Colorado Beetle Leptinotarsa Decemlineata Research Articles

Patterns in the Formation of Isomeric Homologous Series of Epicuticular Hydrocarbons in Colorado Beetle Leptinotarsa decemlineata

Patterns in the Formation of Isomeric Homologous Series of Epicuticular Hydrocarbons in Colorado Beetle Leptinotarsa decemlineata

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.

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.

AN OVERVIEW ON FUNGAL DISEASES AND PESTS ON THE FIELD TOMATO CROPS IN ROMANIA

An inventory of the pathogenic fungi, pests and beneficial fauna is presented. The main fungi causing the economical losses in all regions are Alternaria porri (Ell.) Neerg. f.sp. solani (Ell. et Mart.) Neerg., Colletotrichum atramentadum (Berk. & Br.) Taub. and Phytophthora infestans (Mont.) de By. The aphid species Macrosiphon euphorbiae Hott., Macrosiphon solani Kitt., Myzodes persicae Sulz., the Colorado beetle Leptinotarsa decemlineata Say and the fruit borer Helicoverpa spp. are considered major pests for the tomato crops grown outdoors in Romania because of their damaging populations. An extremely important part in limiting the populations of these pests is played by different species of predators and parasites: the carabids represent 84.0% of the beneficial fauna, coccinelids are 12.0%, pentatomids - 2.8% and chrysopids - 1.2%. The aspects of bio-ecology, epidemiology, yield damages and control are discussed.

Structure-activity relationship of steroidal insecticides. VIII. Cholestane and stigmastane ecdysteroids and their structural analogs

Structural analogs of ecdysteroids were screened for insecticidal activity for larvae of the Colorado beetle Leptinotarsa decemlineata using a contact-feed method. High activity was found for compounds 3, 6b, 7a, and 9a.

Structure-Activity Relationship of Steroidal Insecticides. IX. Cholestane and Stigmastane 5- and 7-Bromo-6-ketosteroids

Steroids 1-16, which are intermediates in the synthesis of ecdysteroids, have been shown to possess insecticidal activity for larvae of the Colorado beetle Leptinotarsa decemlineata. Active growth- and development-regulators were found among them.

Structure-Activity Relationship of Insecticidal Steroids. X. Androstane and Pregnane Derivatives

The androstane and pregnane steroids 1-10 were verified to have insecticidal activity for larvae of the Colorado beetle Leptinotarsa decemlineata. Insect growth and development regulators were found among these compounds.

Identification and biological activity of volatile organic substances emitted by plants and insects. I. Components of the native scents ofLeptinotarsa decemlineata andSolanum tuberosum

The sesquiterpenestrans-caryophyllene and germacrene have been detected in the native scents of male and female individuals of the Colorado beetleLeptinotarsa decemlineata Say by gas-chromato-mass-spectral analysis.trans-Caryophyllene has also been detected in the volatiles emitted by leaves of the potatoSolanum tuberosum L. which indicates its role as food attractant of the Colorado beetle.

Background concentration of 226 Ra in terrestrial animals

Radium (226Ra) accumulation by terrestrial animalswas studied in the territory of the former USSR. Concentrations of226Ra in different soils, plants and animals aresimilar to the background level. For soils it fluctuates in range0.5–1.5 × 10-12 gg-1 (18.3–55 Bq/kg), for plantsbetween 0.1–1.7 × 10-12 gg-1 (3.7–62.1 Bq/kg), and for animals– 0.02–1.5 ×10-12 g g-1(0.73–55 Bq/kg). There were no significant differences in226Ra concentration between animals of different groups. Themaximal 226Ra concentration is marked for the woodlouse Hemilepistus aphganicus from the Badkhyz reserve in Turkmenistan– 1.49 × 10-12g g-1 of dwt (54.4 Bq/kg), the minimal one– for Colorado beetle Leptinotarsadecemlineata from the vicinity of Moscow – 0.02× 10-12 gg-1 of dwt (0.73 Bq/kg). Concentration ratios for linkssoil – plant, plant – animal andprey – carnivore are usually close to 1. A hypothesison the similarity of 226Raconcentration in different animals is discussed.

