Justin M Renkema

• PhD
• Researcher at Agriculture and Agri-Food Canada

Cyclamen mite (Phytonemus pallidus) causes injury to new growth of strawberry plants and is difficult to control because it is protected by folded leaves and plant crowns. Since cyclamen mite is easily transferred from strawberry nurseries to fruiting fields, dipping transplants in biopesticides may reduce initial populations. However, cyclamen mit...

Cyclamen mite is a pest of strawberry that is difficult to control due to its small size and preference for inhabiting concealed spaces in new plant growth. Steam treatment of transplants effectively reduces some strawberry pathogens and may be a valuable tool against cyclamen mite. Strawberry transplants (“Jewel” and “Annapolis”) that were artific...

Drosophila suzukii, spotted-wing drosophila, is an invasive pest in Canada that can lay its eggs into fresh fruits, unlike many of its close relatives. Larval feeding inside fruit causes the fruit to spoil prematurely. Some parasitoids have been found attacking D. suzukii larvae and pupae in regions that D. suzukii has invaded, including Asobara cf...

Background The univoltine leaf beetle Psylliodes attenuata (Koch, 1803) is a pest of Cannabis and Humulus (Cannabaceae) and native to the Palaearctic Region, known from eastern Asia to western Europe. New information First North American records are presented for P. attenuata from Canada: Ontario and Québec. Adult beetle feeding damage to hops Hum...

Cyclamen mite ( Phytonemus pallidus ) causes injury to new growth of strawberry plants and is difficult to control because it is protected by folded leaves and plant crowns. Since cyclamen mite is easily transferred from strawberry nurseries to fruiting fields, dipping transplants in biopesticides may reduce initial populations. However, cyclamen m...

In recent years, there has been an increase in the adventive establishment and spread of parasitoid wasps outside of their native range. However, lack of taxonomic tools can hinder the efficient screening of field-collected samples to document the establishment and range expansion of parasitoids on continent-wide geographic scales. Here we report t...

Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) is an invasive, early-season pest of strawberry in Florida, causing feeding injury to young foliage that results in stunted plant growth and yield loss. Spinetoram, an effective insecticide for thrips pests with up to 3 applications per season permitted in strawberry, is often applied repeatedly...

Spotted-wing drosophila, Drosophila suzukii, is a global pest of soft fruits that is capable of reproducing on a wide range of cultivated and wild plant species. In Canada, D. suzukii was first reported in British Columbia in 2009 and is now widespread across the country. Understanding the genetic structure of D. suzukii populations could be import...

Cyclamen mite is a nearly global pest of strawberry, inhabiting concealed spaces within folded leaves and flower buds emerging from plant crowns. It feeds on new plant tissue causing leaf discoloration and deformation, stunted plants, fruit bronzing and cracking, and yield losses at high population levels. Because ultraviolet-C (UV-C) irradiation i...

Since it inhabits young leaves and buds of strawberry (Fragaria × ananassa Duchesne) crowns, cyclamen mite (Phytonemus pallidus Banks) is a difficult pest to control with biological or chemical means once it is present in a field. Controlled atmosphere temperature treatment (CATT) is a successful technique that has been commercially used in the Net...

Cyclamen mite, Phytonemus pallidus (Banks) (Acari: Tarsonemidae), is a pest of strawberry, Fragaria × ananassa Duchesne (Rosaceae), that injures new growth, resulting in damage to leaves and fruit. The primary source of cyclamen mite in strawberry is infested planting material, and damaged plants tend to occur in small, isolated patches in perennia...

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a ubiquitous global pest of several fruit crops. Trapped adult numbers are used to monitor populations and make control decisions, but differentiating D. suzukii from other trapped Drosophila spp. is laborious. We developed a real-time PCR method for specific detection and semi-quantificati...

Popillia japonica Newman (Japanese beetle) is an invasive, polyphagous pest in North America, as adults feed on plant foliage and larvae on roots. Management in crops relies on foliar and soil applications of insecticides, but entomopathogenic nematodes (EPN) are effective biocontrol agents. In highbush blueberry, mulches (composts, woodshavings, s...

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) also known as spotted-wing drosophila (SWD), is a pest native to Southeast Asia. In the last few decades, the pest has expanded its range to affect all major European and American fruit production regions. SWD is a highly adaptive insect that is able to disperse, survive, and flourish under a...

