Osetljivost populacija kestenjastog brašnara, Tribolium castaneum(Herbst) (Coleoptera: Tenebrionidae) na sintetisane i prirodne insekticide u interakciji sa efektima ekstremne temperature

Abstract

Ispitivana je toksičnost sintetisanih (kontaktnih) insekticida za adulte laboratorijske populacije Tribolium castaneum i osetljivost/rezistentnost populacija iz različitih skladišnih objekata. Parametri toksičnosti (LD parametri i ld-p linije) su utvrđivani posle mikroaplikacije insekticida: dihlorvosa, malationa, pirimifos-metila, hlorpirifos-metila, deltametrina i bifentrina i posle aplikacije insekticidnih preparata: malationa, pirimifos-metila, hlorpirifos-metila, deltametrina sa piperonil butoksidom, bifentrina, tiametoksama, spinosada i abamektina na pšenici u zrnu. Utvrđivani su efekti prirodnih insekticida (inertnih prašiva) na bazi zeolita (Prirodni zeolit, Prirodni zeolit fine granulacije, Modifikovani prirodni zeolit) i diatomejske zemlje (DZ S-1, DZ S-2, Protect-It) pri različitm vlažnostima vazduha na adulte T. castaneum iz laboratorijske i populacija sa promenjenom osetljivošću na insekticide. Utvrđivani su efekti ekstremene temperature od 50°C izlaganjem adulta T. castaneum iz laboratorijske populacije i rezistentnih populacija u brašnu i pšenici u zrnu. U interakciji sa subletalnim ekspozicijama (LT25 i LT50) na 50°C u pšenici u zrnu, utvrđivani su efekti LD50 sintetisanih insekticida i inertnih prašiva (0,25 i 0,5 g/kg). Mikroaplikacijom je utvrđeno da je deltametrin najtoksičniji insekticid za laboratorijsku populaciju, te populacije Nikinci i Jakovo. Za T. castaneum iz Nikinaca selekcionisane pirimifosmetilom najtoksičniji insekticid je hlorpirifos-metil, a za selekcionisane deltametrinom, pirimifosmetil. Malation je kod svih populacija ispoljio najslabiju toksičnost, a kod sedam od 12 populacija diskriminativna doza ovog insekticida je prouzrokovala smrtnost <85%. U pšenici u zrnu za adulte iz laboratorijske populacije, Jakova i Nikinaca selekcionisanih deltametrinom najtoksičniji insekticid je tiametoksam, a za adulte iz Nikinaca i Nikinaca selekcionisanih pirimifos-metilom, deltametrin sa piperonil butoksidom. Populacija Jakovo je razvila rezistentnost na malation, a populacija iz Nikinaca pored malationa ispoljava i rezistentnost na tiametoksam i abamektin. Efikasnost inertnih prašiva zavisi od relativne vlažnosti vazduha i osobina prašiva (sadržaja SiO2 i veličine čestica). Utvrđen je značajan insekticidni potencijal prašiva DZ S-1, DZ S-2 i Prirodni zeolit, dok je preparat Protect-It značajno efikasniji. Visoku efikasnost i redukciju potomstva prašiva su postigla posle 21 dana izlaganja. Nisu utvrđene statistički značajne razlike u osetljivosti na diatomejsku zemlju između laboratorijske populacije i populacija iz Nikinaca i Kikinde koje ispoljavaju promenjenu osetljivost na malation. Nisu utvrđene značajne razlike u delovanju ekstremne temperature 50°C u brašnu i pšenici u zrnu za brašnare iz testiranih populacija. Sintetisani insekticidi značajno povećavaju efikasnost u interakciji sa 50°C, a najveći uticaj interakcije je utvrđen kod bifentrina, dok je kod tiametoksama i abamektina utvrđen najmanji uticaj. Preparat diatomejske zemlje značajno povećava efikasnost u interakciji sa 50°C, dok je kod drugih prašiva utvrđen slab uticaj interakcije na efikasnost.

Toxicity of synthetic (contact) insecticides against adults of laboratory population of Tribolium castaneum and susceptibility/resistance of the populations from different storage facilities was studied. Toxicity parameters (LD parameters and ld-p lines) were determined after microapplication of the following insecticides: dichlorvos, malathion, pirimiphos-methyl, chlorpyrifos-methyl, deltamethrin and bifenthrin and after application of insecticide products: malathion, pirimiphos-methyl, chlorpyrifos-methyl, deltamethrin with piperonyl butoxide, bifenthrin, thiamethoxam, spinosad and abamectin on wheat grain. Effects of natural insecticides (inert dust) based on zeolites (Natural zeolite, Fine granulated natural zeolite, Modified natural zeolite) and diatomaceous earth (DE S-1, DE S-2, Protect-It) against T. castaneum adults from laboratory population and populations with altered susceptibility to contact insecticides at different air humidity, were also determined. Effects of extreme temperature of 50°C were evaluated by exposure of T. castaneum from laboratory population and resistant populations in flour and wheat grain. In interaction with sublethal exposures (LT25 and LT50) at 50°C in wheat grain, effects of LD50 of synthetic insecticides and inert dusts (0,25 and 0,5 g/kg) were established. Using microapplication, it was found that deltamethrin is the most toxic insecticide to laboratory population, and populations from Nikinci and Jakovo. The most toxic insecticide to T. castaneum populations from Nikinci selected with pirimiphos-methyl, was chlorpyrifos-methyl and to populations selected with deltamethrin, it was pirimiphos-methyl. In all populations, malathion expressed the lowest toxicity, and in seven out of 12 populations, discriminative dose of this insecticide caused mortality <85%. The most toxic insecticide in wheat grain to adults from laboratory and populations from Jakovo and Nikinci selected with deltamethrin was thiamethoxam, and to adults from Nikinci and adults from Nikinci selected with pirimiphos-methyl, it was deltamethrin with piperonyl butoxide. Population from Jakovo developed resistance to malathion while population from Nikinci, besides to malathion, showed resistance to thiamethoxam and abamectin. Efficacy of inert dusts depends on relative air humidity and dust properties (SiO2 content and particle size). A notable insecticidal potential of the dusts DE S-1, DE S-2 and Natural zeolite was found, while the product Protect-It had significantly higher efficacy. High efficacy and progeny reduction were obtained after 21-day exposure to inert dusts. No statistically significant differences in susceptibility to diatomaceous earth were found between laboratory population and populations from Nikinci and Kikinda which expressed altered susceptibility to malathion. No statistically significant differences were found for effect of extreme temperature of 50°C in flour and wheat grain on T. castaneum from tested populations. Efficacy of synthetic insecticides was significantly increased in interaction with 50°C, and the strongest effect of interaction was established for bifenthrin, while for thiamethoxam and abamectin the effect was the weakest. Efficacy of diatomaceus earth product was significantly increased in interaction with 50°C, while weak impact of interaction on efficacy of other dusts was observed.