Comparative radial growth of Pinus halepensis Mill. and Pinus brutia in Israël

Comparaison de la croissance en diamètre dans un peuplement mixte de pin d'Alep et de pin Brutia dans huit régions d'Israël

SEMIOCHEMICAL ACTIVITY OF PHEROMONES AND ANALOGUES OF THREE MATSUCOCCUS SPECIES (HEMIPTERA: COCCOIDEA: MATSUCOCCIDAE)

SEMIOCHEMICAL ACTIVITY OF PHEROMONES AND ANALOGUES OF THREE MATSUCOCCUS SPECIES (HEMIPTERA: COCCOIDEA: MATSUCOCCIDAE). The sex pheromone of the Israeli pine bast scale, Matsucoccus josephi Bodenheimer Harpaz (Homoptera: Matsucoccidae), was identified as the ketone (2E,5R,6E,8E)-5,7-dimethyl-2,6,8- decatrien-4-one. The chiral diene chain is common also to the sex pheromones of M. matsumurae Bean Godwin and M. feytaudi Ducasse. The species-specificity of the three pheromones is due to the differences in the second side chain of these ketones. Field and GC- EAD studies indicated that the sex pheromones of each of the three Matsucoccus spp. is a potent kairomone of both males and females of the predator Elatophilus hebraicus Pericart (Hemiptera: Anthocoridae). The response of E. hebraicus to the sex pheromones of M. matsumurae and M. feytaudi is particularly interesting since it does not occur in the distribution area of these two congeneric spp. These results prompted us to prepare a series of analogues with variations in the two side chains in order to probe the structure-activity relationship of the pheromonal/kairomonal attractancy of M. josephi and E. hebraicus. Field results indicate that alterations in the common diene moiety affected the kairomonal activity, while structural changes in the second side chain markedly reduced the pheromonal activity. Key words: stereoisomer

Kairomonal response of the parasitoid Anagyrus spec. nov. near pseudococci to the sex pheromone of the vine mealybug

The occurrence of a kairomonal response of the parasitoid Anagyrus spec. nov. near pseudococci (Hymenoptera: Encyrtidae) to (+)-(1 R, 3 R )- cis -2,2-dimethyl-3-isopropenyl-cyclobutanemethanol acetate (PcA, namely, planococcyl acetate) and ( S )-(+)-lavandulyl senecioate (LS), the respective female sex pheromones of its hosts, the citrus mealybug, Planococcus citri (Risso) and the vine mealybug, Planococcus ficus (Signoret) (Homoptera: Pseudococcidae) was investigated. Attraction to the pheromones was tested by employing pheromone traps in field trials and by static air olfactometer bioassays in the laboratory. Female wasps showed a significant response to LS, in both field and olfactometer experiments. No significant response was registered to the sex pheromone of P. citri. Despite the similarity between the structures of LS and its analogue ( S ) - (+)-lavandulyl isovalerate (LI), no significant response to the latter compound was observed. It seems that differences between the structures of the carboxylate moiety of the respective molecules (LS and LI) markedly affect the kairomonal attractiveness to the parasitoid. The kairomonal response of Anagyrus spec. nov. near pseudococci was neither influenced by the host habitat nor by the host species on which it developed. This suggested innate behaviour of Anagyrus spec. nov. near pseudococci , possibly derived from evolutionary relationships between the parasitoid and P. ficus . The practical implications of the results are discussed

Attraction of Planococcus ficus males to racemic and chiral pheromone baits: flight activity and bait longevity

