D. Thomas Lowery

Agriculture & Agri-Food Canada, Summerland, BC

The ability of an insect to vector a plant virus has been traditionally determined through controlled greenhouse transmission experiments that are notoriously resource and time-consuming and of unreliable outcome. Therefore, before committing to these protracted experiments, it is important that researchers identify biologically viable candidate ve...

BACKGROUND Laboratory bioassays using treated leaf disks of peach were conducted to determine the efficacy of nine insecticides against the green peach aphid (GPA), Myzus persicae (Sulzer). The effects of these insecticides on aphid feeding behaviors and rates of transmission of Turnip mosaic virus (TuMV) to potted rutabaga plants were also determi...

Although sold commercially as myco-insecticides, naturally occurring soil borne entomopathogenic fungi (EPF) pose a unique opportunity for regulating soil-dwelling insect herbivore populations via conservation biological control. Plant identity has a significant effect on soil borne fungi, which may includee EPF. We asked whether the choice of cove...

Spotted-wing drosophila, Drosophila suzukii , (Matsumura) (Diptera: Drosophilidae), has become a serious pest of soft fruit in the Okanagan Valley of British Columbia, Canada since its detection in 2009. The study was conducted to determine the distribution of D . suzukii and damage levels in grapes. Apple cider vinegar-baited traps placed in table...

In perennial plants, root metabolic activity decreases as absorptive roots age and eventually senesce. How this change in activity influences fungi inhabiting those roots is not well known. Particularly for arbuscular mycorrhizal (AM) fungi that rely exclusively on plant-derived carbon, these changes may exert significant pressure on fungi, leading...

The original version of this article unfortunately contained an error in Fig. 1. The y-axis labels for Fig. 1b and d are switched. The correct figures are shown here.

Although plants are known to have a strong influence on soil biota, the effect of groundcover vegetation in perennial cropping systems on soil fungi has been little explored. We surveyed extensively managed vineyards to determine how plant community functional characteristics, soil factors, and irrigation management related to the abundance of two...

AimsThe objective of this study was to determine if vineyard groundcover management can mitigate negative plant-soil feedback caused by soil borne pathogens through changes in root fungal communities. Methods Whole-soil inoculum was collected from a field trial of groundcover identity (exotic grasses, exotic grasses plus legumes, native grasses, an...

Spotted wing drosophila, Drosophila suzukii , utilizes intact ripe fruits for oviposition and larval development. Sweet cherry (Prunus avium) and D. suzukii share a saprophytic microbial community, or microbiome, that colonizes the interior and exterior of the fruit, which bene fits the nutrition and development of the flies. Some of the microbes,...

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 an...

In 2000, the Dideron (D) strain of Plum pox virus (PPV) was detected in commercial peach and nectarine orchards in the Niagara region of Ontario where most of Canada’s stone fruit crops are produced. As part of a disease management research program, peach (Prunus persica L. Batsch) trees in a commercial orchard at Niagara-on-the-Lake were assayed f...

Grapevine red blotch virus (GRBV) is a recently identified virus reported mainly from several grape-growing regions in the USA. To date, no information about the occurrence of GRBV is available in British Columbia (BC). Accordingly, a large-scale survey was conducted across all grape-growing regions of BC to determine the incidence and distribution...

A method was developed for use in a subsequent study to evaluate changes in seasonal susceptibility of orchard peach trees to plum pox virus (PPV) infection by aphids. To understand this, detached healthy leaves would need to be collected from peach trees in the field at different times over the growing season and evaluated for susceptibility to ap...

The residual activity of horticultural mineral oil (HMO) on the ability of green peach aphids, Myzus persicae (Sulzer), (GPA) to transmit Plum pox virus (PPV) to peach was measured by infection rates of detached leaves from plants sprayed with either HMO or water as a control that were inoculated using transfer of 25 viruliferous aphids per leaf at...

Utilization of timed virus acquisition access probes in studies of plum pox virus (PPV) transmission by aphids demonstrated that endemic species transmitted the virus readily from plum, Prunus domestica (L.) Batsch; peach, P. persica (L.); or dwarf flowering almond, P. glandulosa Thunberg., to peach seedlings. The green peach aphid, Myzus persicae...

A method was developed to evaluate susceptibility of peach leaves to Plum pox virus (PPV) infection by aphids. We examined whether virus multiplication could be detected in aphid inoculated detached leaves and if transmission efficiency of PPV by green peach aphids to detached leaves was comparable with that of peach seedlings. Results demonstrated...

