reported that .Thus,efficacy 10 yofAgriculturalZoology Lepinotus reticulatus a reported that spinosad 11 . tomology, Agricultural University of et al found that L. bostrychophila (L.) (Coleoptera: Curculionidae). 3 and is in the public domain in the USA ;maize;rice;wheat G Athanassiou,Laborator ost effective insecticides for all species Sitophilus oryzae 12 Liposcelis paeta ; and James E Throne a 7 and 14 days of exposure, while progeny production was Correspondenceto:Christos and Entomology, AgriculturalAthens, Greece. University E-mail: [email protected] of Athens, 75 IeraUSDA-ARS Odos, Grain 11855 Marketing andAvenue, Manhattan, Production KS 66502, Research USA Center, 1515 College Laboratory of Agricultural Zoology and En Athens, 75 Iera Odos, 11855 Athens, Greece Most studies evaluating efficacy of grain protectants on psocids icularly in amylaceous commodities such as grains. Currently, ∗ a b was less effectivethe on rice weevil, maize thanSimilar results on have wheat beenazadirachtin. against reported adults with of plant extracts such as Enderlein (Psocoptera: Trogiidae)population was levels able on tostudies wheat show achieve and that greater contact riceof insecticides efficacy than among may different have commodities, on even different though maize.protectants most levels are grain labeled Previous with one dose ratecommodity. regardless Moreover, of Athanassiou the target species above were extremelyanalogue tolerant to (JHA) the methoprene. juvenile In hormone contrast, Bucci fenoxycarb was effective against have been done on wheat. However, psocid development isaffected highly by diet. Opit and Throne of insecticides for beetles and mothsis or even not other psocid species necessarilyparticular a psocid good species. predictor of efficacy for control of a Lepinotus reticulatus, Liposcelis entomophila, L. bostrychophila icides; however, newer data indicate that psocids are tolerant . Progeny production was consistently lowest on wheat and rice as more effective on maize than spinosad or pyrethrin. In most is study evaluated the insecticides registered in the USA for use um was highly dependent on the psocid species and commodity. 4 . L. 4,7 et al deltamethrin was generally more effective against exposed parental Liposcelis entomophila ; + while the latter Frank H Arthur L. bostrychophila, 4 ∗ was found to be very Currently, psocids are deltamethrin and pirimiphos-methyl were the m were tolerant to the a,b 2 Moreover, Nayak Liposcelis bostrychophila + deltamethrin and maize treated with pirimiphos-methyl. 8 also found that the three Pearman, while a survey of + 4 . Liposcelis bostrychophila et al 1–3 ; L. paeta Recent studies indicate that their 1 L. bostrychophila L. entomophila Nayak 9 : 1140–1146 www.soci.org This article is a US Government work and In the case of contact insecticides, the use 65 4–6 (Enderlein) and . However, 2009; . Mortality of exposed adult females was recorded after Lepinotus reticulatus L. paeta

L. paeta

Ithasgenerallybeenconsideredthatinsecticidesusedtocontrol development is possible in whole grains. other stored-product pestsHowever, recent are studies document also that the mostspecies effective common found psocid in against stored grains psocids. appearfumigants to be tolerant and to traditional contactbeetle and insecticides moth species. at For example, rates lethal to major Badonnel (Psocoptera: Liposcelididae) is one ofstored-product the most species resistant to thethe fumigant phosphine, egg especially stage. in populations from the first two species indicated thatis this tolerance a natural phenomenon and is not related to resistance. of the carbamateL. entomophila carbaryl failed to control organophosphate (OP) chlorpyriphos-methyl, Pest Manag Sci showed that the three speciespyrethroid noted deltamethrin above were applied tolerant eitherbutoxide, to alone while the the or OP with pirimiphos-methylbostrychophila piperonyl was able to control resistant to dichlorvos. Similarly, 1INTRODUCTION Psocoptera, known as booklicein or psocids, stored-product are frequentlyin grains, found amylaceous often products. in extremely high numbers, to insecticides used to control other stored-grain species. Th Abstract BACKGROUND: Psocids are emerging pests in stored products,their part control is based on the use of fumigants and contacton stored insect maize, rice and wheatand for control of the psocidassessed species after 30 days of exposure. RESULTS: On wheat and rice, chlorpyriphos-methyl psocid species on maize, rice and wheat Christos G Athanassiou, Efficacy of grain protectants against four (www.interscience.wiley.com) DOI 10.1002/ps.1804 Research Article Received: 22 January 2009 Revised: 2 April 2009 Accepted: 11 May 2009 Published online in Wiley Interscience: 22 June 2009 adults than spinosad or pyrethrin,cases, progeny while production pirimiphos-methyl was suppressed w in the treated grains Keywords: treated with chlorpyriphos-methyl CONCLUSIONS: Chlorpyriphos-methyl and commodities. Conversely, efficacy of spinosadPublished or 2009 pyrethr by John Wiley & Sons, Ltd. perhaps the most important category ofgrains emerging pests and in related stored commodities. species was tolerant also tomethyl the with combined the use of pyrethroid chlorpyriphos- bifenthrin.

