Concentrations Of Spinosad Research Articles

Persistence of widespread moderate Spinosad resistance among wild melon fly (Zeugodacus cucurbitae) and oriental fruit fly (Bactrocera dorsalis) populations on the major Hawaiian islands.

Insecticide resistance among invasive tephritid fruit flies poses a great risk to national food security and has the potential to disrupt quarantine and eradication programs, which rely on the efficacy of Spinosad to prevent widespread establishment in North America. During 2022 to 2023 we surveyed the extent of Spinosad resistance of two key species, oriental fruit fly Bactrocera dorsalis, and melon fly Zeugodacus cucurbitae, from 20 sites across five Hawaiian Islands including Kaua'i, O'ahu, Maui, Molokai and the "Big Island" (Hawai'i). We used topical thoracic applications of eight concentrations of Spinosad ranging from 0.028 to 3.6 mg/mL to evaluate the lethal concentration (LC50 and LC99) required to kill wild-caught males. Resistance ratios (RR) were calculated by comparing the LC50 of wild flies to laboratory susceptible lines maintained in colony. Our results identified at least two new sites of concern for melon fly resistance on the Big Island, and at least four sites of concern for oriental fruit fly, all of which were located on the Big Island. At these locations RRs were >5. On O'ahu, melon fly RRs were >10. The persistence of Spinosad resistance is concerning, yet it is a reduction compared to the values reported previously and before changes to Spinosad use recommendations by local extension agents beginning in 2017. For oriental fruit fly, these RR values are the highest levels that have been detected in wild Hawai'i populations. These data suggest that expanded Spinosad reduction and replacement programs are warranted given the ongoing issues with Spinosad resistance in Hawai'i and expansion in the number of species affected. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Biopesticide spinosad: Unraveling ecotoxicological effects on zebrafish, Danio rerio

Biopesticides are natural compounds considered more safe and sustainable for the environment. Spinosad (SPI) is a bioinsecticide used in marketed worldwide, to eradicate a variety of pests. This study aimed to assess the impacts of the SPI on the non-target organism zebrafish (Danio rerio). Several concentrations of SPI were tested to evaluate the acute (0.07–1.0 mg/L) and chronic (0.006–0.100 mg/L) ecotoxicological effects. To evaluate sub-individual effects, antioxidant defense, lipid peroxidation, energy sources, and cholinergic biomarkers were quantified. In both exposures, SPI induced significant effects on antioxidant defense indicating oxidative stress, disrupting energy pathways, and exhibiting neurotoxic effects, under environmentally relevant conditions. Integrated Biomarker Response (IBRv2) showed that with increasing SPI concentrations, an increase in impacts on organisms was recorded. This study demonstrates the vulnerability of a non-target organism to SPI, a bioinsecticide considered environmentally safe. Further research is essential to fully understand the implications of spinosad to aquatic biota.

Spinosad‐infused biodegradable hydrogel beads as a potential organic approach for argentine ant, Linepithema humile (Mayr) (hymenoptera: Formicidae), management in California citrus orchards

AbstractArgentine ant, Linepithema humile (Mayr), disrupts biological control services in California citrus orchards, leading to economically damaging densities of honeydew‐producing hemipteran pests. With the elimination of chlorpyrifos, the sole registered insecticide for L. humile control in California citrus, the development of effective alternatives is necessary. One alternative is aqueous sugar baits laced with minute concentrations (0.0001%) of insecticide. Field trials were conducted to assess the efficacy of spinosad and thiamethoxam‐infused alginate hydrogel beads (HGBs) for L. humile control. Thiamethoxam‐infused HGBs have previously shown high efficacy against L. humile in citrus. Spinosad is approved for organic use, while thiamethoxam, a neonicotinoid, along with other neonicotinoid insecticides, might soon face deregistration in California, underscoring the need for alternative insecticide chemistries for ant control. Therefore, this study aimed to optimize spinosad‐loaded HGBs by identifying efficacious concentrations, application rates, and deployment frequency, and to compare with thiamethoxam‐infused HGBs, the standard reference treatment. Results showed that spinosad‐infused HGBs significantly reduced high‐density L. humile populations in citrus orchards. Notably, the highest spinosad concentration tested (0.01%) demonstrated comparable control to both 0.0001% and 0.01% thiamethoxam concentrations. A tri‐weekly application schedule for spinosad‐infused HGBs provided best control. Trees treated with 125 or 250 g of hydrogels infused with 0.01% spinosad at weeks 0, 3, and 6 displayed significantly reduced ant activities compared to plots treated solely during weeks 0 and 6, as well as control plots lacking HGB applications. Spinosad‐infused HGBs may offer an effective alternative to thiamethoxam‐infused HGBs for control of L. humile in California citrus orchards.

