Pseudococcus Maritimus Research Articles

Effects of germicidal ultraviolet-C light on grape mealybug (Pseudococcus maritimus)

Germicidal ultraviolet-C light (UV–C) has been used to effectively suppress grapevine powdery mildew (Erysiphe necator). However, effects on arthropod pests that would be simultaneously exposed to UV-C during applications directed at E. necator, are poorly understood. The grape mealybug (Pseudococcus maritimus) is one such grapevine pest. We exposed mated P. maritimus adult females in a lab study to UV-C light doses of 100, 200, 500 and 1000 J/m2. UV-C was applied during darkness and was followed by an additional 4 h dark period post-treatment to enhance possible suppressive effects of UV-C. Positive (2% horticultural oil) and negative (untreated) controls were included. Adult female P. maritimus oviposition was observed two weeks after treatment, and hatching of eggs was enumerated four weeks after treatment. UV-C treatment of mated adult females, regardless of dose, did not prevent oviposition or reduce ovisac viability. In a separate lab experiment, first instar P. maritimus nymphs were similarly exposed to UV-C doses of 200 and 1000 J/m2 with and without a 4hr dark period. UV-C treatments were compared to the same positive and negative controls. Nymph mortality was assessed at 24 and 48 h after UV-C treatment. Increasing doses of UV-C treatments, followed by a dark period, had a small, but significant impact on nymph mortality relative to the untreated control. Further studies on the potential sublethal effects (e.g., fecundity or longevity) of single or multiple exposures or increased UV-C doses upon juvenile stages of P. maritimus are warranted, as longer-term and multigenerational effects of UV-C have been observed in other arthropod systems.

Ozonated Water Spray Does Not Suppress Grapevine Powdery Mildew or Grape Mealybug

Ozonated Water Spray Does Not Suppress Grapevine Powdery Mildew or Grape Mealybug

THE MAIN PESTS OF GRAPES AND THE SYSTEM OF FIGHTING THEM

Uzbekistan. Like other cultures, it is damaged by various pests. Depending on morphological features and lifestyle, pests of the grapes damage the various organs of the bushes: the root system, the trunk, young shoots, buds, flowers and berries. Green shoots, leaves and fruits of grapes damage hawk moths. On the above-ground part of the grapevine, there is a grape mealybug, a comma-like shieldworm, and an acacia false guard. Vine leaves are damaged by ticks, cherries, cicadas.

Spatial Roguing Reduces the Incidence of Leafroll Disease and Curtails Its Spread in a Finger Lakes Cabernet franc Vineyard

<h3>Abstract</h3> Leafroll is one of the most economically important viral diseases of grapevines worldwide. Grapevine leafroll-associated virus 1 (GLRaV-1) and grapevine leafroll-associated virus 3 (GLRaV-3) are prevalent in New York vineyards in which low-density grape mealybug populations reside. A five-year experiment was performed in a commercial ‘Cabernet franc’ vineyard in the Finger Lakes region of New York to test the influence of spatial roguing, i.e., the elimination of virus-infected vines and their two immediate within-row neighbors on each side, on the annual incidence of GLRaV-1 and GLRaV-3. In a second treatment, spatial roguing was combined with insecticides. Vines eliminated in both spatial roguing treatments were replaced by clean vines derived from virus-tested stocks. The objective of this study was to reduce temporal virus incidence to less than 1% over two consecutive years and limit virus spread. In both spatial roguing treatments, virus incidence was reduced from 5% in 2016 to less than 1% in 2020-2021. Among vines in the insecticide-free, non-rogued control treatment, virus incidence increased from 5% to 16% from 2016 to 2021. Insecticides applied in 2016-2021 helped significantly reduce grape mealybug populations to near zero annually, while populations in the untreated control vines were 57 to 257-fold higher during the same period. However, insecticides contributed relatively little to limit the number of newly infected vines. Together, these findings highlight the salient contribution of roguing to an overall leafroll disease management response in a vineyard with low disease incidence and low grape mealybug abundance. To our knowledge, this is the first report on the effectiveness of spatial roguing at reducing the annual incidence of leafroll disease in a vineyard.

Pseudococcus maritimus (grape mealybug)

This datasheet on Pseudococcus maritimus covers Identity, Distribution, Hosts/Species Affected, Natural Enemies, Further Information.

