裝配圖胡軍雄,裝配,胡軍雄 Journal of Stored Products Research 42 2006 226 239 during 1999 and 2000 Five locations per elevator were observed the boot pit dump pit headhouse rail ARTICLE IN PRESS This study reports the results from research only No recommendations are given or implied by the US Department of Agriculture Kansas State University or Oklahoma State University C3 0022 474X see front matter r 2005 Elsevier Ltd All rights reserved doi 10 1016 j jspr 2005 02 003 Corresponding author Tel 17857762783 fax 17857762792 E mail address arthur gmprc ksu edu F H Arthur area and tunnel When a grain residue was found the quantity was estimated and a sample taken Adult grain pest insects and beneficial insects were removed and identified Cryptolestes spp and Sitophilus spp comprised about 80 of the pest insects collected The density of Cryptolestes spp appeared to rapidly increase in spring but remained low at other times of the year The density of Sitophilus spp in the residues increased consistently through the warm months peaked immediately after the warmest month and declined gradually as ambient temperatures cooled Pest insects were observed in 41 7 of the 1575 samples examined and beneficial insects were collected from 5 1 of the samples Residue samples taken from the elevator boot pit and tunnel areas contained a greater density of pest insects all species combined than other locations About 42 of the residues were estimated to be smaller than 1 5kg and samples from these residues contained more insects per sample than did samples from larger residues Anisopteromalus calandrae comprised 88 9 of the total number of beneficial insects found Beneficial insects were observed infrequently and mean populations exceeded 1insect kg of residue in any month at only two of the nine elevators Results from our study showed that grain residues within the elevator often contain pest insects Insect populations in grain residues associated with commercial Kansas grain elevators Frank H Arthur a C3 David W Hagstrum a Paul W Flinn a Carl R Reed b Thomas W Phillips c a Grain Marketing and Production Research Center USDA ARS 1515 College Avenue Manhattan KS 66502 USA b Department of Grain Science and Industry Kansas State University Manhattan KS USA c Department of Entomology Oklahoma State University Stillwater OK USA Accepted 18 February 2005 Abstract Grain residues in nine commercial elevators in Kansas were sampled monthly for insects in grain residues 60 day incubation period ARTICLE IN PRESS F H Arthur et al Journal of Stored Products Research 42 2006 226 239 227 In a recent survey of insects collected from grain in the bottom of elevator silos and from discharge spouts Reed et al 2003 Cryptolestes spp Rhyzopertha dominica F Oryzaephilus spp Tribolium spp and Sitophilus spp weevils were observed consistently over a 2 5 year period In the discharge spouts Cryptolestes spp comprised 65 or more of the insects collected in four of the five sampling periods 6 months each Rhyzopertha dominica comprised about 10 of the population most of the time and Sitophilus spp comprised from 3 9 to 23 3 of the and could provide food and harborage when the bins are empty serving as sources of insect infestation for new grain r 2005 Elsevier Ltd All rights reserved Keywords Sanitation Cleaning Elevators Grain Insects 1 Introduction In the central plains region of the United States stored grain insects can quickly infest newly harvested grain in farm bulk bins Hagstrum 1987 1989 Reed et al 1991 Dowdy and McGaughey 1994 Hagstrum et al 1994 Vela Coiffier et al 1997 Hagstrum 2001 A likely source of this infestation is residual grain inside the bins which can be heavily infested with stored grain insects Ingemansen et al 1986 Loschiavo and Smith 1986 Barker and Smith 1987 1990 Sanitation practices such as removing grain residues from inside bins and applying bin sprays are often recommended for farm stored hard red winter wheat in the south central US Reed and Pedersen 1987 Reed and Harner 1998 Reed et al 1990 Cuperus et al 1990 Nevertheless Herron et al 1996 found little correlation between hygiene practices and infestations inside farm bins in Australia Furthermore Reed et al 1990 showed that there was no economic incentive for using insecticides as pre binning sprays to eliminate residual populations inside empty bins even when these sprays appeared to be effective Grain in commercial elevators can become infested with insects quickly as illustrated by a study of 13 elevator sites in Kansas Reed et al 2001 Pitfall traps placed in wheat immediately after storage in these elevators detected insects in half the silos within two weeks In warm climates stored grain insects are known to infest crops in the field summarized by Reed et al 2003 However in climatic zones similar to those of the present study sampling of new grain delivered directly from the field has given little indication of infestation Chao et al 1953 Hagstrum et al 1995 Vela Coiffier et al 1997 