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

Abstract

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.

Residual efficacy of methoxyfenozide applied on different grain commodities for the control of three stored-product insect pests

“…It was concluded that pyriproxyfen was more persistent in the entire testing period, while hydroprene lost its effectiveness after 28 d (Arthur et al, 2009). The results of methoxfenozide persistence are in contrast to those obtained by Liu et al (2016) who found that methoprene (a juvenoid IGR) was effective up to 40 weeks at 1 ppm due to its residual activity in treated wheat. Similarly, Arthur (2019) reported that efficacy of the IGR increased with different combinations of deltamethrin and methoprene were applied to grain, all treatments were effective against T. castaneum for 15 months on maize.…”

Residual Efficacy of Pyriproxyfen on Grain Commodities Against Stored Product Insect Pests

“…Similar findings occured in larvae of T. castaneum and O. surinamensis exposed to the surfaces treated with pyriproxyfen (Arthur et al 2009), T. variabile (Arthur and Hartzer 2018) and methoxyfenozide on grain commodities (Yasir et al 2019b). Conversely, another JHA, methoprene, has residual efficacy for 40 weeks against different stored grain insects (Liu et al 2016). Similarly, Arthur (2019) has pointed out that the ef-ficacy of the IGR increases to 15 months when different combinations of methoprene and deltamethrin are used to control T. castaneum on corn.…”

Residual Efficacy of a Deltamethrin Emulsifiable Concentrate Formulation against Rhyzopertha dominica (F.) and Sitotroga cerealella (Oliver) after Partial Treatment of Brown Rice

“…Another way treated and untreated grains can be mixed is through the practice of “top dressing”, which corresponds to treating only the surface portion of a grain mass. Laboratory and field tests produce mixed results, in that both increases in mortality or reductions of progeny were reported for surface treatments involving top dressing compared to controls, because top dressing offers insects ample opportunities to penetrate through the treated surface into the untreated portion of the grain [11,12]. Furthermore, as discussed in a study with diatomaceous earth [13], stored product insects that penetrate through a treated surface in a grain mass may be able to oviposit in the untreated layers before they die.…”