Braconidae (Hymenoptera) associated with forest and ornamental trees and shrubs in Israel

Data are presented on the occurrence of Braconidae (Hymenoptera parasitica) parasitizing insects associated with forest and ornamental trees and shrubs in Israel. Fifty-five genera of plants are listed, the richest in braconid fauna being tamarisk (9 species); acacia, pistachio and poplar (8 species each); carob and oak (7 species each). Of the 95 species of insect hosts mentioned, 53 are Lepidoptera, mostly Gelechiidae (7 species), Pyralidae (6 species), Noctuidae (5 species), Gracillariidae, Tortricidae, Geometridae, Lymantriidae and Lycaenidae (3 species each); 44 are Coleoptera, mostly Cerambycidae (13 species), Scolytidae (12 species), and Bostrichidae (9 species); three are Diptera. Of the 92 species of braconids listed, of which only 65 have been fully named, 56 develop in Lepidoptera, mostly Noctuidae (15 species), Gelechiidae (11 species) and Pyralidae (9 species); 33 species develop in Coleoptera, mostly Cerambycidae (12 species, Bostrichidae (10 species) and Scolytidae (5 species); and three species develop in Diptera. Thirty-eight species are new to the fauna of Israel; at least three of them are new to science,viz., Gnaptodon, Gildoria andDendrosotinus titubatus Papp.     

Evaluation of biochemical methods for the diagnosis of the avocado sunblotch viroid in Israel

The reliability of biochemical diagnostic methods for avocado sunblotch viroid (ASBV) was evaluated for the Israeli avocado propagation program. Polyacry-lamide gel electrophoresis (PAGE) was compared with hybridization toin vitro ³²P-labeled cDNA and ASBV-RNA probes. Although hybridization to a cDNA probe was the most sensitive method, not all known infected plants were detected. In the light of these results, the problem of diagnosing ASBV in the Israeli propagation program is discussed.     

Arthropod fauna and main insect pests of plane trees in Israel

Fifty-four insect and four mite species are included in a list of the entomofauna of plane trees in Israel. Only two species are monophagous:Phyllonorycter platani (Stgr.) (Lepidoptera: Gracillariidae) andEdwardsiana iranicola Zachv. (Heteroptera: Cicadellidae). Four species are noxious:P. platani, the main insect pest of the plane trees in Israel;Zeuzera pyrina L. (Lepidoptera: Cossidae);Kalotermes flavicollis F. (Isoptera: Kalotermitidae); andE. iranicola. Of much lesser importance areTargionia vitis Sign. (Homoptera: Diaspididae),Heliothrips haemorrhoidalis Bché. andRetithrips syriacus May. (Thysanoptera: Thripidae). About half of the listed species are natural enemies and many are parasites ofP. platani. Details are given on the noxious species, together with recommendations for prevention and control.     

The overwintering mode ofBemisia tabaci and its parasitoids in Israel

Wild and cultivated plants in the vicinity of Kibbutz Nahshon and a few additional locations in Israel were sampled for the presence ofBemisia tabaci Genna-dius (Homoptera: Aleyrodidae). The whiteflies, together with their parasites,Eretmocerus mundus andEncarsia lutea, were found to develop on numerous host species throughout the winter. Especially high levels were reached onLan-tana camara, Abutilon grandifolium andIpomoea batatas. During late winter and spring the population on these hosts declined. From April onwards the populations increased on potatoes and sunflowers.     

Alien scale insects (Hemiptera Coccoidea) in European and Mediterranean countries: the fate of new and old introductions

This contribution focuses on recent interceptions and introductions of alien scale insects and their current distribution in European and Mediterranean countries. Data and collections were gathered in markets, nurseries, and botanical gardens, mostly in Italy, either indoors or outdoors. New or recent records of the following alien species are presented: Exallomochlus hispidus (Morrison); Ferrisia virgata (Cockerell) (Pseudococcidae); Coccus viridis (Green); Milviscutulus mangiferae (Green) (Coccidae); Aonidiella orientalis (Newstead); Aspidiotus destructor Signoret; Aulacaspis tubercularis Newstead; Fiorinia fioriniae Targioni Tozzetti; Lepidosaphes pinnaeformis (Bouché); Pseudaulacaspis brimblecombei Williams (Diaspididae). New data and pest status of Phoenicococcus marlatti Cockerell (Phoenicococcidae) and Trabutina mannipara (Hemprich & Ehrenberg) (Pseudococcidae) are also reported. The possible repeated introductions of the latter from North Africa to south Italy by trans-Mediterranean winds, is hypothesized.     