In elevators it appears likely that a major source of the insects that infest new grain is previously infested grain present when the new crop is received Other likely sources are infested grain residues in empty bins spills and other related debris in and around elevators It is also possible that trucks and railcars used to transport grain to commercial elevators may be infested Dowdy and McGaughey 1996 surveyed four elevators in Kansas and consistently detected insects in the elevator base areas dump pits head houses on the top of the elevators silo head spaces and outside areas They also sampled residual material containing grain dust and did not find insects upon initial examination but did collect some insects primarily dermestids after a insects collected depending on the sampling period In the grain remaining inside empty bins Cryptolestes spp comprised 45 Sitophilus spp represented 32 4 and R dominica comprised 9 of the insects collected Two of the grain elevators reported in Reed et al 2003 were sampled in the present study Most research on insects in grain residues found outside of storage bins has been conducted at farm sites and there is comparatively little research in large commercial grain elevators Spilled grain and other residual grain materials in and around elevators but outside the storage bins may also contain resident insect populations and represent an important source of infestation for new grain There are few published data regarding the composition and abundance of insects in grain residues found inside elevators The purpose of this study was to determine 1 species composition of insects collected from grain residues in commercial elevators but outside the storage bins and 2 distributional and seasonal density patterns of these populations 2 Materials and methods Nine elevators in Kansas with concrete silos were visited monthly in 1999 and 2000 to inspect for accumulations of spilled grain or grain residue including broken grain grain dust and plant trash A few visits 3 of samples were made in January and February of 2001 Although visits ARTICLE IN PRESS F H Arthur et al Journal of Stored Products Research 42 2006 226 239228 Annex Dump Pit Elevator Boot Tunnel Headhouse were made monthly the actual amount of grain varied depending on the time of year and frequency of grain movement through the elevator Similar difficulties were noted in an earlier study by Reed et al 2003 Grain residues were recorded as being in or close to one of the following locations elevator boot tunnel truck dump rail line ground level areas of the headhouse or bin deck level of the headhouse or annex Fig 1 The elevator boot is the enclosed base of the elevator leg and is located in the basement or in a sub basement pit The tunnel houses the reclaim conveyor beneath the annex bins The truck dump is the area above the dump pit Elevator Leg Fig 1 Illustration of the inspection and sampling locations in grain elevators ARTICLE IN PRESS where grain enters the elevator from trucks The rail load area usually is a covered part of the railroad track that passes close to the elevator Samples collected on the rail line including those collected in the rail load area were designated as rail line samples The main elevator legs are housed in the headhouse The roof of the grain storage bins forms the floor of the bin deck level of the headhouse and annex es The bin deck level contains spouts that transport the grain from the elevator leg to the bins or to lateral conveyors Elevator boot areas and boot pits are often damp and the temperature in them is moderated by the subterranean location Spills and residues in this area result from clean out of the elevator boot rare or spills from worn spouts Spills in the tunnel area are often exposed to water from leaks in the wall or floor and the temperature in the tunnel is moderated by its subterranean location The pit of the truck dump is nearly self cleaning because most residues from a previous load are flushed when new grain is subsequently moved through the pit However spills often occur around the dump pits these residues are exposed to ambient air The railroad line is outside the facility and is usually covered by a roof where it passes over the dump pit Spills on the rail line are often the result of railcar clean out Residues in the headhouse ground level consisted of spills from worn grain spouts Spills on the bin deck level may be due to worn spouts or spills from the conveyor belt Typically they are exposed to ambient conditions The amount of grain residue was recorded monthly for each elevator Quantities of residues were estimated by the sampler as either p1 5kg 41 5kg p27kg about one bushel 1 5kgp27kg 5bu and 4135kg Samples of the residues were collected as randomly as possible When the quantity of residue was small it was brushed into a dustpan and placed in a sample bag When a large amount of residue or spillage was present several kg samples were collected from different