Paraphlepsius Irroratus Research Articles

Plants and Insects New to Sable Island, Nova Scotia

During recent inventories, particularly in 2008 and 2009, 8 plants and 17 insects were found that are additions to the flora and fauna of Sable Island, respectively. Additions to the flora include Alnus incana subsp. rugosa, Carex nigra, Frangula alnus, Isoetes tuckermanii, Linaria vulgaris, Mertensia maritima, Panicum dichotomiflorum, and Solidago rugosa. Additions to the insect fauna include Apateticus bracteatus, Barce fraterna, Carabus maeander, Conocephalus fasciatus, Danaus plexippus, Eulithis explanata, Haliplus cribrarius, Harmonia axyridis, Lasioglossum novascotiae, Lateroligia ophiogramma, Lycophotia phyllophora, Muirodelphax arvensis, Nemoria rubrifrontaria, Neoconocephalus retusus, Paraphlepsius irroratus, Scaphytopius acutus, and Spilodiscus arcuatus. The occurrence of Spilodiscus arcuatus is of interest with respect to an apparent decline throughout much of its range. Neoconocephalus retusus and species of Catocala provide an indication of the capability of storms to transport even large insects over substantial distances. The increasing numbers of Danaus plexippus observed may be part of a trend toward the northward movement of migratory insects. Some of the 7 plants are likely recent arrivals, but Isoetes tuckermanii and others may have been previously overlooked.

Pierce's Disease of Grapevines: Identification of the Primary Vectors in North Carolina

ABSTRACT In the past 10 years, the winegrape industry in the southeastern United States has experienced rapid growth; however, further expansion may be inhibited by Pierce's disease (PD). Epidemiological studies were conducted to identify the primary vectors of Xylella fastidiosa, the cause of PD of grape, by surveying sharpshooter population dynamics in the eastern Piedmont and Coastal Plain regions of North Carolina. Sharpshooter species were assessed for the presence of X. fastidiosa in the field. Leafhoppers were trapped in three vineyards in the eastern Piedmont and one vineyard in the northeastern Coastal Plain in 2004 and 2005. Four insects were identified as most abundant: Oncometopia orbona, Graphocephala versuta, Paraphlepsius irroratus, and Agalliota constricta. Adult specimens of O. orbona, G. versuta, and P. irroratus were tested for the presence of X. fastidiosa by nested polymerase chain reaction. In all, 27% of O. orbona, 28% of G. versuta, and 33% of P. irroratus trapped were positive for X. fastidiosa over the two seasons. Transmission experiments demonstrated that both O. orbona and G. versuta have the ability to transmit X. fastidiosa to grape. These vectors are likely to be important in all winegrowing regions of the Southeast, because their presence has been documented throughout the southern states. In DNA analyses, X. fastidiosa strains from insects trapped in North Carolina were genetically similar to one another and to the known "PD strain" from California. This is the first report of these two leafhopper species transmitting X. fastidiosa to grapevines in the Southeast.

Field Detection of X-Disease Mycoplasmalike Organism in Paraphlepsius irroratus (Say) (Homoptera: Cicadellidae) Using a DNA Probe

The seasonal and geographic distribution of X-diseased Paraphlepsius irroratus (Say)was studied in south, central, and northwest Michigan in 1988 and 1989 using a DNA probe. C6c, a fragment of pWXl derived from infected Colladonus montanus (Van Duzee), detected eastern X-disease in diseased P. irroratus . Maximum numbers of infected leafhoppers were detected at the beginning of the emergence of each generation in early June and in late September. In early summer the percentage of X-diseased leafhoppers at the various sites ranged from 12.2 to 43.3%, and in the late season from 3.3 to 36.4%. The X-diseased leafhoppers occurred only in south and central Michigan.