1140 1141 for the 1 9cm)on (Northern − ×  deltamethrin, 23 + × deltamethrin, and deltamethrin, with insecticide). Hence, + + × 4 individuals vial < tment (66%) was still lower than www.interscience.wiley.com/journal/ps Means were separated by the Tukey–Kramer HSD 15 14 The boxes were then placed in an incubator maintained at Lepinotus reticulatus Liposcelis entomophila C. Three of the nine vials were examined for mortality after 13 ◦ Allinsecticidesreducedprogenyproductioninwheatcompared 30 in the centre that wasinternal covered ‘neck’ with of fine-mesh brass the screen. vials The was covered with Fluon with untreated controls (Tables 1 and 2),pyrethrin with treatment more progeny than in the the other insecticides.found No progeny in were the spinosad-treatedhigher wheat. in rice Progeny than productionproduced in in was pyrethrin-treated rice wheat did not or differthat significantly maize. from in The the number control of vials, psocids but was 3RESULTS 3.1 After 7 days of exposure,wheat all adults treated were with deadpercentage in chlorpyriphos-methyl mortality vials was containing not statisticallywheat treated different with spinosad from (Tables 100% 1 and in 2).did In not contrast, mortality exceed 42% inmortality the in pyrethrin the treatment. spinosad treatments Seven was daysmortality only later, slightly in higher, and the pyrethrinmortality trea in thedead other in treatments. rice After treatedwhile 7 with days, mortality chlorpyriphos-methyl all in adultslower the compared were with mortality spinosad on wheat. and Aat similar the pyrethrin trend 14 occurred day treatments exposures, with was nobetween significant the difference pyrethrin in treatment mortality and the controls.dead All after adults were 7 daysmethyl. of After exposure 14 on days of corntreated exposure, treated mortality with with was spinosad, pirimiphos- 100%treatment on had and maize was increased 61% in to untreated controls. 87% in the pyrethrin the data were analyzeddifferences using among treatments a (insecticides one-wayeach and species, ANOVA commodity controls) to and within exposure determine interval,6 by using software. the JMP 7 days, and three were examinedprogeny for mortality production after was 14 recorded days, while 30of days after the the introduction parentalwere individuals repeated 3 in times the byuntreated preparing grains remaining each different time. lots three of vials. treated and Tests 2.5 Data analysis Given that different insecticides(Storicide were II used was on used eachonly only commodity on on maize), the wheat entire and dataseteffects could rice, and not Actellic be interactions was analyzed for (e.g. used main commodity Products, Woonsocket, RI)All to vials were prevent thenfalse psocids floors placed below, from in with escaping. black saturatedRH. NaCl boxes solution (30 to maintain 75% no significant differencespyrethrum in (Tables 1 and mortality 3). Seven between days spinosad later, mortality and on wheat other two insecticides. Finally, progenymaize than production in was wheat lower or in progeny rice. production All compared insecticides with significantly that reduced inno progeny untreated were maize, found and in maize treated with pirimiphos-methyl. 3.2 Complete mortality afterwheat 7 days treated of with exposure chlorpyriphos-methyl occurred only on test at 0.05. ; 1 − (voucher L. entomophila and is in the public domain in the USA (#207). All species L. reticulatus ; Dow Agrosciences, 1 − ; Agriliance, St Paul, MN), L. paeta 1 − C and 75% RH. Adult females ◦ of chlorpyrifos-methyl and 37 mg deltamethrin (Storicide II, 216 mg 1 − + (#202) and : 1140–1146 This article is a US Government work 3 65 2009; of deltamethrin; Bayer Crop Science, Research Triangle L. bostrychophila 1 − 4 weeks old) for use in the tests were obtained by placing So far, there has been no published information on the < Grain protectants against psocids www.soci.org were reared on a mixturekrispies of and 97% 1% cracked wheat wheat germ kernels, at 2% 30 rice Park, NC), whichof is 3 registered ppm on(b) of spinosad wheat chlorpyriphos-methyl and (NAF and rice 313, 0.5 at ppm the 84 deltamethrin; mg rates AI mL MGK, Minneapolis,wheat MN), and which maizemethyl is (Actellic and registered 5E, 2.2 at 480 ppm mg 1.6 AI for ppm mL rice; for and (d) pirimiphos- 2.3 Insects The psocid species used in the tests were which is registered onwere maize evaluated at only 8registered. ppm. on The the above commodities insecticides for which they are specimen #181 placed in theEntomological Kansas and State University Prairie Museum Arthropod(#182), of Research), effectiveness of grain protectantsagainst that some are of registered the in most commonobjectives the psocid USA of species. Therefore, the the presentof study were grain (1) protectants tospecies, registered