Efficacy of Modified Atmospheres on Trogoderma granarium (Coleoptera: Dermestidae) and Sitophilus zeamais (Coleoptera: Curculionidae)

We investigated the efficacy of two types of modified atmospheres (MA) against adults of the khapra beetle, Trogoderma granarium Everts, and the maize weevil, Sitophilus zeamais Motschulsky, under laboratory conditions. Adults of the above species on wheat were exposed to a carbon dioxide (CO2) concentration of 70% or a low oxygen (O2) concentration of 0.1% for durations of 0.67 (16 h), 1, 2, 4, and 6 d and stored in an environmental chamber set at 28 ± 2°C, 70 ± 5% RH, and a photoperiod of 16:8 (L:D) h. After each exposure interval, immediate mortality and knockdown were recorded, and the surviving or knocked down individuals were transferred to normal atmospheres and returned to the environmental chamber, where survival was recorded 7 d later. In addition, after the immediate and delayed mortality counts, all adults were removed from the substrate, and the number of progeny produced was recorded 60 d later. Both MA conditions totally controlled (100% mortality) the adults of T. granarium and S. zeamais immediately after a 6-d exposure or after a 4-d exposure when delayed mortality was taken into account, showing the postexposure effect of the MA. Moreover, high CO2 was more effective than low O2 for S. zeamais, whereas the reverse was true for T. granarium. The 4-d exposure period was crucial for the production of progeny of both species because after that period surviving insects did not produce offspring. Our results show that both MA conditions can be used with success to control these species.info:eu-repo/semantics/acceptedVersio

Factors affecting field performance of pheromone traps for tobacco beetle, Lasioderma serricorne and tobacco moth, Ephestia elutella

Tobacco beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), is one of the most serious insect pests of stored tobacco and traps baited with the female-produced sex pheromone, serricornin, are used for monitoring the pest. In two trapping experiments carried out in tobacco warehouses in Greece, two commercially-available trap and lure systems for L. serricorne were found to be equally effective in terms of numbers of beetles trapped. In contrast to previous reports, anhydroserricornin was unattractive and lures containing serricornin and anhydroserricornin were less attractive than lures containing serricornin only. The sex pheromone of the other main insect pest of tobacco, Ephestia elutella (Hübner) (Lepidoptera: Pyralidae), could be added to the lures without affecting the attractiveness of either pheromones to their respective species. Lures remained attractive for at least four weeks under field conditions, and, in laboratory tests, release of pheromone could still be detected after 30 days at 27°C. The stereoisomeric composition of the serricornin in the two commercial lures was similar with high proportions of the attractive (4S,6S,7S)-isomer. The proportion of the (4S,6S,7R)-isomer was low and this is known to reduce the attractiveness

Comparison of spinetoram, imidacloprid, thiamethoxam and chlorantraniliprole against life stages of Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on concrete

Spinetoram, imidacloprid, thiamethoxam and chlorantraniliprole are new insecticides with novel mode of actions, low mammalian toxicity and low impact to environment. In the present study, the efficacy of these insecticides was tested against Tribolium confusum Jacquelin du Val on concrete. Among the tested insecticides, spinetoram proved to be more effective, providing complete control of T. confusum adults and young larvae after 14 days of exposure. For the young larvae, thiamethoxam at the highest dose and chlorantraniliprole at both doses were equally effective with spinetoram. On the other hand, none of the tested insecticides were able to control T. confisum pupae. Moreover, none of the insecticides had ovicidal effect, with the exception of chlorantraniliprole in some combinations. From the mobile life stages, the most tolerant life stages were old larvae and the most susceptible young larvae. The presence of food (flour) moderated T. confusum mortality. From the results of the present study, we can conclude that spinetoram, thiamethoxam and chlorantraniliprole showed potential and need be further evaluated for surface treatments in stored product facilities. Our work underlined the need for good cleaning and sanitation procedures in warehouses and food processing facilities. (C) 2013 Elsevier Ltd. All rights reserved.Research Committee, University of Thessaly [4133]This study was partially supported by the project number 4133 Research Committee, University of Thessaly. Trade names or commercial products mentioned in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the University of Thessaly

Influence of grain type on the efficacy of spinetoram for the control of Rhyzopertha dominica, Sitophilus granarius and Sitophilus oryzae