Diaprepes abbreviatus L. (Coleoptera: Curculionidae) is an occasional root pest of plasticulture strawberry in central Florida, USA. There are few chemical insecticide options for larval D. abbreviatus in strawberry. Therefore, we tested soil-applied aqueous Steinernema riobrave Cabanillas, Raulston and Poinar (Rhabditida: Steinernematidae), which...

Scirtothrips dorsalis Hood is an invasive and foliar pest of Florida blueberry that reduces plant growth by feeding on new leaf growth. A sampling plan is needed to make informed control decisions for S. dorsalis in blueberry. Fourteen blueberry fields in central Florida were surveyed in 2017 and 2018 after summer pruning to determine the spatial a...

Frankliniella flower thrips are pests of numerous fruit and vegetable crops as they feed and reproduce in the flowers and fruits. The invasive Frankliniella occidentalis (Pergande) from the Southwestern United States, an economic pest in Florida since 2005, and the native Frankliniella bispinosa Morgan are both found in Florida strawberries. The ob...

Scirtothrips dorsalis Hood infest strawberry (Fragaria x ananassa Duchesne, Rosaceae) fields from nearby crop fields and surrounding vegetation and cause injury to plants by feeding on young leaf tissues. Greenhouse and field studies were conducted to determine the short-range movement of S. dorsalis to assess the risk of an early S. dorsalis popul...

The strawberry seed bug, Neopamera bilobata (Say), is an emerging pest of organic and conventional strawberries in Florida. There is limited information on this Rhyparochromidae species. Thus, the type of injury caused is not clearly documented and management recommendations are lacking. In this study, we evaluated the effect of strawberry cultivar...

Drosophila suzukii is a global pest of ripening fruit, and its immature stages developing in fallen fruit are susceptible to entomopathogenic nematodes. In this study, Steinernema riobrave, was as effective as other tested nematodes, killing 80–100% of D. suzukii larvae in sand at 24 and 28°C. Combining Heterorhabditis bacteriophora with S. riobrav...

Generalist invertebrate predators contribute to pest management in agriculture, providing an important ecosystem service, particularly in organically managed fields. DNA-based methods to study food webs and feeding interactions in unrestricted field conditions have transformed dietary analysis of generalist predators. In this study, we used MiSeq n...

Drosophila suzukii (Matsumura) is a major global pest of soft fruit crops. Based on field observations, we tested in the laboratory whether sweet alyssum (Lobularia maritima (L.)) flower volatiles and their major constituent compounds, acetophenone and benzaldehyde, repelled D. suzukii flies. Volatiles from cut flowers and acetophenone reduced numb...

Spotted-wing drosophila ( Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)) is a pest of tender fruit and berry crops because female flies oviposit in ripening fruit. Frequent insecticide applications are needed for control during fruit ripening, with few noninsecticide options available. The effect of interplanting peppermint ( Mentha × pip...

The twospotted spider mite (Tetranychus urticae) is a serious pest of strawberries. The objectives of this study were to determine incidence and severity of twospotted spider mite infestations on transplants and the potential for steam to eliminate them. Mites occurred on transplants of Florida cultivars from each of eight North American nurseries...

Scirtothrips dorsalis Hood is a pest of strawberry in Florida, causing foliar and fruit damage to young plants. A field-plot study was conducted in 2015–16 to compare the efficacy of flupyradifurone (SivantoTM 200 SL, 1035 and 2070 ml ha⁻¹) to spinetoram (Radiant SC®, 740 ml ha⁻¹). Flupyradifurone reduced S. dorsalis by 68-83% on leaves and unripe...

Blueberry maggot ( Rhagoletis mendax Curran (Diptera: Tephritidae)) is a pest of blueberries ( Vaccinium Linnaeus (Ericaceae)). Tephritid flies, including Rhagoletis Loew species, are susceptible to entomopathogenic fungi, but mortality levels depend on life stage targeted. We tested Metarhizium anisopliae (Metschnikoff) (Clavicipitaceae) strain S5...

Flower thrips (primarily Frankliniella spp.) can be significant strawberry pests, and recently in Florida, Scirtothrips dorsalis Hood has become an established, early-season, foliar pest. Insecticides that were used for flower thrips management are now also used for S. dorsalis, resulting in the need to evaluate newer insecticides in order to diver...

Echinothrips americanus Morgan is an important greenhouse foliage pest of vegetable and ornamental plants (Figure 1). This pest is polyphagous, reported from 48 plant families worldwide. The preferred hosts of Echinothrips americanus belong to the Araceae and Balsaminaceae plant families (CABI/EPPO 2014). This pest is native to eastern North Americ...