evaluate the in and efficacy the (2) tocommodities USA – examine maize, against rice variations four and wheat. in psocid efficacy among three AI mL Pest Manag Sci 2.4 Bioassays Lots of 0.5 kgdoses of of the each aforementioned grain insecticidesartists’ by were airbrush using (Badger sprayed a Air-Brush Badger withdispense Company, 100 Franklin the the Park, insecticides respective IL) atthe to a label volume rate, that whichcommodity was to depended be proportional treated. on Another to series the ofequivalent lots volumes specific were of sprayed tap water insecticide with to serve and as theEach untreated controls. individual treatment–commodityuntreated controls, combination, was placed including in aspecies, 0.48 nine L aliquots glass of jar. Then, 10placed for g in each each cylindrical plastic were vials taken (31296 from cm in each vials diameter, jar 8 for cm and in allwere height, placed grains). in Ten each adult vial. females The of vials a had single a species plastic lid with a hole active ingredient [AI] mL 2.2 Insecticides Four commerciallyefficacy available against insecticides psocidsspecific were at grain commodities evaluated the in(a) for labeled the chlorpyriphos-methyl USA. rates These for insecticides were: their use in 22.1 MATERIALS AND METHODS Commodities Untreated, clean and infestation-free wheat (a mixture of var.and Fuller var. Santa Fe), rice (Francis)were and maize used (hybrid in Asgrow the RX899) tests.the Before the moisture beginning content of theto of 13.5%. experiments, the three commodities was adjusted ( females to oviposit in dishes containing coloredby diet, Opit as and described Throne. Indianapolis, IN), whichmaize has and a rice; label (c) pyrethrin rate (PyGanic of Pro 1 SC, ppm 50 for mg wheat, AI mL 5b 9b 7c . . . 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 3b 3b 2a 0a 1a 0a 0a 2a 0a ...... < < < < < < < < < 13 8 13 11 6 0 0 0 1 1 0 0 ± ± ± ± ± ± ± ± ± ± ± ± 6 7 1 8 6 2 0 1 6 3 2 0 ...... : 1140–1146 65 2009; deltamethrin. There deltamethrin at the deltamethrin, but it + + + 9c 29 0b 3 5b 11 . . . 0a 0 0a 0 0a 1 0a 0 8b 0 1 c 115 8c 91 4c 60 4a 0 0.01 17.9 0.01 5.7 0.01 47.9 0.01 49.2 0.01 24.4 0.01 29.8 0.01 36.6 0.01 186.9 0.01 123.9 ...... 0 0 0 0 11 5 4 8 13 7 13 2 < < < < < < < < < Pest Manag Sci ± ± ± ± ± ± ± ± ± ± ± ± 0 0 0 0 1 7 5 3 1 1 7 7 ...... Exposure (days) 5 ppm, respectively, for wheat and rice, (b) spinosad . 0 + 3, 32) Species 4b 61 2b 86 2b 65 . . . = 0 a 100 0 a 100 0 a 100 8 a 100 0c 14 4b 71 3c 21 5a 96 4d 15 ...... 0 0 0 11 11 3 6 9 5 14 4 2 0.01 10.0 0.01 19.7 0.01 26.3 0.01 16.1 0.01 20.6 0.01 37.7 0.01 88.2 0.01 66.2 0.01 51.8 ± ± ± ± ± ± ± ± ± ± ± ± < < < < < < < < < Liposcelis bostrychophila 0 0 0 4 8 5 4 0 0 1 4 8 ...... 7 (mortality) 14 (mortality) 30 (progeny) ties (within each column and commodity, means followed by the same and 3). Progeny productionsimilar on to rice that treated inin with rice the pyrethrin treated controls, with was but chlorpyriphos-methyl no progeny were produced remained at low levels in the other insecticide treatments. All were no progeny produced in themethyl, maize and treated with progeny pirimiphos- productionwith spinosad was and reduced pyrethrin. in maize treated 3.3 As with the other psocidwheat species, there treated were more with deadwith adults chlorpyrifos-methyl in than either in(Tables spinosad 1 wheat or treated and 4).but pyrethrin Mortality higher after was thanslightly extremely 7 that days increased low in at ofof for the 14 days, exposure control pyrethrum, the and vials.rice did treatments. Mortality treated not Significantly was with reach7 only day chlorpyriphos-methyl more 100% in exposure adults any was interval. were After 100% dead 14 for days in of chlorpyriphos-methyl exposure, mortality + chlorpyriphos-methyl at 3 + adults after 7 and 14 days of exposure, and mean progeny production (live individuals This article is a US Government work 0.01 15.5 0.01 20.5 0.01 26.7 0.01 36.7 0.01 5.0 0.01 22.0 0.01 35.4 0.01 36.8 0.01 18.9 and is in the public domain in the USA < < < < < < < < < www.soci.org CG Athanassiou, FH Arthur, JE Throne deltamethrin 100 deltamethrin 100 a + + deltamethrin(Tables 1 + L. reticulatus L. bostrychophila L. entomophila L. paeta FPF P F P FP deltamethrin. Mortality on Lepinotus reticulatus + 9%, and did not differ from < SE) of ± ifferent; HSD test at 0.05) Control 34 Pyrethrum 57 Spinosad 94 Control 6 Pyrethrum 23 Spinosad 80 Control 10 Pyrethrum 41 Spinosad 94 Maize 13.0 Rice 37.2 Maize 7.6 Rice 27.8 Maize 14.4 Rice 60.9 -values from ANOVA for each commodity and species tested (in all cases, df Mean mortality (% F SE) after 30 days of exposure in the treated and untreated commodi ± 1 − For the insecticides used, the dose rates were (a) deltamethrin 7 days Wheat 30.2 Progeny production on wheat was significantly suppressed with Maize Pirimiphos-methyl 100 Rice Chlorpyriphos-methyl 30 days Wheat 19.2 letter are not significantly d a Wheat Chlorpyriphos-methyl Commodity Treatment Table 2. Exposure Commodity Table 1. 