Contact and Gustatory Effects of Spinosad on the Growth or Survivability and Development of Progeny Buildup in Two Successive Generations of Cryptolestes pusillus (Schon.) on Wheat and Rice

The contact and gustatory effects of Spinosad on development, survivability, adult emergence and reproductive potential of Cryptolestes pusillus (Schon.) in two successive generations were conducted. Egg hatching, larval and pupal survivability, and adult emergence were lowest in wheat and rice in 1st generation, whereas, totally controlled the hatching, larval and pupal survivability and adult emergence of C. pusillus was noticed in both the seeds in 2nd generation at 0.63 and 1.25 μg/ml concentrations. The highest PRC value of adult emergence was 97.93% found in wheat and 100% in rice in 2nd generation. The mean developmental period of C. pusillus varied in different concentrations of Spinosad. The highest duration of hatching, larval and pupal periods were observed in treated Spinosad at 1.25μg/ml in wheat in F1 generation, whereas, total control of development was found in F2 generation in the same concentration.

Contact and gustatory effects of Spinosad on inhibition of population build-up of Cryptolestes pusillus (Schon.) (Coleoptera: Cucujidae) after different storage periods in whea

The adult population of Cryptolestes pusillus (Schon.) was significantly (P<0.001) reduced after 3-, 6- and 9-months storage periods at different concentrations of Spinosad than those of control medium. Spinosad at all concentrations reduced mean number of larval 5.33±0.72 to 52.00±0.94, 5.67±1.36 to 32.00±1.41 and 2.67±0.54 to 54.33±0.72 after 3, pupal 3.33±1.09 to 26.00±0.94, 3.33±0.72 to 26.00±1.25 and 2.33±0.29 to 16.33±0.27 after 6 and adult 5.33±1.19 to 62.00±0.47, 2.33±0.27 to 72.00±1.25 and 2.33±1.09 to 58.00±1.25 after 9 months storage period. The percent of repulsion (PRC) were always higher in higher concentrations but lower in lower concentrations in every cases. The total population of C. pusillus was 152.00±1.15 and 790.33±2.60 after 1st and 2.67±1.09 and 20.67±3.34 after 2nd generations. Spinosad effectively reduced the survivability and population of C. pusillus of the treated wheat.

Bioinsecticide spinosad poses multiple harmful effects on foragers of Apis mellifera.

There are multifactorial causes for the recent decline in bee populations, which has resulted in compromised pollination and reduced biodiversity. Bees are considered one of the most important non-target insects affected by insecticides used in crop production. In the present study, we investigated the effects of acute oral exposure to spinosad on the survival, food consumption, flight behavior, respiration rate, activity of detoxification enzymes, total antioxidant capacity (TAC), brain morphology, and hemocyte count of Apis mellifera foragers. We tested six different concentrations of spinosad for the first two analyses, followed by LC50 (7.7mg L-1) for other assays. Spinosad ingestion decreased survival and food consumption. Exposure to spinosad LC50 reduced flight capacity, respiration rate, and superoxide dismutase activity. Furthermore, this concentration increased glutathione S-transferase activity and the TAC of the brain. Notably, exposure to LC50 damaged mushroom bodies, reduced the total hemocyte count and granulocyte number, and increased the number of prohemocytes. These findings imply that the neurotoxin spinosad affects various crucial functions and tissues important for bee performance and that the toxic effects are complex and detrimental to individual homeostasis.

Residual activity of spinosad applied as a soil drench to tomato seedlings for control of Tuta absoluta.

