Leptinotarsa Decemlineata Say Research Articles

Agricultural fungicides inadvertently influence the fitness of Colorado potato beetles, Leptinotarsa decemlineata, and their susceptibility to insecticides

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is an agricultural pest of solanaceous crops which has developed insecticide resistance at an alarming rate. Up to this point, little consideration has been given to unintended, or inadvertent effects that non-insecticide xenobiotics may have on insecticide susceptibility in L. decemlineata. Fungicides, such as chlorothalonil and boscalid, are often used to control fungal pathogens in potato fields and are applied at regular intervals when L. decemlineata populations are present in the crop. In order to determine whether fungicide use may be associated with elevated levels of insecticide resistance in L. decemlineata, we examined phenotypic responses in L. decemlineata to the fungicides chlorothalonil and boscalid. Using enzymatic and transcript abundance investigations, we also examined modes of molecular detoxification in response to both insecticide (imidacloprid) and fungicide (boscalid and chlorothalonil) application to more specifically determine if fungicides and insecticides induce similar metabolic detoxification mechanisms. Both chlorothalonil and boscalid exposure induced a phenotypic, enzymatic and transcript response in L. decemlineata which correlates with known mechanisms of insecticide resistance.

Considerations for selecting disease resistant wild germplasm (Solanum spp.): lessons from a case study of resistance to bacterial soft rot and Colorado potato beetle

Predictions of distributions of resistance phenotypes have been attempted for major diseases in wild potato germplasm. Interestingly, no consistent taxonomic or biogeographic predictors have been identified. However, an important lesson learned was that there are interactions among host plants, environmental factors, and characters of the pathogens. A logical extension of the predictivity project is to examine the dynamics of resistances when multiple biotic stresses are involved. In this study, we found that populations susceptible to a foliar feeding pest [Colorado potato beetle, Leptinotarsa decemlineata (Say)] are resistant to a bacterial pathogen [Pectobacterium carotovorum subsp. carotovorum (Jones, 1901; Hauben et al. 1999)]. We propose that wounds caused by the insect pest allow the bacterial pathogen to gain entry and cause disease. This would lead to strong selection pressure for resistance to the bacterial pathogen. Consequently, when searching for traits of interest in germplasm collections, it is important to consider the complex biotic and abiotic environments in which the source populations evolved.

Variability in metabolic rate and gas exchange patterns of the Colorado potato beetle of winter and prolonged diapauses

AbstractWe compare standard metabolic rate (VCO2) and gas exchange patterns in the Colorado potato beetle (Leptinotarsa decemlineata Say) in winter diapause (i.e. lasting only one overwintering period) with those of beetles in prolonged diapause (i.e. diapause lasting 2 or 3 years). The length of diapause is estimated by the behaviour of the beetles: burrowing into soil as a sign of the beginning of diapause and emergence from the soil as the ending of diapause. Measurement with a flow‐through carbon dioxide (CO2) infrared gas analyzer reveals that most beetles in winter or prolonged diapause display distinct discontinuous gas exchange cycles at 23 °C. Beetles with cyclic gas exchange and continuous breathing do not survive the winter. Beetles in prolonged diapause are characterized by a three‐ to five‐fold lower standard metabolic rates, longer discontinuous gas exchange periods and shorter CO2 releases (open phase) than those in winter diapause.

Oxidative stress and cytogenetic effects in root tip cells ofAllium cepaL. induced by alcoholic extracts ofLeptinotarsa decemlineata(Say)

The harmful potential of the Colorado potato beetle (Leptinotarsa decemlineata (Say)), and its resistance to many insecticides in current use have drawn the attention of specialists across the worl...

Defense Responses and Changes in Symbiotic Gut Microflora in the Colorado Potato Beetle Leptinotarsa decemlineata under the Effect of Endophytic Bacteria from the Genus Bacillus

Phytophagous insects and host plants have a complex of microsymbionts and make up a united co-evolving system with them. Microsymbiotic complexes are actively involved in stress responses of macrosymbionts. We established that a treatment of potato plants with endophytic bacterial strains Bacillus thuringiensis var. thuringiensis-5689, B. th. var. kurstaki-5351, and Bacillus subtilis 26D decreased the survival rate of the plant feeder, Colorado potato beetle Leptinotarsa decemlineata Say. The B. th. strains suppressed phenoloxidase and acetylcholinesterase activities in the beetle hemolymph. An antagonistic relationship was found between endophytic bacteria B. subtilis 26D and beetle symbiotic bacteria from the genera Acinetobacter and Enterobacter, with the former being able to suppress the growth of endophytic colonies. The recombinant B. subtilis strain 26D Cry, containing the B. th. var. kurstaki δ-endotoxin cry1Ia gene, combined the ability of the original B. subtilis 26D strain to suppress the development of beetle symbionts and immune responses with a production of the Cry toxin, thus leading to a high mortality of the phytophage.

