Ефект на Beauveria bassiana (щам ATCC 74040) върху два вида листояди вредители по царевицата в лабораторни условия

In some European countries, the Western corn rootworm, Diabrotica virgifera virgifera, and the cereal leaf beetle, Oulema melanopus, are present in maize stands in high population density, occasionally causing damage of the crops. Susceptibility of adults of these species and larvae of the cereal leaf beetle to the commercially available product Naturalis® based on Beauveria bassiana strain ATCC 74040 was explored in laboratory conditions. The results of the bioassays showed that the fungal strain caused the highest corrected mortality on O. melanopus larvae with average values above 95% for all conidia concentrations (from 2.3 × 102 to 2.3 × 107 conidia/ml) tested. For the adults of the two pests, the average mortality increased positively with concentration of conidia and the values ranges from 9.5% to 94.2% for O. melanopus (concentrations from 2.3 × 102 to 2.3 × 107 conidia/ml) and from 19.3% to 92.4% for D. v. virgifera (concentrations from 2.3 × 103 to 2.3 × 107 conidia/ml). Accordingly, the LC50 values for O. melanopus larvae and adults and D. v. virgifera adults were determined as 4.6, 8.3 × 104 and 4.3 × 105 conidia/ml, respectively. Further studies to confirm the susceptibility of the larvae of the cereal leaf beetle to Naturalis® under field conditions should be conducted.В някои европейски страни западният царевичен коренов червей Diabrotica virgifera virgifera и обикновената житна пиявица Oulema melanopus присъстват в царевичните площи във висока плътност, нанасяйки щети на културите. В лабораторни условия беше изследвана чувствителността на възрастните индивиди от тези видове и ларвите на обикновената житна пиявица към търговския продукт Naturalis®, който съдържа Beauveria bassiana (щам ATCC 74040). Резултатите от опитите показват, че гъбният щам причини най-високата коригирана смъртност на ларвите на O. melanopus със средни стойности над 95% за всички изпитани концентрации на конидиите (от 2.3 × 102 до 2.3 × 107 конидии/ml). За възрастните на двата вида вредители средната смъртност нараства с увеличаване на концентрацията на конидиите и стойностите варират от 9.5% до 94.2% за O. melanopus (концентрации от 2.3 x 102 до 2.3 × 107 конидии/ml) и от 19.3% до 92.4% за D. v. virgifera (концентрации от 2.3 × 103 до 2.3 × 107 конидии/ml). Cтойностите на LC50 за ларвите и възрастните на O. melanopus и възрастните индивиди на D. v. virgifera бяха съответно 4.6, 8.3 × 104 и 4.3 × 105 конидии/ml. Необходимо е да се проведат допълнителни изследвания за потвърждаване на високата чувствителност на ларвите на обикновената житна пиявица към Naturalis® в полеви условия

Seasonal monitoring of the yellow alfalfa geometrid, Isturgia arenacearia (Denis and Schiffermuller, 1775) (Lepidoptera: Geometridae) by pheromone traps in three regions of Bulgaria

Monitoring the seasonal flights of the yellow alfalfa geometrid, Isturgia arenacearia (Denis and Schiffermuller, 1775) (Lepidoptera: Geometridae), was made using home made sticky delta traps baited with pheromone caps purchased from “CSALOMON®” (Plant Protection Institute, Hungary, Budapest). The monitoring was conducted in alfalfa fields in Plovdiv, Pazardjik and Sofia regions in Bulgaria during 2007–2009. The flight of I. arenacearia at the investigated sites started during April and lasted until the end of August — middle of September. Two relatively well-defined peaks indicating two generations were recorded in Sofia region. Thus the flight period of the pest was defined more accurately than previously recorded and proved to be significantly longer than was known for this country. Pheromone baits, products of “CSALOMON®” (Plant Protection Institute, Hungary, Budapest), are potent and very species specific tool for detecting the presence of, and seasonal monitoring of I. arenacearia

Seasonal activity of Plagionotus (Echinocerus) floralis (Pallas) (Coleoptera: Cerambycidae, Cerambycinae) adults in Bulgaria established by attractant baited fluorescent yellow funnel traps

The Lucerne longicorn, Plagionotus (Echinocerus) floralis (Pallas) is a pest on alfalfa, Medicago sativa L. and several other species in the area of its distribution. Seasonal flight activity of adults of this species was studied for first time by CSALOMON® ARb3z fluorescent yellow traps with a floral attractant in alfalfa fields at three sites located in Tracian Lowland (Pazardzhik and Plovdiv) and Sofia Basin (Sofia) zoogeographical regions of Bulgaria. At all three sites P. (Echinocerus) floralis beetles were caught in relatively large numbers. Flight activity of the pest occurs over a period of about two months from the end of May (in Pazardzhik and Plovdiv) and middle of June (in Sofia) until the end of July. In Sofia (2007), the abundance of the pest in an old (5-year-old) alfalfa was significantly higher than in a young (1-year-old) alfalfa. In the untreated fields, air temperature and air humidity had no effect on beetle captures. Our investigations showed that yellow fluorescent VARb3z traps baited with floral lure can be used successfully for detection and seasonal monitoring of P. (Echinocerus) floralis . Data obtained by monitoring of the seasonal activity of adults using baited traps can be useful for forecasting and controlling outbreaks of the pest

Global genetic diversity, lineage distribution, and Wolbachia infection of the alfalfa weevil Hypera postica (Coleoptera: Curculionidae)

The alfalfa weevil (Hypera postica) is a well‐known example of a worldwide‐distributed pest with high genetic variation. Based on the mitochondrial genes, the alfalfa weevil clusters into two main mitochondrial lineages. However, there is no clear picture of the global diversity and distribution of these lineages; neither the drivers of its diversification are known. However, it appears likely that historic demographic events including founder effects played a role. In addition, Wolbachia, a widespread intracellular parasite/symbiont, likely played an important role in the evolution of the species. Wolbachia infection so far was only detected in the Western lineage of H. postica with no information on the infecting strain, its frequency, and its consequences on the genetic diversity of the host. We here used a combination of mitochondrial and nuclear sequences of the host and sequence information on Wolbachia to document the distribution of strains and the degree of infection. The Eastern lineage has a higher genetic diversity and is found in the Mediterranean, the Middle East, Eastern Europe, and eastern America, whereas the less diverse Western lineage is found in Central Europe and the western America. Both lineages are infected with the same common strain of Wolbachia belonging to Supergroup B. Based on neutrality tests, selection tests, and the current distribution and diversification of Wolbachia in H. postica, we suggested the Wolbachia infection did not shape genetic diversity of the host. The introduced populations in the United States are generally genetically less diverse, which is in line with founder effects