Tuta absoluta (Lepidoptera: Gelechiidae) is difficult to control by means of foliar insecticides, partly because of the endophytic feeding behavior of its larvae. The biopesticide spinosad is applied as a foliar spray for control of T. absoluta and has systemic properties when applied as a soil drench to the growing medium of tomato plants. The aims of this study were to determine the: (i) instar-dependent tolerance of larvae to spinosad; (ii) efficacy of spinosad drench application for the control of larvae; (iii) residual period of systemic activity of spinosad in leaves and fruit after drenching; and (iv) effect of spinosad drenching on tomato plant growth parameters. The estimated LC50 value (Lethal Concentration at which 50% of the larvae died) differed between instars. The LC50 for second-instar larvae (0.41 ppm) to spinosad was significantly lower than that for third- (0.64 ppm) and fourth-instar (0.63 ppm) larvae. The LC80 value (Concentration at which 80% of the larvae died) for fourth-instar larvae (2.48 ppm) was 2.6- and 1.7-fold higher than that for the second- and third-instar larvae, respectively. The spinosad concentration recorded in leaves at 25 days after treatment (DAT; 0.26 μg g-1 ) was significantly lower than that in leaves sampled at 3, 10 and 15 DAT. High larval mortalities were, however, recorded for the duration of the experiment, which lasted 25 days (equivalent to one T. absoluta generation). Systemic spinosad effectively controlled T. absoluta larvae over a prolonged period. However, drenching this insecticide violates the recommendation of the Insecticide Resistance Action Committee to avoid treating consecutive insect generations with the same mode of action and can therefore result in the evolution of insecticide resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Effect of Spinosade on Three Species of Stored Product Insects

The relative efficacy of the biological compound Spinosad was tested in five concentrations (1%, 2%, 3%, 4% and 5%) mg / kg of covered food mixed with the food of the southern cowpea weevil and the grain beetle of vermicelli and the rusty flour beetle. The results of the study showed The highest killing rates are 100%, 89.7% and 59.7% for each of the siren beetles, the southern cowpea weevil and the rusty flour beetle, respectively, after the exposure period of 196 hours. The results of the study also showed that there was no development in the life of the three species of insects. The stores and for all the concentrations of spinosad used, with a high significant difference with the comparison factor. Also, the compound spinosad gave good protection for cowpea seeds, wheat and pulp. The rate of food loss was reduced compared with the comparison treatment in which the loss rate increased very clearly as a result of the activity of the population of the insect species of the three studied beetles.

Combinations of insecticides with carbon dioxide for the management of Sitophilus oryzae (Linnaeus 1763) on stored wheat: An approach to reduce the application rates of insecticides

Efficacy of insecticides chlorpyrifos-methyl (CH), deltamethrin (DE) and spinosad (SP) was evaluated alone and in binary combinations with carbon dioxide (CA) against Sitophilus oryzae (L.). Mortality of S. oryzae adults was recorded after 3, 7 and 14 days, and progeny production and wheat weight loss were assessed after 90 days for all treatments. In individual treatments, the mortality of S. oryzae adults was 69.5, 79.8, 50.7 and 61.4% after 14 days of exposure to the highest concentration of CA (30%), CH (0.5 mg/kg), DE (1.0 mg/kg) and SP (0.5 mg/kg), respectively. Mortality of S. oryzae adults was higher in combined treatments at all tested rates than individual treatments. Mortality of adults of 100% was obtained in combined treatments of CH (0.5 mg/kg) + CA (30%) after 3 days and DE (1.0 mg/kg) + CA (30%) after 14 days of exposure. Combinations of SP + CA were more effective than CH + CA and DE + CA as 100.0% mortality was achieved in combined treatments of SP at 0.25 mg/kg with CA at 20 and 30%, and SP at 0.5 mg/kg with CA at 20 and 30% after 3 days of exposure. Progeny production of S. oryzae was decreased significantly in all treatments compared with untreated wheat grains after 90 days of exposure. High rates induced progeny reduction of 100% and complete protection of wheat grains against damage caused by S. oryzae after 90 days. Moreover, germination percentages of wheat seeds treated with CH at 0.5 mg/kg, DE at 1.0 mg/kg, CA at 30% and CH at 0.5 mg/kg + CA at 30% were 90.6, 86.7, 86.7 and 90.0, respectively. Our results indicate that the combination of insecticides with CA appears promising as an approach for the control of S. oryzae.