Genetic mapping identifies loci that influence tomato resistance against Colorado potato beetles

The Colorado potato beetle (CPB; Leptinotarsa decemlineata Say), the most economically important insect pest on potato (Solanum tuberosum L.), also feeds on other Solanaceae, including cultivated tomato (Solanum lycopersicum L.). We used tomato genetic mapping populations to investigate natural variation in CPB resistance. CPB bioassays with 74 tomato lines carrying introgressions of Solanum pennellii in S. lycopersicum cv. M82 identified introgressions from S. pennellii on chromosomes 1 and 6 conferring CPB susceptibility, whereas introgressions on chromosomes 1, 8 and 10 conferred higher resistance. Mapping of CPB resistance using 113 recombinant inbred lines derived from a cross between S. lycopersicum cv UC-204B and Solanum galapagense identified significant quantitative trait loci on chromosomes 6 and 8. In each case, the S. galapagense alleles were associated with lower leaf damage and reduced larval growth. Results of both genetic mapping approaches converged on the same region of chromosome 6, which may have important functions in tomato defense against CPB herbivory. Although genetic mapping identified quantitative trait loci encompassing known genes for tomato acyl sugar and glycoalkaloid biosynthesis, experiments with acyl sugar near-isogenic lines and transgenic GAME9 glycoalkaloid-deficient and overproducing lines showed no significant effect of these otherwise insect-defensive metabolites on CPB performance.

Plant Resistance to Colorado Potato Beetle (Coleoptera: Chrysomelidae) in Diploid F2 Families Derived From Crosses Between Cultivated and Wild Potato.

Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), is a serious global pest of potato, Solanum tuberosum L. Management of L. decemlineata has relied heavily on insecticides, but repeated evolution of insecticide resistance has motivated the exploration and development of alternative strategies, such as plant resistance. The recent development of two diploid potato families derived from crosses between cultivated and wild potato species (S. chacoense and S. berthaultii) has provided a unique opportunity to reexamine plant traits for resistance breeding. In this 2-yr study, we surveyed select F2 clones for the induction of L. decemlineata mortality and a reduction in defoliation in no-choice feeding assays when challenged with adults and larvae from three sites in Wisconsin. We tested for an association with glandular trichome density and foliar levels of the glycoalkaloids chaconine and solanine. Several potato clones demonstrated resistance in specific feeding assays, but none excelled consistently across experiments. Mortality and defoliation generally differed significantly among L. decemlineata populations, which could be indicative of heritable variation in beetle responses to plant defenses or variation in the physiological status of the beetle populations tested. Contrary to expectations, higher trichome density increased mortality or decreased defoliation in only a few cases, and levels of mortality and defoliation were unrelated to foliar glycoalkaloid content, warranting further investigation of the defense mechanisms of resistant clones. In addition to identifying several potential L. decemlineata resistance sources, this study underscores the need to include multiple insect populations in surveys of plant resistance to this diverse pest.

Involvement of methoprene-tolerant (Met) in the determination of the final body size in Leptinotarsa decemlineata (Say) larvae