14 days Wheat 22.0 at 1 ppm for all commodities, (c) pyrethrum at 1.6 ppm for wheat and maize and at 2.2 ppm for rice and (d) pirimiphos-methyl at 8 ppm for maize. vial www.interscience.wiley.com/journal/ps treated with spinosad increased56% to on 84%, wheat butrice treated it than did with not pyrethrin. intreated exceed Mortality with wheat, chlorpyriphos-methyl was with lower 96% in mortality after 7 days in rice deltamethrin, but the increase inother mortality was treatments. negligible All for adults the on were maize dead treated after with 7 pirimiphos-methyl,mortality days between with the of no pyrethrin exposure treatment differences and in the14 controls. days After of exposure, 99%with of spinosad the were exposed dead, adults and inon there maize maize was treated treated an with increase pyrethrin indifference such between mortality that this there treatment was and the a controls. significant all three insecticides in comparisontheuntreatedwheat,butthegreatestlevelofsuppressionoccurred with progeny production on inwheattreatedwithchlorpyrifos-methyl mortality in untreated controls. Afterwas the 100% mortality 14 day on rice exposure, treated there wtih chlorpyriphos-methyl rice treated with pyrethrin was

1142 1143 1c 6c 5c 3b 0c 3b 1c 0c 0b 0b ...... 5c 0b 6b 0a 2a 0a 9b 1a 9ab 8b 4ab 0a 3a 6a ...... 14 9 17 21 9 1 0 0 0 1 0 5 19 49 14 21 16 6 21 18 0 0 0 0 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 5 9 1 0 4 5 0 3 0 1 2 7 5 5 9 8 7 9 0 3 0 9 3 7 ...... deltamethrin, but deltamethrin, but + + deltamethrin, there was 5b 8 8c 26 + . . 1 b 106 1c 52 2b 42 0a 0 0a 0 0a 0 1c 65 1a 0 7c 81 8c 82 6b 6 7d 84 8b 7 ...... 0a 0 0a 0 3c 82 8c 1 7b 10 6 bc 134 1a 0 4 c 298 3 d 161 ...... 0 0 0 4 12 1 4 5 4 4 11 7 0 0 5 7 7 9 10 1 11 10 2 3 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 0 0 0 4 0 9 0 7 3 3 6 4 ...... 0 0 5 3 4 5 7 9 0 6 7 8 ...... Exposure (days) Exposure (days) www.interscience.wiley.com/journal/ps 5 ppm, respectively, for wheat and rice, (b) spinosad 5 ppm, respectively, for wheat and rice, (b) spinosad . . 0 0 + + 2b 52 1b 55 0b 84 6b 76 6b 45 . . 5b 75 . 0 a 100 0 a 100 9c 14 6c 60 4b 98 4 a 100 6c 10 5c 16 9c 13 . . . 0 a 100 . . 1c 23 . . . 7 a 100 7bc 26 . 4a 98 9c 30 6c 13 5c 9 . . 7d 6 ...... 0 0 6 7 4 4 10 13 14 2 3 2 0 5 12 6 9 11 1 5 13 2 4 1 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Liposcelis paeta 0 0 6 8 0 6 2 8 2 3 9 6 0 . . 9 . 1 . . 3 3 . 9 . 8 8 . 5 . 9 9 . . 3 ...... 7 (mortality) 14 (mortality) 30 (progeny) 7 (mortality) 14 (mortality) 30 (progeny) ties (within each column and commodity, means followed by the same ties (within each column and commodity, means followed by the same mortality for the other two insecticidesfrom did the not control. differ At significantly thethe 14 rice day treated exposure, mortality withremained was chlorpyriphos-methyl 100% at in low levelswas for nearly the 100% other after 7 two days insecticides. of Mortality exposure in maize treated with 3.4 All adults weretreated dead with after chlorpyriphos-methyl lower 7 days mortality in ofdifferences the in exposure mortality spinosad between in the treatment pyrethrincontrols the treatment and (Tables and 1 there wheat the and were 5).only At slightly no increased the for the 14 day spinosadAlmost and all exposure, of pyrethrin the exposed treatments. mortality adults were was dead after 7in days of rice exposure treated with chlorpyriphos-methyl L. chlorpyriphos-methyl at 3 chlorpyriphos-methyl at 3 + + adults after 7 and 14 days of exposure, and mean progeny production (live individuals adults after 7 and 14 days of exposure, and mean progeny production (live individuals and is in the public domain in the USA deltamethrin 95 deltamethrin 100 deltamethrin 93 deltamethrin 97 a a + + + + Liposcelis entomophila Liposcelis bostrychophila SE) of SE) of ± ± ifferent; HSD test at 0.05) ifferent; HSD test at 0.05) Control 15 Pyrethrum 17 Spinosad 90 Control 3 Pyrethrum 8 Spinosad 52 Control 5 Pyrethrum 47 Spinosad 61 Control 8 Pyrethrum 18 Spinosad 71 Control 8 Pyrethrum 23 Spinosad 48 Control 3 Pyrethrum 17 Spinosad 74 : 1140–1146 This article is a US Government work 65 in rice was the highest among the species tested, 2009; Mean mortality (% Mean mortality (% SE) after 30 days of exposure in the treated and untreated commodi SE) after 30 days of exposure in the treated and untreated commodi ± ± 1 1 − − deltamethrin (Tables 1 and 4). Progeny production of For the insecticides used, the dose rates were (a) deltamethrin For the insecticides used, the dose rates were (a) deltamethrin There