Ppm Spinosad Research Articles

Fly responses to food colour, orientation and toxic bait composition in Drosophila suzukii

AbstractToxic baits comprising a combination of food attractants and a toxicant could contribute to the control of the spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), a major invasive pest of soft fruit and berries. Laboratory cage experiments revealed that flies of both sexes were significantly more attracted to dried red droplets of 0.3% sucrose solution and were more likely to consume red‐coloured droplets compared to blue, green or colourless droplets. Flies of both sexes showed a tendency to feed on dried droplets placed on the floor of the cage rather than droplets presented upside‐down on the roof or on the cage side‐wall. When offered commercial insecticides (5–50 parts per million active ingredient) in dried sucrose solution, fly mortality of both sexes was highest in the spinosad treatment, lowest in abamectin and intermediate in deltamethrin and spinetoram‐based products. Male flies had significantly higher mortality than females. A mixture of 25 ppm spinosad with 1.3% sucrose +1.3% corn syrup +1.3% glycerol (named 4% mixture) was consumed by female flies more than any of the components alone. Addition of 1% apple juice to the 4% mixture resulted in an additional increase in spinosad‐induced mortality. In contrast, the addition of apple cider vinegar, increasing concentrations of apple juice (5%–10%), or the addition of the yeasts Saccharomyces cerevisiae or Hanseniaspora uvarum (5 × 106 cells/mL) did not increase fly mortality for reasons that were unclear. We conclude that the combination of 4% mixture +1% apple juice could prove to be a useful bait for the delivery of spinosad or other biorational insecticides for D. suzukii control, although this requires field testing in commercial fruit production settings.

Alteration of unfolded protein responses and autophagy signaling represented the molecular basis underlying saccharin toxicity to Drosophila (Diptera: Drosophilidae).

The purpose of this study was to develop a new control method for Drosophila using saccharin sodium dihydrate (saccharin), an artificial sweetener that is safe for humans and the environment, and to elucidate its mode of action. In this study, we confirmed that saccharin can dose-dependently inhibit the development of or kill vinegar flies (VFs) and spotted wing Drosophila (SWDs). In addition, we found that low concentrations of saccharin induced a similar effect as starvation in Drosophila, whereas high concentrations of saccharin induced changes in the unfolded protein response (UPR) and autophagy signaling that were unlike starvation and inhibited development or killed the VF and the SWD by performing real-time quantitative polymerase chain reaction analyses. Spinosad is a widely used plant protection agent for SWD control. When saccharin was cotreated with 0.25-1.0 ppm spinosad, an additive insecticidal activity was observed only at high concentrations of saccharin. However, when saccharin was cotreated with 2.0 ppm spinosad, an additive insecticidal activity was observed at low concentrations of saccharin. Taken together, alteration of UPR and autophagy signaling represented the molecular basis underlying saccharin toxicity to Drosophila and concurrent spraying of an insecticide with saccharin could enhance the insecticidal activities.

Can spinosad be effective for the integrated management of Anastrepha ludens (Tephritidae) in soil and fallen fruit, and be compatible with the parasitoid Diachasmimorpha longicaudata (Braconidae)?

Tephritid fruit flies are susceptible to insecticide treatments when leaving infested fruit to pupate in the soil and when emerging as adults. Laboratory experiments involved placing third instar larvae of the Mexican fruit fly, Anastrepha ludens on sand treated with the naturally-derived insecticide spinosad (SpinTor 12SC). Negative correlations were detected between the concentration of spinosad and pupation and adult emergence. Treatment of pupae significantly reduced adult longevity, which could impact pest reproduction as adult flies require approximately two weeks to reach sexual maturity. Brief immersion of naturally infested oranges in 33–66 ppm spinosad solution also significantly reduced adult emergence. Exposure to spinosad-treated sand (33 ppm) did not adversely affect the foraging behavior or mortality of the braconid parasitoid Diachasmimorpha longicaudata. We conclude that effective control of A. ludens in soil with spinosad is possible but will likely require application of high concentrations of the insecticide, which may not be economically viable under conventional fruit production schemes. In the case of organic orchards surrounded by wild hosts that harbor large fly populations, targeted spinosad soil applications might be desirable as fly numbers could be significantly reduced without harming parasitoids.

