Efficacy of the insect growth regulators methoprene, fenoxycarb and diflubenzuron against Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) on maize and paddy rice

VanGundy³

et al. 2016

Insects

A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

Section: Discussionsupporting

confidence: 58%

Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat

Liu

VanGundy³

et al. 2016

Insects

“…In previous studies, treatment of an entire experimental unit of grain with 1 mg kg −1 methoprene gave effective control of R. dominica 6, 9–11. Chanbang et al 9 showed nearly complete suppression of R. dominica progeny on rice treated with 1 mg kg −1 , while Samson et al 13 reported residual control of R. dominica progeny for 48 weeks on rice and maize at this same rate. The present results indicate that treatment of a part of the grain quantity with methoprene may reduce progeny production of R. dominica , at least at the laboratory level tested here.…”

Section: Discussionmentioning

confidence: 93%

“…Methoprene is the only IGR registered as a grain protectant in the United States (USA) and has been shown to reduce progeny production of several stored‐grain insect pests, including R. dominica 6, 7, 9–12. With many grain protectants, efficacy can vary depending on the specific grain commodity, but there is little published research concerning the activity of methoprene on grains other than wheat 9, 13. The application of an insecticide on the upper surface of the grain mass, known also as ‘top dressing’, is one of the solutions suggested in order to reduce the total amount of residues in the final product.…”

Section: Introductionmentioning

confidence: 99%

Efficacy of layer treatment with methoprene for control of Rhyzopertha dominica (Coleoptera: Bostrychidae) on wheat, rice and maize

Athanassiou

Pest Management Science

Throne

2011

“…data regarding the effects of temperature or humidity on the efÞcacy of IGRs. In one study by Samson et al (1990), lesser grain borers, Rhyzopertha dominica (Fauvel), were exposed on rice treated with methoprene, fenoxycarb, or dißubenzuron. The rice was held at 25ЊC, 70 and 90% equilibrium relative humidity, and there was no consistent difference in efÞcacy of the IGRs due to humidity.…”

Section: Discussionmentioning

confidence: 99%

Susceptibility of Last Instar Red Flour Beetles and Confused Flour Beetles (Coleoptera: Tenebrionidae) to Hydroprene

2001

Last instar larvae of the red flour beetle, Tribolium castaneum (Herbst), and the confused flour beetle, Tribolium confusum Jacquelin du Val, were either exposed for 8-144 h on concrete treated with 1.9 x 10(-3) mg(AI)/per cm2 hydroprene, or continually exposed on concrete treated with 9.8 x 10(-4) to 1.9 x 10(-3) mg[AI]/per cm2 hydroprene. In both tests, larvae were exposed and held at 27 or 32 degrees C and 40, 57, or 75% RH. When larvae were exposed with no food to hydroprene for different time intervals, then transferred to untreated concrete containing flour, consistent effects were produced only at 144 h. At this exposure interval, the percentage of beetles arrested in the larval stage after 3-4 wk was generally greater at 75% RH compared with 40 and 57% RH, but there were no differences between species or temperature. The percentages of dead adult red flour beetles and live adults with morphological deformities were also greatest at 75% RH, and defects were more prevalent in red flour beetles than in confused flour beetles. When larvae were continually exposed to different concentrations of hydroprene on concrete that contained flour, the percentage of arrested larvae, dead adults, and live adults of both species generally increased with concentration. There were more deleterious effects at 75% RH compared with either 40 or 57% RH, and effects were more pronounced in the red flour beetle compared with the confused flour beetle. In both experiments, temperature effects were variable and inconclusive. Results indicate that continual exposure of last instar red flour beetle and confused flour beetle to hydroprene can limit population development, but exposure intervals of >6 d may be required for maximum effectiveness.