Vector-pathogen-host plant relationships of clover phyllody mycoplasmalike organism and the vector leafhopperParaphlepsius irroratus

Vector-pathogen-host plant relationships of clover phyllody mycoplasmalike organism and the vector leafhopper<i>Paraphlepsius irroratus</i>

Temperature-Dependent Pathogenicity of the X-Disease Mycoplasma-Like Organism to its Vector, Paraphlepsius irroratus (Homoptera: Cicadellidae

The effect of the X-disease mycoplasma-like organism (MLO) on the longevity of Paraphlepsius irroratus (Say) was investigated at four fluctuating temperatures averaging 15, 20, 25, and 30°C. The X-disease MLO in diseased leafhoppers was assayed with a radiolabeled cDNA probe. At the two lower temperatures, the X-disease MLO is pathogenic to P. irroratus . At 15 and 20°C, healthy leafhoppers lived 62 ± 16 ( |$\bar x$| ± SE) and 52 ± 22 d, respectively, whereas X-diseased leafhoppers lived 35 ± 21 and 23 ± 9 d, respectively. In the 25–30°C temperature range, MLO pathogenicity was masked by the temperature effect on leafhopper survival. At 25 and 30°C, longevity of healthy leafhoppers was 15 ± 9 and 7 ± 3 d, respectively, whereas X-diseased leafhoppers lived 14 ± 4 and 7 ± 4 days, respectively. Below 20°C, the MLO accounted for a 32% reduction in leafhopper longevity compared with <6% above 25°C. The MLO acquisition ranged from 32.4 to 36.9% with no difference ( P ≤ 0.05) between temperature regimes.

Dispersal of Paraphlepsius irroratus (Say) (Homoptera: Cicadellidae) in Peach and Cherry Orchards

Dispersal of the leafhopper vector of X-disease, Paraphlepsius irroratus (Say) within and into peach and cherry orchards was monitored by a mark, release, and recapture experiment. Field-collected adults were marked using fluorescent dyes and released at locations in and outside of two orchard sites. The marking method did not significantly affect leafhopper flight activity or survival. Dispersal was monitored using yellow sticky board traps for 21 d following each release, and the data were fitted to equations. The overall leafhopper recapture rate within 60 m was 2.35%. Dispersal rate for the first and second generations averaged 2.9 and 3.8 m/d. Wind was the major factor influencing leafhopper dispersal direction, as mean dispersal direction correlated significantly with mean wind direction ( r = 0.94, P ≤ 0.05). Temperature affected leafhopper activity; this was particularly apparent with second-generation adults active at temperatures approximately 11°C less than first-generation adults. There was no significant difference in the overall dispersal behavior between first and second generations. Implications of this movement to the spread of X-disease are discussed.

Some factors affecting the transmission of eastern peach X-mycoplasmalike organism by the leafhopperParaphlepsius irroratus

Some factors affecting the transmission of eastern peach X-mycoplasmalike organism by the leafhopper<i>Paraphlepsius irroratus</i>

Crepuscular Movement of Paraphlepsius irroratus (Say) (Homoptera; Cicadellidae) Between the Groundcover and Cherry Trees

Crepuscular movement of the leafhopper vector of X-disease, Paraphlepsius irroratus (Say), between orchard groundcover and fruit tree foliage and back was monitored by light-trapping and sweeping within a sour cherry orchard. The adult leafhoppers spent the day within orchard groundcover, and at twilight they moved into fruit tree foliage. There was no significant difference in this diurnal behavior between the two adult generations. Leafhopper density found in several within-orchard subhabitats (i.e., groundcover, sour cherry foliage, sweet cherry foliage) changed significantly over a 24-h period. The active crepuscular mass flight into the trees in the evening was contrasted to the passive movement back into the orchard groundcover the following morning.