Head segmentation in the embryo of the Colorado beetleLeptinotarsa decemlineata as seen with anti-en immunostaining.

Segmentation in the head of the embryo of the Colorado beetleLeptinotarsa decemlineata is described on the basis of anti-engrailed (en) immunostaining of germ band stages. Six segmental units can be identified with this technique. Three segmentalen stripes can be distinguished in the gnathal region, a weak stripe interrupted medially shows the intercalary segment rudiment, a pair of oblique stripes indicate the antennal segment, and one pair of preantennalen spots are taken to indicate a sixth segment. In the broad head lobes of the beetle the spacing of the six segmental units as demarcated byen regions is similar to that in other parts of the germ band. The results are discussed with respect to old and new data concerning the number of head segments and origin of the compound eye in insects.

From CLIMEX to PESKY, a generic expert system for pest risk assessment1

CLIMEX, a climate‐matching model, is described in relation to pest risk assessment. The rationale for the development Of CLIMEX is given and its various functions are illustrated with examples, using the Colorado beetle Leptinotarsa decemlineata. The beetle's climatic requirements are first inferred from its native distribution in North America. They are then used to project the relative favourableness of Europe and Asia for population growth and persistence. The role is illustrated Of CLIMEX, in association with PESKY, a prototype version of a generic expert system for pest risk assessment, in the assessment of the risk of the beetle being transferred from France to China. Finally, CLIMEX is used to search for places in North America with climates best matching that of Beijing (CN), in order to target collection of possible biocontrol agents for use against the beetle in that area, should it become established there.

Cuticular Hydrocarbons of the Colorado Beetle Leptinotarsa decemlineata say

Abstract The cuticular hydrocarbons of the Colorado beetle Leptinotarsa decemlineata say consist of 2-methylalkanes, internally branched monomethylalkanes, dimethyl-, trimethyl-and tetramethyl-alkanes. The hydrocarbons differ from those of most of the other insects so far investigated. The major components were found to be the dim ethyl branched alkanes, 2,6-and/or 7,22-dimethyl-octacosane and the tetram ethylalkane, 3,10,16,23-tetram ethyltritriacontane. The hydrocarbons identified are members of homologous series which differ by two m ethylene groups. The identification of hydrocarbons was achieved by mass spectrom etry and gas chromatographic determination of Kovats retention indices on two high efficiency capillary columns coated with Dexsil 300 and OV-1.

Substances antiappétantes pour insectes phytophages présentes dans Angelica silvestris et Heracleum sphondylium

Eleven furocoumarins from Angelica silvestris and Heracleum sphondylium were tested for their antifeedant activity gainst two insect larvae: Mythimna unipuncta and the Colorado beetle Leptinotarsa decemlineata. Angular furocoumarins show a smaller effect that the corresponding linear homologues. The following order of activity is observed for substituents: ▪ 4-Methoxybenzofuran, a synthetic analogue shows also medium activity. But the most active component is a sesquiterpene: the known bisabolangelone.

Oxidation of proline and pyruvate by flight muscle mitochondria of the Colorado beetle, Leptinotarsa decemlineata say

Mitochondria isolated from the flight muscles of the Colorado beetle Leptinotarsa decemlineata show high rates of respiration for proline and pyruvate. The rate of oxidation of Krebs cycle intermediates is comparatively low. The amount of alanine formed during in vitro oxidation of proline is equal to the amount of proline used. The results suggest that proline oxidation leads to pyruvate formation and subsequent alanine synthesis. The specific activity of NAD-dependent malic enzyme is high and is supposed to participate in pyruvate formation. In the presence of low proline concentrations, pyruvate and proline oxidations are fully additive. At proline concentrations above 1 mM both oxidations do not seem to occur simultaneously.

