Parasitism of egg-batches of the cedar processionary moth<Emphasis Type="Italic">Traumatocampa ispartaensis</Emphasis> in Turkey

Studies were carried out on the egg material ofTraumatocampa ispartaensis Doganlar & Avcı (Lep.: Notodontidae) collected onCedrus libani A. Rich. A total of 95 egg-batches were sampled over two annual generations ofTr. ispartaensis. The number of eggs in each egg-batch varied between 39 and 245 and the length of the batches varied between 7 and 36 mm. The mean number of eggs per batch was found to be 119 and 122 in 1999 and 2000, respectively. Based on field data the oviposition period continued from mid August to mid September. The mean hatching rate of the host was found to be 85.8% and 88.9%, whereas the impact of egg parasitoids accounted for 11.3% and 7.4%, respectively in the 2 years.Ooencyrtus pityocampae (Mercet) was observed as the most abundant egg parasitoid, followed byOoencyrtus sp. nearmasii (Mercet) andTrichogramma brassicae Bezdenko. Based on the emergence dynamics of the egg parasitoids in the laboratory, it seems thatO. pityocampae emerged mainly in June whereasO. sp. nearmasii andT. brassicae emerged mainly in May. http://www.phytoparasitica.org posting Feb. 3, 2003.     

Effect of different hosts onThaumetopoea pityocampa populations in northeast Portugal

A study was carried out at the Natural Park of Montesinho, NE Portugal, in order to evaluate the effect of different pine species (Pinus pinaster Ait.,P. nigra Arn. andP. sylvestris L.) onThaumetopoea pityocampa populations. The structure of the egg batches, the impact of the egg parasitoids on natural mortality of the pest and the species of parasitoids present, as well as their emergence dynamics, were analyzed. The length of the egg batches varied among pine species with the longest ones onP. nigra. The mean number of eggs per batch differed betweenP. sylvestris and the two other hosts studied, with fewer eggs per batch on the first. No differences were found in the size of eggs among pine species. The egg mortality varied between 25.8% and 33.0%, with no differences among hosts. Parasitism was the main cause of death.Baryscapus servadeii (Mercet.) was the most abundant parasitoid species, followed byOoencyrtus pityocampae (Dom.) andTrichogramma embryophagum Htg.B. servadeii dominated in the egg batches collected fromP. pinaster andP. nigra, whereasO. pityocampae was most frequent onP. sylvestris. The emergence ofB. servadeii started in the middle of March and continued until August, with the emergence peak at the end of May. The emergence ofO. pityocampae started at the end of April and continued throughout September, with maximum values in June. http://www.phytoparasitica.org posting Sept. 20, 2006.     

New Ichneumonidae (Hymenoptera) parasitoids of forest insect pests in Bulgaria

During the period 1989–1998 investigations were carried out on the parasitoids of some forest insect pests in Bulgaria. Twenty-one ichneumonid species are reported for the first time in Bulgaria as parasitoids of different coleopteran, lepidopteran, and hymenopteran hosts. From these, 6 parasitoids are new records for the parasitoid complexes of the hosts:Exochus decoratus Holmgr. onEudemis profundana (Den. & Schiff.) andGelechia turpella (Den. & Schiff.);Lissonota culiciformis Grav.—onParanthrene tabaniformis (Rott.);Lissonota unicincta Holmgr.—onG. turpella; Xorides gracilicornis (Grav.)—onXylotrechus sp.; andEriborus terebrator Aubert—onClostera anastomosis (L.). Most parasitoids developed as primary parasitoids in the hosts.Itoplectis alternans (Grav.) is a primary parasitoid ofNycteola asiatica (Krul.) and a hyperparasitoid ofE. terebrator: Acropimpla pictipes (Grav.) is secondary parasitoid onAnacampsis populella (Cl.). With the exception of two species ofOlesicampes genus, which destroyed over 50% ofStauronematus compressicornis (F.) andPristophora conjugata (Dahlm.) larvae, andE. terebrator which killed 15.4% ofC. anastomosis population, the rest of the parasitoids occurred in low densities, and did not play an important role in reducing the number of their hosts.     