Toxicity of Insecticides to Tomato Pinworm, Tuta absoluta (Meyrick) Populations from Tamil Nadu

Tomato pinworm, Tuta absoluta is a serious and notorious pest on tomato. Control mainly relies on insecticides because of their high infestation levels on all plant parts and life stages of the crop. This study, investigated the efficacy of different insecticides, against Tuta absoluta for different populations in laboratory conditions. The LC50 ranged from 0.27 to 2.0 ppm for chlorantraniliprole, from 1.01 to 2.25 ppm for flubendiamide, from 0.32 to 0.90 ppm for spinosad, from 0.98 to 6.52 ppm for imidacloprid, from 0.82 to 6.38 ppm for indoxacarb, from 967.32 to 1911.98 ppm, for chlorpyriphos, The resistance ratios ranged from 1.1 to 7.7-fold difference in all six cases. The laboratory experimental results showed that chlorantraniliprole and spinosad were the most toxic insecticides as compared to other chemicals and showed homogenous response to them.

<p class="Body">Selective biorational treatments for managing the storage mites, Tyrophagus putrescentiae (Schrank) and Aleuroglyphus ovatus (Troupeau) under laboratory conditions

Mites have lately emerged as economically important pests of stored products. Recently, addition of natural origin compounds individually or as a combination with predators have provided a considerable value for controlling these pests. In this study, the efficacy of the bacterium-derived pesticides, spinosad and spinetoram, and the combination of each of them with the predator Cheyletus malaccensis Oudemans was evaluated against two storage mite pests, Tyrophagus putrescentiae (Schrank) and Aleuroglyphus ovatus (Troupeau) under optimal abiotic conditions for pest development. After 21d, the terminal density was estimated for both astigmatid mite species exposed to diet (experiment I) treated with either spinosad or spinetoram (concentrations range of 0.01-2 ppm). Estimation was also done with diet (experiment II) treated with either spinosad or spinetoram (0.5 ppm) and/or the predator at initial predator/prey ratio (0.02). The density of predator was also determined after 21 days. Application of spinosyns significantly reduced population of T. putrescentiae and A. ovatus. The reduction potential increased with increasing concentration. Complete control of T. putrescentiae and A. ovatus was achieved by the application of spinosad at 1 and 2 ppm, respectively. As measured by rC50 and rC90 (concentration for 50% and 90% suppress of population in comparison to control), spinosad was more toxic to T. putrescentiae and A. ovatus than spinetoram. Furthermore, T. putrescentiae was more susceptible to spinosad than A. ovatus. Conversely, it was less susceptible to spinetoram than A. ovatus. The populations of both mite species were successfully suppressed by the sole application of C. malaccensis. Although the density of predatory mites was not affected by the presence of 0.5 ppm spinosad, it was almost eradicated by spinetoram at 0.5 ppm. A combination of spinosad at 0.5 ppm with two individuals of C. malaccensis mites (ratio 0.02) outperformed spinosad used alone at the same former concentration in reduction efficiency of the pest populations by 12% for T. putrescentiae and 25% for A. ovatus within 21 days.

Molecular Impacts of Spinosad and Emamectin Benzoate onSpodoptera littoralisBoisd. Larvae (Lepidoptera: Noctuidae)

Biopesticides are biologically-derived agents, that are usually applied in a manner similar to chemical pesticides, but achieve pest management in an environmentally-friendly way. Among the most promising biopesticides, is the bacterial insecticide; Spinosad and Emamectin benzoate. Therefore, in the present study, fourth instar larvae of S. littoralis were allowed to feed on leaves previously dipped with 1, 10, 50 and 100 ppm of spinosad and 0.5, 1, 2 and 10 ppm of emamectin benzoate for 72 hrs and then were used to screen alterations in protein profiles and DNA by using SDS- PAGE and RAPD-PCR, respectively. Results of SDS-PAGE analysis revealed that the protein profiles of S. littoralis changed after larval treatment with spinosad and emamectin benzoate and new proteins were observed in treated larvae. RAPD technique was used to detect genetic differences between control and fourth instar larvae of S. littoralis which treated with spinosad and emamectin benzoate.

