Effectiveness of Spinosad on Four Classes of Wheat Against Five Stored-Product Insects

Abstract

Spinosad is a commercial reduced-risk pesticide that is naturally derived. Spinosad's performance was evaluated on four classes of wheat (hard red winter, hard red spring, soft red winter, and durum wheats) against adults of the lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); sawtoothed grain beetle, Oryzaephilus surinamensis (L.); red flour beetle, Tribolium castaneum (Herbst); and larvae of the Indianmeal moth, Plodia interpunctella (Hübner). Beetle adults (25) or P. interpunctella eggs (50) were exposed to untreated wheat and wheat treated with spinosad at 0.1 and 1 mg (AI)/kg of grain. On all untreated wheat classes, adult beetle mortality ranged from 0 to 6%, and P. interpunctella larval mortality ranged from 10 to 19%. The effects of spinosad on R. dominica and P. interpunctella were consistent across all wheat classes. Spinosad killed all exposed R. dominica adults and significantly suppressed progeny production (84-100%) and kernel damage (66-100%) at both rates compared with untreated wheat. Spinosad was extremely effective against P. interpunctella on all wheat classes at 1 mg/kg, based on larval mortality (97.6-99.6%), suppression of egg-to-adult emergence (93-100%), and kernel damage (95-100%), relative to similar effects on untreated wheats. The effects of spinosad on S. oryzae varied among wheat classes and between spinosad rates. Spinosad was effective against S. oryzae, O. surinamensis and T. castaneun only on durum wheat at 1 mg/kg. Our results suggest spinosad to be a potential grain protectant for R. dominica and P. interpunctella management in stored wheat.

Effects of Short Exposures to Spinosad-Treated Wheat or Maize on Four Stored-Grain Insects

“…Before this, spinosad has already been proved very effective against a range of stored-grain insect species, even at lower rates than the application rate, in both laboratory (Fang et al 2002a, Toews and Subramanyam 2003, Nayak et al 2005, Daglish and Nayak 2006 and Þeld tests (Maier et al 2006, Subramanyam et al 2007, Daglish et al 2008. Due to the above-mentioned characteristics and its low mammalian toxicity, spinosad is a desirable alternative to the use of traditional grain protectants, especially organophosphorous insecticides (OPs), which often are very toxic to mammals.…”

Efficacy of spinosad and abamectin against different populations of red flour beetle (Tribolium castaneum Herbst) in treated wheat grain

“…Some earlier studies (Subramanyam et al, 1999;Fang et al, 2002;Nayak et al, 2005) have shown that T. castaneum is the least susceptible stored-product pest to spinosad and that the recommended dose of 1 mg/kg cannot control adults of this species. After a 14-day exposure period, Subramanyam et al (1999) recorded a mortality of 52% among T. castaneum adults on wheat treated with spinosad at the dose of 6 mg/kg, and Fang et al (2002) reported that a full control of T. castaneum adults required spinosad doses exceeding 4 mg/kg, while Huang and Subramanyam (2007) found a 98% efficacy of spinosad at 2 mg/ kg after 12 days of contact of T. castaneum adults.…”

“…After a 14-day exposure period, Subramanyam et al (1999) recorded a mortality of 52% among T. castaneum adults on wheat treated with spinosad at the dose of 6 mg/kg, and Fang et al (2002) reported that a full control of T. castaneum adults required spinosad doses exceeding 4 mg/kg, while Huang and Subramanyam (2007) found a 98% efficacy of spinosad at 2 mg/ kg after 12 days of contact of T. castaneum adults. In those studies, spinosad applied to wheat at the dose of 5 mg/kg reached 97% efficacy only against adults of laboratory populations of T. castaneum.…”

“…One of the ways to manage the problem of resistance of stored-product insects to different insecticides and to alleviate selection pressure in practice is to introduce new insecticides. The latest studies have shown that the neonicotinoid thiamethoxam and synthesized natural insecticides spinosad and abamectin are as effective as the contact insecticides used so far (Fang et al, 2002;Arthur et al, 2004;Athanassiou et al, 2008b;Kavallieratos et al, 2009;Andrić et al, 2011;Wakil et al, 2013).…”

EFFICACY OF NEW CHEMISTRY INSECTICIDE SPINOSAD ALONG WITH SOME PLANT EXRACTS AS GRAIN PROTECTANT AGAINST Rhyzopertha dominica (F.) (COLEOPTERA: BOSTRYCHIDAE)

“…Fang et al (2002) studied that spinosad is a feasible reduced-risk pesticide that is naturally derived. The spinosad against R. dominica and P. interpunctella and T, castaneum was proved very effective.…”