Wheat, corn, and brown rice were treated with different combinations of a deltamethrin suspension concentrate (SC) formulation and a new emulsifiable concentrate (EC) formulation, at rates of either ...0.5 or 1.0 ppm alone or in combination with 1.25 and 2.5 ppm methoprene (10 treatments in all, including an untreated control). Treated commodities were stored at ambient conditions on the floor of an empty grain bin in Manhattan, KS, USA, in 5-kg lots for individual replicates. The commodities were sampled and bio-assayed every three months for 15 months by exposing 10 mixed-sex parental adults of selected adult stored product insects on 70⁻80 g of the commodity. For all treatments, there was no regression of declining efficacy with respect to the month. Therefore, the data were combined for analysis. On wheat and brown rice, there was no reproduction of
(Fabricius) in any of the treatments, and there was no weight loss in either commodity that was caused by feeding of the parental adults or developing progeny. There was reproduction of
(L.) on wheat but, for several combinations, the EC formulation gave better suppression of progeny compared to the standard SC. However, on brown rice, only the combination of 1.0 ppm deltamethrin EC and 2.5 ppm methoprene was different than other treatments with respect to progeny development, sample weight loss caused by feeding, and weight of the feeding damage itself. Progeny production was correlated with grain damage. No progeny of
(Herbst) developed on the treated corn, but there was some variation in insect damage, with less damage in those treatments involving the EC formulation. Progeny production of
(Motschulsky) was at the lowest in the combination of 1.0 ppm deltamethrin EC and 2.5 ppm methoprene. The resulting insect damage was the lowest in this combination as well. Results of this study were used by the registrant (Central Life Sciences) in the United States (US) to modify the commercial formulation to replace the deltamethrin SC with the EC, at label rates of either 0.5 ppm EC+ 1.25 ppm methoprene, or 1.0 ppm EC + 2.5 ppm methoprene, on wheat, corn, and rice.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We evaluated the knockdown effect caused by four insecticides: alpha-cypermethrin, chlorfenapyr, pirimiphos-methyl and fipronil against Tribolium confusum and Oryzaephilus surinamensis adults. ...Furthermore, for the same species and insecticides, we developed a âlethality indexâ, to assess knockdown patterns. For this purpose, 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 on the treated surfaces. Also, after 1, 3, 5, 7 and 14 d of exposure, a lethality index was calculated with an equation resulting in values from 0 to 100, where 100 indicated complete mortality and 0 complete survival. For the lethality index calculation, each adult exposed on the surface was ranked from 0 to 4, based on a scale as follows; 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 high and near 100 for all insecticides after 5d of exposure for O. surinamensis, while for T. confusum adults the lethality index was consistently low for alpha-cypermethrin, suggesting that that recovery occurred. Among the insecticides examined here, chlorfenapyr was the only one that was more effective on concrete than on metal, while the reverse was noted for the other three insecticides.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(Fab.), the lesser grain borer, and
(Olivier), the Angoumois grain moth, are internally feeding stored product insects that can infest raw grains. In this test, brown rice was treated with 0.5 and ...1.0 ppm of a new emulsifiable concentrate (EC) formulation of the pyrethroid deltamethrin and stored for 12 months. One day after treatment, and every 3 months for 12 months, treated rice was mixed with untreated brown rice in the following ratios: 0:100 (untreated controls), 10:90, 25:75, 50:50, 75:25, and 100:0 (all treated). Bioassays were conducted by exposing 10 parental adults of each species on the rice mixtures and assessing progeny production, feeding damage, and weight loss. The progeny of
ranged from 105.6 F₁ adults on untreated brown rice to 69.4 F₁ adults on 100% treated rice, but there was little feeding damage or weight loss. The progeny production of
declined from 177.4 F₁ adults on untreated rice to 9.8 F₁ adults on 100% treated rice. Weight loss and feeding damage were correlated with progeny production. The results show that the new deltamethrin formulation could be used for protection of brown rice, but
may be less susceptible to deltamethrin compared to
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The fumigant methyl bromide (MB) is being phased out of production and usage to control stored-product insects in flour and rice mills, as well as feed and food production plants, in the United ...States and other developed countries throughout the world. A phase-out schedule has also been established for undeveloped counties under a delayed timeline compared to the one established for developed countries. Whole-plant alternatives to MB treatment, such as the fumigant sulfuryl fluoride and heat, can be used in place of MB, but they have some limitations as well, which will be briefly discussed in this review. Hence, residual surface treatments with contact insecticides and insect growth regulators and aerosol applications are receiving increased attention for incorporation into management programs that historically relied on MB fumigations. This review will focus on recent research with contact insecticides and aerosols for controlling stored-product insects in structures and how they can be viewed as options for control to alleviate concerns regarding the phase-out and reduced availability of MB for structural fumigations. A brief discussion of emerging pest species or groups, and how they can be controlled with surface treatments and aerosols, is also included in the review.
