Efficacy of high temperatures against stored product insects

Vorratsschädliche Insekten sind Spezialisten, die in der Lage sind, trockene pflanzliche Materialien aufzuspüren, zu besiedeln und damit über die Befeuchtung durch Respiration dem Abbau durch weitere Organismen (Pilze, Milben, Bakterien) zuzuführen. Auf diese Weise sind sie die Auslöser eines Kompostierungsprozesses. Durch ihr hervorragendes Orientierungsvermögen entlang eines Duftstoffgradienten finden sie sich regelmäßig in Vorratslagern und Gebäuden der Lebens- und Futtermittelverarbeitung ein, falls sie nicht bereits mit befallenen Produkten passiv eingeschleppt wurden. In der Praxis der Schädlingsbekämpfung in Deutschland werden zunehmend auch Verfahren der Hitzeentwesung in Gebäuden angeboten, die der Begasung mit giftigen Gasen Konkurrenz machen und auch in Betrieben des Ökolandbaus eingesetzt werden können. Einen Überblick über den Einsatz extremer Temperaturen im Vorratsschutz vermitteln die Arbeiten von Fields (1992), Burks et al. (2000) und Adler & Rassmann (2000). Laborversuche unter definierten Temperaturen hatten zum Ziel, die Widerstandsfähigkeit bestimmter Arten und ihrer Entwicklungsstadien zu überprüfen. Darüber hinaus wird kurz über Erfahrungen in der Praxis berichtet.Storage structures and buildings for food processing such as flour mills or bakeries can be disinfested by heat. This is done in Germany either by the use of ex-proof electric heaters or fossil-fuel burners, in which case heated air is fan-forced from outside into the structure through flexible ducts. Data presented here are from laboratory studies and practical heat treatments from 2001-2006 and summarize the relative sensitivity of immature and adult Mediterranean flour moths Ephestia kuehniella (Lepidoptera, Pyralidae), tobacco beetles Lasioderma serricorne (Coleoptera, Anobiidae), lesser grain borers Rhizopertha dominica (Col., Bostrychidae), granary weevils Sitophilus granarius and maize weevils S. zeamais (Col., Curculionidae), flat grain beetles Cryptolestes pusillus (Col., Cucujidae) and rustred flour beetles Tribolium castaneum (Col., Tenebrionidae). While the moth larvae proved rather sensitive towards high temperatures, the larvae and pupal stages of lesser grain borer and tobacco beetle where quite tolerant with 370 min required in lab studies for complete control at 50°C for both species. At 55°C complete control was achieved in up to 45 min. Experiences from practical treatments showed that it is difficult to achieve uniform temperatures at all locations in a large flour mill. In a number of cases, lethal temperatures could not be reached close to the outside walls in areas with faulty insulation, in narrow corners in the cellar or roof construction, and in insulating materials such as bag stacks of flour, packaging material, tightly packed electric cables, larger amounts of grain, malt, dust or garbage. All materials should be removed prior to treatment and difficult zones should be intensely heated, treated with diatomaceous earth or other contact insecticides in order to secure a complete disinfestation

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

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!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

Physical control of stored product insects

Given the declining number of chemical agents for pest control, non-chemical methods gain importance in stored product Integrated Pest Management. Physical methods play an important role not only in pest control, but also in pest prevention (e.g. product cooling, drying, insect-proof storage and packaging) and pest monitoring (e.g. measurement of temperature, product density, movement or bioacoustics). In pest control, heat disinfestation has become an established method for empty structures. A difficulty is that insulators such as large amounts of flour, dust or bag stacks with products need to be removed prior to treatment. Freezing at temperatures of minus 18°C is a method to disinfest high-value products without the risk of deteriorating product quality. However, energy costs may be the limiting factor. For fine and powdery goods such as flour, sieving and milling is the only choice because just mechanical methods can lead to effective pest control in this substrate. In future, processing steps leading to  pest control (e.g. heating, milling, extrusion) should be combined with pest exclusion, ventilation and temperature management in order to keep product quality high and pest control efforts at a minimum. Keywords: control, heat, cold, impact, sievin

Comparative lethality of rice husk ash and a diatomaceous eartht adults of four storage beetles: Poster