Spinosyns Delivered in Sugar Meals to Aedes aegypti and Aedes albopictus (Diptera: Culicidae): Acute Toxicity and Subacute Effects on Survival, Fecundity, and Fertility.

Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits. This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC50 concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

Influence of temperature on spinosad toxicity in different populations of Plutella xylostella (Linnaeus)


 Diamond back moth, Plutella xylostella (Linnaeus) is one of the major insect-pest of cole crops, causing high yield losses. In present study, larval populations of P. xylostella, collected from different regions of Punjab i.e. Amritsar, Kapurthala, Malerkotla and Ludhiana were exposed to different concentrations of spinosad at 15, 20, 25 and 30 °C for evaluation of LC values. The LC (Lethal 50 50 concentration) increased from lower (15 °C) to higher (30 °C) temperature for all populations of P. xylostella. Negative correlation was observed between the temperature coefficient and toxicity of spinosad towards P. xylostella populations, which decreased with increase in temperature. The LC 50 values varied among different populations of P. xylostella i.e. Amritsar populations with higher LC values 50 followed by Kapurthala, Malerkotla and Ludhiana populations. The temperature and insecticide exposure history both affected the toxicity of spinosad for P. xylostella. The information would be helpful in developing management strategies for P. xylostella according to prevailing environment conditions.

Sublethal concentrations of spinosad synergize the pathogenicity of fungi to larvae of Ephestia kuehniella (Lepidoptera: Pyralidae)

We evaluated the efficacy of four entomopathogenic fungi (EPF) and their compatibility with the bioinsecticide spinosad for control of Ephestia kuehniella (Zeller) under laboratory conditions. Three EPF, including Beauveria bassiana (Balsamo-Criveili) Vuillemin isolates Z1 and Iran 1395C, Lecanicillium (= Verticillium) lecanii (Zimmerman) Zare & Gams, isolate Iran 229, and Purpureocillium (Paecilomyces) lilacinum (Thom) Luangs-ard, Hywel-Jones & Samson, isolate Iran 1026 were tested against third and fifth larval instars of Ephestia kuehniella using a filter paper bioassay. Mortality caused by the EPF ranged from 63.3-72.5% for third instars and 50-65.5% for fifth instars, with LT50 ranging from 8.4-10.5 d and 10.1-12.9 d, respectively. The effect of spinosad at LC10 (= 26.2 ppm) on EPF spore germination was evaluated and found to be negligible, ranging from 0% for B. bassiana Z1 to 5.7% for P. lilacinum. The LC50 values for spinosad against third and fifth instar E. kuehniella larvae were 452.5 and 1446 ppm, respectively. Subsequently, spinosad at LC10 was applied to third instar E. kuehniella larvae 24 h before application of the EPFs at LC50. The addition of spinosad to applications of L. lecanii and B. bassiana Z1 and Iran1395C isolates synergized their pathogenicity to E. kuehniella larvae, whereas the effect was merely additive for P. lilacinum. Our results suggest that these EPF isolates can be used effectively in combination with spinosad for management of E. kuehniella in stored products.

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.

Toxicological and histological studies on the effect of spinosad or vinegar on Culex pipiens larvae (Diptera: Culicidae)

Efficacy of Spintor® 24% SC (spinosad) and vinegar were studied to control Culex pipiens larvae by testing different concentrations of spinosad (10, 50, 100, 500 and 1000 µl/10 ml) or vinegar (125, 250, 500 and 750 µl/10 ml). The percentage mortality of larvae was increased by increasing concentrations and time. While 100 % mortality was obtained at the concentration 1000 µl/10 ml of spinosad after 48 h, in the case of vinegar treatment 100 % mortality was obtained at the concentration of 750 µl/10 ml after 72 h. Both spinosad and vinegar exhibited a histological effect on the midgut by degeneration of the epithelial cells, the disintegration of the plasma and basement membranes and extensive disruption of the cellular microvillar. Generally, spinosad manifested a higher level of activity against Cu. pipiens larvae than vinegar.