We tested the effect of simultaneous infestation by adults of the lesser grain borer,
Rhyzopertha dominica
(F.) and the rice weevil,
Sitophilus oryzae
(L.) on six sorghum varieties. For this purpose, ...vials containing sorghum and either each species alone or both species were placed at 30 °C and 65% relative humidity. After ten days, all parental adults were removed and the vials were returned to the same conditions. Five weeks later the vials were emptied, to record adult emergence, the percentage of insect damaged kernels (IDK), and frass weight. Our results indicated that progeny production capacity for both species was not affected by the simultaneous presence of
R. dominica
and
S. oryzae
, and that adult emergence was more of a variety- mediated parameter. Both species had previously shown similar preferences towards specific sorghum varieties. IDK and frass were higher in vials containing
R. dominica
alone rather than
S. oryzae
alone, but these indicators were not always related to progeny production. Specifically, the most and the least frass production was noted on Sumac and PE sorghum varieties for both species, respectively. When the two species were placed together in the same vial, the most frass production was noted in the Non-Waxy Burgundy and Sumac varieties. Our results suggest that varietal resistance in sorghum could be utilized to help reduce post-harvest infestations by
S. oryzae
and
R. dominica
.
Knockdown and mortality of adults of the red flour beetle, Tribolium castaneum (Herbst) and the confused flour beetle, Tribolium confusum Jacquelin du Val, were assessed after exposure to two contact ...insecticides, chlorfenapyr and cyfluthrin, on a concrete surface. Individuals were rated on a scale for knockdown of exposed adults according to their mobility from 1, representing immobilized adults to 5, representing normally moving (similar to the controls). Only cyfluthrin gave immediate knockdown. Adults were rated at 1, 3 and 7 days post-exposure. After the final assessment, adults were discarded and the same procedure was repeated for 5 consecutive weeks with new adults exposed on the same treated surfaces. Despite initial knockdown, many individuals did not eventually die after exposure to cyfluthrin. In contrast, adults exposed to chlorfenapyr were not initially knocked down after exposure but most died after 7 days. These trends were similar during the entire 5-week residual testing period. The storage of the treated dishes in illuminated or non-illuminated conditions did not affect the insecticidal effect of either insecticide. The results of the present study can be further implemented towards the design of a "lethality index" that can serve as a quick indicator of knockdown and mortality rates caused after exposure to insecticides.
The red flour beetle,
Tribolium castaneum
(Herbst), and the confused flour beetle,
Tribolium confusum
Jacquelin du Val, are capable of exploiting any rip, tear, or defect in packaged food and infest ...the contents. Incorporating packaging materials with insecticides is a novel technological approach that is gaining interest as a preventative measure to deter packaging infestations. The objective of this experiment was to determine the effect of deltamethrin-incorporated packaging on
T. castaneum
and
T. confusum
adult fecundity. Treatment arenas consisted of deltamethrin-incorporated packaging secured to ~ 62 cm
2
plastic Petri dishes. Ten male or female adults of either species were exposed on treated or untreated packaging for time intervals ranging from 0.67 to 168 h. Males and females were then cross-mated: One exposed male paired with one exposed female; exposed male with unexposed female; unexposed male with exposed female; and unexposed male with unexposed female. Pairs were held in a 7-dram vial for 7 days, removed, and vials held for emergence of
F
1
adults. There were no progeny when mating pairs of
T. castaneum
male were exposed for ≥ 48 h, while 168 h of exposure was necessary to prevent progeny production of
T. confusum
mated pairs.
T. castaneum
was more susceptible compared to
T. confusum
. This study showed adult beetles are capable of recovering from knockdown and produce progeny, but long-term exposure to treated material inhibited the
F
1
generation. Integrating deltamethrin-incorporated packaging material into an existing integrated pest management program could provide additional protection of packaged food products.