In the tobacco hornworm Manduca sexta, juvenile hormone (JH) is critical for the control of species-specific size. However, whether the basic helix-loop-helix/Per-Arnt-Sim domain receptor methoprene-tolerant (Met) is involved remains unconfirmed. In the present paper, we found that RNA interference (RNAi)-aided knockdown of Met gene (LdMet) lowered the larval and pupal fresh weights and shortened the larval development period in the Colorado potato beetle Leptinotarsa decemlineata. Dietary introduction of JH into the LdMet RNAi larvae rescued neither the decreased weights nor the reduced development phase, even though JH ingestion by control larvae extended developmental time and caused large pupae. Moreover, the transcript levels of five genes involved in prothoracicotropic hormone and cap 'n' collar isoform C/Kelch-like ECH associated protein 1 pathways were upregulated in the LdMet silenced larvae. Ecdysteroidogenesis was thereby activated; 20-hydroxyecdysone (20E) titer was increased; and 20E signaling pathway was elicited in the LdMet RNAi larvae. Therefore, JH, acting through its receptor Met, inhibits PTTH production and release before the attainment of critical weight. Once the critical weight is reached, JH production and release are averted; and the hemolymph JH is removed. The elimination of JH allows the brain to release PTTH. PTTH subsequently stimulates ecdysteroid biosynthesis and release to start larval-pupal transition in L. decemlineata.

A Comparison of Resistance to Imidacloprid in Colorado Potato Beetle (Leptinotarsa decemlineata Say) Populations Collected in the Northwest and Midwest U.S.

The Colorado potato beetle, Leptinotarsa decemlineata Say, is a serious pest of potato, Solanum tuberosum L., worldwide. Leptinotarsa decemlineata has a history of repeated adaptation to insecticides, and exhibits a geographic pattern of decreasing insecticide resistance from east to west in the USA. Imidacloprid is one of the most widely used insecticide in western states. In this study, we measured imidacloprid resistance among larval and adult L. decemlineata from ten locations in the Columbia Basin (southeastern Washington and northeastern Oregon) using topical LD50 bioassays, and compared them to estimates from ten locations in Minnesota and Wisconsin. Larval and adult imidacloprid LD50’s and mean percent mortality were generally lowest in Washington and Oregon, but some sites exhibited reductions in mortality comparable to those observed at some Wisconsin sites. Adult LD50’s suggest L. decemlineata in the Columbia Basin may be evolving in response to selection by neonicotinoid insecticides, but larval data suggest high susceptibility to imidacloprid remains in most populations. Future work should expand resistance monitoring efforts to include more regions in the West and other insecticide modes of action.

Effect of Teflubenzuron Ingestion on Larval Performance and Chitin Content in Leptinotarsa decemlineata

The potential of teflubenzuron was assessed in a series of laboratory studies in order to achieve consistent, long-term, integrated management of the Colorado potato beetle, Leptinotarsa decemlineata (Say). Teflubenzuron exhibited excellent stomach toxicity to the larvae. Its larvicidal activity was comparable with those of cyhalothrin, chlorantraniliprole and spinosad. Moreover, the teflubenzuron-fed larvae consumed less foliage, grew slower, and needed a longer period to develop, in a dose dependent manner. Most of these larvae died during larval-larval molting, larval-pupal ecdysis or adult emergence. Furthermore, chitin contents in body carcass (without midgut) and integument specimen of the teflubenzuron-fed larvae significantly decreased, whereas the chitin amount in the midgut peritrophic matrix was not affected. In addition, uridine diphosphate-N-acetylglucosamine-pyrophosphorylase gene (LdUAP1), which was mainly responsible for chitin biosynthesis in ectodermally-derived tissues, was suppressed after teflubenzuron ingestion, in contrast to its partner LdUAP2 for chitin formation in the midgut peritrophic matrix. In a word, by inhibition of chitin production in ectodermally-derived tissues, teflubenzuron is an effective benzoylurea insecticide to L. decemlineata larvae. It can be a valuable tool in effective integrated pest management and insecticide resistance management programs against L. decemlineata.

Lethal and Sublethal Effects of Mineral Oil on Potato Pests.

Mineral oil is a product used to reduce Potato Virus Y transmission in potato fields. However, there is little information available about other effects that oil may have on insect pests of potato. To better understand how mineral oil affects potato pests, we performed a series of experiments testing the effects of oil on mortality, behavior, and development of potato aphids, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae), green peach aphids, Myzus persicae (Sulzer) (Hemiptera: Aphididae), and Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). All three species showed negative behavioral responses to oil-treated potato foliage. Oil treatment also increased aphid mortality. Colorado potato beetle mortality was not affected, but developing on oil-treated potato plants resulted in prolonged development and smaller adults. Additionally, oil acted synergistically with the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae); Colorado potato beetle larvae were killed more rapidly when sprayed with both products compared with when sprayed with B. bassiana alone. Based on these results, mineral oil has the potential for expanded use in potato IPM programs.

