Effects of Spinosad and Abamectin on different Populations of Rice Weevil Sitophilus oryzae (L.) in Treated Wheat Grain
Efekti spinosada i abamektina na različite populacije pirinčanog žiška Sitophilus oryzae (L.) u tretiranoj pšenici u zrnu
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Author
Andric, Goran
Kljajic, Petar
Prazic Golic, Marijana
Keywords
S. oryzaeWheat grain
Spinosad
Abamectin
Effects
pšenica u zrnu
spinosad
abamektin
efekti
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Show full item recordAbstract
In laboratory conditions (25±1ºC and 60±5% r.h.) effects of natural insecticides spinosad
and abamectin on five S. oryzae populations (laboratory, Šid, Gornji Milanovac, Žabari
and Novi Pazar) were investigated. Both insecticides for all tested populations were applied
to untreated wheat grain at following rates 0.25, 0.5, 1.0 and 2.0 mg AI/kg, subsequently
25 adults were added in each plastic vessels (V=200 cm3) containing 50 g of treated wheat,
in four replicates, for each population tested. Mortality of weevils was determined after 2-,
7- and 14-days, and the effect on progeny production was determined 8-weeks from parental
exposure.
Efficacy of spinosad and abamectin after 2-days of weevil exposure for all tested populations
and all application rates was <15%. After 7-days of exposure, the efficacy was ≥95%
for weevils from Žabari, in wheat treated with 2 mg/kg of spinosad and abamectin, and
for weevils from Gornji Milanovac, only in wheat treated with 2 mg/kg of spinosad. After
14-days of exposure the efficacy ≥95% was found for laboratory weevils and weevils from
Žabari and Gornji Milanovac, in wheat treated with 1 and 2 mg/kg of spinosad, and for S.
oryzae from Novi Pazar and Šid, in wheat treated with 2 mg/kg of spinosad. At the same time
for all tested populations abamectin at rates of 0.5, 1.0 and 2.0 mg/kg was 94-100% efficien
t. No insecticide achieved total (100%) progeny reduction in tested populations of S.
oryzae, while high progeny reduction (≥95%) was found only in weevils which were in contact
with wheat treated with 1 and 2 mg/kg of abamectin. The results showed that for highly
efficient control of different populations of S. oryzae in wheat grain, ≥2 mg/kg of abamectin,
and, particularly, spinosad should be applied. U laboratorijskim uslovima (25±1ºC i 60±5% r.v.) su ispitivani efekti prirodnih insekticida
spinosada i abamektina na pet populacija S. oryzae (laboratorijska, Šid, Gornji Milanovac, Žabari
i Novi Pazar). Oba insekticida su za sve testirane populacije naneti na netretiranu pšenice
u zrnu u dozama 0,25, 0,5, 1,0 i 2,0 mg a.m./kg, nakon čega je u plastične posude (V=200
cm3) sa po 50 g tretirane pšenice, u četiri ponavljanja za svaku testiranu populaciju, stavljano
po 25 adulta S. oryzae. Smrtnost žižaka je utvrđivana posle dva, sedam i 14 dana, a posle
ukupno osam nedelja od izlaganja roditelja je utvrđivan uticaj na produkciju potomstva.
Efikasnost spinosada i abamektina je posle dva dana izlaganja žižaka kod svih testiranih
populacija i svih količina primene bila <15%. Posle sedam dana izlaganja efikasnost od
≥95% utvrđena kod žižaka iz Žabara, u pšenici tretiranoj dozom od 2 mg/kg spinosada i
abamektina, i kod žižaka iz Gornjeg Milanovca, samo u pšenici tretiranoj dozom od 2 mg/
kg spinosada. Posle 14 dana izlaganja efikasnost ≥95% je utvrđena kod laboratorijskih žižaka
i žižaka iz Žabara i Gornjeg Milanovca, u pšenici tretiranoj dozama od 1 i 2 mg/kg spinosada,
i kod S. oryzae iz Novog Pazara i Šida, u pšenici tretiranoj dozom od 2 mg/kg spinosada.
Istovremeno je kod svih testiranih populacija abamektin u dozama 0,5, 1,0 i 2,0 mg/kg
bio efikasan 94-100%. Nijedan insekticid nije potpuno (100%) redukovao potomstvo ispitivanih
populacija pirinčanog žiška, dok je visoka redukcija potomstva (≥95%) utvrđena samo
u kontaktu žižaka sa pšenicom tretiranom dozama od 1 i 2 mg/kg abamektina. Rezultati
istraživanja su pokazali da je za visoko efektivno suzbijanje različitih populacija S. oryzae u
pšenici u zrnu potrebno primeniti ≥2 mg/kg abamektina, i, posebno, spinosada.