were generally large numbers of progeny produced Maize Pirimiphos-methyl 100 Maize Pirimiphos-methyl 100 Rice Chlorpyriphos-methyl Rice Chlorpyriphos-methyl letter are not significantly d letter are not significantly d a CommodityWheat Chlorpyriphos-methyl Treatment Table 4. a vial CommodityWheat Chlorpyriphos-methyl Treatment Table 3. vial at 1 ppm for all commodities, (c) pyrethrum at 1.6 ppm for wheat and maize and at 2.2 ppm for rice and (d) pirimiphos-methyl at 8 ppm for maize. at 1 ppm for all commodities, (c) pyrethrum at 1.6 ppm for wheat and maize and at 2.2 ppm for rice and (d) pirimiphos-methyl at 8 ppm for maize. Grain protectants against psocids www.soci.org Pest Manag Sci in wheat treatedligible with production either in spinosad+ wheat or treated pyrethrin, with chlorpyriphos-methyl but neg- adults died afterpirimiphos-methyl, while 7 days no significantbetween of differences pyrethrum exposure were and noted interval, in the similar trends maize control. were noted, At treatedmortality. with the only with a 14 slight day increase exposure in and especially high in the riceNo progeny treated production with occurred in spinosad maize treated or with pirimiphos- pyrethrin. methyl, and fewer progenyspinosad were treatments. produced in the pyrethin and bostrychophila 19 . ± 9c 2d 2c 1 . . . 4c 2b 4b 1b 8ab 0a 8bc 6a 1a − ...... adults et al 6 7 12 4 15 2 12 1 0 1 0 0 L. paeta. ± ± ± ± ± ± ± ± ± ± ± ± 1 3 7 0 1 6 1 7 0 2 8 2 was higher ...... : 1140–1146 65 S. oryzae L.bostrychophila the present data 3 2009; Corcyra cephalonica and on rice and maize. The L. reticulatus , as mortality in untreated However, the present results 4bc 8 5b 41 5b 40 . . . 0a 0 0a 0 0a 0 1d 18 9cd 2 4b 35 7c 11 6c 93 8c 93 22 ...... 0 0 0 4 5 11 12 6 4 11 1 1 L.reticulatus Pest Manag Sci ± ± ± ± ± ± ± ± ± ± ± ± 0 0 0 1 9 8 1 8 4 6 4 6 ...... L. reticulatus L. entomophila Exposure (days) and there were no significant differences Many of these insecticides have been evalu- reared on maize were always more susceptible 5 ppm, respectively, for wheat and rice, (b) spinosad . 0 + 12,20,21 S.oryzae 0 a 100 3b 14 3b 18 5 a 100 8b 37 1 a 100 9b 31 7b 18 3c 14 7b 55 7b 3 2c 5 ...... 0 3 3 1 3 1 7 3 6 7 1 3 L. entomophila ± ± ± ± ± ± ± ± ± ± ± ± 0 3 0 8 7 9 7 0 5 7 3 8 ...... Newer insecticides, such as metabolite-based substances or 7 (mortality) 14 (mortality) 30 (progeny) in population growth of present results support previousa studies relatively showing poor diet thatcontrols exceeded for maize 60% after is 14 days. Conversely, controlfor mortality the othercommodities. However, three apart specieslikely from to was control have generally mortality,that, a maize negative low for effect is all on onthan species, all psocid for progeny development, the three production given While other was this three lower effect commodities,chemical on is properties especially maize apparently of for the influenced commodities by used, the physical and ated with success againstcases many stored-grain have pests, proven andample, in more some was effective more than effectiveon OPs. than sunflower pirimiphos-methyl Spinosad, seeds on for against(Stainton) maize (Lepidoptera: ex- Pyralidae). the or rice moth, are indicative only forand the hence generalizations varieties/hybrids should be tested avoided. Athanassiou in this study, show that OPs are superior to spinosad and pyrethrum for the diet. In that study, populationon growth of wheat anddiet rice for than on maize, while wheat was the best reported that the rearingemerged before medium exposure from to which that DEs study, affected their susceptibility. In to DEs than thoseDE-treated reared substrate. on This characteristic wheat mayeffect or on have barley, the some efficacy regardless indirect of ofhere. insecticides Taking the for into account the the psocid overall progeny species production,the tested most rice suitable was commodity for plant extracts, are promisingas for wider alternatives use to asto grain traditionally mammals. protectants, used OPs which are very toxic for both treated and untreated substrates. Inmostcaseswasloweronricethanontheothercommodities,which addition, mortality in may be directly related more with developmental parameterswith than the insecticidal efficacy per se. (within each column and commodity, means followed by the same letter are 16 . chlorpyriphos-methyl at 3 found et al + 17 . et al have different , while efficacy This article is a US Government work and is in the public domain in the USA adults after 7 and 14 days of exposure, and mean progeny production (live individuals vial www.soci.org CG Athanassiou, FH Arthur, JE Throne deltamethrin 98 deltamethrin 100 a + + Rhyzoperthadominica through differences in S. oryzae L. entomophila Liposcelis paeta Inthecaseofpsocids,Opitand and 18 SE) of R. dominica ± Control 13 Pyrethrum 10 Spinosad 16 Control 3 Pyrethrum 15 Spinosad 10 Control 7 Pyrethrum 14 Spinosad 46 noted that spinosad dust performance varied L. reticulatus 11 . et al Variations among cultivars of a specific commodity, Mean mortality (% found that 3 For the insecticides used, the dose rates were (a) deltamethrin Progeny production was significantly suppressed in wheat Maize Pirimiphos-methyl 97 Rice Chlorpyriphos-methyl a CommodityWheat Chlorpyriphos-methyl Treatment Table 5. SE) after 30 days of exposurenot in significantly the different; treated HSD and test untreated at commodities 0.05) at 1 ppm for all commodities, (c) pyrethrum at 1.6 ppm for wheat and maize and at 2.2 ppm for rice and (d) pirimiphos-methyl at 8 ppm for maize. of this dust didR. not dominica. vary with commodity in tests with adults of as well asdevelopment variations of stored-grain among insects, which may commodities,affect in turn the will indirectly susceptibility also to affect insecticides. the Chanbang on wheat, rice and maize against adults of population growth rates on different types of amylaceous-based that the hull characteristicsa of higher certain infestation rice leveloviposition varieties by and may induce insectto fecundity. use For varietal this resistancecertain protectants reason, as such it as a DEs. is control tool feasible in conjunction with www.interscience.wiley.com/journal/ps found that certain diatomaceous earths (DEs) had different efficacy levelsagainstadultsofthelessergrainborer, (F.) (Coleoptera: Bostrychidae) on eightAthanassiou grain commodities. Also, 4The DISCUSSION four species testedto varied the remarkably insecticides, in theirthe and three susceptibility there commodities. The was characteristicsare also of a variation key grain in elements commodity contact-insecticide-based efficacy that strategy, in on spite are of evidence that often shows insecticidal overlooked efficacy will when often planninginsecticide vary and the a depending commodity that is upon treated. This the isin often trials specific the with case diatomaceous earth. For example, Kavallieratos pirimiphos-methyl, but did nottreatments.Afterthe14 exceed 17% dayexposure,mortalityincreasedtoabout in any38% in of the the spinosad other treatment,pyrethrin treatment. with a negligible increase in the treated with chlorpyrifos-methyl, and there were morethe progeny spinosad in treatment than inand the 5). pyrethrin Similar treatment results occurred (Tables in 1 rice,of while progeny for was maize low, the even in number thedifference control between vials, the but spinosad there was treatments still and no the controls. Throne

1144 1145 L. on ,and :1208–1212 91 deltamethrin J Econ Entomol L.reticulatus . + L. bostrychophila, on wheat. However, the :455–467 (2005). J Econ Entomol , while beta-cyfluthrin and , where progeny production 41 on maize, spinosad was only :605–615 (2008). foundthatthesameformulation 32 at constant temperatures and relative . 101 Liposcelis entomophila L. decolor et al and and L. reticulatus www.interscience.wiley.com/journal/ps Liposcelis bostrychophila, L. entomophila L. entomophila J Stored Prod Res L. entomophila and J Econ Entomol Lepinotus reticulatus (Psocoptera: Liposcelididae). :616–622 (2008). grain protectant against resistant beetle and psocidgraininAustralia. pests of stored psocid humidities. 101 Lepinotus reticulatus phosphine against paeta (1998). In summary, the results of the present study clearly suggest There are no data available so far for the efficacy of pyrethrin on 1 Nayak MK, Daglish GJ and Byrne VS, Effectiveness of spinosad as a 2 Opit GP and Throne JE, Population growth and development of 3 Opit GP and Throne JE, Effects of diet on population growth of psocids 4 Nayak MK, Collins PJ and Reid SR, Efficacy of grain protectants and all commodities and moderately effective. Finally, pyrethrum was generallyon ineffective rice andknowledge of moderately pesticide selectivity, effective inspecies conjunction and with on commodity, the will target provide wheat the knowledgejudicious and necessary management for of psocids maize. in stored This protectants. grains with registered chlorpyriphos-methyl was more effective thanspinosad the or application chlorpyriphos-methyl alone of against L. entomophila, L. paeta ACKNOWLEDGEMENTS The authors thanktechnical support. Ann They RedmonOpit also for and their thank comments on NgunzaMention Manoj an of trade earlier names Kisangani Nayak or version commercial products of in and for this thisis publication solely manuscript. George for the purpose of providing specificnot information and imply does recommendation or endorsement byDepartment the of United Agriculture. States REFERENCES that the efficacy of grain protectants differsand among psocid among species commodities. Chlorpyriphos-methyl