The vine mealybug (VM), Planococcus ficus (Signoret), is a worldwide pest and affects mainly grapevine and figs. In Israel, (S)-lavandulyl senecioate [(S)-LS] and (S)-lavandulyl isovalerate [(S)-LI] were identified from VM reared for several generations on potato sprouts, when compared with the identification of only (S)-LS from feral females. Racemic lavandulyl senecioate (LS) can be used for fieldwork because the unnatural enantiomer is benign and does not affect the activity of the pheromone. Lures loaded with 200 lg of LS remained active for 24 weeks but it is recommended to replace lures after 12 weeks to preserve constant and high attractiveness. Delta sticky traps, baited with 50 or 200 lg of LS were used to determine the daily flight pattern and the seasonal flight activity including vine plant infestation. A positive correlation between peak mealybug density and male capture was observed strengthening the usefulness of the pheromone traps for monitoring the pest. Addition of racemic or the two enantiomers of lavandulyl isovalerate (LI) to LS decreased the capture of VM males. The level of inhibition varied during 2003–2004. Both enantiomers of LI displayed the same antagonistic activity. Addition of (S)-lavandulol to the pheromone resulted in shutdown of the traps. Inhibition by the antipode, (R)-lavandulol, was moderate indicating a certain degree of chiral discriminatio

THE CITRICULUS MEALYBUG, PSEUDOCOCCUS CRYPTUS HEMPEL, AND ITS NATURAL ENEMIES IN ISRAEL: HISTORY AND PRESENT SITUATION

THE CITRICULUS MEALYBUG, PSEUDOCOCCUS CRYPTUS HEMPEL, AND ITS NATURAL ENEMIES IN ISRAEL: HISTORY AND PRESENT SITUATION. The citriculus mealybug, Pseudococcus cryptus Hempel, was first discovered in Israel in 1937 and very rapidly became a key pest of citrus. However, since the early 1940s, the mealybug population has sharply decreased. This occurred in parallel with the establishment of the introduced parasitoid Clausenia purpurea Ishii, which was then believed to be the main cause of the biological control of the mealybug. Since the late 1980s, outbreaks of P. cryptus have been recorded mainly in new citrus varieties, such as red grapefruits, pomelo, “sweety” and several peeling varieties. The current outbreaks are probably related to the susceptibility of these mentioned varieties to P. cryptus, and to the adverse effects of Insect Growth Regulators to coccinellid predators, especially Scymnus spp. The introduced C. purpurea and two other local encyrtid parasitoids, Leptomastix near algirica and Anagyrus diversicornis Mercet, rarely emerged from samples of P. cryptus collected during 1996-1998. Four further parasitoid species were introduced into Israel during 1996-1997 against P. cryptus: from central Asia, the platygasterids Allotropa burrelli Muesebeck and A. convexifrons Muesebeck and the encyrtid, Pseudaphycus malinus Gahan; and from Japan, Anagyrus sawadai Ishii. A. convexifrons and A. sawadai successfully parasitized P. cryptus and, therefore, were released in the field but only A. sawadai has so far been recovered. A considerable reduction in population densities of the pest has been recorded since May, 1998, in the major release site of the latter species. Key words: distribution, host plants, Pseudococcus comstocki, P. citriculus, P. viburni, IGR, Coccinellidae, Planococcus citri, P. ficus, Aonidiella aurantii, Ceroplastes floridensis, Anagyrus pseudococci, Leptomastidia abnormis, Leptomastix flavus, Cryptolaemus montrouzieri, Cecidomyiidae, Sympherobiidae, Chrysopidae