BIOLOGY AND REARING OF PARAPHLEPSIUS IRRORATUS (HOMOPTERA: CICADELLIDAE), A VECTOR OF PEACH X-DISEASE

AbstractA method of rearing Paraphlepsius irroratus (Say) under artificial conditions was developed by using a leguminous plant species as the oviposition host and a gramineous species as the food plant for nymphs. Nymphs completed their development on all 10 gramineous species tested. Total time for completion of the 5 nymphal instars ranged from 31.8 to 59.2 days, depending on the plant species used. With the exception of Alopecurus pratensis, all monocotyledonous species tested were found to be suitable food plants for nymphs, allowing 50% or more of the insects to survive for 3 weeks or more. Only 5 dicotyledonous species supported a similar survival level of nymphs. Adult survival remained above the 50% level on Apium graveolans var. dulce, 6 members of the Leguminosae, and all members of Composite with the exception of Callistephus chinensis. Survival of adult leafhoppers on monocotyledons was relatively high after 1 week but considerable mortality followed longer confinement. Although nymphs emerged from eggs laid on a wide range of plant species, the numbers recorded on monocotyledons suggest that monocots are important as oviposition hosts for P. irroratus in nature.

Occurrence and seasonal distribution of leafhopper vectors of the X-disease causal agent in methoxychlor-sprayed and unsprayed peach orchards

Leafhopper (LH) (Homoptera: Cicadellidae) populations were monitored in a peach orchard in which eight blocks of 10 trees each were unsprayed or sprayed seven times in 1979 and three times in 1980 with methoxychlor. Of 7552 LH trapped during both years, 1335 adults of six species known to transmit the mycoplasma-like causal agent of X-disease (X-vectors) were recorded: Paraphlepsius irroratus (Say), 703; Scaphytopius acutus (Say), 439; Colladonus clitellarius (Say), 88; Norvellina seminuda (Say), 65; Gyponana lamina (Delong), 39; and Fieberiella florii (Stål), three. In sprayed blocks, total LH, total X-vectors and total P. irroratus and S. acutus adults (the most abundant X-vectors), were reduced by 49%, 46%, 43% and 50% respectively. In 1979, during one of two periods of peak adult LH activity, total LH, total X-vectors, P. irroratus and S. acutus were reduced by 56–73%, 22–48%, 26% and 62–85% respectively. In 1980, during the first period of adult leafhopper activity, total LH, total X-vectors, P. irroratus and S. acutus populations in sprayed trees were reduced by 72%, 56%, 50% and 60% respectively. The value of reducing X-vector populations, especially those of major X-vectors such as S. acutus and P. irroratus, for disease control is unknown, but should be considered for integrated management of X-disease.

Factors Affecting Colonization of an Orchard by Leafhopper (Homoptera: Cicadellidae) Vectors of Peach X-Disease

The importance of distance from wild host plants, plant species composition of ground cover, and symptomatic discoloration of foliage to pattern of colonization by leafhopper (Homoptera: Cicadellidae) vectors of X-disease was studied in an unsprayed peach orchard in Middlefield, Middlesex County, Conn., during 1980. Five leafhopper vectors captured from 22 May to 4 November on yellow sticky traps hung in 90 peach trees and at 10 locations among wild host plants at the orchard edge were Scaphytopius acutus (Say) ( n = 34,262), Colladonus clitellarius (Say) ( n – 5,640), Paraphlepsius irroratus (Say) ( n = 1,717), Norvellina seminuda (Say) ( n = 105), and Gyponana lamina DeLong ( n = 43). Each species was more abundant at the orchard edge than in the orchard. There were significant, negative correlations between the densities of S. acutus, C. clitellarius , and P. irroratus on peach trees and distance of peach trees from bordering wild host plants for the first 2-week trapping period during which these leafhoppers were abundant. These data indicate that adults invaded the orchard from its edge. However, after this initial invasion by adults, leafhopper distributions in the orchard were not affected by proximity of peach trees to wild host plants bordering the orchard. Instead, leafhoppers selectively colonized trees whose ground cover was predominantly wild host plants. Hosts for S. acutus and C. clitellarius included red clover, Trifolium pratense L. (Leguminosae), and several species of Rosaceae; hosts for P. irroratus included these and Graminae, in particular Dactylis glomerata L. Density of S. acutus was positively correlated with percent T. pratense in ground cover and also was significantly lower on X-diseased trees with discolored foliage than on nondiseased trees.