Physiological and Ultrastructural Alterations in the Crayfish Procambarus clarkii Treated with Spinosad (Bacterial Derived Insecticide)

Physiological and ultrastructural investigations have been carried out on Procambarus clarkii exposed to sublethal concentrations of Spinosad insecticide. The study showed that the highest mortality percentage was 88% for males and 70% for female occurred at 64 × 10³ ppm Spinosad. The lethal toxicity (LC50) was 24.1 g/l and 29.8 g/l for males and females respectively. Exposure to 1/2 LC50 (12.07 g/l). Spinosad for 7 days caused many physiological disorders including decrease the haemolymph glucose levels and elevated uric acid levels.12.07 g/l Spinosad resulted in a significant decrease in the total proteins of haemolymph, hepatopancreas and muscles in both males and females. The total cholesterol and triglycerides levels were significantly increased in both haemolymph and hepatopancreas and decreased in muscles of males. On the other hand, cholesterol and triglycerides levels were significantly decreased in haemolymph, hepatopancreas and muscles of females. TEM examinations of male hepatopancreas exposed to 12.07 g/l Spinosad for 7 days revealed ruptured microvilli of absorptive cells, deformed mitochondria, destructed rough endoplasmic reticulum, vacuolated cytoplasm, pyknotic nuclei and appearance of vesicles containing small dark granules.

Increased efficacy and extended shelf life of spinosad formulated in phagostimulant granules against Spodoptera frugiperda.

Spinosad is recommended for control of Spodoptera frugiperda (J.E. Smith) larvae; its application with phagostimulants may reduce the quantity of active ingredient required for effective pest control. Spinosad (Tracer®) was formulated in maize flour matrix granules and three field tests compared 10-100 ppm a.i. granules (equivalent to 0.24-2.4 g a.i. ha-1 ) with Tracer as an aqueous spray (200 ppm a.i.; 60 g a.i. ha-1 ), and the recommended application rates of Bacillus thuringiensis, a chemical and an untreated controls were performed. The 100 ppm spinosad granules resulted in similar S. frugiperda mortality compared with the chemical treatments in all three field trials, and resulted in a significantly higher maize grain yield compared with unformulated and control treatments (4141 vs. 2857 and 2407 kg ha-1 , respectively) that was similar to the chemical treatment (3778 kg ha-1 ). Bioassays of granules stored at room and cold temperatures showed that after 5 years, ∼ 70% of the original activity remained (OAR) of spinosad when formulated as granules. Nevertheless, after 9 years, efficacy was reduced (26.2% and 48.5% OAR) at both room (25 °C) and refrigerated temperatures (4 °C). Spinosad, in the granular phagostimulant formulations evaluated in this study, had advantages measured as high efficacy and long shelf life. © 2017 Society of Chemical Industry.

Evaluation of spinetoram and spinosad for control of Prostephanus truncatus, Rhyzopertha dominica, Sitophilus oryzae, and Tribolium confusum on stored grains under laboratory tests