locations and placed in labeled sample bags Samples were transported to the laboratory where they were weighed and characterized as to grain type Extremes of heat or cold were avoided during sample transport and the samples were stored at room temperature for a maximum of five days before analysis To facilitate accurate identification of insects each sample was sieved through various wire mesh screens to separate as much as possible the live insects from the grain and trash Adults of Typhaea stercorea L hairy fungus beetle R dominica and Ahasverus advena Walt foreign grain beetle were identified to species Adults of the following were identified to genera because closely related species are sometimes found in stored grain Sitophilus Cryptolestes Tribolium and Oryzaephilus Adults of the four parasitoid wasps Habrobracon Bracon hebetor Say Anisopteromalus calandrae Howard Theocolax Choetospila elegans Westwood and Cephalonomia waterstoni Gahan also were identified to species Data for the two years in which these samples were collected were combined and the Statistical Analysis System SAS Institute 2001 was used to analyze these data Raw data were transformed using the square root in an attempt to normalize variances for purposes of means testing but non transformed means and other statistics are reported here to facilitate intuitive interpretation Insect density is reported as the number of live adult insects per kg of residue The general linear models GLM procedure was used to determine the significance of various factors with respect to insect distribution When a significant model effect was observed means were separated using the Waller Duncan k ratio t test The correlation procedure CORR was used to correlate numbers of beneficial insect species with those of their primary host among the pest insect species The F H Arthur et al Journal of Stored Products Research 42 2006 226 239 229 frequency procedure FREQ was used for categorical analysis and w 2 tests ARTICLE IN PRESS F H Arthur et al Journal of Stored Products Research 42 2006 226 239230 3 Results In total 46 725 pest insects and 933 beneficial insects were collected and identified from 1575 grain residue samples The mean sample size was 559 6712 5g SE of grain residue The mean insect population density varied from 16 5 to 66 2 kg between individual grain elevators Table 1 but means were not significantly different because variability was great Because there was no significant relationship r C00 28 P 0 42 between the storage capacity of the elevator and the insect density all species combined data from all elevators were combined for further analysis The predominant insect species in all residue samples were Sitophilus spp and Cryptolestes spp comprising 50 3 and 30 7 respectively of the total number of insects collected In the majority of the residue samples 58 3 no pest insects were found Of the samples in which pest insects were found 3 2 contained p1 insect kg 44 7 contained 41 insects p10 kg 39 6 contained 410 p100 insects kg and 12 5 contained 4100 insects kg The highest density of pest insects all species and of Sitophilus spp in particular was found in the smallest residues o1 5kg compared with the other three size categories Table 2 The density of the other insect species did not differ significantly by estimated size of the residue Samples from residues found in or near the elevator boot pit and tunnel contained higher insect densities than did residues from the dump pit headhouse or rail line Table 3 This relationship was true for each of the dominant species individually For example the density of both Sitophilus spp and Cryptolestes spp was more than four times greater in samples from or near the boot pit than in samples from the dump pit headhouse areas or on the rail line Density of Tribolium spp in samples from the boot pits and tunnels was at least twice as great as from any of the other locations Samples identified as wheat were the most common type 42 8 Other residue samples were identified as maize 17 7 sorghum 14 0 a mixture of wheat and sorghum 3 4 or a mixture of maize wheat and sorghum 14 1 About 8 4 were called other because the material consisted of uncommon mixtures of grains and dust Mixtures of wheat and sorghum had a greater density of Sitophilus spp and all species combined than did samples of either sorghum or wheat individually and the population density of Tribolium spp was lowest in residues that contained only sorghum Table 4 The density of Sitophilus spp was markedly different in residues of different grains with an average of nearly 31 kg in wheat sorghum mixtures but less than 7 kg in sorghum residues The density of Tribolium spp also was significantly affected by the composition of the residue Of the species present in high numbers only the density of Cryptolestes spp was not affected by type of grain in the residue sample Table 4 Of the insects found only in low numbers a significantly higher density of T