Origin of Pest Lineages of the Colorado Potato Beetle (Coleoptera: Chrysomelidae).

Colorado potato beetle (Leptinotarsa decemlineata Say [Coleoptera: Chrysomelidae]) is a pest of potato throughout the Northern Hemisphere, but little is known about the beetle's origins as a pest. We sampled the beetle from uncultivated Solanum host plants in Mexico, and from pest and non-pest populations in the United States and used mitochondrial DNA and nuclear loci to examine three hypotheses on the origin of the pest lineages: 1) the pest beetles originated from Mexican populations, 2) they descended from hybridization between previously divergent populations, or 3) they descended from populations that are native to the Plains states in the United States. Mitochondrial haplotypes of non-pest populations from Mexico and Arizona differed substantially from beetles collected from the southern plains and potato fields in the United States, indicating that beetles from Mexico and Arizona did not contribute to founding the pest lineages. Similar results were observed for AFLP and microsatellite data . In contrast, non-pest populations from the states of Colorado, Kansas, Nebraska, New Mexico, and Texas were genetically similar to U.S. pest populations, indicating that they contributed to the founding of the pest lineages. Most of the pest populations do not show a significant reduction in genetic diversity compared to the plains populations in the United States. We conclude that genetically heterogeneous beetle populations expanded onto potato from native Solanum hosts. This mode of host range expansion may have contributed to the abundant genetic diversity of contemporary populations, perhaps contributing to the rapid evolution of climate tolerance, host range, and insecticide resistance.

Situation with Colorado beetle Leptinotarsa decemlineata Say resistance to insecticides in the North-Western region of Russia

The results of long-term monitoring of insecticide resistance in the Colorado potato beetle in the North-Western region of the Russian Federation are presented. The formation of group resistance to pyrethroids and neonicotinoids in the Leningrad, Pskov, Novgorod, Vologda and Kaliningrad pest populations was established. The formation of cross-resistance to Spinosad in populations highly resistant to pyrethroids was revealed. In a number of populations, the development of resistance to organophosphorous drugs was noted. Against this background, the formation of multiple resistance to the control means in the populations of Colorado potato beetle was found. The reasons for the formation of insecticide-resistant populations of phytophage are the intensive use of insecticides of different chemical classes in its control, as well as the introduction of resistant pest genotypes from neighboring regions. To identify the development of resistance in the Colorado potato beetle to insecticides, it is necessary to monitor this process, which is based on the use of phenotypic method for assessing changes in the structure of populations under the influence of toxic effects, and toxicological method based on testing larvae of 2nd stage with diagnostic concentrations of drugs.

Role of environmental abiotic factors in limiting the Colorado potato beetle distribution in Northwestern Russia

The Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera, Chrysomelidae) was successfully acclimatized after 1998 in Leningrad Region and on neighborhood territories with similar termal conditions. The expansion and development of the pest in this region are limited only by excessive moistening of the soil, causing nearly total elimination of developing pupae and diapausing adults due to physiological suffocation.

Biological activity of zeolite-containing tripoli against some agricultural pests

The toxicity of zeolite-containing tripoli (siliceous sedimentary rock) of the Khotynetz deposit (Orel Oblast) was studied in the laboratory for the first time for aphid Aulacorthum solani Kalt., Colorado beetle Leptinotarsa decemlineata Say and spider mite Tetranychus urticae Koch. Using different treatment methods of processing test objects with a tripoli (dusting or dipping in suspension and supernatant of leaves, populated by aphids, or putting aphids on treated leaves), no ovicidal properties of the preparation were found. However, the larvicidal and moderate imagocidal action against sucking pests was found. Depending on the method of treatment, the obtained mortality rates of Aulacorthum solani (resistant and susceptible populations) and Tetranychus urticae fluctuated within the range 70.4–83.0 % and 46.6–80.4 %, accordingly. Study of the effect of tripoli on the Leptinotarsa decemlineata, showed the larvicidal activity decreasing with age: the highest rates (60–100 %) were estimated for larvae of younger pest ages, and absence of efficacy was found for larvae of older ages and imagoes.The presence of phytotoxic properties in tripoli was not established. The results suggest that study of toxic effect of this unique natural substance on pests should be continued in field. At the same time, in order to obtain high toxic effect, the tripoli application rate and multiplicity of treatments can be increased by 2–3 times.