Detection and estimation of Citrus Tristeza Virus infection rates based on Elisa Assays of packing house fruit samples

Enzyme-linked immunosorbent assay (ELISA) proved to be a sensitive detector for citrus tristeza virus (CTV) in orange fruits (Citrus sinensis (L.) Osbeck). Samples of five fruits were taken from 350-kg packing house containers and tested by ELISA to predict the infection rate of CTV in two infected orange groves. The predicted infection rates, 1% and 11%, were in reasonable agreement with the observed rates of 1% (15/1400) and 16% (324/2053), respectively. The 360 test samples from reputedly uninfected groves all tested negative. These results suggest that the ELISA procedure may provide a general method of detecting viral or other systemic pathogenic infections using the fruit as the test material in place of tree tissue. Fruit samples can be collected routinely at the packing house to reduce test costs.     

Control of phytophthora leaf blight of taro (Colocasia esculenta) by fungicides and roguing

Six fungicides were evaluated under laboratory and field conditions for control of Phytophthora leaf blight of taro,Coloeasia esculenta, incited byPhytophthora colocasiae. Inin vitro tests Deraosan 65W was the most effective in inhibiting the mycelial growth of the test pathogen followed by Difolatan 80W, Fytolan (copper oxychloride), Apron 35F, Topsin-M 50W and Dithane Z-78 75W. Excellent control was obtained with Demosan 65W and Difolatan 80W, good control with Apron 35F, fair control with Fytolan, and poor control with Topsin-M 50W and Dithane Z-78 75W. Results ofin vivo tests were correlated with those of thein vitro tests. Roguing of infected leaves did not eradicate the pathogen but can only delay epiphytotics.     

Phenotypic and genotypic structure of Phytophthora infestans populations on tomato and potato in the North of Thailand in 2000–2002

A total of 80 single–lesion isolates of Phytophthora infestans were collected from tomatoes and potatoes in several locations in Chiang Mai and Tak provinces in 2000–2002. These isolates were analyzed for mating type, metalaxyl sensitivity, mitochondrial DNA (mtDNA) haplotype RFLP pattern as determined by probe RG57, and for microsatellite markers. All isolates were A1 mating type. Isolates from tomato were usually sensitive to metalaxyl, but isolates from potato were usually resistant to metalaxyl. With one exception, all tomato isolates were related to the US-1 clonal lineage. With two exceptions, all potato isolates were related to two European lineages. In these two provinces, the populations of P. infestans on tomatoes are clearly different from those on potatoes.     

Feeding deterrents forphilosamia ricini (samia cynthia subsp.Ricini) fromtithonia diversifolia

Tagitinin A and C and hispidulin isolated fromTithonia diversifolia (Hemsl.) Gray, were potent feeding deterrents, when evaluated against 4th instar caterpillars of the Eri-silkworm(Philosamia ricini Hutt.) (Lepidoptera: Saturniidae); tagitinin F was not.     

Effect of avermectin B1 on the development and fecundity of the california red scale,Aonidiella auranth,and on two of its natural enemies:Chilocorus bipustulatus andAphytis holoxanthus

Various immature stages of male and female California red scale,Aonidiella aurantii (Maskell) (Homoptera: Diaspididae), were treated with avermectin B₁ (MK-936) at concentrations ranging from 10 to 100 ppm. Treatments at 10 ppm completely arrested crawler development and 20 and 100 ppm caused 100% mortality of 48-h and 7-day-old male and female 1st instar nymphs, respectively. The development of the 2nd instar was slightly affected by MK-936 at up to 40 ppm. Sublethal doses of the chemical applied to immature stages caused no dramatic reduction in the fecundity of the subsequent, mature females. MK-936 applied to male prepupal and pupal stages and mated females did not prevent male emergence, nor did it affect the ability of males to copulate and inseminate female scales, or the female fecundity. The development and adult emergence of treatedAphytis holoxanthus DeBach (Hymenoptera: Aphelinidae) larvae and pupae parasitizingChrysomphalus aonidum L. scales were not influenced by a 9 ppm MK-936 treatment; leaves sprayed with this concentration had residual toxicity onA. holoxanthus adults for only 24 h post-treatment. Feeding byChilocorus bipustulatus L. (Coleoptera: Coc-cinellidae) on 0.9 ppm MK-936-treated Florida red scales resulted in 100% mortality of 2nd instars and induced sterility in the females.     

Sensitive detection of two plant viruses by enzyme-amplified elisa

Enzyme-amplified ELISA (enzyme-linked immunosorbent assay) increased the sensitivity of detection of citrus tristeza virus and papaya ringspot virus in plant sap by 25- and 125-fold, respectively, compared with direct double antibody sandwich ELISA. The advantages of the new substrate system for the detection of low concentrations of viruses in plants are discussed.     