Spinetoram and spinosad have been evaluated against certain stored-product insect pests with success but there are no data available on the comparison of the efficacy of these two novel compounds in stored grains. Thus, laboratory bioassays were conducted to compare spinetoram and spinosad as grain protectants against Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) adults, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) adults, and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) adults and larvae. Factors such as treatment (1 ppm spinetoram, 1 ppm spinosad, 0.1 ppm spinetoram + 0.9 ppm spinosad, 0.5 ppm spinetoram + 0.5 ppm spinosad, and 0.9 ppm spinetoram + 0.1 ppm spinosad), exposure interval (1, 2, 7, and 14 days), temperature (20, 25, and 30 °C), and commodity (barley, maize, rye, and wheat) were evaluated. Progeny production was assessed after 60 days of exposure. Concerning temperatures, for P. truncatus adults, after 14 days of exposure, all adults were dead in treatments except of the case of spinosad alone at 20 °C. Offspring emergence was completely suppressed in all treatments at 20 and 25 °C. For R. dominica adults, after 7 days of exposure, the overall mortality ranged from 92.8 to 100 %. After 14 days of exposure, all adults were dead in all treatments of the combined use of spinetoram and spinosad at 25 and 30 °C. Progeny production was completely suppressed in all treatments at 30 °C. For S. oryzae adults, after 7 days of exposure, all S. oryzae were died at 25 and 30 °C in all treatments except in the case of spinosad alone. Offspring emergence was very low in all treatments and temperatures except in the case of spinosad alone at 30 °C. For T. confusum adults, after 1, 2, and 7 days of exposure, the overall mortality was low in all treatments and temperatures. Concerning commodities, for R. dominica adults, after 7 and 14 days of exposure, the overall mortality was >97 %. Offspring emergence was very low in all commodities. For S. oryzae adults, after 7 and 14 days of exposure, the overall mortality was increased exceeding 91 % except in the case of spinosad alone 7 days after exposure in barley. Progeny production was high in barley and rye in all treatments. For T. confusum adults, after 7 and 14 days, the overall mortality was low in barley, rye, and wheat. No offspring emergence was recorded in all treatments and commodities. For T. confusum larvae, after 14 days of exposure mortality was further increased, but did not reach 100 % for any of the combinations tested. The results of the present study suggest that the simultaneous application of spinetoram and spinosad was generally equally effective with the use of either spinosad or spinetoram alone. Furthermore, the increase of dose of either compound resulted in the same mortality levels. Thus, no benefits were achieved when spinetoram and spinosad were used simultaneously on grains, regardless of the proportion of each ingredient. These issues should be seriously considered when control measures against stored-product insects are designed.

Toxicity of spinosad on common green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) larvae via ingestion technique under laboratory conditions

The use of selective insecticides could improve conservation of natural enemies and therefore contribute to the success of integrated pest management programmes. In this study, the toxicity of one selective insecticide, spinosad to common green lacewing Chrysoperla carnea (Stephens) was evaluated. Several stages of C. carnea larvae were exposed to spinosad via ingestion technique under laboratory conditions. The used quantities of spinosad were less than the maximum recommended rate given on the product label. In ingestion bioassay tests, a direct relationship was detected between the concentration of spinosad and mortality rate of first instar larvae. So that, the applied of 250 and 2500 ppm of spinosad caused 35 and 90% mortality, respectively. Mortality rate was recorded 1–3 days of post treatment. An implementation of 250 ppm of spinosad on second and third instar larvae showed negligible mortality rate after 3 days, whereas the first instars larvae suffered 35% mortality. On the basis of collected data we could conclude that spinosad is not merited to be considered to have an environmental safety profile on C. carnea similar to well-established conventional biological insecticides.

Evaluation of susceptibility of Rhyzopertha dominica (F.), Sitophilus granarius (L.) and Cryptolestes ferrugineus (Stephens) to spinosad

In this research, we evaluated the toxicity of different concentrations of spinosad to one-day-old adult of Rhyzopertha dominica (F.), Sitophilus granarius (L.) and Cryptolestes ferrugineus (Stephens). The exposure times were 24, 48 and 72 h in all experiments. In contact tests for R. dominica, the maximum mortality rate was achieved with 500 ppm of spinosad after 72 h exposure. The application of 400 ppm of spinosad after 72 h caused maximum mortality in S. granarius. For contact treatment, the complete control of C. ferrugineus was obtained with 500 ppm spinosad at 72 h exposure time. It is possible to recommend 500 ppm of spinosad for complete control of the tested insects through contact application. Estimated LC50 values of spinosad in 72 h after exposure for adults of R. dominica, S. granarius and C. ferrugineus were 1287, 279 and 53.17 ppm, respectively. The results show that C. ferrugineus is the most susceptible insect to spinosad in these experiments.