TRIALS FOR THE CONTROL OF THE CITRUS MEALYBUG IN CITRUS ORCHARDS BY AUGMENTATIVE RELEASE OF TWO ENCYRTID PARASITOIDS

TRIALS FOR THE CONTROL OF THE CITRUS MEALYBUG IN CITRUS ORCHARDS BY AUGMENTATIVE RELEASE OF TWO ENCYRTID PARASITOIDS. Since the 1980s, the citrus mealybug Planococcus citri (Risso) has become a key pest in Israel, owing to intensive planting of highly susceptible varieties, the introduction of Insect Growth Regulators (which adversely affect coccinellids) and the development of resistance to chlorpyrifos. Management of the mealybug populations in citrus orchards by augmentative releases of parasitoids was investigated between 1993 and 1996 in a series of tests involving the release of 5,000-10,000 Leptomastix dactylopii (Howard) (Encyrtidae) per hectare. Results showed no significant effect on the density of the mealybug on the fruits. In general, the establishment of L. dactylopii was poor and population levels were inferior to those of the naturally occurring Anagyrus pseudococci (Girault) (Encyrtidae). In 1996-1997, augmentative early-spring releases of A. pseudococci at the rates of 10,000-50,000 individuals per hectare markedly increased the population density of A. pseudococci during April and June but had no significant effect on either the mealybug infestation or on fruit damage caused by the pest and its fruit moth associates. Key words: grapefruit, persimmon, custard apple, coffee, cacao, Citrus, Diospyros, Annona, life cycle, damage, Coccidoxenoides peregrinus, Cryptolaemus montrouzieri, Sympherobius sanctus, mass rearing, cork ring, potato sprout, potato trap, low temperatures, fruit moths

Probable overwintering of adult Hyalomma rufipes in Central Europe

Hyalomma spp. ticks (Acari: Ixodidae) represent a public health threat because of their prominent role in the transmission of Crimean- Congo haemorrhagic fever (CCHF) virus. Moreover, these ticks can transmit other medically important arboviruses such as Thogoto, Dhori, West Nile, and Bhanja viruses; human pathogenic bacteria like Rickettsia conorii, R. aeschlimannii, and Anaplasma marginale; and protozoans like Theileria annulata and Babesia caballi (Huba ´lek and Rudolf, 2011). Many records of larval and nymphal H. marginatum ticks on birds migrating from North Africa and Southern Europe into Central and Northern Europe have been published

Type-2 fuzzy linear systems

Fuzzy Linear Systems (FLSs) are used in practical situations where some of the systems parameters or variables are uncertain. To date, investigations conducted on FLSs are restricted to those in which the uncertainty is assumed to be modeled by Type-1 Fuzzy Sets (T1FSs). However, there are many situations where considering the uncertainty as T1FSs may not be possible due to different interpretations of experts about the uncertainty. Moreover, solutions of FLSs are T1FSs which do not provide any information about a measure of the dispersion of uncertainty around the T1FSs. Therefore, in this research a model of uncertain linear equations system called a type-2 fuzzy linear system is presented to overcome the shortcomings. The uncertainty is represented by a special class of type-2 fuzzy sets – triangular perfect quasi type-2 fuzzy numbers. Additionally, conditions for the existence of a unique type–2 fuzzy solution to the linear system are derived. A definition of a type-2 fuzzy solution is also given. The applicability of the proposed model is illustrated using examples in the pulp and paper industry, and electrical engineering

Decay constants and mixing parameters in a relativistic model for q\barQ system

We extend our recent work, in which the Dirac equation with a ``(asymptotically free) Coulomb + (Lorentz scalar $\gamma_0\sigma r$) linear '' potential is used to obtain the light quark wavefunction for $q\bar Q$ mesons in the limit $m_Q\to \infty$, to estimate the decay constant $f_P$ and the mixing parameter $B$ of the pseudoscalar mesons. We compare our results for the evolution of $f_P$ and $B$ with the meson mass $M_P$ to the non-relativistic formulas for these quantities and show that there is a significant correction in the subasymptotic region. For $\sigma =0.14{{\rm ~GeV}}^{-2}$ and \lms =0.240{\rm ~GeV} we obtain: $f_D =0.371\; ,\; f_{D_s}=0.442\; ,\; f_B=0.301\; ,\; f_{B_s}=0.368 {\rm ~GeV}$ and $B_D=0.88\; ,\; B_{D_s}=0.89\; ,\; B_B=0.95\; ,\; B_{B_s}=0.96\; ,\;$ and $B_K=0.60$.Comment: 13 pages, Latex, 3 figures (included