for wheat and rice andeffectiveintermsofmortalityfromparentalexposuresandreduced pirimiphos-methyl for maize wereprogeny highly production, and this trend was consistentandcommodities.Incontrast,withtheexceptionof among species of pyrethrum had aL. very poor bostrychophila performance onchlorfenapyr concrete were highly against effective. The present results confirmreduced the efficacy of pyrethrin; hence,progeny, in pyrethrum might spite not of be theto effective control reduction as psocids in in a stored grain products. protectant grainsagainstpsocids.Inthelightofthepresentfindings,pyrethrinwas not particularly effectiveexcept against any on of maize. thesurvival of psocid the Paradoxically, parental individuals species, was high in in mostproduction cases, progeny this was commodity, notablyoften although suppressed, similar and to that this forspecies suppression pirimiphos-methyl. to The pyrethrin was most was susceptible wasextremelylow.Guedes chlorpyriphos-methyl dose used in that study can be consideredhigh, as and such an application may not be practicallyto feasible owing increased residues on theneeded grain. Additional to experimentation investigate is spinosad-basedbe more combinations effective that against psocid could species. , L. + + 31 re- 8 . noted but was L. paeta reported 26 et al found no found that 23 The present 28 . 7 . and reported that also reported , where results and is in the public domain in the USA L. paeta et al 30 , but controlled L. bostrychophila . 29 et al . ,butnotagainst deltamethrin never and et al on steel surfaces, but et al + found that pirimiphos- (Pearman) (Psocoptera: 7 . reported that pirimiphos- L. paeta C. cephalonica. L. reticulatus 27 . et al L. paeta and L. bostrychophila L. entomophila . The mortality levels noted in the et al However, the efficacy was no- and L. entomophila only on wheat and maize. In contrast, but ineffective against Liposcelis decolor was sensitive to chlorpyriphos-methyl on on wheat and maize. Nayak and Daglish L. paeta. : 1140–1146 This article is a US Government work 65 for 8 weeks. Similarly, Nayak L. reticulatus, L. entomophila, L. bostrychophila and especially and L.bostrychophila L. bostrychophila The potential of the combined use of OPs with syn- For example, Huang and Subramanyam 2009; , given that progeny production for the last two . In spite of the fact that progeny production in the T. confusum L. paeta L. entomophila L. entomophila 7,23–26 also found that 1 ppm of spinosad on wheat was effective L. bostrychophila L. paeta 1 L. paeta . Spinosad was most effective for Grain protectants against psocids www.soci.org effective against present study were higher than those obtained in previoushence, studies; based on the present results, pirimiphos-methyl isagainst effective the species tested on maize.far There for are no stored relative maize, datadifferences and so in the any commodity differences and the could insect be strains used. attributed to with reduced adultet al mortality and progeny production. Nayak spinosad was ineffective against were similar todeltamethrin and pirimiphos-methyl. those Spinosad was most obtained effective against with chlorpyriphos-methyl reached a mean of two progeny.generally Similarly, more pirimiphos-methyl effective was on maize than thewith other no two insecticides, progeny of anywith species being pirimiphos-methyl. produced Collins in maize treated L. entomophila. ergized pyrethrins has been evaluated in theas case of well. other species that concrete, while thisL. insecticide entomophila had reduced efficacy against methyl was unable to control similar results for the combination of spinosadmethyl and chlorpyriphos- on wheat. In contrast, Chintzoglou and species was high. Consequently, spinosada is wide not spectrum effective of against stored-product psociduse species. The of combined spinosad withits efficacy other against contact psocid insecticides species. might However, Daglish increase against deltamethrin failed to provide long-termagainst protection on concrete found that a combination of 1 ppmPest Manag Sci spinosad with 10 ppm deltamethrin was by farand the rice, most with effective practically protectant nogiven on variations wheat in that efficacy among 93–100% species, 7 days adult of exposure. mortality In was a previous recorded study, Nayak after only control of the four psocid species tested. Chlorpyriphos-methyl the presence of DE increased the efficacyadults of of spinosad dust against that the simultaneous use ofefficacy synergized of pyrethrins pirimiphos-methyl increased against the results indicate that the simultaneous use of chlorpyriphos-methyl and deltamethrin, in oneand single rice formulation, against can protectand wheat wheat and rice was not totally eliminated,in the the number of treatment progeny