Comparison of spinosad with three traditional grain protectants against Prostephanus truncatus (Horn) and Ephestia kuehniella (Zeller) at different temperatures

The insecticidal effects of deltamethrin, chlorpyriphos-methyl, pirimiphos-methyl, and spinosad were evaluated against adults of Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) and larvae of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). Spinosad was applied at 1 and 0.5 ppm, deltamethrin at 0.5 ppm, chlorpyriphos-methyl at 2.25 ppm, and pirimiphos-methyl at 4 ppm. All tests were carried out on wheat for E. kuehniella and in maize for P. truncatus, at three temperature levels, 20, 25, and 30 °C. Mortality of the exposed individuals of P. truncatus was measured after 7, 14, and 21 days of exposure, and 60 days later, the progeny production in the treated and untreated substrate was recorded. In the case of Ephestia kuehniella, mortality was assessed after 25 days. Spinosad was highly effective against P. truncatus adults, even at 0.5 ppm, but 1 ppm provided a better “speed of kill” and a higher suppression of progeny production. Mortality of the exposed P. truncatus adults after 21 days of exposure on maize treated with 0.5 ppm of spinosad was 100 %, regardless of the temperature level tested. A complete (100 %) mortality level was also noted in the case of maize treated with deltamethrin and pirimiphos-methyl, while in the case of chlorpyriphos-methyl, mortality at the 21 day exposure ranged between 61 and 90 %. Progeny production was completely suppressed only on maize treated with deltamethrin. In contrast, pirimiphos-methyl was the most effective grain protectant for E. kuehniella, since mortality was usually <99 %. In general, for both species tested, temperature had a significant effect on mortality, but this trend was different at different insecticides.

&lt;p&gt;&lt;strong&gt;Efficacy of spinosad against the poultry red mite, &lt;/strong&gt;&lt;strong&gt;&lt;em&gt;Dermanyssus gallinae &lt;/em&gt;&lt;/strong&gt;&lt;strong&gt;(Mesostigmata: Dermanyssidae), in laboratory and field trials*&lt;/strong&gt;&lt;/p&gt;

The poultry red mite, Dermanyssus gallinae (De Geer), is the most economically important ectoparasite in poultry houses in many countries around the world. The lack of efficacy of commercial products in its control results from poor application and/or from its resistance to active ingredients. A new insecticide, spinosad, was tested against mobile stages of the red mite in laboratory and field populations. Laboratory trials showed increasing efficacy five days (adults) and six days (nymphs) after exposure. Laboratory results were confirmed in a field trial conducted under commercial conditions. The trial was conducted in three separate houses on farms with high natural mite populations. The first and second houses were sprayed with concentrations of 2,000 and 4,000 ppm of spinosad (2 and 4 g/L), whereas the third house was used as an untreated control. Spraying was conducted using a sprayer (Stadikopumpe VAAR 252- 200 LE, Dinklage, Germany) with a 200 L reservoir with permanent stirring, a 50 m long flexible tube with a double jet system, and jet size of 0.08 mm. The pressure used was 6–10 bar. Sampling was conducted immediately before the application and once a week for 56 days in the first house and 93 days in the second. In the first house, almost 100% reduction in mite numbers was observed until 28 days post treatment; 74.3% reduction was observed 49 days after treatment. In the second house, rates of reduction were higher than 90% until day 77. The untreated control house maintained high red mite infestations throughout the experimental period. The results showed effective control of all mobile stages of D. gallinae with spinosad.

Spinosad Toxicity to Simulium spp. Larvae and Associated Aquatic Biota in a Coffee-Growing Region of Veracruz State, Mexico

Spinosad is a naturally derived insecticide that has shown potential as a mosquito larvicide. To determine the activity of spinosad against blackflies, late-instar larvae from a community comprising Simulium triittatum (63.6%) and seven other species, including three known vectors of onchocerciasis in Mexico (S. metallicum, S. ochraceum, and S. callidum), were subjected to concentration-mortality laboratory bioassays following World Health Organization guidelines. Cephalic capsule measurements confirmed the relatively homogeneous distribution of experimental larvae. The 50% lethal concentration of spinosad was estimated at 1.48 ppm spinosad (95% confidence interval: 1.07-2.33) for a 10-min exposure period, whereas larvae treated with 0.05 ppm of the organophosphate temephos experienced 61% mortality. Immature aquatic insects were identified to genus and tested for their susceptibility to spinosad in the laboratory. After exposure to 12 ppm spinosad for 10 min, ephemeropterans, odonates, trichopterans, and hemipterans did not experience significantly increased mortality over that of untreated controls, whereas a significant increase in mortality was observed in spinosad-treated Plecoptera (P < 0.001). Tilapia and trout fry exposed to 12 ppm spinosad for 10 min did not experience increased mortality at 24-h postexposure over that of the controls. We conclude that spinosad is less toxic than temephos to these blackfly species, but is likely to have a low impact on nontarget members of the aquatic community.