The role of the monoterpene composition inPinus spp. needles, in host selection by the pine processionary caterpillar,Thaumetopoea pityocampa

This paper presents preliminary results on attempts to extract and characterize the volatile secondary metabolites contained in needles of differentPinus species and to ascertain the role played by these substances on the behavior ofThaumetopoea pityocampa (Denis et Schiffermüller) females, which show a marked preference, during the oviposition period, for some indigenous and exotic species of host plants existing in mixed formation. Limonene is the most abundant monoterpene extracted fromP. pinea needles, the least favored species of pine processionary caterpillar (PPC) females, although it is present in only very low amounts in otherPinus species. An increase was observed in limonene production byP. pinea at the start of the flight period of the PPC adult, and subsequently at the beginning of the females’ oviposition period. Assays carried out in two pine stands in central Italy showed that limonene, emulsified with water and sprayed on foliage of four different pine species plants,P. sylvestris, P. nigra, P. pinaster andP. radiata, during the PPC oviposition period, provided a satisfactory degree of protection. In fact, the number of egg clusters collected from treated plants was often lower than the number of egg clusters collected from control plants and was comparable to the number of egg clusters laid onP. pinea plants. In particular (R)-(+)-limonene, although not produced in nature by pines, was the most effective deterrent. However, the effect of (S)-(-)-limonene, the enantiomer biosynthesized by pines, was also adequate.     

Ovipositional response ofHelicoverpa armigera to different cotton genotypes

The ovipositional response ofHelicoverpa armigera (Hübner) to different cotton varieties and species was studied under caged conditions. Maximum oviposition (51.6 eggs/female) was recorded on LH 900, a variety ofGossypium hirsutum, and minimum oviposition (3.0 eggs/female) on G 27, a variety ofG. arboreum. Oviposition, in general, was low (3 to 6.5 eggs/female) onarboreum cottons as compared withhirsutum. Of the number of factors found to affect the oviposition ofH. armigera, the trichome length on the upper surface of the leaf, rather than the density, was positively correlated (r = 0.687*). Among different months in the cropping season, oviposition was maximum (552.7) during April. Oviposition was higher on leaves than on other plant parts.     

Weed hosts ofVerticillium dahliae in crete: Susceptibility, symptomatology and significance

A survey of common and uncommon weed species usually showing Verticillium wilt symptoms was carried out during 1992–2000 in Crete, Greece.Verticillium dahliae was isolated in 48 out of 182 sampled fields, in which several weed species were grown, from several locations in Oropedio, Lasithi. Altogether, 124 isolates ofV. dahliae were recovered from the vascular stem-tissue of 19 weed species, belonging to ten botanical families. Pathogenicity trials with 13 out of 19 weed species that have never been reported as hosts of the fungus, using for inoculation isolates which originated from the same weed species, resulted in infection of all of them, showing various disease symptoms. Seven weed species (Anthemis melanolepis, Cardaria draba, Convolvulus arvensis, Erodium sp.,Euphorbia helioscopia, Helminthotheca echioides andSinapis alba) are new hosts worldwide, and six additional species (Euphorbia sp.,Lactuca serriola, Raphanus raphanistrum, Sinapis arvensis, Sonchus oleraceus andTrifolium sp.) are new hosts for Greece. The most susceptible (isolation frequency: 27.9–52.8%, moderate disease severity) species were:Capsella bursa-pastoris, C. draba, Chenopodium album, Senecio vulgaris andSolanum nigrum. Less susceptible (isolation frequency: 4.8–17.8%, slight disease severity) were:Amaranthus sp.,A. melanolepis, C. arvensis, Erodium sp.,Euphorbia sp.,E. helioscopia, H. echioides, L. serriola, Malva sylvestris, R. raphanistrum, S. alba, S. arvensis, S. oleraceus andTrifolium sp. Some species —C. draba, C. album, L. serriola andS. nigrum L. — that usually showed external and vascular wilt symptoms, occasionally exhibited only reduced growth. Visible symptoms under natural field conditions in all 13 weed species that had never been reported as hosts ofV. dahliae were similar to those observed after their artificial inoculation. The fungus was not isolated fromFoeniculum vulgare ssp.piperitum, Oxalis corniculata andStellaria media, among other species. http://www.phytoparasitica.org posting Sept. 18, 2002.     