A recent study showed the potential of the DA Perten 7200 NIR Spectrometer in detecting chlorpyrifos-methyl pesticide residue in rough, brown, and milled rice. However, this instrument is still ...lab-based and generally suited for point-of-sale testing. To provide a field-deployable version of this technique, an existing light emitting diode (LED)-based instrument that provides discrete NIR wavelength illumination and reflectance spectra over the range of 850–1550 nm was tested. Spectra were collected from rough, brown, and milled rice at different pesticide concentrations and analyzed for quantitative and qualitative measurement using partial least squares regression (PLS) and discriminant analysis (DA). Simulations for two LED-based instruments were also evaluated using corresponding segments of spectra from the DA7200 to represent LED illumination. For the simulation of the existing LED-based instrument (LEDPrototype1) fitted with 850, 910, 940, 970, 1070, 1200, 1300, 1450, and 1550 nm LED wavelengths, resulting R2 ranged from 0.52 to 0.71, and the correct classification was 70.4% to 100%. The simulation of a second LED instrument (LEDPrototype2) fitted with 980, 1050, 1200, 1300, 1450, 1550, 1600, and 1650 nm LED wavelengths showed R2 of 0.59 to 0.82 and correct classifications of 66% to 100%. These LED wavelengths were selected based on the significant wavelength regions from the PLS regression coefficients of DA7200 and the commercial availability of LED wavelengths. Results showed that it is possible to use a multi-spectral LED-based instrument to detect varying levels of chlorpyrifos-methyl pesticide residue in rough, brown, and milled rice.
BACKGROUND
There has been a push to diversify integrated pest management (IPM) programs away from exclusive fumigant use in food facilities. Residual insecticides increasingly have been included ...among plans. In stored products, sublethal toxicity has been neglected in favor of evaluating direct mortality. Here, we evaluated the movement of Tribolium castaneum, Rhyzopertha dominica, Sitophilus oryzae and Sitophilus zeamais in response to aged residues of an existing (Diacon IGR+® with 11.4% methoprene + 4.75% deltamethrin) and novel (Gravista® with 2.85% methoprene + 1.2% deltamethrin + 33.3% piperonyl butoxide synergist) residual insecticide.
RESULTS
Using the maximum labeled rate and two exposure times for each species, we assessed distance moved and velocity on wheat, rice and corn. Assessments were made from commodity residues aged between 0 and 12 months (at 3‐month intervals). We found that after exposure, movement was reduced by 50–88% and equally by adults exposed to each insecticide formulation compared to untreated controls. After initial application, predicted distance moved increased from 4 to 14 m then 28 m in a 24 h period at 3 and 12 months post‐application, respectively. Effectiveness of each insecticide at suppressing movement generally declined by 9–12 month post‐application.
CONCLUSIONS
Given the quick and dramatic increases in sublethal movement after initial application, our results suggest that sanitation programs in post‐harvest environments are extremely important and it may be beneficial to pair chemical control with monitoring to prevent dispersal of affected insects to new areas of a facility. Published 2020. This article is a U.S. Government work and is in the public domain in the USA
In this study, we evaluated the movement of Tribolium castaneum, Rhyzopertha dominica, Sitophilus oryzae and Sitophilus zeamais in response to aged residues of an existing (Diacon IGR+ with 11.4% methoprene +4.75% deltamethrin) and novel (Gravista® with 2.85% methoprene +1.2% deltamethrin +33.3% piperonyl butoxide synergist) residual insecticide, and found that after exposure, movement was reduced by 50–88% and equally by each formulation compared to untreated controls. After initial application, predicted distance moved increased from 4 m to 14 m then 28 m in a 24 h period at 3 and 12 months post‐application, respectively.
Published 2020. This article is a U.S. Government work and is in the public domain in the USA
Stored products represent an enormous economic output, but insects regularly immigrate into stored products from the surrounding landscape throughout the postharvest supply chain. Long-lasting ...insecticide-incorporatednetting (LLIN), which usually contains an incorporated pyrethroid, has been used as part of a strategy to reduce the spread of malaria in tropical regions since the 1990s and has only recently been considered for its application in pre- and postharvest agricultural contexts. The goal of this study was to determine how short-term exposure to LLINs in the laboratory impacts the locomotory behavior and mortality for adult Tribolium castaneum (Herbst), (Coleoptera: Tenebrionidae) red flour beetle, and Rhyzopertha dominica (Fauvel), (Coleoptera: Bostrichidae) lesser grain borer, at different periods of time after exposure. Exposure to LLINs resulted in multiple-fold reductions in the distance moved and elevated angular velocity in both species that quickly took effect and persisted even after 168 h compared with adults exposed to control netting. R. dominica was somewhat more susceptible than T. castaneum to LLINs. Finally, the dispersal capacity of both species, measured as ability to move to a remote resource patch, was significantly impaired or absent after exposure to LLINs compared to adults exposed to control netting. Our results demonstrate that LLINs are a promising new technology for reducing infestation by stored product insects since even short exposures limit movement and ultimately lead to knockdown and death.
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