Efficacy of spinosad and methoprene, applied alone or in combination, against six stored-product insect species

Efficacy of the insecticides spinosad and methoprene, applied alone or in combination to wheat, was evaluated against six stored-product insect species, Rhyzopertha dominica, Sitophilus oryzae, S. granarius, Cryptolestes ferrugineus, Oryzaephilus surinamensis, and Liposcelis bostrychophila. The concentrations of the insecticides were 0.1 and 0.5 ppm for spinosad and 1 and 5 ppm for methoprene. Parental mortality of R. dominica was 100% on wheat treated with either rate of spinosad, with no progeny production in any combination treatment. Parental mortality of S. oryzae did not exceed 62%, and progeny production was not reduced by any insecticide treatment. All S. granarius adults exposed on wheat treated with spinosad alone at 0.5 ppm were killed, but parental mortality was reduced when methoprene was added. Progeny production was reduced in treatments containing spinosad. Mortality of adult C. ferrugineus was 97% or greater in treatments containing spinosad, but adult mortality of O. surinamensis and L. bostrychophila was not reduced by insecticide treatments. The specific combinations of spinosad and methoprene evaluated in our study would have no benefit over spinosad used alone for control of any of the six species tested.

Insecticidal action of the combined use of spinosad and deltamethrin against three storedproduct pests in two stored hard-wheat varieties.

The combined use of spinosad with deltamethrin against adults of Sitophilus oryzae, Sitophilus granarius and Tribolium confusum was evaluated in a series of laboratory bioassays in two hard wheat varieties (Athos and Sifnos). Two groups of bioassays were carried out. In the first group of bioassays, spinosad or deltamethrin were applied alone at the tested wheat varieties at the doses of 0.01, 0.1 and 0.5 ppm for spinosad and 0.125 ppm for deltamethrin. In the second group of bioassays, the tested wheat varieties were treated with the combination of the above spinosad rates with 0.125 of deltamethrin. In both series of bioassays, mortality of the tested species was evaluated after 7 d of exposure on the treated wheat varieties at 25 o C and 65% r.h. Mortality for all species was always significantly higher in Athos than Sifnos. The highest mortality of S. oryzae (73 and 40% for Athos and Sifnos respectively) or S. granarius (88% and 58% for Athos and Sifnos respectively) was recorded in the cases that spinosad was applied alone at 0.5 ppm. On the contrary, in the case of T. confusum , 0.125 ppm of deltamethrin was significantly more effective than any of the application rates of spinosad either when applied alone or in combination with deltamethrin. Despite the fact that the highest mortality of S. granarius adults was recorded after exposure on the wheat varieties treated with 0.1 ppm of spinosad x 0.125 ppm of deltamethrin, in light of the results of the present study, the combination of spinosad with deltmethrin requires further investigation since in most of the tested cases of the present study, single application of spinosad or deltamethrin was more effective or of equal effectiveness than the respective combination of spinosad with deltamethrin. Keywords : Spinosad, Deltamethrin, Tribolium, Sitophilus , Wheat, Variety