ELECTROANTENNOGRAM RESPONSES OF THE COLORADO BEETLE, LEPTINOTARSA DECEMLINEATA, TO PLANT VOLATILES

Electroantennogram responses of Colorado beetles were recorded to 53 plant volatiles including isomers. The system of antennal olfactory receptors is selective, even at high doses several compounds cause fairly small responses. Diminishing the concentration to a moderate stimulus strength reduces the number of perceptible chemicals. Distinct electroantennogram responses are obtained to a group of closely related components, namely the general green leaf volatiles trans‐2‐hexen‐1‐ol, cis‐3‐hexen‐1‐ol, hexanol‐1, trans‐2‐hexenal, hexanal and cis‐3‐hexenyl‐acetate, and to isomers such as trans‐3‐hexen‐1‐ol and cis‐2‐hexen‐1‐ol. The threshold concentration of the most effective compound, trans‐2‐hexen‐1‐ol is 1.2 × 108 molecules per ml of air. The antennal olfactory receptors of the Colorado beetle are sensitively tuned to the perception of these general green leaf volatiles. As olfactory receptors of a number of phytophagous insects have been reported to respond to these components, this volatile complex probably plays a part in the host selection behaviour of various phytophagous insects.RÉSUMÉELECTROANTENNOGRAMMES DU DORYPHORE (LEPTINOTARSA DECEMLINEATA) EN REPONSE A DES SUBSTANCES VOLATILES VEGETALESLes électroantennogrammes de Leptinotarsa decemlineata en présence de 53 substances volatiles (y compris des isomères) ont été enregistrés. Le système des récepteurs olfactifs antennaires est sélectif, même à des doses élevées plusieurs composés ne provoquent que d'assez faibles réponses. La diminution de la concentration jusqu'à une puissance stimulante modérée réduit le nombre de substances perçues. Des électroantennogrammes différents ont été obtenus pour un groupe de composés très voisins, à savoir les substances volatiles de feuilles vertes: trans‐2‐hexen‐1‐ol, cis‐3‐hexen‐1‐ol, hexanol‐1, trans‐2‐hexenal et cis‐3‐hexenyl‐acetate, et aux isomères tels que trans‐3‐hexen‐1‐ol et cis‐2‐hexen‐1‐ol. La concentration seuil du composé le plus efficace, trans‐2‐hexen‐1‐ol, est de 1,2 × 108 molécules par ml d'air. Les récepteurs olfactifs antennaires du Doryphore sont sensoriellement ajustés à la perception de ces substances volatiles générales des feuilles vertes. Comme les récepteurs olfactifs de nombreux insectes phytophages ont été signalés comme répondant à ces composés, ce complexe volatile joue probablement un rôle dans le comportement de sélection de l'hôte par différents insectes phytophages.

Age-dependent changes in juvenile hormone esterase and general carboxyesterase activity in the hemolymph of the colorado potato beetle, Leptinotarsa decemlineata

An in vitro method has been developed for the quantitative estimation of juvenile hormone (JH) esterase activity in the hemolymph of the Colorado beetle Leptinotarsa decemlineata Say. The apparent K m value for JH-esterase was determined. JH-esterase and general carboxyesterase activities were estimated throughout the life cycle and under different photoperiodic conditions. High activities were observed in fourth instar larvae and in beetles just before diapause. Lower activities were found in third instar larvae, long-day, diapause and post-diapause beetles. Similar variations were found in general carboxyesterase activity but not in protein concentration. A possible role for the esterase in the regulation of the JH titer is discussed.

Glandular hairs on Solatium polyadenium lessen damage by the Colorado beetle

SUMMARYFour‐lobed glandular hairs on the leaves and stems of the potato species Solanum polyadenium provide a form of resistance to larvae of the Colorado beetle Leptinotarsa decemlineata. On contact, a sticky material was discharged from these hairs trapping a few larvae and encasing the feet of others. Larvae with encased feet fell from the plants to die.