Serological recognition of Streptomyces species causing scab on potato tubers

Antisera were prepared against extracts of two tyrosinase-positiveStreptomyces spp., one of which caused a “deep” and the other a “russet” scab. Tyrosinase-positiveStreptomyces isolates not reacting with either of these antisera proved to be nonpathogenic to potato tubers, with few exceptions only. Not all isolates reacting with one or both antisera, however, were pathogenic and so all the serological positive ones had to be tested for pathogenicity to potato tubers. To obtain this relative specificity the antisera had to be absorbed with an extract of a non-pathogenic tyrosinase-positive isolate.     

Identification and species status of the mango biotype of Colletotrichum gloeosporioides in Ghana

Research work was carried out to identify and ascertain the species status of the mango biotype of Colletotrichum gloeosporioides infecting mangoes in Ghana. Forty five isolates of Colletotrichum species were collected from 12 districts in Ghana while five each were obtained from mango fruits from Florida, Mexico and Puerto Rico. The entire internal transcribed spacer region, partial beta-tubulin gene and partial glyceraldehyde-3-phosphate dehydrogenase gene of isolates were sequenced and used in phylogenetic studies. The results of the sequence analysis of the first ribosomal transcribed spacer (ITS 1) region showed that 35 % of the isolates from Ghana and all the five isolates from Mexico were the mango biotype of C. gloeosporioides, while the others were not. Phylogenetic studies showed that the mango biotype of the pathogen was Colletotrichum asianum but not C. gloeosporioides as previously thought. However, the other isolates that were not the mango biotype were identified as Colletotrichum siamense and Colletotrichum species which had probably cross-infected mango from other fruit crops in the field.     

Pyrethroid synergism and prevention of emergence inTribolium castaneum andMusca domestica vicina by the insect growth regulator RO 13-5223

Ethyl [2-(4-phenoxyphenoxy)ethyl] carbamate (RO 13-5223) at a dietary concentration of 100 mg kg^-1 synergized the toxicity of thetrans- andcis-isomers of permethrin and cypermethrin in inhibiting the growth (measured as gain in larval weight) ofTribolium castaneum andMusca domestica vicina. With both species the synergism factor forcis-cypermethrin with 100 mg kg^-1 synergist was 1.5- to twofold for RO 13-5223 and about fourfold for piperonyl butoxide. Synergism was more pronounced with first instar than with fourth instarT. castaneum larvae. Methoprene was not a pyrethroid synergist withT. castaneum larvae, so the synergistic effect of RO 13-5223 appears to depend on its structural features and not its insect-growth-regulator activity. Joint application of RO 13-5223 and pyrethroids resulted in a dual effect on bothT. castaneum andM. domestica: increased inhibition of larval growth due to pyrethroid synergism, and progeny suppression — expressed by larval and pupal mortality — due to RO 13-5223 juvenilizing activity.     

The distribution of passionfruit ringspot virus in its main host plants in Ivory Coast

A field survey and testing of leaf samples have given an impression of the distribution of passionfruit ringspot virus in twoAdenia and twoPassiflora spp. in Ivory Coast. The data suggest thatAdenia spp. are the original host plants of the virus. Introduction to Ivory Coast of the virus withP. edulis seems unlikely. Since theAdenia spp. prefer forest and shrub vegetations and aphid flights are shorter in the dryer savannah areas of the North, the cultivatedP. edulis has chances to remain healthy over a prolonged period of growth, which is excluded in the South of the country.     

Development of conventional and real-time PCR protocols for specific and sensitive detection of Colletotrichum capsici in chilli (Capsicum annuum L.)

Anthracnose, caused by Colletotrichum capsici, is a major disease of chilli (Capsicum annuum L.) affecting both fruit and seed quality. The pathogen is both internally and externally seedborne. However, a rapid and sensitive method for detection of this pathogen in seeds is currently limited. In this study, a polymerase chain reaction (PCR) method based on sequence characterized amplified region (SCAR) marker was developed for specific and sensitive detection of C. capsici in chilli seeds and fruits. The developed SCAR primers were highly specific to C. capsici and resulted in the amplification of an expected 250-bp fragment from genomic DNA of all seven of the C. capsici isolates tested. No amplification occurred when the SCAR primers were tested with genomic DNA from three other fungal isolates and four other Colletotrichum species. The SCAR primers successfully amplified similar sized fragments from DNA derived from C. capsici-infected chilli fruits. The molecular detection sensitivity of C. capsici was 1 pg of purified C. capsici DNA template and 25 ng of DNA from C. capsici-infected chilli fruits. A real-time PCR assay was also developed using SYBR Green chemistry for detection of C. capsici in chilli fruits and seeds. The standard curve obtained showed a linear correlation between copy number of the cloned target DNA sequence of C. capsici and cycle threshold (Ct) values, with R² of 0.98. These PCR-based assays may be highly useful in detection of this important pathogen in chilli seeds and fruits in plant quarantine laboratories.     

