Simulated Warehouse Research Articles

EVALUATION OF GORE-TEX® LAMINATE ENVELOPES1,2 TO PROTECT WOOLENS AGAINST INSECTS

Gore-Tex® membrane, made of expanded polytetrafluoroethylene, laminated to a non-woven polyester fabric and made into envelopes with a zip lock closure, has been used for shipment and storage of archeological finds, feathers, furs, leather, textiles and museum specimens. Laboratory and simulated warehouse studies showed that these envelopes also have the potential for protecting woolens against larvae of the black carpet beetle, Attagenus unicolor (Brahm), the furniture carpet beetle, Anthrenus flauipes LeConte, and the webbing clothes moth, Tineola bisselliella (Hummel).

Quality Changes of Vine‐Ripened Tomatoes within the Postharvest Handling System

ABSTRACTQuality characteristics of fresh‐market tomatoes were monitored throughout the postharvest handling system to determine the nature and extent of color and firmness changes at component handling steps. Greatest changes in hue and chroma were observed during simulated warehouse ripening and storate (12.5°C). Greatest changes in color value (lightness) and firmness were noted during simulated retail ripening and storage (21°C). Tomatoes harvested at carlier stages of maturity tended to maintain firmness longer and remained lighter as the hue changed from pink to red than those harvested at later stages. Shipping of tomatoes at the ‘pink’ stage or beyond requires modification of handling techniques to slow ripening starting at the packing house.

Suppression of the Rice Weevil, Sitophilus oryzae (Coleoptera: Curculionidae), Inside and Outside of Burlap, Woven Polypropylene, and Cotton Bags by the Parasitic Wasp, Anisopteromalus calandrae (Hymenoptera: Pteromalidae)

In simulated warehouse rooms, single release of 50 pairs of the parasitic wasp, Anisopteromalus calandrae (Howard), in 8,250 g of scattered wheat infested with ca. 1,500 rice weevils, Sitophilus oryzae (L.), resulted in 76.1% suppression. Small bags of cotton, burlap, and woven polypropylene containing 275 g of infested wheat retarded the ingress of A. calandrae , because none of the cotton bags and only 30.0 and 47.0% of the burlap and polypropylene bags, respectively, contained parasitized weevils. Overall, 12.9 and 18.7% of the S. oryzae populations were suppressed in burlap bags and polypropylene bags, respectively. However, when only bags containing parasitized weevils were considered, suppression averaged ca. 55% in the burlap and 49% in the polypropylene. A. calandrae significantly reduced the number of S. oryzae emerging from scattered infested wheat, thus protecting uninfested wheat inside cotton, burlap, and polypropylene bags placed adjacent to the infested wheat.

Evaluation of Permethrin as an Insect-Resistant Treatment on Paper Bags and of Tricalcium Phosphate as a Suppressant of Stored-Product Insects1

Long-term warehouse tests in Egypt and simulated warehouse tests in the United States were conducted to determine the insect resistance of permethrin-treated, pyrethrins-treated, and untreated, multiwall paper bags. The bags contained a high-protein, blended cereal (ICSM) fortified with either tricalcium phosphate (TCP), an insect suppressant, or a combination of calcium phosphate and calcium carbonate (Ca). During 12 months of storage in Egypt, fewer permethrin-treated bags were infested (10.2–16.0%) than pyrethrins-treated bags (22.4–41.7%) or untreated bags (41.4–48.7%). Similar results were obtained in simulated warehouse tests. TCP was less effective than the treated bags and decreased the quantity of ICSM containing excessive populations (> 1,000 insects per bag) by ca. 7.72% compared with ICSM with Ca. A grease-proof paper barrier prevented movement of permethrin into the ICSM in bags stored for 28 months. During 1 year of storage, permethrin at up to 0.72 ppm was found in the ICSM in bags without a barrier ply. During 1 year of storage, there was little loss of permethrin from the outer treated ply of empty bags with or without a grease-proof barrier ply.

Mating Competitiveness of Irradiation-Substerilized Males of the Tobacco Moth1

Males of Ephestia elutella (Hubner), substerilized with 15 krad of gamma irradiation, were released at ratios of 4:1 and 9:1 to untreated males into a simulated empty warehouse. The mating competitiveness of irradiated males was 91 to 93% as good as that of the untreated males, and the percentage of hatched eggs was reduced accordingly. In trials where irradiated males and untreated males were released, the majority (55.8 to 73.5%) of the F1 progeny was offspring of the irradiated males and inherited sufficient genetic damage to be sterile when intermated. These results suggest that populations of the tobacco moth within tobacco storages might be greatly reduced or eliminated by the release of a high ratio of substerilized males.

Population Suppression of Trogoderma glabrum by Using Pheromone Luring for Protozoan Pathogen Dissemination12

Subsequent generations of Trogoderma glabrum (Herbst) were substantially suppressed after a single introduction of protozoan pathogen spores, Mattesia trogodermae Canning, into dense, adult male populations via pheromone-baited, spore-transfer sites. When using simulated warehouse conditions and an experimental design for optimizitig pathogen dispersal, dense (32 F adults/m2), treated populations increased only 4-fold in the 1st posttreament generation (vs. a 24-fold increase in controls) and fell to below pretreatment levels by the 2nd generation (vs. a total 100-fold increase in controls). In low density tests (2 F adults/m2), treated populations and controls increased 12-fold during the 1st generation. A 48-h exposure of pheromone-spore-transfer sites was sufficient to distribute effective spore doses within a radius of 1.25 m around sites in the dense population tests. Spore transfer from sites to subsequent T. glabrum generations was mainly by larval ingestion of either dead, contaminated adults, or larval food which adults had contaminated by contact. Treatment of spore-transfer sites with synthetic sex pheromone, ( E )-14-methyl-8-hexadecenal, attracted males and also induced attempted copulation with the pheromone source, aiding in spore transfer to males.

Effectiveness of Green and Ultraviolet Light in Attracting Stored-Product Insects to Traps

Tests were conducted under simulated warehouse conditions to compare the effectiveness of green and ultra-violet (UV) light alone and in combination for attracting stored-product insects to traps. No significant increases occurred in the number of insects captured with the UV light when compared with the combined green and UV light. The almond moth, Cadra cautella (Walker), and the Indian-meal moth, Plodia interpunctella (Hübner), preferred the independently operating green light. However, significantly less cigarette beetles, Lasioderma serricorne (F.); flat grain beetles, Cryptolestes pusillus (Schönherr); and lesser grain borers, Rhyzopertha dominica (F.), were attracted to the independently operating green light.

Insecticide Residue in Foods Subjected to Aerosols Under Simulated Warehouse Conditions1

Nine different kinds of foods packaged in various standard military domestic and oversea containers were exposed to thermal aerosols of a DDT-lindane formulation every 28 days for 2 years. Foods in packages on which DDT and lindane were deposited by regular aerosol applications were analyzed after 27, 83, 251, 587, and 617 days. Flour packaged in cotton bags contained 0.8 and 2.3 ppm of lindane and DDT, respectively, after exposure to deposits from I application. The amount of DDT and lindane in beans, coffee, and flour packaged in jute or cotton bags increased with the number of applications. All foods except sugar, which sorbed neither insecticide, contained DDT and lindane after exposure to deposits from 9 applications.