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

The effect of short exposures to spinosad-treated wheat, Triticum aestivum L., or maize, Zea mays L., was evaluated against adults of four stored-product insect species: lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); and the psocid Lepinotus reticulatus (Enderlein) (Psocoptera: Trogiidae). Adult mortality of these species was recorded after 0, 2, 4, 8, 16, and 40 h on commodities treated with 1 ppm of spinosad (immediate mortality). Then, the surviving individuals were removed and placed on untreated wheat or maize, and mortality was recorded again 7 d later (delayed mortality). Progeny production then was determined 65 and 35 d later for the beetles and psocids, respectively. Among the four species tested, R. dominica was the most susceptible, and immediate mortality after 40 h reached 78 and 72% on wheat and maize, respectively. Moreover, 7 d later, all adults that had been exposed for >2 h were dead on both commodities. Progeny production was significantly reduced in comparison with the controls, and no progeny were found when parental adults had been exposed for >8 or >4 h on wheat and maize, respectively. For S. oryzae, 40-h exposures significantly increased delayed mortality on both wheat and maize, but progeny production still was high. Generally, no effect of short exposures was noted for T. castaneum. For L. reticulatus, despite the fact that the increase of exposure interval increased mortality on maize, progeny production was not avoided. With the exception of T. castaneum, more progeny were found on wheat than on maize. The results of the current study indicate that R. dominica is very susceptible after short exposures to spinosad-treated substrate, but the other species are able to survive and reproduce at the exposure range examined.

Persistence and efficacy of spinosad on wheat, maize and barley grains against four major stored product pests

The insecticidal and residual effect of spinosad on wheat, maize and barley grain was evaluated in the laboratory against adults of Sitophilus oryzae (F.) (Coleoptera: Curculionidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), Tribolium confusum (DuVal) (Coleoptera: Tenebrionidae), Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) as well as against larvae of T. confusum. Spinosad was applied as a solution to 2 kg lots of each commodity at three concentrations, 0.1, 0.5 and 1 ppm, and the treated grain quantities were kept at 25 °C and 65% RH. Samples were taken from each concentration-commodity combination at the day of storage and every 30 d for 6 consecutive months (6 bioassays). The test species were exposed for 14 d to the samples and mortality and reproduction were assessed over this exposure interval. With the exception of T. confusum, 1 ppm of spinosad was highly effective against the remainder of the tested species and provided protection for a period of storage at least 4 months. Although in general, spinosad performance was not very much affected by the grain type, efficacy on maize was less stable over the 6-month period of storage and declined sooner compared to the other commodities. Spinosad almost suppressed progeny production of R. dominica during the storage period, but did not suppress progeny of the other species, since progeny were recorded even 30 d post application especially with the lowest of the tested concentrations. The results of this study indicated that spinosad may provide suitable protection for 6 months against S. oryzae or R. dominica, but is not suitable for long-term protection against T. confusum or C. ferrugineus.

Efficacy of Tracer 240 SC and Steward 150 SC Against First and Second Instar Larvae of Helicoverpa Armigera by Using the Leaf DIP Method

Different concentrations of Steward 150 SC and Tracer 240 SC were tested under laboratory conditions against first and second instar larvae of Helicoverpa armigera. Results showed that these insecticides are very effective. The maximum mortality was observed by both insecticides and they can be used in the Integrated Plant Management (IPM) programme of any crop. For first instar, 300 ppm spinosad and 200 ppm indoxacarb can give complete mortality after 48 hours. For second instar larvae, 400 ppm spinosad can give maximum mortality (4.667), while 200 ppm of indoxacarb can give complete mortality after 48 hours.

Toxicity of spinosad and Beauveria bassiana to the black cutworm, and the additivity of subletal doses

The main objective of this study was to assess the susceptibility of the black cutworm (Agrotis ipsilon) to the biopesticide spinosad and to a commercial formulation (GHA strain) of the entomopathogenic fungus, Beauveria bassiana. Secondly, we quantified the effects of sublethal doses of spinosad on a number of A. ipsilon fitness parameters, and interactions resulting from simultaneous applications of sub-lethal doses of spinosad and B. bassiana. Under laboratory conditions, A. ipsilon third instar larvae were highly susceptible to spinosad, with an estimated LC50 of 50 ppm. The entomopathogenic fungus, B. bassiana had a lower efficacy with an estimated LC50 of 7×107 spores mL−1. Topical applications of 5, 7.5 and 10 ppm of spinosad on third instar larvae reduced larval size and increased time to pupation and to emergence. However, pupal and adult weights were not significantly different between treated and control individuals. Additivity was observed from most spinosad–B. bassiana combinations tested, thus indicating compatibility between products. We concluded that spinosad is a promising tool for controlling black cutworm larvae alone or in combination with other products.