Manipulating Orchard Ground Cover to Reduce Invasion by Leafhopper Vectors of Peach X-Disease1

Adults of six leafhopper vectors of X-disease. Colladonus clitellarius (Say). Fieberiella florii (Stal). Gyponana lamina DeLong. Norvellina seminuda (Say). Paraphlepsius irroratus (Say), and Scaphytopius acutus (Say) invaded an experimental peach block in Hamden, Conn. The number and species of leafhoppers captured on clear sticky traps hung in peach trees 6 m apart varied depending upon which of four different ground cover types was beneath. The greatest number of adult leafhoppers trapped between 10 June and 28 October 1980 were from plots where ground cover was pure red clover, Trifolium pratense L. ( n = 1,115). Significantly fewer adults were trapped on peach trees with mixed weeds, mainly rosaceous species ( n = 575). pure orchard grass, Dactylis glomerata L. ( n = 364). or bare ground ( n = 211) beneath. Most S. acutus ( n = 878) occurred on trees with red clover beneath. whereas relatively few occurred on trees with either orchard grass or bare ground beneath. The most abundant leafhopper vector. P. irroratus . ( n = 1,289) did not discriminate among ground cover types; a substantial portion of the population was captured on trees in all but the plots with bare ground. Managing the orchard floor free of host plants to discourage invasion by leafhopper vectors may reduce the spread of peach X-disease.

Spatial and Seasonal Distributions of Leafhopper Vectors of Peach X-Disease in Connecticut

Adults of 6 leafhopper vectors of peach X-disease were captured on yellow sticky traps hung on peach trees and on wild host plants at 18 sites including 16 peach orchards in Connecticut. They were Scaphytopius acutus (Say) (comprising 61.7% of the total leafhoppers; n = 13131), Colladonus clitellarius (Say) (18. 1%), Paraphlepsius irroratus (Say) (15.8%), Gyponana lamina DeLong (3.7%), Norvellina seminuda (Say) (0.4%), and Fieberiella florii (Stal.) (0.3%). The seasonal distributions of these leafhoppers indicated that G. lamina and F. florii are univoltine, that S. acutus, C. clitellarius and N. seminuda are bivoltine, and that P. irroratus is trivoltine. The trapping period during which the greatest number of leafhoppers was caught occurred at least 2 wks earlier on wild host plants at the orchard edge than on peach trees even though leafhoppers matured simultaneously on both. On wild hosts, fewer leafhoppers were trapped in autumn than in summer while on peach trees more were trapped in autumn than in summer. These data indicate that leafhopper vectors invade the peach orchard from bordering wild host plants. Orchards that had ground cover comprised of wild host plants had the largest populations of leafhoppers and the highest incidence of X-disease. The percent of peach trees showing disease symptoms was correlated with leafhopper densities which indicates the role of wild host plants in the epidemiology of peach X-disease.

Leafhopper Fauna of X-Diseased Peach and Cherry Orchards in Southwest Michigan12

During a 2-year period, 70 species of leafhoppers were collected on sticky-board traps placed in and around several X-diseased peach and sour cherry orchards in southwest Michigan. Of those species known to be X-disease vectors, Paraphlepsius irroratus (Say) and Scaphytopius acutus (Say) were most abundant, whereas Colladonus clitellarius (Say). Norvellina seminuda (Say), and Fieberiella florii (Stål) were found only in low numbers. Many more P. irroratus were trapped in cherry orchards than in peach orchards, whereas S. acutus was slightly more common in peach orchards. Both species appear to have 2 generations/year. The importance of 7 additional species as possible vectors is discussed.

Transmission of Clover Phyllody Virus by the Leafhopper, Paraphlepsius irroratus (Say)

AbstractClover phyllody virus was transmitted from ladino clover to ladino clover by Paraphlepsius irroratus (Say). The preinfective period of the insect following acquisition of the virus was between 21 and 28 days. Nineteen of 25 plants fed on by leafhoppers that had completed their preinfective period became infected.