Identification of Differentially Expressed miRNAs in Colorado Potato Beetles (Leptinotarsa decemlineata (Say)) Exposed to Imidacloprid.

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is a significant pest of potato plants that has been controlled for more than two decades by neonicotinoid imidacloprid. L. decemlineata can develop resistance to this agent even though the molecular mechanisms underlying this resistance are not well characterized. MicroRNAs (miRNAs) are short ribonucleic acids that have been linked to response to various insecticides in several insect models. Unfortunately, the information is lacking regarding differentially expressed miRNAs following imidacloprid treatment in L. decemlineata. In this study, next-generation sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify modulated miRNAs in imidacloprid-treated versus untreated L. decemlineata. This approach identified 33 differentially expressed miRNAs between the two experimental conditions. Of interest, miR-282 and miR-989, miRNAs previously shown to be modulated by imidacloprid in other insects, and miR-100, a miRNA associated with regulation of cytochrome P450 expression, were significantly modulated in imidacloprid-treated beetles. Overall, this work presents the first report of a miRNA signature associated with imidacloprid exposure in L. decemlineata using a high-throughput approach. It also reveals interesting miRNA candidates that potentially underly imidacloprid response in this insect pest.

Landscape genomics of Colorado potato beetle provides evidence of polygenic adaptation to insecticides.

The ability of insect pests to rapidly and repeatedly adapt to insecticides has long challenged entomologists and evolutionary biologists. Since Crow's seminal paper on insecticide resistance in 1957, new data and insights continue to emerge that are relevant to the old questions about how insecticide resistance evolves: such as whether it is predominantly mono- or polygenic, and evolving from standing vs. de novo genetic variation. Many studies support the monogenic hypothesis, and current management recommendations assume single- or two-locus models. But inferences could be improved by integrating data from a broader sample of pest populations and genomes. Here, we generate evidence relevant to these questions by applying a landscape genomics framework to the study of insecticide resistance in a major agricultural pest, Colorado potato beetle, Leptinotarsa decemlineata (Say). Genome-environment association tests using genomic variation from 16 populations spanning gradients of landscape variables associated with insecticide exposure over time revealed 42 strong candidate insecticide resistance genes, with potentially overlapping roles in multiple resistance mechanisms. Measurements of resistance to a widely used insecticide, imidacloprid, among 47 L. decemlineata populations revealed heterogeneity at a small (2km) scale and no spatial signature of origin or spread throughout the landscape. Analysis of nucleotide diversity suggested candidate resistance loci have undergone varying degrees of selective sweeps, often maintaining similar levels of nucleotide diversity to neutral loci. This study suggests that many genes are involved in insecticide resistance in L.decemlineata and that resistance likely evolves from both de novo and standing genetic variation.

Toxicological and behavioral effects of some plant extract on Colorado potato beetle, Leptinotarsa decemlineata Say, 1824 (Coleoptera: Chrysomelidae)

Alti bitki ekstraktinin [ Heracleum platytaenium Boiss (Apiaceae), Humulus lupulus L. (Cannabaceae), Achillea millefoliu m L. (Asteraceae), Acanthus dioscoridis L. (Acanthaceae), Phlomoides tuberosa (L.) Moench (Lamiaceae), Bifora radians Bieb. (Apiaceae) ], Leptinotarsa decemlineata Say 1824 (Coleoptera: Chrysomelidae)’ye karsi repellent, ovisidal ve yumurta birakmayi engelleyici etkileri test edilmistir. Bitkilerin vejetatif aksamlarindan hazirlanan methanol ekstraktlari L. decemlineata uzerinde test edilmistir. En yuksek ovisidal etki besinci gun itibari ile H. platytaenium uygulamasinda gozlemlenmis ve bunu A. millefolium ekstraktinin etkisi izlemistir. Heracleum platytaenium ekstraktinin etkinligini %15 yumurta acilim orani ile A. millefolium ekstraktinin etkinligi takip etmistir. Diger bitki ekstraktlarinda onemli olum gozlenmemistir. Ikinci seri denemelerde Patates boceginin yumurtalarina karsi H. platytaenium ’un doz-etki calismalari yurutulmustur. Onemli derecede dusuk yumurta acilim orani sadece %7.5 [w/v (bitki ekstrakti/aseton)] konsantrasyonda %1 etki ile gozlemlenmistir. En yuksek yumurta birakmayi engelleyici etki H. platytaenium ekstraktinda gorulmus ve bu muamelede hic yumurta birakilmamistir. Bitki ekstraktlari yuksek oranda repellent aktivite gostermis ve bu aktivite inkubasyon suresine bagli olarak artmistir. Test edilen bitki ekstraktlari arasinda en yuksek derecede uzaklastirici etki %0.01’lik oransal deger ile ilk 15 dakikada A. millefolium ekstraktinda saptanmistir. Bu sonuclar H. platytaenium ekstraktinin L. decemlineata kontrolunde onemli bir potansiyele sahip oldugunu ortaya koymustur.