Leafhoppers (Hemiptera: Cicadellidae) are pests of many temperate crops, including grapevines (Vitis species). Uncontrolled populations can induce direct and indirect damage to crops due to feeding that results in significant yield losses and increased mortality in infected vineyards due to virus, bacteria, or phytoplasmas vectored by leafhoppers....

Climbing cutworms in the genus Abagrotis are economically important pests of grapes in the Okanagan Valley of British Columbia (BC). Grapes are recently introduced into many areas of the region, and the association between crop and pest is new and still evolving. This has led to limited information being available on pest management strategies, inc...

The growing season for many pests is during the summer where temperatures are often high; however, not all pests conform to this pattern. Abagrotis orbis is a climbing cutworm pest of vineyards in the Okanagan Valley. Eggs are laid and hatch in the fall and larvae overwinter as early instars. In the spring, the larvae begin to climb the grape vine...

Thirteen plant species were tested for their suitability as hosts for Abagrotis orbis (Grote), a climbing cutworm pest of grapevines in British Columbia. Choice tests were also conducted to investigate larval feeding preferences for the Brassicaceae species joi choi, Brassica rapa variety. Chinensis L., spring draba; Draba verna L.; and shepherd's...

Les larves d'Abagrotis orbis (Grote) (Lepidoptera : Noctuidae) sont des chenilles grimpantes qui peuvent endommager les vignes, Vitis vinifera L. (Vitaceae), au début du printemps lorsqu'elles consomment les bourgeons. Un attractant sexuel serait probablement utile pour la détection de cet insecte dans les vignes à échelle commerciale. L'acétate de...

Dix-huit espèces de vers-gris ont été récoltées en train de s'alimenter la nuit sur la vigne, Vitis sp. L. (Vitaceae), dans le centre-sud de la Colombie-Britannique en avril et mai de 2004 à 2008. Dix espèces appartiennent aux genres Abagrotis Smith ou Euxoa Hübner; Abagrotis orbis (Grote), A. nefascia (Smith) et A. reedi Buckett représentent plus...

A disease affecting cultivated highbush blueberry (Vaccinium corymbosum) was first reported in the Fraser valley of British Columbia in 2000. Symptoms were similar to those of the disease caused by the Blueberry scorch virus (BlScV), and the diagnosis was supported by an enzyme-linked immunosorbent assay (ELISA), using a polyclonal antibody. Two Bl...

Water spinach, a specialty vegetable and a member of the sweet potato family, is cultivated for Asian markets in California (United States) and Ontario (Canada). Foliar diseases of this vegetable observed in commercial greenhouses of Ontario in 1993 and 1994, as well as in greenhouses of California in 1998, were attributed respectively to Phyllosti...

Green apple aphid, Aphis pomi De Geer, and Aphis spiraecola Patch (both Hemiptera: Aphididae), are sympatric aphid species that are pests of apples (Malus spp.) and other crops. A. spiraecola has been shown to be significantly more tolerant to several insecticides compared with A. pomi. To establish the mechanisms contributing to this difference in...

A survey of the incidence and severity of diseases, insects, nematodes, and abiotic problems affecting oriental cruciferous vegetables was conducted in southern Ontario within a 120 km radius of Toronto during repeated visits to growers' fields and greenhouses in 1993 and 1994. This is the first such survey conducted in the principal area of produc...

Climbing cutworms (Lepidoptera: Noctuidae) are serious pests of grapes in the southern interior of British Columbia. Abagrotis orbis is the most common of the 18 species collected from grapevines in the Okanagan Valley. Damage assessments suggested that the occurrence of winter annual mustards (Brassicaceae) in the vine rows decreased the number of...

Phytoplasmas are bacterial plant pathogens consisting of more than 50 phylogenetic groups that cause devastating diseases in various crops worldwide. They are obligate parasites restricted to the phloem tissue of the host plant and are transmitted from plant to plant mostly by leafhoppers (Hemiptera: Cicadellidae). They reproduce within the tissues...

Morphometric techniques, DNA mitochondrial cytochrome c oxidase subunit 1 gene (COI) barcoding, and microsatellite flanking region sequences were used to assess the reliability of suggested morphological characters in distinguishing the green apple aphid (Aphis pomi De Geer) from the spirea aphid (Aphis spiraecola Patch), and to assess variation wi...

Can. J. Plant Sci. 89:677 -692. British Columbia has climatic conditions suitable for the production of a wide range of high-value fruit crops, and has the highest rate of increase of organic production in Canada. This review assesses the current status of organic fruit production using a case study of the three most valuable fruit crops currently...

