Trapping Tribolium castaneum (Coleoptera: Tenebrionidae) and Other Beetles in Flourmills: Evaluating Fumigation Efficacy and Estimating Population Density

Abstract

This paper reports beetle pests common to flourmills targeted during a series of trapping studies over a two-year period in flourmill 1 and a one year period in flourmill 2. Objectives were (1) use pheromone-baited traps to detect T. castaneum (Herbst) and other pest species present for their distribution over space and time, (2) monitor T. castaneum activity before and after fumigations to assess efficacy of the treatment, and (3) correlate counts of T. castaneum via trap capture against direct T. castaneum counts from samples of the milled flour to assess the value of trap data to estimate relative size of the pest population. Traps were deployed in two different flourmills over two consecutive years. T. castaneum was the most commonly trapped beetle during both years in mill 1. In mill 2, Typhaea stercorea (L.) and Cryptolestes ferrugineus (Stephens) were both captured in higher numbers than T. castaneum. In mill 1, trap capture was higher overall during Year 2 for most of the species compared with capture during Year 1, likely due to a dust cover modification made for the pitfall trap used in Year 2. Trap capture was also evaluated by location within the mills and a significant difference was found in the capture of T. stercorea during both years in mill 1. T. castaneum captures were significantly reduced following most fumigations, which used methyl bromide in milling areas and phosphine in bulk-stored finished flour. However, in most cases trap catches showed that beetle populations were not eliminated. Trap captures after fumigation suggest either that the fumigations were not entirely effective, or that full grown adult beetles were entering the mill soon after fumigation. When captures of T. castaneum from traps in two spaces of mill 1 during Year 2 were compared with counts of beetles from samples of siftings collected in the finished flour, the correlation coefficients were nearly significant for both sets of traps.

Synthetic and Natural Insecticides: Gas, Liquid, Gel and Solid Formulations for Stored-Product and Food-Industry Pest Control

“…Laboratory studies on ants and cockroaches are frequently followed by field validations [ 38 , 416 , 417 ]. The effects of aerosols and fumigants on stored-product insect pests under field conditions of store flourmills are well documented [ 54 , 201 , 418 , 419 , 420 ]. In contrast, with rare exceptions [ 421 , 422 ], most studies concerning the activity of residual insecticides on stored-product arthropods are mostly performed under laboratory conditions [ 35 , 332 , 401 ].…”

Microbial vectoring capacity by internal‐ and external‐infesting stored product insects after varying dispersal periods between novel food patches: An underestimated risk

“…bullet lure, #IL‐703, Insects Limited, Westfield, IN, USA). In addition, three ground traps were deployed that consisted of commercially available pitfall traps (Dome®, Storgard, Trécé, Adair, OK, USA) with two connectible pieces (Doud et al., 2021 ; Doud & Phillips, 2020 ), containing a central well where a Sitophilus spp. lure was added along with a 5 g of whole maize as a kairomone bait.…”

Attraction, mobility, and preference by Lasioderma serricorne (Coleoptera: Ptinidae) to microbially-mediated volatile emissions by two species of fungi in stored grain

“…The bottom of the bins was roughened with sandpaper to provide traction. The traps consisted of commercially-available pitfall traps (Storgard, Trece, Adair, OK, USA) with two connectible pieces 68 , 69 , containing a central well where the treatments were added as bait. Traps were baited with treatments in Table 2 and placed in one corner inside the bins.…”