First report of Pseudococcus viburni (Hemiptera: Pseudococcidae) in Colombia: Morphometric and molecular analysis, with notes on morphological variation in specimens from Brazil and Colombia

AbstractThe obscure mealybug Pseudococcus viburni (Signoret) (Hemiptera: Pseudococcidae) is recorded for the first time from Colombia based on specimens collected on Opuntia cylindrica (Lam.) DC., Mammillaria sp. (Cactaceae), Escallonia paniculata (Ruiz &amp; Pav.), Roem. &amp; Schult. (Escalloniaceae), Ficus carica L. (Moraceae), Coffea arabica L. (Rubiaceae), Citrus sp. (Rutaceae), Cestrum nocturnum L. and Solanum betaceum Cavanilles (Solanaceae). Multiple methods were used to identify P. viburni because it belongs to the “Pseudococcus maritimus” complex, a group composed of more than 60 species with high variation in morphological characteristics. The specimens were identified based on the morphology and morphometric analysis of third‐instar nymphs and adult females. This morphological identification was corroborated by data on geographical distribution, plant hosts and a molecular identification using two different loci, CO1 (mtDNA) and the 28S ribosomal gene (nuclear genome). An updated list of species of Pseudococcus Westwood recorded from Colombia and information on morphological variation found in the studied specimens from Brazil and Colombia are provided.

Control of citrus mealybug Planococcus citri (Risso) on three grapevines varieties and its effect on fruits quality

Grape mealybug consider the most universally important vineyard insect pest. Insecticides are the main strategy to grapevine insect control. The result showed that the recommended rate of Imidacloprid is succeeded in controlling of mealybug since its initial reduced of the infestation were 89.26, 84.21and 85.71 % for first season and 82.71, 82.94 and 83.56 % for second season for Flame seedless, Early sweet seedless and Sugraone seedless, respectively. Meanwhile, the total mean of reduction after 3,7, 14 and 30 days were 95.79, 64.83 and 72.82 % for first season and 85.20, 66.33 and 69.84 % for second season on Flame seedless, Early sweet seedless and Sugraone seedless, respectively. On the other hand, the total mean of reduction after 3,7, 14 and 30 days were 72.56, 80.40 and 82.50% for first season and 68.88, 76.13 and 75.56% for second season on Flame seedless, Early sweet seedless and Sugraone seedless, respectively. In addition, all of them are above 70% reduction. From these results, it should be suggested using some effective alternatives such as Palmito compound in controlling mealy bug incompatible program with chemical insecticides instead of conventional individuals' insecticides. The grapevine variety, Early sweet seedless showed the significant superiority in the quality traits. Under conditions of this investigation, the grapevine variety, Early sweet seedless was recorder the highest values for yield per vine, TSS and total sugar% in both seasons.

Exploring Grower-sourced Data to Understand Spatiotemporal Trends in the Occurrence of a Vector, Pseudococcus maritimus (Hemiptera: Pseudococcidae) and Improve Grapevine Leafroll Disease Management.

Grapevine leafroll disease is a significant concern in the wine grape industry, as it spreads rapidly and contributes to economically significant reductions in yield and grape quality. Our objective was to utilize 5 yr of grower-sourced data from Napa (California, USA) to improve local and regional disease management efforts. Specifically, we applied a spatially integrated multivariate clustering technique to improve understanding of spatiotemporal trends in Pseudococcus maritimus (Ehrhorn) male populations-the primary vector in the region. We also implemented generalized linear mixed models to evaluate the effects of two key practices, insecticide sprays and roguing, on disease incidence. Results show P. maritimus has a biannual flight pattern in the study area, with the first flight peaking in early May and the second between early August and early September. Clusters of P. maritimus flight data fall largely within the vineyard footprints of individual growers, but also showed clear neighborhood effects. We found that when disease incidence within a block is <1%, consistent monitoring and removal of diseased vines is required to contain within-block spread. As within-block disease incidence grows to 1-20%, both insecticide applications and roguing are effective practices to reduce spread. At incidence levels >20%, roguing is a critical practice. Our results emphasize the importance of individual management efforts, but also the value of programs that engage the wider neighboring community and highlight the power of community data collection to guide decision-making.

Grapevine Leafroll-associated Virus 3 Vectored by Pseudococcus maritimus at Low Population Levels

<i>Grapevine Leafroll-associated Virus 3</i> Vectored by <i>Pseudococcus maritimus</i> at Low Population Levels

The Efficacy of Two Sivanto Products on Grape Mealybug Infestations, 2020

The Efficacy of Two Sivanto Products on Grape Mealybug Infestations, 2020

Evaluation of RNA Interference for Control of the Grape Mealybug Pseudococcus maritimus (Hemiptera: Pseudococcidae).