Fungi on roots and stem bases of asparagus in the Netherlands: species and pathogenicity

A survey was made to identify the most important soilborne fungal pathogens of asparagus crops in the Netherlands. Ten plants were selected from each of five fields with a young (1–4 y) first planting, five fields with an old (6–13 y) first planting and five fields with a young replanting. The analysis included fungi present in the stem base and the roots of plants with symptoms of foot and root rot or showing growth decline without specific disease symptoms. Isolates of each species were tested for pathogenicity to asparagus on aseptically grown plantlets on Knop's agar. Symptoms were caused byFusarium oxysporum, F. culmorum, Botrytis cinerea, Penicillium verrucosum var.cyclopium, Cylindrocarpon didymum, Phialophora malorum, Phoma terrestris andAcremonium strictum. F. oxysporum was by far the most common species and was isolated from 80% of the plants. Not all of its isolates were pathogenic to asparagus. Symptoms were caused by 67%, 78% and 93% of the isolates obtained from young first plantings, old first plantings and replantings, respectively.F. culmorum was isolated from 31% of the plants. Two other notorious pathogens of asparagus,F. moniliforme andF. proliferatum, did not occur in our samples.Species causing symptoms in the vitro test that were found on more than 5% of the plants were additionally tested for their pathogenicity in pot experiments.F. oxysporum f.sp.asparagi caused severe foot and root rot, significantly reduced root weights and killed most of the plants.F. culmorum caused lesions on the stem base often resulting in death of the plant.P. terrestris, a fungus only once reported as a pathogen of asparagus, caused an extensive root rot, mainly of secondary roots that became reddish. The fungus was isolated in only a few samples and is not to be regarded as an important pathogen in Dutch asparagus crops.P. malorum caused many small brown lesions on the stem base and incidentally also on the upper part of small main roots. This is the first report of its pathogenicity to asparagus. The fungus is one of the organisms inciting spear rust and it reduced crop quality rather than crop yield.P. verrucosum var.cyclopium andC. didymum did not cause symptoms in pot experiments.Because of its predominance on plants with foot and root rot and its high virulence,F. oxysporum f.sp.asparagi was considered to be the main soilborne pathogen of asparagus in the Netherlands.     

Selection forMeloidogyne incognita virulence against resistance genes from tomato and pepper and specificity of the virulence/resistance determinants

Experiments were designed to analyze the relationships between the root-knot nematodeMeloidogyne incognita and resistant tomato and pepper genotypes. From a natural avirulent isolate, near-isogenic nematode lineages were selected with virulence either against the tomatoMi resistance gene or the pepperMe3 resistance gene. Despite the drastic selection pressure used, nematodes appeared unable to overcome the pepperMe1 gene, therefore suggesting some differences in the resistance conferred byMe1 andMe3 in this species. Nematodes virulent onMi-resistant tomatoes were not able to reproduce onMe1-resistant nor onMe3-resistant peppers, and nematodes virulent onMe3-resistant peppers were not able to reproduce onMi-resistant tomatoes nor onMe1-resistant peppers. These results clearly demonstrate the specificity ofM. incognita virulence against resistance genes from both tomato and pepper, and indirectly suggest that gene-for-gene relationships could occur between these two solanaceous crops and the nematode.     

