Effects of spinosad and abamectin on different populations of rice weevil Sitophilus oryzae (L.) in treated wheat grain

In laboratory conditions (25?1.C and 60?5% r.h.) effects of natural insecticides spinosad and abamectin on five S. oryzae populations (laboratory, Sid, Gornji Milanovac, Zabari 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 Zabari, 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 Zabari and Gornji Milanovac, in wheat treated with 1 and 2 mg/kg of spinosad, and for S. oryzae from Novi Pazar and Sid, 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.

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Effects of Five Insect Growth Regulators on Progeny Production, Productivity Index, Development, and Adult Emergence of the Rice Weevil, Sitophilus oryzae (L.) (Coleoptera : Curculionidae)

Applied Entomology and Zoology ◽

10.1303/aez.18.281 ◽

1983 ◽

Vol 18 (2) ◽

pp. 281-283

Author(s):

J.M. MKHIZE ◽

A.P. GUPTA

Keyword(s):

Growth Regulators ◽

Sitophilus Oryzae ◽

Adult Emergence ◽

Rice Weevil ◽

Productivity Index ◽

Progeny Production ◽

Insect Growth Regulators ◽

Insect Growth ◽

Index Development

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Effects of 50°C temperature on Sitophilus granarius (L.), Sitophilus oryzae (L.) and Sitophilus zeamais (Motsch.)

Pesticidi i fitomedicina ◽

10.2298/pif1103221p ◽

2011 ◽

Vol 26 (3) ◽

pp. 221-227 ◽

Cited By ~ 1

Author(s):

Marijana Prazic-Golic ◽

Goran Andric ◽

Petar Kljajic

Keyword(s):

Sitophilus Oryzae ◽

Wheat Grain ◽

Progeny Production ◽

Maize Weevil ◽

Granary Weevil ◽

Total Period ◽

Weevil Species ◽

Short Term Exposure ◽

Lethal Time ◽

F1 Generation

Adults of laboratory populations of granary weevil (S. granarius), rice weevil (S. oryzae) and maize weevil (S. zeamais) were exposed at the temperature of 50?C to determine lethal time (parameters LT20, LT50 and LT99) and progeny production/reduction in F1 generation at mentioned temperature. For each exposure and each species 25 adults aged 2-5 weeks, in four replicates, were used. In the first treatment, the insects were exposed for 6, 10, 14, 16, 18, 20, 22, 26 and 30 min in plastic dishes (V=200 cm3) with 1.8 ? 0.2g of untreated coarse wheat. In the second treatment, in dishes with 100 g of untreated wheat grain the adults were exposed for 90, 100, 110, 120, 130, 140, 150, 165 and 180 min. After the exposure, the adults were placed in 100 g of untreated wheat grain, in four replicates, at 25 ? 1?C and 60 ? 5% r.h., for recovery. After one, two and seven days of recovery, the weevils were separated by sifting of wheat, and the mortality was determined, and after total period of eight weeks from the exposure of parents, the effect on progeny in F1 generation was determined. Lethal time for weevils was determined by probit analysis, and progeny production/reduction by analysis of variance. After weevils exposure in coarse wheat and after one, two and seven days of recovery, S. oryzae adults were the most susceptible (LT50 12.48-13.68 min), and the most tolerant were adults of S. granarius (LT50 17.79-20.89 min). After insects exposure in wheat grain, the most susceptible were S. granarius and S. oryzae (LT50 107.11-120.73 min), and the most tolerant S. zeamais (LT50 139.90-155.35 min). After exposure of parents of all three weevil species, in coarse wheat, progeny reduction at 100% level is after 22 min. However, after exposure of parents of all three weevil species in wheat grain, progeny reduction at 100% level in S. granarius is after 130 min, in S. oryzae after 150 min, and at 99.7% level in S. zeamais after 180 min. The investigations indicated that short-term exposure of weevils from Sitophilus genus at the temperature of 50?C adversely affects their survival and progeny production, as well as that there is a potential for its successful use as a physical measure in control of storage pest insects.

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Susceptibility of Twelve Genotypes of Triticale to the Rice Weevil (Coleoptera: Curculionidae) and the Lesser Grain Borer (Coleoptera: Bostrichidae)2

Journal of Entomological Science ◽

10.18474/0749-8004-26.3.339 ◽

1991 ◽

Vol 26 (3) ◽

pp. 339-344 ◽

Cited By ~ 7

Author(s):

J. E. Baker ◽

F. H. Arthur ◽

P. L. Bruckner

Keyword(s):

Moisture Content ◽

Growth Parameters ◽

Oryza Sativa L ◽

Sitophilus Oryzae ◽

Brown Rice ◽

Rice Weevil ◽

Rhyzopertha Dominica ◽

Progeny Production ◽

Lesser Grain Borer ◽

Total Progeny

Population development by the rice weevil, Sitophilus oryzae (L.) and feeding damage caused by the lesser grain borer, Rhyzopertha dominica (F.), were assessed on twelve triticale (X Triticosecale Wittmack) genotypes maintained at 25°C and at 11.7 or 14.2% moisture content. Among genotypes at 14.2% moisture content, total progeny production by the rice weevil ranged from 7.1 (GA82014) to 8.8 (87AB13541) weevils per female-day; mean time to adult emergence ranged from 35.5 (GA82014) to 36.9 days (87AB13541 and CT4699); and rate of emergence (a measure of the slope of the cumulative emergence curve at the average emergence day) ranged from 0.59 (87AB 13541) to 0.72 (‘Morrison’). Although there were some statistical differences among these population growth parameters on different triticale genotypes, all genotypes were at least as susceptible as the long grain brown rice (Oryza sativa L.) and soft red winter wheat (Triticum aestivum L., cultivar ‘Florida 302’) controls tested concurrently. Development time of rice weevils was significantly delayed and total progeny production after 65 days was reduced about 17-fold on triticale genotypes at 11.7% moisture content. About 3-fold more frass was produced by lesser grain borers feeding for 7 days at 25°C on triticale genotypes at 14.2% moisture content compared to that obtained on genotypes at 11.7% moisture content. Significantly more feeding and frass production by lesser grain borers occurred on triticale and wheat than occurred on rice.

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