Simple SummaryRNA interference (RNAi) is a defense mechanism that protects insects from viruses by targeting and degrading RNA. This feature has been exploited to reduce the expression of endogenous RNA for determining functions of various genes and for killing insect pests by targeting genes that are vital for insect survival. When dsRNA matching perfectly to the target RNA is administered, the RNAi machinery dices the dsRNA into ~21 bp fragments (known as siRNAs) and one strand of siRNA is employed by the RNAi machinery to target and degrade the target RNA. In this study we used a cocktail of dsRNAs targeting grape mealybug’s aquaporin and sucrase genes to kill the insect. Aquaporins and sucrases are important genes enabling these insects to maintain water relations indispensable for survival and digest complex sugars in the diet of plant sap-feeding insects, including mealybugs. In our experiments, administration of dsRNA caused a reduction in expression of the target genes and an increase in insect mortality. These results provide support for the application of RNAi to control the grape mealybug.The grape mealybug Pseudococcus maritimus (Ehrhorn, 1900) (Hemiptera: Pseudococcidae) is a significant pest of grapevines (Vitis spp.) and a vector of disease-causing grape viruses, linked to its feeding on phloem sap. The management of this pest is constrained by the lack of naturally occurring resistance traits in Vitis. Here, we obtained proof of concept that RNA interference (RNAi) using double-stranded RNA (dsRNA) molecules against essential genes for phloem sap feeding can depress insect survival. The genes of interest code for an aquaporin (AQP) and a sucrase (SUC) that are required for osmoregulation in related phloem sap-feeding hemipteran insects (aphids and whiteflies). In parallel, we investigated the grape mealybug genes coding non-specific nucleases (NUC), which reduce RNAi efficacy by degrading administered dsRNA. Homologs of AQP and SUC with experimentally validated function in aphids, together with NUC, were identified in the published transcriptome of the citrus mealybug Planococcus citri by phylogenetic analysis, and sequences of the candidate genes were obtained for Ps. maritimus by PCR with degenerate primers. Using this first sequence information for Ps. maritimus, dsRNA was prepared and administered to the insects via an artificial diet. The treatment comprising dsRNA against AQP, SUC and NUC significantly increased insect mortality over three days, relative to dsRNA-free controls. The dsRNA constructs for AQP and NUC were predicted, from sequence analysis to have some activity against other mealybugs, but none of the three dsRNA constructs have predicted activity against aphids. This study provides the basis to develop in planta RNAi strategies against Ps. maritimus and other mealybug pests of grapevines.

Gill's mealybug, Ferrisia gilli, can Transmit Grapevine Leafroll-associated Virus-3 after a 24-hour Acquisition Time

Grapevine leafroll disease (GLD) is a virus disease present in all grapevine-growing regions of the world. Mealybugs and scale insects have been reported as vectors of some grapevine leafroll-associated viruses belongs to the ampeloviruses (family Closteroviridae) in particular with grapevine leafroll-associated virus-1 (GLRaV-1) and GLRaV-3. Both grape (Pseudococcus maritimus) and Gill’s mealybugs are commonly present in Virginia vineyards, but we have limited information on acquisition and transmission of GLRaV-3 by Gill's mealybug (Ferrisia Gilli). We conducted acquisition and transmission assays in the greenhouse to examine the threshold for shorter acquisition time of GLRaV-3 with F. gilli. Approximately 67% and 58% rates of GLRaV-3 acquisition by F. gilli following 24 and 48 hours, respectively, of feeding period were documented. F. gilli first instars fed on a GLRaV-3-positive grapevine for 24 and 48 hours successfully transmitted GLRaV-3 to healthy grapevines after 24 hours of feeding/transmission time. The quick acquisition demonstrated in this study could be one of the factors that promoted the rapid expansion of GLRaV-3-infected vines in vineyards documented in previous studies.

Effectiveness of imidacloprid, spirotetramat, and flupyradifurone to prevent spread of GLRaV-3 by grape mealybug, Pseudococcus maritimus (Hemiptera: Pseudococcidae)

Pseudococcus maritimus status as an economic pest increased substantially after it was identified as a key vector of most grape vine leafroll-associated viruses (GLRaVs). Of these viruses, GLRaV-3 is the most economically destructive. Current control recommendations for slowing the spread of GLRaVs include one to two applications of insecticides to reduce vector populations. Systemic insecticides require the insect to feed before death or paralysis occurs. It was unknown if systemic insecticides could paralyze or kill P. maritimus quickly enough to reduce their ability to vector GLRaVs. Hence, we tested imidacloprid, spirotetramat, and flupyradifurone to see if these insecticides would have any effect on P. maritimus’ efficiency to vector GLRaV-3 on treated grapevines. We conclude that these systemic insecticides do not convey any additional protection to grapevines. However, these insecticides are still useful for reducing vector populations and indirectly reduce the potential spread of GLRaVs among vines in vineyards.