Neem (Azadirachta indica) seed kernel extracts and azadirachtin as oviposition deterrents against the melon fly (Bactrocera cucurbitae) and the oriental fruit fly (Bactrocera dorsalis)

Neem(Azadirachta indica A. Juss.) seed kernel (NSK) extracts,viz., NSK aqueous suspension (NSKS), ethanolic extract of NSK (EtOH. NSK), hexane extract of NSK (neem oil), ethanolic extract of the hexane extract (EtOH. oil) and acetone extract of deoiled NSK powder (Acet. DNSKP) at 1.25-20% concentrations, and pure azadirachtin at 1.25-10 ppm, were evaluated as oviposition deterrents toBactrocera cucurbitae (Coq.) andB. dorsalis Hendel. NSKS at ≥5% under choice test conditions, and at all concentrations (≥1.25%) in no-choice tests significantly deterred oviposition in both species. Similarly, EtOH. NSK was significantly active at all the concentrations tested for both species in choice and no-choice tests. However, with neem oil and EtOH. oil sensitivities of the two species differed considerably. Both extracts deterred oviposition byB. cucurbitae at all the concentrations tested under both choice and no-choice test conditions. On the other hand, withB. dorsalis, neem oil was significantly deterrent only at 20% in both test regimes and at 5% and 20% for EtOH. oil under choice and no-choice test conditions, respectively. Acet. DNSKP significantly deterred oviposition by both species at all concentrations tested. Azadirachtin failed to deter oviposition in either species.     

Analysis of nematodes and soil-borne fungi fromAmmophila arenaria (Marram grass) in Dutch coastal foredunes by multivariate techniques

A survey was carried out at nine locations in the Dutch coastal foredunes to identify the species of soil borne fungi and nematodes associated withAmmophila arenaria (Marram grass).Ammophila arenaria is a sand binding grass that is very important for the stabilization of coastal foredunes. Degeneration of the plants occurs at stabilized sites and is supposed to be caused by a combination of soil-borne fungi and nematodes. Canonical correspondence analysis (CCA) and two-way indicator species analysis (TWINSPAN) were used to examine which fungal and nematode species usually coexist in the rhizosphere of vigorous and early declining stands ofA. arenaria. In total, 47 species of fungi and 10 genera of plant-parasitic nematodes were found. According to CCA, the community of soil organisms of stands that were more than 10 years old was significantly different from recently established stands of 3 years old. Also, the community of soil organisms isolated from calcareous locations differed significantly from that of lime-poor locations. No relationship between the vigour of the plants (vigorous vs. early declining) and the soil borne species composition was found, although in roots of vigorous stands, the number of nematodes was higher than that of early declining stands. A relatively large group of soil organisms occurred generally. This group possibly contains an ubiquitous pathocomplex that cause the growth reducing effects of biotic origin which generally occur inA. arenaria. Analysis of this group of nematodes and fungi by TWINSPAN resulted in 9 different combinations of concurring soil organisms of which 5 combinations were present at all investigated locations. Two of the latter combinations contained both nematodes and fungi. The first contained three endoparasitic nematodes (Meloidogyne maritima, Heterodera spp. andPratylenchus sp.) that concurred with the fungusMucor hiemalis. The second group containedHeterodera spp.,Telotylenchus ventralis, Filenchus sp. together with the potentially plant-pathogenic fungiMicrodochium bolleyi and Fusarium culmorum, as well as the fungiMortierella sp. andTrichoderma harzianum, all in relatively high numbers.It is concluded that both CCA and TWINSPAN are valuable exploratory techniques, especially when used in combination, to detect possible combinations of soil organisms which may be involved in the degeneration ofA. arenaria. Further identifications of harmful organisms should be obtained from experiments.     

Within-plant distribution of the leaf miner Tuta absoluta (Meyrick) immatures in processing tomatoes,with notes on plant phenology

Bacteria of the genus Serratia are often associated with insects, often carry distinctive pigments and can be readily isolated onto diagnostic selective media. Bacterial marking of parasitoids has been used in studies to determine rate of oviposition and host acceptance, and it provides a rapid indication of ovipositor penetration. The technique has been applied to parasitoid-weevil and parasitoid-lepidoptera interactions. Bacterial marking has the potential to be used in parasitoid dispersal studies and its use in IPM is discussed.     

Two new species of egg parasitoids (hymenoptera: Encyrtidae) of wood-boring beetle pests from China

Oobius agrili sp.n. andAvetianella xystrocerae sp.n. (Hymenoptera: Encyrtidae) are described from China. Morphological characters of the new species are illustrated.O. agrili is an egg parasitoid of the emerald ash borerAgrilus planipennis Fairmaire (Coleoptera: Buprestidae) andA. xystrocerae is an egg parasitoid of the wood borerXystrocera globosa (Olivier) (Coleoptera: Cerambycidae). The two new species are potential biocontrol agents of economically important pest insects. The type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing (IZCAS). http://www.phytoparasitica.org posting May 17, 2005.     