Antioxidant status and ultrastructural defects in the ovaries of red palm weevils (Rhynchophorus ferrugineus) intoxicated with spinosad

AbstractRed palm weevil, Rhynchophorus ferrugineus, destroys palms almost all over the world, especially in the Middle East, where dates are a strategic crop in arid places. In view of the urgent need to combat this destructive pest, effective pesticides with high environmental safety should be sought. Spinosad is a pesticide of bacterial origin that is presumed to have a high degree of environmental safety and is effective in combating a wide range of insect pests. In this study, the efficacy of spinosad was evaluated in females of R. ferrugineus. The lethal concentration for 50% of the treated females was calculated at 44.3 ppm. The effects of spinosad concentrations of 10, 50 and 200 ppm on the activity of catalase (CAT), glutathione S‐transferase (GST) and superoxide dismutase (SOD) in the ovaries were assessed. In addition, the pathological effects of these concentrations were documented on the ultrastructure of the follicle cells and ooplasm. The results showed a significant increase in CAT activity only in response to treatment with 200 ppm. Treating the females with different spinosad concentrations resulted in varying intensity changes in cell organelles, where the most pronounced sign of programmed cell death was at the concentration 200 ppm. This study demonstrates the possibility of using spinosad as an insecticide against females of R. ferrugineus.

Side effects of chlorantraniliprole, phosalone and spinosad on the egg parasitoid, Trichogramma brassicae.

The combined use of chemicals and biological control is not always a successful strategy owing to the potential side effects on biocontrol agents. Lethal and sublethal effects of three commonly used insecticides were assessed on adult and immature stages of the egg parasitoid Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae). Recommended field concentrations of chlorantraniliprole, phosalone and spinosad caused mortality on preimaginal stages by 24, 87, and 98%, respectively. Lethal effects on parasitoid adults exposed to the insecticide dry residues were estimated as median lethal concentrations (LC50) that were 13.28, 0.25, and 0.03 µg a.i. ml-1 for chlorantraniliprole, phosalone, and spinosad, respectively. The effect of a low lethal concentration (LC30) of the compounds was evaluated on various adult biological traits, such as longevity, fecundity, emergence rate and other life table parameters. All compounds caused detrimental effects on all the estimated demographical indexes. Chlorantraniliprole affected the net reproductive rate, mean generation time and doubling time in comparison to the control; while, phosalone and spinosad adversely affected all assessed parameters. Phosalone and spinosad significantly reduced gross reproductive rate, net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time and doubling time and reduced longevity, fecundity, emergence rate related to other biological parameters in comparison with control. The results suggest that all compounds are not fully compatible with the activity of T. brassicae, and that the inclusion of chlorantraniprole, spinosad and phosalone into Integrated Pest Management (IPM) involving this parasitoid has to be avoided. Nevertheless, further studies in open field conditions and on a multiple generation scale are necessary for providing a more definitive conclusion on the IPM suitability of the three tested insectcides.

A Spinosad-Based Formulation Reduces the Survival and Alters the Behavior of the Stingless Bee Plebeia lucii.

The decline in bee populations worldwide has been associated with the use of pesticides in crop systems where these insects forage. The use of biopesticides, like spinosad, is preferred as an alternative method to control pests, because it is considered safer to non-target insects. In this study, we evaluated the lethal and sublethal effects of the spinosad-based formulation Tracer® on foragers of the stingless bee Plebeia lucii Moure (Apidae: Meliponini). Groups of bees were fed a pure diet (negative control) or a diet at different concentrations of spinosad. Positive control groups consisted of bees orally exposed to a diet with the neonicotinoid imidacloprid. Next, flight behavior, body mass, and respiration rate were evaluated in surviving bees. The results showed that bees´ survival was reduced by all concentrations of spinosad, when compared with the negative control. Bee locomotion-walking and flight-was reduced in accordance with the increase in spinosad concentrations; however, body mass and respiration rate were not altered. Our results show that the use of Tracer® in ecosystems visited by P. lucii can reduce forager bee survival and reduce their locomotion, generating a negative impact on pollination services provided by these bees.