A Survey of Virginia Vineyards Revealed High Incidences of Grapevine Rupestris Stem Pitting-Associated Virus, Grapevine Red Blotch Virus, and Two Mealybug Species

We investigated the prevalence of viruses infecting grapevines in Virginia, identity of disease vectors, and potential factors affecting virus incidence. Tested viruses were grapevine leafroll-associated virus (GLRaV-1 and -4), grapevine fleck virus (GFkV), grapevine virus A (GVA), grapevine virus B (GVB), grapevine rupestris stem pitting-associated virus (GRSPaV), tomato ringspot virus (ToRSV), grapevine vein clearing virus (GVCV), grapevine red blotch virus (GRBV), and grapevine Pinot gris virus (GPGV). We documented wide distributions of GRSPaV (54%) and GRBV (24%) and common occurrences of grape (Pseudococcus maritimus) and Gill’s (Ferrisia gilli) mealybugs among vineyards. This is the first report of GLRaV-1, GLRaV-4, GVA, GVB, GRSPaV, and obscure mealybug (Pseudococcus viburni) in Virginia. We also documented significant association (P ≤ 0.05) of the presence of mealybugs and GVA and GVB. With younger vines, significantly lower incidences were found for viruses that were listed (i.e., tested for a certification) by the Foundation Planting Service’s and the National Clean Plant Network’s grape programs. On the other hand, there was a lack of the age effect on incidence of GRSPaV and GRBV, which were not listed until recently. These results suggest the importance of clean plant material and vector management for grapevine virus disease management in Virginia.

Sulfur Dioxide Fumigation for Postharvest Control of Mealybugs on Harvested Table Grapes.

Laboratory fumigations with sulfur dioxide (SO2) were conducted under ultralow oxygen (ULO) and normal atmosphere to determine their effects on mortality of grape mealybug, Pseudococcus maritimus (Ehrhorn), and vine mealybug, Planococcus ficus Signoret, and postharvest quality of table grapes. Three- and 4-d fumigation treatments with 100 ppm SO2 under 30 ppm ULO condition and normal atmosphere resulted in 100% mortality of eggs and nymphs/adults of vine mealybug. The 3- and 4-d SO2 fumigations under the ULO condition and the normal atmosphere were also effective against grape mealybug with egg mortalities of 85.8% and 98.8% and nymph/adult mortalities of 99.0% and 100%, respectively. There was no significant difference between SO2 fumigations under ULO and the normal atmosphere in insect mortality. One-day fumigation treatments with 400 and 500 ppm SO2 achieved 89.8% and 95.8% mortality of grape mealybug eggs, respectively, and achieved 100% mortality of grape mealybug nymphs and adults. None of the treatments used in this study adversely affected quality of the six table grape cultivars used in the studies. SO2 fumigation under either ULO or normal atmosphere is potentially a useful means for postharvest control of mealybugs on harvested table grapes.

Incidence of Grapevine Leafroll Disease: Effects of Grape Mealybug (Pseudococcus maritimus) Abundance and Pathogen Supply.

Studies of spatiotemporal dynamics are central to efforts to characterize the epidemiology of infectious disease, such as mechanism of pathogen spread and pathogen or vector sources in the landscape, and are critical to the development of effective disease management programs. To that end, we conducted a multi-year study of 20 vineyard blocks in coastal northern California to relate the dynamics of a mealybug vector, Pseudococcus maritimus (Ehrhorn) (Hemiptera: Pseudococcidae), to incidence of grapevine leafroll disease (GLD). In each vineyard block, a subset of vines were scored visually for relative mealybug abundance, disease was quantified by visual assessment, and virus presence was verified using standard laboratory molecular assays. GLD incidence was analyzed with a classification and regression tree, and with a hierarchical model that also captured variability among blocks and heterogeneity within blocks. Both analyses found strong interannual variability in incidence, with the hierarchical model also capturing substantial between- and within-block heterogeneity, but with significant contributions of vector abundance and pathogen supply (prior disease incidence) to the frequency of newly diseased vines. These results strengthen further the conclusion that mealybug vectors are causally related to pathogen spread in this system and are therefore an important target for management. Moreover, they are consistent with relatively efficient secondary spread of the pathogen, suggesting an important role for the removal of diseased vines as a tool to mitigate further damage.

Pumpkin as an Alternate Host Plant for Laboratory Colonies of Grape Mealybug.

