Fungi on red raspberry from lesions associated with feeding wounds of cane midge (Resseliella theobaldi)

Two types of vascular lesion are described from the base of canes in plantations infested by raspberry cane midge ( Resseliella theobaldi ); (1) brown lobate lesions ('patches') confined to midge feeding areas, (2) brown lesions spreading proximally and distally from the point of infection ('stripes'). Either or both types of lesion may be presented in individual canes. Isolations from (1) produced principally Fusarium avenaceum ; isolations from tissues where (1) and (2) are contiguous gave Leptosphaeria coniothyrium and F. avenaceum ; isolations from (2) arising from old cane stub wounds in the absence of midge gave L. coniothyrium .
The important secondary role of fungi in the midge blight complex is confirmed, but the involvement of L. coniothyrium in the complex is unclear because it also infects stub wounds on midge-infested canes.     

Resistance to raspberry cane midge (Resseliella theobaldi) and its association with wound periderm in Rubus crataegifolius and its red raspberry derivatives

Rubus parviflorus, R. odoratus and F₂ plants from the cross R. crataegifolius x R. idaeus were resistant to the raspberry cane midge (Resseliella theobaldi) when exposed to the pest in an insectary or in the field. Histological studies of R. crataegifolius and one of its hybrids with R. idaeus showed that resistance was associated with a wound periderm of suberised and lignified cells. These cells were formed from the primary cortex and phelloid cells of the polyderm as a rapid response to the occurrence of natural splits and wounds which are the oviposition sites of R. theobaldi. In the hybrid, new tissues from this wound periderm prevented the peeling of the mature primary cortex, thereby precluding serious midge attack, and resulted in a reticulate appearance on the cane surface, a distinctive cane feature useful for identifying resistant segregates.     

Vigour control, an integrated approach to cane, pest and disease management in red raspberry (Rubus idaeus)

The first flush of young canes of red raspberry (Rubus idaeus) was removed at different dates in spring, using the contact herbicide dinoseb. In comparison with untreated plots, cane removal increased fruit yield, controlled excessive cane vigour, and improved the health status of vegetative canes in a plantation infested by raspberry cane midge (Resseliella theobaldi). At the end of the growing season vegetative canes on treated plots were shorter and thinner, and sustained less physical injury than those on untreated plots. Access to the fruit at harvest was also improved. Reduced competition between fruiting and vegetative canes increased yield in the year of treatment by an average of 35%. Yield was not affected by date of cane removal, but growth of replacement cane was reduced below optimum when first flush cane was removed after mid-May. The later the canes were removed, the less was the incidence of pest and diseases. Cankers and lobate vascular lesions (‘patches’) resulting, respectively, from the feeding of first and second generation midge larvae (with associated fungi) affected fewer canes in treated than in untreated plots. Significantly fewer live larvae of R. theobaldi were recovered in the following winter from soil in plots treated on or after 11 May than from untreated plots. The main effect of vigour control on R. theobaldi and midge blight was that replacement canes provided fewer egg-laying sites (natural splits) than did the first flush canes on untreated plots. The incidence of spreading vascular lesions (‘stripes’) attributed to Leptosphaeria coniothyrium infecting either physical wounds (cane blight) or midge feeding wounds (midge blight) was substantially less in treated than untreated plots. Cane botrytis (Botrytis cinerea) and spur blight (Didymella applanata) were also less common in treated plots. Interactions between vigour control and pest and disease incidence are discussed in relation to the efficient management of cv. Glen Clova in eastern Scotland.     

Disease measurement in a study of apple scab epidemics

The growth and yield increases in red raspberry which followed the repeated application of benomyl were not due to the suppression of pests. Benomyl had little effect on numbers of aphids and nematodes which, anyway, were insufficiently abundant to cause damage. Benomyl did, however, decrease the earthworm population. In the following years, when benomyl was no longer applied, significantly more canes died from midge blight in the plots treated most frequently with benomyl than in the untreated. This was probably a consequence of increased infestation by larvae of the raspberry cane midge (Resseliella theobaldi) in the benomyl-treated plots because benomyl increased the extent of cane splitting and hence the number of egg-laying sites for cane midge.     