The anthocoridae of Israel (heteroptera)

Data are presented on the 26 species of Anthocoridae of Israel, five of which are new to this country. Five species are abundant; two of them (both monophagous) reduce significantly the populations of their preys —Elatophilus hebraicus Per. feeding onMatsucoccus josephi (Coccoidea: Margarodidae), a destructive pest of Aleppo pine, andMontandoniola moraguesi (Put.) feeding onGynaikothrips ficorum (Thysanoptera), deforming the leaves ofFicus microcarpa; the three other abundant species areAnthocoris nemoralis (F.) — preying mostly on psyllids and aphids,Scoloposcelis pulchella (Zett.) — destroying the young stages of pine bark beetles, andCardiastethus nazarenas Reut. — feeding on many groups of small arthropods. Contribution from the Agricultural Research Organization. No. 2621-E, 1989 series.     

Pathogenic fungi involved in root rot of peas in the Netherlands and their physiological specialization

Research on root rot pathogens of peas in the Netherlands has confirmed the prevalence ofFusarium solani, F. oxysporum, Pythium spp.,Mycosphaerella pinodes andPhoma medicaginis var.pinodella. Aphanomyces euteiches andThielaviopsis basicola were identified for the first time as pea pathogens in the Netherlands. Other pathogens such asRhizoctonia solani andCylindrocarpon destructans were also found on diseased parts of roots. F. solani existed in different degrees of pathogenicity, and was sometimes highly specific to pea, dwarf bean of field bean, depending on the cropping history of the field.A. euteiches was specific to peas, whereasT. basicola showed some degree of physiological specialization.     

Effects of a primitive cotton accession on feeding ofspodoptera littoralis andhelicoverpa armigera and on oviposition ofBemisia tabaci

A primitive cotton(Gossypium hirsutum L.) accession, V-64, from the Caribbean Islands was bioassayed for antibiosis against pests of this crop in comparison with the commercial strains Acala SJ-2 and Pima S-5. V-64 reduced weight gain and leaf consumption ofSpodoptera littoralis andHelicoverpa armigera, and significantly reduced oviposition ofBemisia tabaci. The leaf pigment glands in V-64 were larger and more abundant than in the commercial strains, and the feeding ofH. armigera on these glands was avoided, indicating that the glands probably constituted the major resistance character in V-64. Contribution from the Agricultural Research Organization. No. 3187-E, 1991 series.     

Fusarium Redolens f.sp asparagi, Causal Agent of Asparagus Root Rot, Crown Rot and Spear Rot

Two Fusarium species, F. oxysporum f.sp. asparagi and F. proliferatum, are known to be involved in the root and crown rot complex of asparagus. We have investigated reports on the involvement of F. redolens, a third species, which until recently was considered conspecific with F. oxysporum because of morphological similarities. RFLP analysis of the rDNA internal transcribed spacer region and AFLP fingerprinting identified eight strains from asparagus unambiguously as F. redolens. Four of these were tested and found to be pathogenic to asparagus either in this study (two strains) or in a previous one in which they were classified as F. oxysporum (three strains). Disease symptoms and disease development were the same as with F. oxysporum f.sp. asparagi and F. proliferatum. Present data and literature reports identify F. redolens as a host-specific pathogen involved in root, crown and spear rot of asparagus. The pathogen is formally classified as F. redolens Wollenw. f.sp. asparagi Baayen.     

A new<Emphasis Type="Italic">Aphidius</Emphasis> species (Hymenoptera: Braconidae: Aphidiinae) from high-montane areas of southeastern Europe

Aphidius montenegrinus sp.n. from Serbia and Montenegro is described and illustrated. It parasitizedAcyrthosiphon daphnidis Ilharco, onDaphne alpina L. The parasitoid was described and illustrated using scanning electron microscope photographs and line drawing. The new species is a member of theAcyrthosiphon aphid parasitoid guild and was collected from Zabojsko Jezero Lake in Montenegro. The parasitoid and the hyperparasitoid spectrum ofA. daphnidis are presented for the first time. http://www.phytoparasitica.org posting April 30, 2004.     