stercorea was found in the samples classified as a mixture of wheat maize and sorghum than any other type of sample The mean density of T stercorea R dominica A advena and Oryzaephilus spp in the residue samples did not exceed 2 insects kg regardless of the time of year Fig 2A D Numbers of T stercorea peaked in April and September the beginning and the end of the warm season and were low at other periods Densities of Oryzaephilus spp also showed two peaks in June and October In contrast the greatest densities of R dominica were observed in three consecutive winter months The density of Sitophilus spp was 45 insects kg in the residue samples throughout the year except for the coldest winter months which suggests that low temperatures ARTICLE IN PRESS Table 1 Density of live adult pest insects per kilogram mean 7 SE from residues collected over all sampling times percentage of residue samples infested with pest insects and total number of samples and adult live beetles of each species by elevator Elev Elev n a Sitophilus Cryptolestes Tribolium Typhaea stercorea Rhyz opertha dominica Oryzaephilus Ahasverus advena Total Infested A 6 4 5 94 7 4 02 16 52 7 9 28 1 66 7 1 19 0 00 7 0 00 0 27 7 0 16 0 08 7 0 08 0 00 7 0 00 24 47 7 11 68 43 8 B 9 4 17 05 7 6 87 0 87 7 0 40 0 86 7 0 52 0 07 7 0 07 0 32 7 0 17 0 32 7 0 23 0 19 7 0 11 19 68 7 7 09 30 8 C 124 31 28 7 12 59 6 22 7 1 88 2 51 7 0 87 0 04 7 0 03 0 09 7 0 04 0 28 7 0 10 0 05 7 0 05 40 45 7 13 86 47 6 D 152 13 45 7 3 36 51 33 7 33 65 0 53 7 0 20 0 25 7 0 09 0 50 7 0 19 0 03 7 0 02 0 04 7 0 03 66 15 7 35 71 46 7 E 192 7 91 7 3 23 17 31 7 8 28 2 58 7 1 99 0 12 7 0 08 0 97 7 0 47 0 14 7 0 10 0 33 7 0 33 29 35 7 9 85 41 7 F 174 12 04 7 3 78 5 38 7 2 11 2 22 7 0 89 0 17 7 0 09 0 09 7 0 08 0 24 7 0 10 0 03 7 0 02 20 18 7 5 74 44 8 G 186 29 15 7 7 25 6 04 7 1 62 14 60 7 10 74 0 13 7 0 10 0 04 7 0 03 0 28 7 0 13 0 14 7 0 10 50 37 7 13 85 54 8 H 311 4 79 7 1 88 5 20 7 1 75 4 17 7 2 38 0 92 7 0 64 0 08 7 0 52 0 55 7 0 42 0 04 7 0 04 16 48 7 4 99 37 3 I 278 11 29 7 3 44 0 89 7 0 29 3 28 7 2 32 0 05 7 0 03 0 17 7 0 11 0 81 7 0 57 0 03 7 0 02 16 52 7 4 33 33 8 Total 1575 21 570 16 960 6384 428 644 591 144 46 725 a n number of samples Table 2 Number of live adult insects a per kg mean 7 SE and percentage of residue samples infested with pest insects by estimated size of residue Residue size Kg Sitophilus Cryptolestes Tribolium Typhaea stercorea Rhyzopertha dominica Oryzaephilus Ahasverus advena Total Infested o 1 5 19 36 7 3 31a 16 46 7 7 34a 6 40 7 3 06a 0 30 7 0 18a 0 39 7 0 12a 0 46 7 0 22a 0 15 7 0 09a 43 52 7 9 17a 44 0 1 5 27 9 83 7 2 15b 3 83 7 0 89a 3 07 7 1 44a 0 38 7 0 33a 0 53 7 0 33a 0 47 7 0 30a 0 07 7 0 04a 18 16 7 3 23b 40 5 27 135 10 19 7 3 11b 9 46 7 5 23a 0 74 7 0 25a 0 07 7 0 04a 0 20 7 0 11a 0 14 7 0 07a 0 03 7 0 02a 20 84 7 7 44b 39 1 4 135 5 33 7 1 79b 8 42 7 6 23a 1 39 7 0 69a 0 10 7 0 06a 0 46 7 0 30a 0 06 7 0 04a 0 00 7 0 00a 15 78 7 7 28b 39 1 Data combined over all elevators and sampling visits n 705 482 230 and 158 for each size category from smallest to largest Means within columns followed by the same letter are not significantly different P X 0 05 Waller Duncan k ratio t test SAS Institute a ANOVA model significant with respect to total number of insects PROC GLM SAS Institute F 6 2 df 3 1571 P o 0 01 F H Arthur et al Journal of Stored Products Research 42 2006 226 239 231 ARTICLE IN PRESS Table 3 Number of live adult insects a per kg mean 7 SE and percentage residue samples infested with pest insects by inspection location Location Sitophilus Cryptolestes Tribolium Typhaea stercorea Rhyzopertha dominica Oryzaephilus Ahasverus advena Total Infested Boot pit 40 08 7 7 90a 9 31 7 2 80ab 10 94 7 5 73a 0 14 7 0 06a 0 70 7 0 35a 1 23 7 0 56a 0 11 7 0 08ab 62 54 7 12 92a 71 1 Dump pit 8 52 7 1 54b 6 50 7 1 66bc 1 11 7 0 27b 0 43 7 0 29a 0 44 7 0 19a 0 14 7 0 04b 0 02 7 0 02b 17 16 7 2 56b 45 3 Headhouse 3 38 7 1 44c 6 88 7 2 74bc 1 47 7 0 48b 0 09 7 0 04a 0 23 7 0 08a 0 07 7 0 04b 0 01 7 0 01b 12 10 7 3 48b 29 7 Rail line 8 16 7 2 41b 2 61 7 1 42c 4 76 7 4 30b 1 17 7 1 07a 0 14 7 0 10a 1 01 7 0 95b 0 05 7 0 04b 17 89 7 5 96b 35 4 Tunnel 37 09 7 8 49a 33 97 7 20 94a 11 31 7 8 20a 0 01 7 0 01a 0 80 7 0 65a 0 67 7 0 54b 0 43 7 0 27a 84 28 7 25 24a 53 1 Data combined for all elevators and sampling visits n 142 417 626 147 and 243 for each location from top to bottom Means within columns followed by the same letter are not significantly different P X 0 05 Waller Duncan k ratio t test SAS Institute a ANOVA model significant with respect to total number of insects PROC GLM SAS Institute F 29 3 df 4 1570 P o 0 01 Table 4 Number of live adult insects a per kg mean 7 SE and percentage residue samples all elevators and visits infested by pest insect by grain type in the residue including wheat W maize M sorghum S wheat sorghum WS wheat sorghum maize WSM and other O Grain n b Sitophilus Cryptolestes Tribolium Typhaea stercorea Rhyzopertha dominica Oryzaephilus Ahasveru