中国寄生于荔枝瘿蚊的红眼姬小蜂属一新种(膜翅目:小蜂总科:姬小蜂科)(英语)

本文记述了我国南方姬小峰科红眼姬小蜂属Mangocharis一新种,荔枝瘿蚊红眼姬小蜂M.litchiiYang et Luo.该种单个内寄生于严重危害荔枝叶片的荔枝叶瘿蚊Mayetiola sp.幼虫或跨期寄生于该害虫的卵—幼虫期,在自然控制这种害虫上具有重要作用.红眼姬小蜂属在我国首次发现.     

A NEW EULOPHID PARASITIZING LITCHI GALL MIDGE FROM CHINA (HYMENOPTERA: CHALCIDOIDEA)

Abstract  Mangocharis litchii sp. nov. is described from south China as a parasitoid of Mayetiola sp. on leaf of litchi tree. The gall midge is a serious pest of the fruit tree in south China. The biology of the new chalcidoid is also dealt with. The genus Mangocharis is new to China.     

Identification of quantitative trait loci for cane splitting in red raspberry (Rubus idaeus)

Cane splitting, a normal feature of raspberry growth, can lead to plant infestation by cane midge followed by fungal infection, with losses in yield of up to 50 % if left untreated. The extent of splitting in the Latham × Glen Moy reference mapping population was assessed over six years and in three environments and quantitative trait loci (QTL) were identified across linkage groups (LG) 2, 3, 5 and 6. Cane splitting QTL on LG 3 and 5 co-locate with QTL for plant vigour. The cane splitting QTL on LG 6 is associated with the QTL for resistance to root rot caused by Phytophthora rubi. Broad-sense heritability for cane splitting ranged from 25.6 % in 2007 to 49.1 % in 2008 in this population. Season and environment were also found to influence cane splitting in this population. Several genes involved in general plant growth and in defence responses lie within these QTL. This is a first step towards identifying the genetic basis of cane splitting in raspberry and the development of genetic markers for use in raspberry breeding programmes.     

Predatory role of Neoseiulus fallacis (Acari: Phytoseiidae): spatial and temporal dynamics in Washington red raspberry fields

The seasonal abundance of spider mites and their predator Neoseiulus fallacis (Garman) (Acari: Phytoseiidae) was determined during three consecutive years in Washington State red raspberry fields. Tetranychus urticae Koch (Acari: Tetranychidae), Eotetranychus carpini borealis (Ewing) (Acari: Tetranychidae), and N. fallacis were commonly found in Skagit and Whatcom Counties. E. carpini borealis colonized the fruiting canes earlier in the season than T. urticae. The two phytophages overlapped in midseason, but T. urticae entered diapause earlier than E. carpini borealis and N. fallacis. Densities of N. fallacis increased with increase in spider mite densities. However, the numerical response of the predator was more evident for T. urticae than for E. carpini borealis. Nevertheless, the predator was spatially associated with the two prey species. The spatial and seasonal distribution of N. fallacis in relationship to host plant phenology and prey distribution may influence the effectiveness of this predator as a biological control agent against spider mites in red raspberry. Densities of the predator increased too late to prevent spider mite damage. The predatory role of N. fallacis could be enhanced by introducing or conserving predators that are more tolerant to climatic factors that prevail in and around the cane canopy in the beginning of the season.     

A technique for scoring midge blight of red raspberry, a disease complex caused by Resseliella theobaldi and associated fungi

A scoring technique is described for assessing midge blight using maps representing vascular lesions beneath periderm damaged by second generation larvae of Resseliella theobaldi . Individual canes were scored and some components of yield examined. Yield was not affected until lesions covered more than 20% of the stele surface at the base of canes. Midge blight scores increased with cane girth, probably because splitting of the cortex was most extensive in stout canes.     

Changes in the fat body during the post-embryonic development of the predator Toxorhynchites theobaldi (Dyar & Knab) (Diptera: Culicidae)

Several studies have focused on understanding the biochemistry and morphology of the fat body of the hematophagous mosquito Aedes aegypti (L.) (Diptera: Culicidae). In contrast, few studies, if any, have focused on morphological characters of the fat body in other mosquitoes, especially non-hematophagous taxa such as the culicid Toxorhynchites. Larvae of Toxorhynchites prey upon the larvae of other mosquito species and are used in vector mosquito control. We investigated aspects of the fat body trophocytes, including the morphometric analyses of the lipid droplets, protein granules and nuclei, during Toxorhynchites theobaldi (Dyar & Knab) post-embryonic development. Following the body weight increase from larval stage L2 to L4, the size of lipid droplets within the trophocytes also increase, and are likely the result of lipogenesis. Lipid droplets decrease in size during L4 to the female pupal stage and increase once again during the period from newly-emerged to mature adult females. Protein granules are observed for the first time in female pupae, and their appearance might be related to protein storage during metamorphosis. The size of the nucleus of trophocytes also increases during larval development, followed by a decrease during metamorphosis and an additional increase as adult female ages. In conclusion, the morphology of the fat body of T. theobaldi changes according to the developmental stage. Our study provides for the first time important insights into T. theobaldi fat body development and contributes to understand this species biology.     