Targeted expression of insecticidal hybrid SN19 gene in potato leads to enhanced resistance against Colorado potato beetle (Leptinotarsa decemlineata Say) and tomato leafminer (Tuta absoluta Meyrick)

The expression of insecticidal genes must be induced at appropriate time and in sufficient amount to confer protection against targeted pests. However, the increased scientific reports of resistance development in insect pest against insecticidal delta-endotoxins, produced by Bacillus thuringiensis, provide impetus for the development of alternative insect management strategies. The present study was conducted to investigate the importance of targeted expression of a hybrid insecticidal gene (SN19) in potatoes. For this purpose, two plant expression vectors were constructed by cloning hybrid SN19 gene (cry1Ba-domain I–III and cry1Ia-domain II) under the control of a wound-inducible promoter isolated from Asparagus officinalis (AoPR1) and CaMV 35S promoter, and were transferred to Agrobacterium tumefaciens strain EHA 105. Four potato genotypes (Marabel, Innovator, Tokat 10/1 and Tokat 6/24) were transformed with EHA 105 strain harboring pTF101.1 35S–SN19 and pTF101.1 AoPR1–SN19 constructs. Phosphinothricin (PPT) was used at concentration of 1 mg/l for selection of primary transformants. PCR results showed the presence of both introduced SN19 and bar genes in 43 plants out of total 154 putative transgenics. Expression of SN19 protein in primary transformants was confirmed by Western blot assays. The mechanical wounding of transgenic plants exhibited more accumulated levels of SN19 proteins during post wounding period. Leaf biotoxicity assays with Colorado potato beetle (Coleoptera) and tomato leafminer (Lepidoptera) exhibited 100% mortality of the pests in primary transformants. Based on our mortality results with both constructs, we concluded that the potato transgenic lines exhibited targeted expression of insecticidal gene under the control of AoPR1 promoter upon insect wounding with eliminated toxicity of Cry protein and hence can be further used effectively in potato breeding programme.

ContacToxicity of Six Plant Extracts to Different Larval Stages of Colorado Potato Beetle (Leptinotarsa decemlineata SAY (Col: Chrysomelidae))

Discovery of new eco-friendly methods for insect pest management is very important in integrated pest management program. Contact toxicity of six plant extracts i.e. Acanthus dioscoridis L. (Acanthaceae), Achillea millefolium L. (Asteraceae), Bifora radians Bieb. (Apiaceae), Heracleum platytaenium Boiss (Apiaceae), Humulus lupulus L. (Cannabaceae) and Phlomoides tuberosa (L.) Moench (Lamiaceae), were tested on the 1st to 4th instar larvae of Colorado potato beetle (Leptinotarsa decemlineata Say. (Coleoptera: Chrysomelidae)). The H. platytaenium and H. lupulus extracts were the most effective among the tested extracts, so dose-response bioassay was carried out only with H. lupulus and H. platytaenium against larval stages of Colorado potato beetle. The H. platytaenium extract was the most effective extract with calculated LD50 values 0.126, 0.204, 0.206 and 0.458 μL insect-1, LD90 values were calculated as 0.345, 0.342, 0.402, 0.566 μL insect-1 for 1st, 2nd, 3rd and 4th instars larvae respectively. These results indicate that H. platytaenium and H. lupulus extracts have great potentials as insecticides in the management of larvae of L. decemlineata.