Involvement of Phytophthora cryptogea in sweet cherry decline in Turkey

Sweet cherry is a major commercial crop in Turkey, the most important producer of the fruit worldwide. Sweet cherry decline was observed in an orchard in Ankara province of Turkey. Affected young trees exhibited reduced tree vigor, yellowing and wilting of leaves, and dieback symptoms resulted in tree death. A Phytophthora sp. was consistently isolated from necroses that appeared on taproots and crowns. The pathogen was identified as Phytophthora cryptogea based on several morphological features and DNA sequence of the internal transcribed spacer (ITS) region. P. cryptogea was pathogenic on excised shoots and 1-year-old cherry rootstocks. This is the first report of P. cryptogea causing disease of sweet cherry in Turkey.     

Analysis of genetic and virulence variability of Stemphylium lycopersici associated with leaf spot of vegetable crops

Stemphylium lycopersici (Enjoji) W. Yamam was initially described from tomato and has been reported to infect different hosts worldwide. Sequence analyses of the internal transcribed spacer (ITS) regions 1 and 2, including 5.8S rDNA (ITS-5.8S rDNA) and glyceraldehyde-3-phosphate dehydrogenase (gpd) gene, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies were conducted to analyze 46?S. lycopersici isolates. Stemphylium lycopersici isolates used in this study were obtained from diseased tomato (Solanum lycopersicum L.), eggplant (Solanum melongena L.), pepper (Capsicum annuum L.) and lettuce (Lactuca sativa L.) from major vegetable growing regions of Malaysia, including the three states of Pahang, Johor and Selangor between 2011 and 2012. Phylogenetic analysis of a combined dataset of the ITS-5.8S rDNA and gpd regions indicated that all isolates were clustered in the sub-cluster that comprised S. lycopersici, and were distinguished from other Stemphylium species. Cluster analyses using the UPGMA method for both RAPD and ISSR markers grouped S. lycopersici isolates into three main clusters with similarity index values of 67 and 68 %. The genetic diversity data confirmed that isolates of S. lycopersici are in concordance to host plants, and not geographical origin of the isolates. All S. lycopersici isolates were pathogenic on their original host plants and showed leaf spot symptoms; however, virulence variability was observed among the isolates. In cross-inoculation assays, the representative isolates were able to cause leaf spot symptoms on eggplant, pepper, lettuce and tomato, but not on cabbage.     

Biological and Serological Characterization of Zucchini Yellow Mosaic and Watermelon Mosaic Virus-2 Isolates in Israel

Cucurbit potyviruses were collected in the field in Israel and subcultured in indicator plants in a greenhouse. Partial characterization of the Israeli cucurbit potyviruses was done on the basis of host reaction using cucurbits, peas andChenopodium spp. as hosts. Further classification of potyviruses was done by enzyme-linked immunosorbent assay (ELISA) and serological specific electron microscopy (SSEM). By these methods it was possible to identify three of the four isolates as strains of the zucchini yellow mosaic virus, while the fourth was identified as watermelon mosaic virus-2. Two of the ZYMV isolates were nonaphid-transmissible following prolonged mechanical transmission in a greenhouse. Both of these isolates were found to produce helper components capable of assisting the transmission of virions from a transmissible isolate but not those of their own.     

Response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae to azadirachtin and salannin

The effect of azadirachtin and salannin, two triterpenoids isolated from seeds of neem (Azadirachta indica A. Juss), on the feeding response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae, was investigated. Styropor (foamed polystyrene) lamellae were painted on both sides with a mixture of 5% sucrose with different concentrations of either azadirachtin or salannin dissoled in methanol-water (3∶7). Azadirachtin strongly suppressed feeding inS. littoralis larvae even at 0.001%, whereas salannin showed some antifeedant activity at 0.005% and above. Larvae ofE. insulana were deterred from feeding on azadirachtin-treated lamellae even at 0.005%, whereas salannin was effective only at 0.01% and above. Azadirachtin applied on cotton leaves deterred larvae ofS. littoralis from feeding at all concentrations ranging between 0.001 and 0.02%.