lepidoptera: Pyralidae), is a serious worldwide pest of dates and other crops, both in the field and in storage. Infestation by this pest significantly limits the sale and export of dates. Modified atmospheres, the temperature manipulations, are the best eco-friendly alternatives in stored product protection. We examined temperature regulation as an ecologically friendly method of pest management in stored food commodities, in particular, its effects on characteristics of C. cautella biology, including development time, oviposition period, fecundity, fertility, and longevity of adults reared on date cultivar 'Khodari,' at temperatures of 15, 25, and 35 ± 1 °C, with 65 ± 5% relative humidity and a photoperiod of 15:9 (L:D) h. Six larval instars were recorded at each temperature. Larval development was sluggish at 15 °C; therefore, daily observations were terminated after 180 d of the larval span for this temperature. Total larval spans of 48.95 ± 0.76 and 32.12 ± 1.08 d were recorded at 25 °C and 35 °C, respectively. A mean ovipositional period of 5.80 ± 0.44 d yielding 213.60 ± 13.41 eggs per female, with hatchability of 85.94 ± 2.97%, was recorded at 25 °C, whereas at 35 °C, a mean ovipositional period of 1.60 ± 0.26 d yielded 19.80 ± 5.11 eggs per female, with no hatchability. These differences were highly significant. Our observations of poor development at 15 °C, lower numbers of eggs and absence of hatchability at 35 °C, together with head capsule measurements and growth ratios, can be of benefit when planning management strategies to reduce C. cautella infestation.

Toxicity and repellency of dimethoate, pirimiphos-methyl and deltamethrin against Tribolium castaneum (Herbst) using different exposure methods

Tribolium castaneum, the red flour beetle, is one of the major pests of cereal grains and their products. Infestation of raw food products by T. castaneum can be tackled by use of insecticides which offer a rapid and effective control method for different insect pests. In the present study, toxicity and repellency of three widely used insecticides was assessed on adult red flour beetles to investigate how a flour substrate affects the results of the standard laboratory toxicity and repellency test methods. The red flour beetles were exposed to the organophosphates dimethoate and pirimiphos-methyl and the pyrethroid deltamethrin, following the original and two modified residual film methods (toxicity assessment) and by the area preference method to assess repellency. Since the conditions of exposure (glass and filter paper surfaces as exposure substrates) in the original methods are quite different compared to the exposure carried out in stored-product protection, methods were modified to include flour as an exposure substrate. The results showed that according to the LC50 values, toxicity of the investigated insecticides could be arranged in the following order: pirimiphos-methyl > dimethoate > deltamethrin. Also, both mortality and repellency were dependent on the exposure methods, i.e. presence and treatment of flour substrate. Mortality was significantly reduced in comparison to the original method. Repellency was recorded when beetles were exposed to deltamethrin using flour as a substrate, whereas using the filter paper surface (original method) repellency was not obtained. The results of the present study clearly indicate that there is an influence of substrate on the susceptibility of T. castaneum to insecticides and that the efficacy of different insecticides is affected by exposure substrate.