Separation of two leafhopper populations of theCirculifer haematoceps complex on different host plants in Israel

TwoCirculifer leafhopper populations of thehaematoceps complex have been collected in large numbers in Israel for several years. One of these leafhoppers inhabited prickly saltwort (Salsola kali) plants on sandy soil on the Mediterranean coast. It has a narrow host range and was found to survive for one generation on turnip. The other leafhopper population was collected in 1986 on common goosefoot (Chenopodium album) plants in the Golan Heights. This population is polyphagous and in the laboratory reproduced well onMatthiola incana, turnip, sugar beet andChrysanthemum coronarium; however, reproduction was nil onPhaseolus vulgaris and very low onBrassica oleracea, Portulaca oleracea andCarthamus tinctorius. Contribution from the Agricultural Research Organization. No. 2502-E, 1988 series.     

Natural occurrence of citrinin in rice grains and its biocontrol byTrichoderma hamatum

Paddy rice was sampled from El-Sharkia, El-Gharbia, El-Dakahlia and Kafr El-Shekh governorates, Egypt. Of the 30 samples taken, ten were contaminated with the mycotoxin citrinin. An average of 6.79 × 10⁴ fungal spores per gram rice was found. The isolated fungi represented 47 species and 28 genera. The predominant genera wereAspergillus, Cladosporium andPenicillium. Aspergilli were represented by 22 species;Aspergillus niger andA. flavus had the highest occurrence.Penicillium viridicatum produced the highest amount of citrinin on glucose ammonium nitrate salts broth and rice grains, and hence this isolate was selected as a good producer of citrinin in this study. The presence ofTrichoderma hamatum reduced the amount of citrinin produced byP. viridicatum compared with its respective control. The excessive growth ofT. hamatum onP. viridicatum was increased with time. Viability ofP. viridicatum conidia decreased byT. hamatum with an increase in the incubation period. Chitinases and 1,3-β-glucanase enzyme activity ofT. hamatum increased with extending the incubation period onP. viridicatum mycelia up to maximum values at 72 and 84 h, respectively.T. hamatum led to a decrease in the production of citrinin byP. viridicatum on rice grains compared with the respective control values. http://www.phytoparasitica.org posting Dec. 19, 2004.     

First report of Rhizomonas sp. causing corky root of lettuce in Europe

Typical symptoms of corky root were observed on iceberg lettuce (Lactuca sativa L.) in the Netherlands and England, on prickly lettuce (Lactuca serriola L.) in Spain, and on sowthistle (Sonchus oleraceus L.) in Greece. Slow-growing bacteria with similar colonies as strains ofRhizomonas suberifaciens or otherRhizomonas species were isolated from soil surrounding plants with corky root symptoms using lettuce seedlings as bait. Crude lysate from all strains was tested for DNA homology with DNA fromR. suberifaciens strain CA1 (R. sub. CA1) andRhizomonas sp. strain WI4 (R. sp. WI4). Strains that had homology values higher than that ofR. sp. WI4 orR. sub. CA1 were tested for pathogenicity on 1-wk-old lettuce seedlings, cv. Salinas, Two strains from the Netherlands induced typical symptoms of corky root on lettuce. These strains tested negative with monoclonal antibody MAb-Rs1 specific forRhizomonas suberifaciens in an enzyme-linked immunosorbent assay (ELISA). They had low DNA homology withR. sub. CA1 (4–9%) and low to moderate DNA homology withR. sp. WI4 (4–17%). Some nonpathogenic strains had moderate to high levels of DNA homology withR. sub. CA1 orR. sp. WI4 (19–84%). All strains had fatty acid profiles similar to those ofRhizomonas species. This is the first report ofRhizomonas sp. causing corky root of lettuce in Europe.