In North America, elm yellows, aster yellows (AY), and X-disease phytoplasmas have been detected in American grapevines (1), and recently, Bois noir was detected in Canadian vineyards from British Columbia (BC) and Ontario (ON) (2). Typical symptoms of grapevine yellows (GY) include leaf rolling and chlorosis, uneven or total lack of lignification...

Transmission of potato vims Y to sweet pepper by the green peach aphid, Myzus persicae (Sulzer), was inhibited by foliar applications of 1.0% or 2.0% neem seed oil to infected source plants or to uninfected recipient plants. Neem seed oil interfered with virus acquisition and inoculation in a manner comparable to that of a commercial horticultural...

Every 2 weeks during the 2001–2003 growing seasons, 10–20 highbush blueberry, Vaccinium corymbosum ‘Berkeley’ (Ericaceae), trap plants were placed in two commercial fields in which the proportion of plants infected with Blueberry scorch virus (BIScV, all strain BC-2) ranged from 0.14 to 0.54. In 2003, Nicotiana occidentalis (Solanaceae) trap plants...

Experiments were conducted to determine potential interactions between kaolin particle film and three insecticides on neonate larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). Kaolin did not significantly affect the toxicity of azinphosmethyl or indoxacarb to an insecticide-susceptible population w...

Anagrus spp. are important natural regulators of leafhoppers infesting grapes, tree fruits, and other crops in south central British Columbia (BC). Predominantly four species of these egg parasitoids, A. atomus (L.), A. avalae Soyka, A. daanei Triapitsyn, and A. erythroneurae Triapitzyn and Chiappini, were reared from dormant host plants and from s...

Surveys conducted in the South Okanagan Valley, British Columbia, revealed that a new leafhopper pest of grapes, the western grape leafhopper (WGL), Erythroneura elegan- tula Osborn, was widespread and often abundant in vineyards on the east side of the valley from just north of Penticton south to the United States border. Infestations oc- curred o...

Laboratory bioassays using leaf disks of apple dipped in test solutions of insecticides demonstrated that the apple aphid, Aphis pomi De Geer, and the spirea aphid, Aphis spiraecola Patch, differed significantly in susceptibility to a number of insecticides registered for control of aphids on apple (Malus spp.). Compared with A. pomi, A. spiraecola...

Susceptibilities to the neonicotinyl insecticide imidacloprid were determined for clones of apple aphid, Aphis pomi De Geer, and spirea aphid, Aphis spiraecola Patch, collected from conventional and organic apple orchards and from crab apple and wild apple in Washington state and British Columbia over a period of 6 yr. For aphids collected during 1...

Blueberry scorch virus(BlScV) is a carlavirus that causes a serious disease of blueberries (Vaccinium corymbosum L.) in North America (2). In aphid-transmission studies of BlScV using blueberry as host and test species, we found the rate of transmission to be low, and a lengthy incubation period was required before BlScV could be detected. For sequ...

Tebufenozide, an insect growth regulator that acts as an ecdysone agonist, was applied at recommended label rate to apple trees in August 1997 and May 1998. Foliar residues were determined by high-performance liquid chromatography from samples collected 2, 24, 48 and 96 h post-spray, and at weekly intervals thereafter for 9 weeks in 1997 and 11 wee...

The susceptibility of a clone of green apple aphid, Aphis pomi (De Geer), to the neonicotinyl insecticide imidacloprid was determined by direct and indirect bioassay techniques. Aphid numbers were assessed on potted apple seedlings treated with various concentrations of imidacloprid, adults were dipped in test solutions as per the Food and Agricult...

Adult and sixth instar obliquebanded leafroller, Choristoneura rosaceana (Harris), exposed previously as fifth instar larvae to sub-lethal concentrations of neem, Azadirachta indica A. Juss., seed oil contained in artificial diet were more susceptible to topically applied pyrethroid, carbamate and organophosphate insecticides than C. rosaceana rear...

Populations of obliquebanded leafroller, Choristoneura rosaceana Harris, and three-lined leafroller, Pandemis limitata Robinson, were obtained from seven sites in the Okanagan and Similkameen Valleys of British Columbia and assayed for their responses to three insecticides using a leaf disk bioassay. Lethal concentration ratios (LCRs) were calculat...

Populations of fruittree leafroller, Archips argyrospila (Walker), and European leafroller, Archips rosana L., were obtained from eight sites in the Okanagan Valley, British Columbia, and assayed for their responses to five insecticides using a leaf-disk bioassay and neonate larvae. Lethal concentration ratios (LCR values) were calculated for all p...