Lethality of rice husk ash (RHA) and a diatomaceous earth (SilicoSec) (DE) to adults of Sitophilus zeamais, S. granarius, Lasioderma serricorne and Callosobruchus maculatus was investigated under controlled conditions of 25 ± 2° C and 60 ± 3% relative humidity. Each product was tested at 0.05 g to 0.5 g/20 g of grain respectively in glass Petri dishes against 20 adults of each beetle. Adult mortality was observed up to 10 days post treatment. RHA/DE mixtures (1:1, 3:1 and 1:3 ratios) were also tested at 2% of grain weight. Additionally, RHA and DE were tested at low dosages (0.01 g to 0.04 g/20 g) against adults of C. maculatus alone. The DE generally produced significantly higher mortality of all the adult storage beetles and at earlier observation times, than RHA at the lower dosages (< 0.2 g). Adult mortality produced by RHA and DE in S. zeamais and S. granarius increased with increase in dosage from 0.05 g to 0.5 g. The RHA/DE mixtures generally produced similar mortality of all the adult storage beetles irrespective of post-treatment exposure time. The S. zeamais and S. granarius were generally more tolerant to the DE and RHA treatments than L. serricorne and C. maculatus. Percentage mortality of C. maculatus adults when DE was applied at low dosages (0.01 g to 0.04 g) was generally higher than RHA applied at similar dosages, up to 3 days-post treatment. All treatments produced 100% mortality of C. maculatus adults 4 days-post treatment. The data further confirm the efficacy of DE and RHA as insecticidal dusts at the dosage rate of 0.5 g or more per kg of grain.Lethality of rice husk ash (RHA) and a diatomaceous earth (SilicoSec) (DE) to adults of Sitophilus zeamais, S. granarius, Lasioderma serricorne and Callosobruchus maculatus was investigated under controlled conditions of 25 ± 2° C and 60 ± 3% relative humidity. Each product was tested at 0.05 g to 0.5 g/20 g of grain respectively in glass Petri dishes against 20 adults of each beetle. Adult mortality was observed up to 10 days post treatment. RHA/DE mixtures (1:1, 3:1 and 1:3 ratios) were also tested at 2% of grain weight. Additionally, RHA and DE were tested at low dosages (0.01 g to 0.04 g/20 g) against adults of C. maculatus alone. The DE generally produced significantly higher mortality of all the adult storage beetles and at earlier observation times, than RHA at the lower dosages (< 0.2 g). Adult mortality produced by RHA and DE in S. zeamais and S. granarius increased with increase in dosage from 0.05 g to 0.5 g. The RHA/DE mixtures generally produced similar mortality of all the adult storage beetles irrespective of post-treatment exposure time. The S. zeamais and S. granarius were generally more tolerant to the DE and RHA treatments than L. serricorne and C. maculatus. Percentage mortality of C. maculatus adults when DE was applied at low dosages (0.01 g to 0.04 g) was generally higher than RHA applied at similar dosages, up to 3 days-post treatment. All treatments produced 100% mortality of C. maculatus adults 4 days-post treatment. The data further confirm the efficacy of DE and RHA as insecticidal dusts at the dosage rate of 0.5 g or more per kg of grain

Vorräte richtig lagern und schützen

Beitrag zum Themenschwerpunkt III Spezielle Gartenschädling

Biological control in stored product protection: what to consider around the protection of stored food stuffs

Seit über zehn Jahren werden in Deutschland biologische Gegenspieler kommerziell zum Einsatz in Lagerungs- und Verarbeitungsbetrieben pflanzlicher Vorräte ange­boten. Dabei hat sich das Angebot verschiedener Parasitoidenarten stetig vergrößert. Im Vergleich zum Feld ist das Vorratslager aber ein künstliches Habitat, das bei geeigneten Bedingungen schnell die Massenvermehrung von Vorratsschädlingen ermöglicht. Werden die geeigneten Nützlinge schon bei geringer Schädlingsdichte frei­gelassen, ermöglicht die biologische Bekämpfung eine Unterdrückung der Entwicklung einer Schädlingspopulation. Eine Kontamination der Lebensmittel durch Rückstände der Gegenspieler kann verhindert werden, so lange vor der weiteren Verarbeitung ein Reinigungsschritt erfolgt oder wenn die Parasitierung außerhalb des Vorratsgutes stattfindet.For more than ten years biological control agents for stored product protection in storage rooms and food processing industry have been commercially available in Germany. In this time the number of offered parasitoids increased gradually. Compared to biological control in the field, a storage room is an artificial habitat that may allow rapid population increase of pests in case of suitable conditions. Provided that suitable beneficials are released at a low host density, a suppression of a pest population can be achieved. A contamination of food stuffs with residues of beneficials can be avoided as long as a cleaning step is possible prior to further food processing or if parasitization takes place outside of the stored product

Session on stored product protection in the frame of the Conference for Plant Protection in Berlin Introduction: Farewell of the director of the institute Prof. Dr. Christoph Reichmuth

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