Fitness consequences of the combined effects of veterinary and agricultural pesticides on a non-target insect

Pesticides and veterinary products that are globally used in farming against pests and parasites are known to impact non-target beneficial organisms. While most studies have tested the lethal and sub-lethal effects of single chemicals, species are exposed to multiple contaminants that might interact and exacerbate the toxic responses of life-history fitness components. Here we experimentally tested an ecotoxicological scenario that is likely to be widespread in nature, with non-target dung communities being exposed both to cattle parasiticides during the larval stage and to agricultural insecticides during their adult life. We assessed the independent and combined consumptive effects of varying ivermectin and spinosad concentration on juvenile life-history and adult reproductive traits of the widespread yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Larval exposure to ivermectin prolonged development time and reduced egg-to-adult survival, body size, and the magnitude of the male-biased sexual size dimorphism. The consumption by the predatory adult flies of spinosad-contaminated prey showed an additional, independent (from ivermectin) negative effect on female clutch size, and subsequent egg hatching success, but not on the body size and sexual size dimorphism of their surviving offspring. However, there were interactive synergistic effects of both contaminants on offspring emergence and body size. Our results document adverse effects of the combination of different chemicals on fitness components of a dung insect, highlighting transgenerational effects of adult exposure to contaminants for their offspring. These findings suggest that ecotoxicological tests should consider the combination of different contaminants for more accurate eco-assessments.

Influence of spinosad on the reproductive potential of Tribolium castaneum (Herbst), (Coleoptera: Tenebrionidae) infesting wheat

Spinodad of different concentrations were screened against Tribolium castaneum (Herbst) reared on four local wheat varieties to observed the effects on reproductive potentials for two successive generations.The lowest number of eggs laid was 119 (23.80±0.97) observed in Shatabdi- 21 (S-21) in 45 d in F1 and 15 (3.00±0.71) in 15 d in F2 generation when treated at 0.12ìl/g of spinosad. Spinosad at all concentration totally inhibited egg laying oroviposition rate on day 45 in all wheat varieties except P-24 variety in F1 generation.The lowest fertility was found in Shatabdi-21 variety as 12.61percent in F1 and 6.67 percent in F2 generation at 0.12ìl/g.The latent effect of spinosad on number of eggs, larva, pupa and adult obtained in Shatabdi-21 as 2.00±0.32,0.80±0.37, 0.40±0.40 and 0.20±0.20 at 0.12ìl/g of spinosad in F2 generation.There was no significant difference between the number of males and females in F2 generation wheat varieties. Spinosad ultimately reduced the fecundity, fertility and decreased the egg to adult survivability in four wheat varieties compared to control and F1 and F2 generations. Results of the research revealed that comparatively higher concentrations of spinosad that used in this study would potentially control development and reproductive potentiality of T. castaneum in wheat varieties.

Identification of Thrips Species and Resistance of Frankliniella occidentalis (Thysanoptera: Thripidae) to Malathion, Spinosad, and Bifenthrin in Blackberry Crops

Mexico is among the most important blackberry producers in the world. In this crop, thrips damage is associated with poor fruit set. The objectives of this study were to identify the main thrips species associated with the flowers of cultivated blackberries, and to determine the resistance level of 13 field-collected populations of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), to the insecticides malathion, bifenthrin, and spinosad in the states of Michoacan and Jalisco, Mexico. Verification of F. occidentalis was conducted by morphology and PCR amplification of the cytochrome oxidase I (COI) partial gene using LCO and HCO primers The susceptibility of adult thrips to insecticides was determined using residual contact exposure on bean (Phaseolus vulgaris L.; Fabaceae) leaf sections dipped into aqueous solutions of 8 different concentrations of malathion, bifenthrin, and spinosad. The morphological identification of thrips from 8 different sampling zones confirmed that the main thrips species associated with blackberry flowers was F. occidentalis. However, Retanathrips funestus (Hood), Frankliniella insularis (Franklin), Frankliniella tolucensis Watson, Taenothrips frici (Uzel), and Isoneurothrips australis Bagnall (all Thysanoptera: Thripidae) also were found. Most of the evaluated populations of F. occidentalis showed significant differences from the susceptible population in terms of the level of resistance to bifenthrin, malathion, and spinosad. The resistance ratios (RR50) for malathion varied from 36 to 2,458, followed by 4 to 974, and 2 to 248 in bifenthrin and spinosad, respectively. These results suggest the need to establish insecticide resistance management programs, particularly in zones that resulted in the highest levels of insecticide resistance.