Populations of obliquebanded leafroller, Choristoneura rosaceana (Harris), were collected from organic and conventionally managed orchards located in the Okanagan and Similkameen Valleys of British Columbia Neonate F1 progeny were assayed for resistance to azinphosmethyl, tebufenozide, methoxyfenozide, and indoxacarb using a leaf disk bioassay. Sig...

Larvae of the obliquebanded leafroller,Choristoneura rosaceanaL. (Lepidoptera: Tortricidae), were fed artificial diet containing various doses of neem oil. After 6 days of feeding, larvae (6th instar) were assayed for activities of midgut esterases and glutathione transferases. Midgut protein contents were also determined, as were larval fresh and...

Exposure of adult green peach aphid, Myzus persicae (Sulzer), and lettuce aphid, Nasonovia ribisnigri (Mosley), for 3 d to a 1.0% solution of neem seed oil applied to leaf disks reduced the number of live offspring by 82 and 66%, respectively, compared with controls. Fourth-instar N. ribisnigri were more sensitive than adults to the sterilizing act...

Neem, Azadirachta indica A. Juss. (Meliaceae), seed oil (NSO) added to meridic diet at concentrations as low as 0.016% reduced pupation and prevented adult eclosion of obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). At a rate of 0.0016%, NSO reduced the fitness of C. rosaceana, resulting in longer developmenta...

Neem [Azadirachta indica (A. Juss.)] seed oil (NSO) applied in three concentrations, 0.5%, 1% and 2%, to potted plants infested with green peach aphid,Myzus persicae (Sulzer), totally prevented adult eclosion of larval coccinellids,Coccinella undecimpunctata L., and reduced adult eclosion of syrphids,Eupeodes fumipennis (Thompson), to 11%, 7% and 0...

Neem,Azadirachta indica (A. Juss.), seed oil (NSO) applied to leaf discs at a concentration of 1.0% resulted in 94% to 100% mortality of second instar nymphs of currant-lettuce aphid,Nasonovia ribis-nigri (Mosley), and green peach aphid,Myzus persicae (Sulzer), after nine days. The equivalent amount of pure azadirachtin (AZA) (≈40 ppm), the princip...

Leaf disk choice test bioassays demonstrated that formulated neem seed oil (NSO) was equally deterrent to first- and third-instar nymphs and adult strawberry aphids,Chaetosiphon fragaefolii (Cockerell). Concentrations of NSO resulting in 50% feeding deterrence were approximately 1.1% for this species. The rapid disruption of aphid feeding (<1 hr) w...

Laboratory and field trials with formulated neem seed oil (NSO) and neem seed extract (NSE) demonstrated that these materials are effective aphicides. NSO sprays to intact plants in the laboratory resulted in significant reductions in numbers of green peach aphids, Myzus persicae (Sulzer), on peppers and rutabagas; currant-lettuce aphids, Nasonovia...

Leaf disk choice test bioassays demonstrated that formulated neem seed oil (NSO) was equally deterrent to first- and third-instar nymphs and adult strawberry aphids,Chaetosiphon fragaefolii (Cockerell). Concentrations of NSO resulting in 50% feeding deterrence were approximately 1.1% for this species. The rapid disruption of aphid feeding (C. fraga...

In laboratory studies of the transmission of turnip mosaic virus (TuMV) by the green peach aphid, Myzus persicae (Sulzer), applications of 1% mineral oil (Sunoco Sunspray 6 E) or combinations of oil and cypermethrin (15.2 ppm) to rutabaga foliage, Brassica napobrassicae (L.), reduced infection >80%. In field evaluations, sprays of 3% oil were more...

From 14 to 26% of apterous green peach aphids, Myzus persicae (Sulzer), placed on leaflets of potato treated with deltamethrin, fenvalerate, pirimicarb, and methamidophos dispersed to untreated leaflets, compared with only 2-6% of aphids placed on control or dimethoate-treated leaflets. Apterous buckthorn aphids, Aphis nasturtii (Kaltenbach), dispe...

Apterous green peach aphids (GPA), Myzus persicae (Sulzer), collected from plots of potatoes treated with azinphosmethyl (AM) and reared in the laboratory on leaf disks of potato, produced ca. 28% more offspring than GPA from untreated plots. The rate at which offspring were produced for the subsequent two generations did not differ for either grou...

Apterous green peach aphids, Myzus persicae (Sulzer), collected from potato plots treated with azinphosmethyl, when caged on either treated or nontreated foliage, produced 20-30% more offspring than aphids that were not exposed to the insecticide. The increase in fecundity resulted directly from the action of the insecticide on the reproduction of...