The efficacy of spinetoram against adults of three major stored grain beetle species, the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae) and the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) in seven grain commodities was evaluated under laboratory conditions. Spinetoram residues in each grain were quantified using high-performance liquid chromatography (HPLC) with UV detection. The tested grains were hard wheat, soft wheat, oats, rye, triticale, paddy rice and maize. Spinetoram was applied at three dose rates: 0.1, 1 and 10 ppm (mg of active ingredient per kg of grain) and bioassays were carried out at 25 °C and 60% r.h. Mortality of the exposed adults was assessed after 7 and 14 d of exposure while progeny emergence was recorded 65 d after the last exposure interval (14 d). Among the tested species, R. dominica was highly susceptible to spinetoram for all commodities tested, since 100% mortality was noted after 14 d of exposure at 1 and 10 ppm. From the two Sitophilus species, S. granarius was more susceptible to spinetoram than S. oryzae, while for both species 0.1 ppm was not effective. For these two species, spinetoram efficacy differed among the tested commodities. In general, mortality was higher in hard wheat for both Sitophilus species in comparison with the other grains, while the lowest mortality levels were recorded in oats and soft wheat for S. granarius and in maize and soft wheat for S. oryzae. Progeny production was low in the case of R. dominica, and F1 adult emergence was recorded mostly at 0.1 ppm. For both S. granarius and S. oryzae, the highest progeny production was noted in soft wheat. Spinetoram residue determination in each grain at the dose rate of 10 ppm, did not show any differences among the treated commodities. © 2015 Elsevier Ltd

Effect of Nitrogen on Stored-Product Insect Control at Industrial Scale

In this study, we evaluated the insecticidal effect of nitrogen against Sitophilus granarius (L.), Sitophilus oryzae (L.), Rhyzopertha dominica (F.), Prostephanus truncatus (Horn), Tribolium confusum Jacquelin du Val, and Oryzaephilus surinamensis (L.). Four trials were conducted in chambers containing flour in bags or sacks with >99% nitrogen level. Adults of all the above species, as well as immature life stages (eggs, larvae, and pupae) of T. confusum were used in the trials. Our results showed that nitrogen caused high mortality for all species and life stages tested. Some survival was recorded for R. dominica and T. confusum pupae. Low progeny production was recorded for S. granarius, S. oryzae, and R. dominica. In conclusion, our trials indicated that a high nitrogen environment can provide satisfactory control of various primary and secondary stored-product insect species

Using a Lethality Index to Assess Susceptibility of <i>Tribolium confusum</i> and <i>Oryzaephilus surinamensis</i> to Insecticides

<div><p>We evaluated knockdown caused by four insecticides: alpha-cypermethrin, chlorfenapyr, pirimiphos-methyl and fipronil against adults of <i>Tribolium confusum</i> Jacquelin Duval, the confused flour beetle and <i>Oryzaephilus surinamensis</i> (L.), the sawtoothed grain beetle. Bioassays were conducted on concrete and metal surfaces. Adults of the tested species were exposed on both surfaces treated with the above insecticides at two doses (low and high). Knockdown assessment was done after 15, 30 and 60 min of adult exposure in the treated surfaces. Also, after 1, 3, 5, 7 and 14 d of exposure, a lethality index was calculated with an equation resulting to values from 0 to 100, where 100 indicated complete mortality and 0 complete survival. We also developed a lethality index by ranking each adult on each surface from 0 to 4, 0: adults moved normally, 1: adults were knocked down, but were able to walk for short intervals, 2: adults were knocked down and unable to walk, but with visible movement of antennae etc., 3: adults were knocked down, with very minimal movement of the tarsi and the antennae and 4: adults were dead (no movement). Knockdown of adults immediately after exposure (15–60 min) was higher for pirimiphos-methyl followed by alpha-cypermethrin, for both dose rates tested and species, but only on the metal surface. The lethality index was nearly 100 for all insecticides after 5d of exposure for <i>O</i>. <i>surinamensis</i>, while for <i>T</i>. <i>confusum</i> the adult lethality index was considerably lower for alpha-cypermethrin, suggesting that that recovery from knockdown occurred. Chlorfenapyr was the only insecticide that was more effective on concrete than on metal, while the reverse was noted for the other three insecticides. These results show that knockdown has different levels, which can be used as indicators of insect mortality or recovery.</p></div

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Mean Knockdown of <i>T</i>. <i>confusum</i> adults on metal surfaces at low and high dose.

<p>Mean Knockdown (% ± SE) of <i>T</i>. <i>confusum</i> adults on metal treated with chlorfenapyr (chl), alpha-cypermethrin (cyp), fipronil (fip) and pirimiphos-methyl (pir), at the low and the high dose rate of each insecticide after 15 min, 30 min and 1 h exposure intervals.</p