Synergism of insecticidal action and effects on detoxifying enzymes in vivo of lambda-cyhalothrin and malathion by some nitrogen heterocycles in resistant and susceptible strains of Tribolium castaneum

The interactions of the synthetic pyrethroid, lambda-cyhalothrin and malathion were studied with purines, pyrimidines, caffeine and some other related nitrogenous compounds in resistant and susceptible strains of Triboliurn castaneum (Herbst.) The results were compared with those obtained with a known synergist, piperonyl butoxide (PBO) and precocene I. Adenine, cytosine, guanine, thymine and uracil synergised lambda-cyhalothrin, especially in the susceptible strain, with maximum effect at a 1:1 mass ratio, with the effect decreasing with increasing proportion of the heterocycle. The order of synergism of lambda-cyhalothrin was; precocene I > PBO > the nitrogenous compounds, in both resistant and susceptible strains. On the other hand, caffeine (lethal effect increased about twice), barbital (about twice), isobarbituric acid (less than twice) and bromacil (up to eight times) synergised malathion in malathion-resistant strains and antagonised in the susceptible strains. Total in-vivo esterases, carbox-ylesterases and cytochrome P₄₅₀ of susceptible and resistant strains showed significantly increased activity or content when treated with either insecticide plus a heterocyclic compound. Exceptions were with bromacil and malathion and for the malathion-specific strain, Kano-C with malathion and the N-heterocycles.     

Effect of fungal metabolites and some derivatives against Tribolium castaneum (Herbst) and Nezara viridula (L.)

Two fungal metabolites, aspyrone (3-(1,2-epoxypropyl)-5-hydroxy-6-methyl-5,6-dihydropyran-2-one) and asperlactone (3-(1,2-epoxypropyl)-5-(1-hydroxyethyl)-5-furan-2-one) were isolated from an Aspergillus ochraceus Wilhelm strain showing IGR activity against Tribolium castaneum (Herbst). Synthetic derivatives of aspyrone were produced using published methods. These derivatives together with aspyrone and asperlactone were tested for insect growth-regulating activity against T. castaneum, and for ovicidal activity against Nezara viridula L. Of the compounds tested asperlactone appeared to be the most active.     

Quick knockdown results in high mortality: is this theory correct? A case study with phosphine and the red flour beetle

BACKGROUND

The fumigant phosphine is used all over the world for disinfestation of stored grains and commodities. Adults of 23 different populations of Tribolium castaneum from 10 different countries were evaluated for phosphine resistance using a modification of the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK). Adults were exposed to 3000 ppm and recorded for 5–270 min for their mobility.

RESULTS

Among the tested populations, high levels of phosphine resistance were recorded in populations from Brazil, Serbia, and Spain. No survivals were recorded after 7 days post exposure for eight of 23 in a tested population.

CONCLUSIONS

Our work revealed four scenarios: 1, quick knockdown–low (or no) recovery; 2, Slow knockdown–high recovery; 3, Quick knockdown–high recovery; and 4, Slow knockdown–low recovery. Our data indicate that post exposure period is critical for the evaluation and characterization of phosphine resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

电子束处理对杂拟谷盗的辐照效应

利用不同剂量的电子束对杂拟谷盗幼虫、成虫进行辐照处理,研究其辐照效应.结果表明:杂拟谷盗幼虫对电子束辐照的敏感性高于成虫.幼虫经250 Gy剂量辐照后,可以完全阻止其发育为成虫,在14 d内全部死亡;成虫经250 Gy剂量辐照后,则需42 d才能全部死亡,而且不能产生下一代成虫.250Gy的剂量可以作为电子束辐照防治杂...     

Laboratory evaluation of diatomaceous earth deposits mined from several locations in central and southeastern Europe as potential protectants against coleopteran grain pests

Diatomaceous earth (DE) deposits from regions of central and southeastern Europe were evaluated for their insecticidal efficacy against Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) in comparison with the commercially available DE formulation SilicoSec. The effects of temperature, RH, grain commodity (wheat, barley, maize, rice), application method (spraying vs. dusting) were evaluated. FYROM, a DE from the Former Yugoslavian Republic of Macedonia, was the most effective of the DE deposits for grain treatment, whereas the least effective was from Greece (named Crete). However, for surface treatment, Slovenia was the most effective followed by Elassona 1 and Begora. Increase of temperature increased DE efficacy, while the reverse was noted with the increase of RH. Furthermore, the DEs were more effective in barley or wheat than in maize or rice. Neither the mined DEs nor SilicoSec were able to suppress progeny production of the tested species after previous exposure on the treated commodities. Generally, dust application of DEs was more efficacious than spraying against S. oryzae and T. confusum. However, spraying of wheat significantly reduced the bulk density (test weight) compared to dusting. For surface treatment, after 1 d of exposure, Slovenia was the most effective of the mined DEs followed by Elassona 1 and Begora, whereas after 6 d of exposure the mortality was almost complete (>99%) with all three DEs. More than 6 d of exposure were required for an effective control of T. confusum adults with the remainder of the mined DEs.     