with chlorpyrifos-methyl Liposcelididae), ported that chlorpyriphos-methyl with synergizedvery bifenthrin was effective against bostrychophila, L. entomophila methyl with carbaryl provided long-term protection against further increase in efficacy from the combined usechlorpyriphos-methyl of or spinosad methoprene and against several stored-grain beetle species. Moreover, Subramanyam tably increasedmethyl with and carbaryl. the Moreover, on combined sorghum, Daglish use of chlorpyriphos- L. bostrychophila not on concrete. However, Nayak Pestic JEcon :347–353 44 : 1140–1146 65 J Stored Prod Res Pest Manag Sci Pest Manag Sci Pest Manag Sci J Stored Prod Res J Econ Entomol J Stored Prod Res Corcyra cephalonica :356–362 (2003). 2009; 61 :71–76 (2008). 44 J Stored Prod Res id psocid species (Psocoptera: hree liposcelidid psocid species n LM, Chlorpyriphos-methyl plus , spinosad, and combinations of yl and s-methoprene against five jic KE, Maier DE, Thompson GD and Pest Manag Sci Pest Manag Sci :293–302 (1996). o surface insecticides. 32 J Stored Prod Res , Organophosphorothioates and synergised :1021–1030 (2007). 26 et al :640–650 (2002). 95 (L.) populations, obtained from different rearing media, J Stored Prod Res Crop Prot :373–384 (1983). 14 :279–284 (2008). :343–353 (2003). :235–241 (1995). :1357–1363 (2000). :191–198 (2004). :104–109 (2007). :1314–1322 (2008). Entomol four classes of wheat against five stored-product insects. oryzae to three44 diatomaceous earth formulations. future. (Psocoptera: Liposcelididae) infesting stored grain. 39 Simpson BW, synthetic pyrethroids asSci grain protectants on bulk wheat. either methopreneColeoptera or in maize synergized31 in phenothrin Queensland, Australia. for controlinsects of in wheatplus with synergized pyrethrins. pirimiphos-methyl and pirimiphos-methyl four organophosphatessurfaces against on threeLiposcelididae) concrete liposcelid infesting93 and stored galvanized products. steel of spinosad, chlorpyrifos-meth stored-grain beetles. (Stainton) to pirimiphos-methyl pirimiphos-methyl and60 synergized pyrethrins. persistence of organophosphorus insecticides mixed withas carbaryl structural treatments against t Pitts JJ, Evaluation of spinosad as afarms. grain protectant on three Kansas spinosad dust, in combinationtwo with stored-grain diatomaceous beetle earth,(2008). against species. chlorpyrifos-methyl for management(Psocoptera: of Liposcelididae) resistant of psocid stored pests grain. 63 Acute lethalstored-product psocids and t behavioural sublethal responses of two 64 22 Huang F and Subramanyam B, Responses of 21 Fang L, Subramanyam B and Arthur F, Effectiveness of spinosad on 20 Arthur FH, Grain protectants: current status and prospects for the 24 Bengston M, Davies RAH, Desmarchelier JM, Henning R, Murray W, 25 Daglish GJ, Eelkema M and Harriso 26 Huang F and Subramanyam B, Management of five stored-product 27 Collins PJ, Nayak MK and Kopittke R,28 Residual Daglish GJ, Impact of resistance efficacy on the efficacy of binary combinations of 23 Nayak MK, Collins PJ and Kopittke RA, Residual toxicities and 29 Subramanyam B, Toews MD, Ilele 30 Chintzoglou GJ, Athanassiou CG and Arthur FH, Insecticidal effect of 31 Nayak MK and Daglish GJ, Combined treatments of spinosad and 32 Guedes RNC, Campbell JF, Arthur FH, Opit GP, Zhu KY and Throne JE, Pest :455–460 Sitophilus :976–981 Badonnel .Duxbury Pest Manag 15 Rhyzopertha J Stored Prod 101 This article is a US Government work J Econ Entomol and is in the public domain in the USA J Stored Prod Res www.soci.org CG Athanassiou, FH Arthur, JE Throne InsectSci :251–256 (2006). :157–161 (1994). 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Influence of grain type on the susceptibility of different Res Rhyzopertha dominica of diatomaceous earth and varietal resistance. 5 Nayak MK, Collins PJ, Pavic H and Kopittke RA, Inhibition of egg 6 Nayak MK and Collins PJ, Influence of concentration, temperature and 7 Nayak MK, Collins PJ and Kopittke RA, Comparative residual 8 Daglish GJ, Wallbank BE and Nayak MK, Synergised bifenthrin plus 9 Dou W, Wang JJ and Zhao ZM, Toxicological and biochemical 13 Greenspan L, Humidity fixed points of binary saturated aqueous 12 Athanassiou CG, Kondodimas DC, Kavallieratos NG and Anagnou 14 Sall J, Lehman A and Creighton L, 16 Kavallieratos NG, Athanassiou CG, Paschalidou FG, Andris AS and 15 Sokal RR and Rohlf FJ, 17 Chanbang Y, Arthur FH, Wilde GE and Throne JE, Hull characteristics 10 Buchi R, Effects of two11 insect growth Athanassiou CG, regulators on Kavallieratos the NG, booklouse Chintzoglou GJ, Peteinatos GG, 19 Athanassiou CG, Kavallieratos NG, Vayias BJ and Panoussakis EC, 18 Chanbang Y, Arthur FH, Wilde GE and Throne JE, Control of www.interscience.wiley.com/journal/ps

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