The grape mealybug, Pseudococcus maritimus (Ehrhorn; Hemiptera: Pseudococcidae), is the primary vector of Grapevine Leafroll associated Viruses (GLRaVs) in Washington State vineyards. Rearing laboratory colonies of grape mealybug has proven difficult. Several host plants were tested to determine their suitability for use as an alternate host plants for laboratory colonies of grape mealybug. Of the plants tested, colonies of grape mealybug were successful on pumpkin (Cucurbita pepo cv 'Connecticut field') leaves and vines. Mealybugs were able to develop from the crawler stage, through developmental instars, and adults were able to reproduce viable offspring. To date this is the only successful study to raise grape mealybugs on a cucurbit. Pumpkin appears to be a viable alternate host plant for laboratory colonies of the grape mealybug.

Epidemiology and Genetic Diversity of Grapevine Leafroll-Associated Viruses in British Columbia.

Grapevine leafroll disease (GLD) is a complex associated with one or more virus species belonging to the family Closteroviridae. The majority of viruses in this complex are vectored by one or more species of mealybugs (Pseudococcidae) and/or scale insects (Coccidae). Grape-growing regions of British Columbia (BC), including Okanagan, Similkameen, and Fraser valleys and Kamloops (BC central interior), Vancouver, and Gulf islands, were surveyed during the 2014 and 2015 growing seasons for the presence of four major grapevine leafroll-associated viruses, including Grapevine leafroll-associated virus 1 (GLRaV-1), GLRaV-2, GLRaV-3, and GLRaV-4. In total, 3,056 composite five-vine samples were collected from 153 Vitis vinifera and three interspecific hybrid vineyard blocks. The results showed GLRaV-3 to be the most widespread, occurring in 16.7% of the composite samples, followed by GLRaV-4 (3.9%), GLRaV-1 (3.8%), and GLRaV-2 (3.0%). Mixed infections of two or more GLRaVs were found in 4.1% of the total samples. The relative incidence of GLRaVs differed among regions and vineyard blocks of a different age. Characterization of partial CO1 region from a total of 241 insect specimens revealed the presence of Pseudococcus maritimus, Parthenolecanium corni, and other Pulvinaria sp. in BC vineyards. Spatial patterns of GLRaV-3 infected grapevines in three vineyard blocks from three different regions in the Okanagan Valley showed variable degrees of increase in disease spread ranging from 0 to 19.4% over three growing seasons. Regional differences in the relative incidence and spread of GLD underline the need for region-based management programs for BC vineyards.

First Report of Little cherry virus 1 affecting European Plum (Prunus domestica) in Belgium

Little Cherry Disease (LChD), one of the major viral diseases of cherry worldwide, can be caused by two viruses (Little cherry virus 1 and 2), both Closteroviridae members. LChD has an important impact on both yield and fruit quality in commercial sweet and sour cherry (Prunus avium L. and Prunus cerasus L.) (Ruiz-Garcia et al., 2016). LChV-1 (genus Velarivirus) is known to be graft-transmissible and is spread via infected propagated plant material, but no vector has been identified. For LChV-2 (genus Ampelovirus) at least two species of mealybugs (Hemiptera, Pseudococcidae) are known to transmit the virus, namely the apple mealybug (Phenacoccus aceris Signoret) and grape mealybug (Pseudococcus maritimus Ehrhorn). During two growing seasons (2013-15), intensive surveys were conducted in Belgium to monitor the incidence of LChD in sweet and sour cherries and in ornamental Prunus spp., revealing widespread occurrence of both LChV-1 and 2 (De Jonghe et al. 2016). In the close vicinity of a sweet cherry (Prun...

Accumulation of amino acids and phenolic compounds in biochemical plant responses to feeding of two different herbivorous arthropod pests

The study aimed at comparing the changes in the content of free amino acids, phenolic compounds and the activity of PAL and TAL caused by two piercing-sucking arthropods: the grape mealybug (Pseudococcus maritimus Ehrh.) and the two-spotted spider mite (Tetranychus urticae Koch) in the leaves of orchid and strawberry, respectively. The obtained results show that the amino acid content and the ratio of amino acids to phenolic compounds increased in both plant species infested by the mealybug and the mite. However, such response was weakly dependent on changes in activity of the analysed enzymes. The pest feeding affected accumulation of the phenolic compounds, since the induction of the PAL activity in mealybug-infested orchid leaves during the first 5 h of the experiment preceded the increase in phenolic compounds during the first week of insect feeding. Instead, the increased activity of TAL was accompanied by elevated levels of phenolic compounds in the leaves of strawberry infested by mites. Mechanisms of biochemical plant responses induced by infestation of the studied herbivorous arthropods are discussed.