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

Abstract

Studies on residual efficacy of insecticides with reduced risk are necessary for strategies on their use and application frequency. Within these insecticides, insect growth regulators, such as pyriproxyfen, have been successfully used to control stored grain pests. The objective of this study was to evaluate the residual efficacy of pyriproxyfen in larvae of the stored grain pests Oryzaephilus surinamensis, Tribolium castaneum and Trogoderma granarium. Grains of wheat, maize, rice, and oats were exposed to pyriproxyfen at concentrations of 1, 2 or 4 mg kg -1 . Six bioassays were performed by releasing the insects on treated grains after different post treatment periods (0, 2, 4, 8, 12 and 16 weeks). Adult emergence of the three insect species was reduced at tested concentrations in all treated grains. For all bioassays the residual efficacy of pyriproxyfen decreased with increase in the post treatment period. At 4 mg kg -1 , the adult emergence did not exceed 16% at week 0 and it was <40% at week 12 in all tested insect species on all grains, but it increased at week 16. The residual effect of pyriproxyfen was more effective in wheat followed by oats, maize and rice for T. castaneum and T. granarium, whereas against O. surinamensis pyriproxyfen was more effective in oats followed by wheat, maize and rice. Results show that pyriproxyfen has potential for residual control of O. surinamensis, T. castaneum and T. granarium, and may be used for replacement of conventional neurotoxic insecticides for managing the insect pests of stored commodities.

Toxicity and Sublethal Effect of Farnesyl Acetate on Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

“…Meanwhile, only 0–36% of early-instar and 25–74% of late-instar Asian citrus psyllid, D. citri , survived to adults after exposure to pyriproxyfen [ 53 ]. Adult emergence of stored grain pests, Oryzaephilus surinamensis (L.) , Tribolium castaneum (Herbst), and Trogoderma granarium (Everts), was also reduced when exposed to pyriproxyfen [ 60 ].…”

Residual Efficacy of Novaluron Applied on Concrete, Metal, and Wood for the Control of Stored Product Coleopteran Pests

“…Similarly, O. surinamensis was found to be more tolerant than T. castaneum when exposed to treatments of surfaces with pyriproxyfen and hydroprene [ 49 ]. In a recent study, Yasir et al [ 25 ] found T. granarium more tolerant compared to O. surinamensis and T. castaneum when larvae of these species were exposed to pyriproxyfen-treated grain commodities.…”

“…Arthur and Hartzer [ 14 ] reported that, when the larvae or eggs of T. castaneum or T. variabile were exposed to concrete surfaces on which combined formulations of novaluron and pyriproxyfen had been applied at their labeled rates, no adults emerged in T. castaneum for 16 weeks and emergence did not exceed 25% in T. variabile for 0–8 weeks. Similarly, pyriproxyfen has been found to be effective for 12 weeks when the larvae of T. castaneum , T. granarium and O. surinamensis were exposed to treated grain commodities [ 25 ] and for 8 weeks when larvae of T. castaneum and O. surinamensis were exposed to the treated surfaces [ 49 ].…”

“…Insect growth regulators (IGRs) possess great pest-control potential and their adoption in the food industry has been widely considered [ 12 , 15 , 16 , 17 ], particularly for control of stored product insects [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. A prominent use of IGRS is to spray them onto uncovered metal, wood, or concrete surfaces, as in a study by Boukouvala and Kavallieratos [ 27 ] that evaluated six different insecticides on concrete for control of Trogoderma granarium Everts (Coleoptera: Dermestidae), including pyriproxyfen, sprayed at a rate of 2.3 mg/m 2 , s -methoprene at 3 mg/m 2 , and deltamethrin at 1100 mg/m 2 .…”

Evaluation of Spinosad Applied to Grain Commodities for the Control of Stored Product Insect Pests

“…Untreated, clean and infestation free four different grain commodities wheat, maize, rice and oats were obtained from local grain market for use in the treatments. The treatments of grains with concentrations of 0.25, 0.50 and 1.00 mg Kg -1 spinosad diluted in distilled water were performed according to Yasir et al (2020) with few modifications. Briefly, a total of 4.2 Kg grains from each commodity were treated with the each desired spinosad concentrations.…”