Cane blight (Leptosphaeria coniothyrium) in mechanically harvested red raspberry (Rubus idaeus)

Leptosphaeria coniothyrium, the cane blight pathogen, was the fungus most commonly isolated from vascular lesions developing from mechanical harvester wounds on first-year red raspberry canes. When inoculated to scalpel wounds, it induced similar lesions which were later associated with bud failure and cane death as were infected wounds on machine damaged canes. Cane resistance increased from May until August, inoculations later than July inducing only small lesions and rarely causing bud failure.     

Modifying glucosinolates in oilseed rape – Giamoustaris & Mithen (1995): a top‐twenty paper in the Annals of Applied Biology

Part of the reason for the under‐exploitation of physical resistance traits in plant breeding is that the genetic basis and heritability of these traits is poorly characterised, and any associations of particular traits with pest and disease resistances have yet to be determined. In raspberry, some associations between architectural traits and disease resistances have been demonstrated, for example cane hairs and resistance to cane diseases. The aim of this work is to examine a range of traits, including leaf trichomes, leaf density, cane density, bush density, lateral length and lateral numbers, to determine the heritability and therefore breeding potential of these traits. The effect of these traits against aphids and spider mites, two important pests in raspberry, was examined. Chromosomal regions with candidate genes regulating these traits were identified as the first step to understanding the genetic control.     

Factors affecting the development of cane blight (Leptosphaeria coniothyrium) on red raspberries in Washington, Scotland and Germany

The effects of cultivar, virulence of isolates of Leptosphaeria coniothyrium, cane maturation and wound healing were examined in a series of inoculation experiments carried out over a 3–yr period in three countries in an attempt to explain why cane blight has caused serious yield losses in machine-harvested red raspberries in Europe, but not in the Pacific Northwest of America. Three isolates of L. coniothyrium from Puyallup (USA), Dundee (UK) and Dossenheim (FRG) were pathogenic on the three test cultivars Willamette, Malling Jewel and Glen Isla in all the experiments. Isolates and cultivars differed for aggressiveness and susceptibility respectively but their ranking was dependent on the test conditions and the differences were small and unlikely to explain the differences in incidence and severity of cane blight in raspberry fields in Scotland and the Pacific Northwest. Conditions at Dossenheim were most favorable for lesion development. At all sites, canes inoculated in late summer produced shorter lesions than those inoculated earlier. A delay between wounding and inoculation produced shorter lesions than simultaneous wounding and inoculation.     

A New Species of Schizomyia Kieffer (Diptera: Cecidomyiidae) on Rubber Vine and Other Asclepiadaceae in Madagascar

A new species of gall midge, Schizomyia cryptostegiae Gagné, that forms leaf and bud galls on Cryptostegia grandiflora in Madagascar is described and its biology summarised. the gall midge is a candidate for the biological control of C. grandiflora in northern Queensland, Australia.     

Morphological,genetic and symptomatic identification of an invasive jujube pest in Korea,Dasineura jujubifolia Jiao & Bu (Diptera: Cecidomyiidae)

Correct identification of invasive species is an important step for further management of this species. New type of leafcurling gall midge feeding on jujube, Ziziphus jujube Miller (Rhamnaceae), was discovered in Korea in 2011. At that time, this species was not identified as specific level, so it was recorded as Dasineura sp. Since then, the jujube gall midge has become a serious alien insect pest in Korea. In this study, this jujube gall midge was surveyed by collecting damaged leaf samples from different major jujube-producing regions in Korea. Morphological, genetic and symptomatic identification of this invasive jujube pest identified as Dasineura jujubifolia Jiao & Bu. Here we provided its taxonomic status, geographical distribution, morphological characteristics of all stages and infestation symptoms. In addition to classical morphological characters, mitochondrial COI barcoding sequences were generated for several specimens. The possible pathway of invasion and subsequent socioeconomic consequences were discussed.     