低氧条件下赤拟谷盗成虫呼吸速率研究

研究了在30℃,不同氧浓度条件下赤拟谷盗Tribolium castaneum成虫的呼吸速率.在30℃条件下将试虫置于氧气浓度分别为21%、15%、10%、5%、3%、2%和1%的环境中,用SKW-3型微量呼吸检压仪测定呼吸速率.测定结果表明:赤拟谷盗成虫在上述一系列氧浓度下的耗氧量分别为2.54±0.03、2.44±0.05、2.41±0.10、2.23±0.05、1.99±0.03、1.85±0.06和0.97±0.02 μL/insect·h;随着氧浓度的降低,试虫的呼吸速率逐渐降低,可见低氧对赤拟谷盗成虫的呼吸速率影响与害虫的致死机理有关.     

Persistence and efficacy of two diatomaceous earth formulations and a mixture of diatomaceous earth with natural pyrethrum against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on wheat and maize

Laboratory tests were conducted to assess the insecticidal and residual effects of three diatomaceous earth (DE) formulations, Insecto, PyriSec and SilicoSec, against Tribolium confusum Jacquelin du Val on wheat and maize. Quantities of wheat and maize were treated with the above formulations at 500, 1000 and 1500 mg kg(-1) and stored at 25 degrees C and 55% relative humidity (RH). Samples were taken on the day of storage and every 30 days until completion of a 360 day period of storage. Adults of T. confusum were exposed to these samples at 25 degrees C and 55% RH and the mortality was measured after 24 and 48 h and 7 and 14 days of exposure. Adult mortality was higher on wheat than on maize. At the beginning of the storage period, mortalities after 14 day exposure on maize treated with the highest rate were 60, 63 and 81% for Insecto, PyriSec and SilicoSec respectively, while on wheat the mortality was 100% for all DEs. On the same commodities 360 days after treatment the respective mortality figures for wheat were 99, 98 and 100%, while in the case of maize they did not exceed 7%. Generally, mortality at exposures < or =48 h decreased with increasing storage time. Furthermore, although mortality on wheat increased with dose, the increase in DE dose from 1000 to 1500 mg kg(-1) resulted in only a small increase in mortality. Thus a DE treatment of 1000 mg kg(-1) was shown to provide long-term protection of wheat against T. confusum, although higher DE application rates and exposure intervals are needed for a satisfactory level of protection of maize against this pest.     

Movement behavior in response to landscape structure: the role of functional grain

Landscape structure can influence the fine-scale movement behavior of dispersing animals, which ultimately may influence ecological patterns and processes at broader scales. Functional grain refers to the finest scale at which an organism responds to spatial heterogeneity among patches and extends to the limits of its perceptual range. To determine the functional grain of a model insect, red flour beetle (Tribolium castaneum), we examined its movement behavior in response to experimental flour landscapes. Landscape structure was varied by manipulating habitat abundance (0%, 10%, 30%, and 100%) and grain size of patches (fine-2 × 2 cm, intermediate-5 × 5 cm, and coarse-10 × 10 cm) in 50 × 50 cm landscapes. Pathway metrics indicated that beetles used a similar proportion of all landscape types. Several pathway metrics indicated a graded response from the fine to the coarse grain landscape. Lacunarity analysis of beetle pathways indicated a non-linear change in space use between the fine and intermediate landscapes and the coarse-grained landscape. Beetles moved more slowly and tortuously (with many turns), and remained longer in both the overall landscape and individual patches, in fine-grained compared to coarse-grained landscapes. Our research demonstrates how detailed examination of movement pathways and measures of lacunarity can be useful in determining functional grain. Spatially explicit, organism-centered studies focusing on behavioral responses to different habitat configurations can serve as an important first step to identify behavioral rules of movement that may ultimately lead to more accurate predictions of space use in landscapes.     

几种中药材对赤拟谷盗的致死作用及其趋避性研究

用中药材丁香、细辛、陈皮、吴茱萸、花椒、千年健对仓虫赤拟谷盗成虫的致死作用和趋避作用进行了研究。结果表明:6种中药材对赤拟谷盗成虫的致死效果为丁香>细辛>陈皮>吴茱萸>花椒>千年健。当丁香与其他5种药材一起同贮或分别贮存时,丁香里始终不见赤拟谷盗,在千年健里赤拟谷盗分布较多,而在其他几种药材中分布明显减少。各种中药材对拟谷盗的驱虫作用有明显差异。     

水菖蒲活性物质β-细辛醚对赤拟谷盗的熏蒸作用

为了确定水菖蒲活性成分β-细辛醚对赤拟谷盗的熏蒸效果,采用密封熏蒸方法测定了β-细辛醚对赤拟谷盗幼虫、蛹和成虫的熏蒸作用.结果表明:β-细辛醚对赤拟谷盗3种虫态均有一定的熏蒸作用,且对赤拟谷盗低龄幼虫的熏蒸效果要比高龄幼虫明显;当β-细辛醚熏蒸浓度为200μL/L时,熏蒸48 h后蛹的校正死亡率为34.32%;β-细辛醚对赤拟谷盗成虫熏蒸120 h后的LC50为116.48μL/L.