Host plant-mediated interactions between Tetranychus urticae and Eotetranychus carpini borealis (Acari: Tetranychidae)

Competitive interactions between Tetranychus urticae and Eotetranychus carpini borealis were investigated under laboratory and greenhouse conditions. When placed first to colonize red raspberry leaves, T. urticae caused extinction of E. carpini borealis populations. E. carpini borealis had detrimental effects on T. urticae but did not cause T. urticae population extinction. The area used by E. carpini borealis for egg deposition decreased with an increase in the number of T. urticae eggs. Red raspberry showed an induced response to T. urticae and E. carpini borealis feeding after two weeks of infestation. Population growth of each species was reduced on plants that were previously infested by conspecifics but inducible response by one species had no effects on the other species.     

Resistance to Botrytis cinerea in canes of Rubus idaeus and some related species

Mycelial inoculation of canes with Botrytis cinerea proved a useful method for assessing Rubus material for resistance. When canes were inoculated in summer resistant genotypes developed relatively small lesions which produced few small sclerotia in the following spring. The size of lesions in autumn generally provided the best discrimination between genotypes. Very strong resistance was found in several species, of which Rubus pileatus and R. occidentalis are the most useful for breeding; hybrids of raspberry with these species or with R. crataegifolius also had strong resistance. The resistance shown by a derivative of red raspberry cv. Chief was less strong, as was the resistance conferred by gene H, which determines cane pubescence.     

Identification and dietary relevance of antioxidants from raspberry

In this paper we review the current literature on antioxidants from fruit of red raspberry (Rubus idaeus) and place these in context concerning what is known from other food species. The review concentrates on the methods of antioxidant testing, the diversity of antioxidants in raspberry, effects of ripeness, cultivar, storage and processing techniques, and the bioavailability of raspberry antioxidants in humans after eating the fruit. It is clear that raspberry, like several other fruits and vegetables such as tomato, strawberry, kiwi and broccoli, represents a valuable contrasting source of potentially healthy compounds and can represent an important component of a balanced diet.     

Host plant susceptibility to the swede midge (Diptera: Cecidomyiidae)

The relative resistance and susceptibility of various cruciferous plants to swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), damage was investigated to provide growers with planting recommendations and to identify potential sources of resistance to the swede midge. Broccoli cultivars experienced more severe damage than cabbage, cauliflower, and Brussels sprouts. The broccoli 'Paragon', 'Eureka', and 'Packman' are highly susceptible to the swede midge, whereas 'Triathlon' and 'Regal' showed reduced susceptibility to damage and slower development of damage symptoms. No differences were found between normal and red cultivars of cabbage and cauliflower in damage severity and progression of damage symptoms. Four new plant species (Brassica juncea Integlifolia group, Erucastrum gallicum (Willd.) O. E. Shulz., Lepidium campestre (L.) R.Br., and Capsella bursa-pastoris (L.) Medic.) are reported as hosts of the swede midge. The weed species Descurainia sophia (L.) Webb, Camelina microcarpa Andrz. ex Dc., and Erysimum cheiranthoides L. exhibited no damage symptoms, and they seem to be nonhost crucifers for the swede midge.     

Life cycle and paratenesis of American gordiids (Nematomorpha: Gordiida)

To complete their life cycle, gordiids must make a transition from aquatic to terrestrial environments. However, epibenthic aquatic larvae and their terrestrial definitive hosts do not overlap in habitat. This has led many investigators to suggest that infections are acquired through the ingestion of insects, which become infected as aquatic larvae with gordiid cysts and subsequently carry gordiids to land. This proposed life cycle was experimentally tested using 3 common American species of gordiids: Gordius robustus, Paragordius varius, and Chordodes morgani. Cysts of all 3 species survived the metamorphosis of Tanytarsus sp., a midge. Subsequent infection trials of definitive hosts with cysts from imagos show that cysts surviving the metamorphosis of insects remained viable and free of host internal defense reaction. Data from naturally infected mayflies, Callibaetus sp., show that encystment and survival of gordiids within aquatic insects occur in nature. Paratenesis between paratenic hosts was also shown to be possible in these 3 species. This latter finding appears to indicate that cysts formed in spurious paratenic hosts may not be lost but may eventually transfer to normal paratenic hosts.