Extension article on greenhouse thrips pest

Drosophila suzukii is an invasive pest and economic threat to berry crops in Europe and the Americas. Current methods of control of this pest rely primarily on frequent applications of insecticides; therefore, there is a need for alternative control methods to reduce insecticide reliance. In this study, we evaluated the biological control potential...

This 21-page fact sheet is chapter 16 of the 2018 Vegetable Production Handbook. Written by Vance M. Whitaker, Nathan S. Boyd, Natalia A. Peres, Johan Desaeger, Joseph W. Noling, and Justin Renkema, and published by the Horticultural Sciences Department, 2018. HS736/CV134: Chapter 16. Strawberry Production (ufl.edu)

The aim of this 9-page document is to inform Florida strawberry producers and Extension personnel on the compatibility of registered miticides and insecticides with commercially available predatory mites used as biological controls. Written by Braden Evans, Karol Krey, and Justin Renkema and published by the UF/IFAS Entomology and Nematology Depart...

The false chinch bug, Nysius raphanus Howard, is a small, greyish, native North American herbivorous seed bug. It is recognized as the most serious pest among members of the genus Nysius, but reports of heavy infestations and serious crop damage are uncommon. Includes: Introduction - Distribution - Description and Life Cycle - Host Plants - Damage...

The striped cucumber beetle, Acalymma vittatum F. (Figure 1) is a serious agricultural pest of plants in the family Cucurbitaceae in eastern North America. Crops affected by larval and adult feeding include cucumber, Cucumis sativus L., cantaloupe, Cucumis melo L., pumpkin, Cucurbita pepo L., and other Cucurbita spp. (Dill and Kirby 2016). The stri...

The pale damsel bug, Nabis capsiformis (Germar), one of the most widespread Nabis species, is a generalist predator that can be found in open areas, including coastal habitats (Lattin 1989). It is commonly reported throughout the southeastern United States, in a variety of ecosystems, it is particularly common in field and row crop agroecosystems....

http://entnemdept.ufl.edu/creatures/VEG/BEAN/striped_cucumber_beetle.html common name: striped cucumber beetle scientific name: Acalymma vittatum F. (Insecta: Coleoptera: Chrysomelidae)

common name: false chinch bug scientific name: Nysius raphanus Howard (Insecta: Hemiptera: Lygaeidae)

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposits in ripening fruit, larvae render crops unmarketable, and significant economic losses can occur. Biological control research has focused on individual natural enemy species against immature D. suzukii. Here we combine two predators and an entomopathogenic nematode, expecting species c...

Background: Drosophila suzukii (Matsumura) is a major fruit pest in temperate regions worldwide, but in sub-tropical Florida, winter-grown strawberries have not been severely affected. Zaprionus indianus Gupta is another invasive drosophilid species and a pest of some tropical fruits. To improve monitoring, trapping systems for D. suzukii and Z. i...

Flower thrips (mainly Frankliniella spp.) (Thysanoptera: Thripidae) are common in Florida strawberries, causing bronzed fruit and reduced yields. As control relies on just a few insecticides, there is a need to evaluate novel management options and insecticides. The entomopathogenic nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernemati...

During the past 2 strawberry-growing seasons in Florida (Oct to Mar in 2015-2016 and in 2016-2017), broad mite, Polyphagotarsonemus latus (Banks), was found on the upper sides of young strawberry leaves and on fruit. Damage symptoms were similar to those reported from other affected crops: Leaf curl, browning and yellowing of leaf tissue and bronzi...

Chilli thrips, Scirtothrips dorsalis Hood, is a pest of berry crops in Florida, damaging strawberry transplants in the fall and blueberry flushes in late spring and summer. To begin developing a sampling plan for making control decisions, we characterized the spatial distribution of S. dorsalis in strawberry and blueberry fields. Eight strawberry f...

Drosophila suzukii (Matsumura) is a recent invasive pest of soft fruits in North and South America and Europe. Control relies on frequent applications of synthetic insecticides. Additional tactics are needed for development of an effective integrated pest management program. Study objectives were to evaluate the repellency and oviposition deterrent...

Short-range dispersal and rate of spread of damage of chilli thrips among strawberry plants.

Drosophila suzukii Matsumura is an economically important pest of soft and small fruit crops. Unlike other drosophilid flies, D. suzukii is capable of infesting ripe and partially ripe fruit, which poses a significant pest management challenge, as there is no tolerance for infested or damaged fruit in the marketplace. As a result, producers in many...

Spotted wing drosophila (Drosophila suzukii) is a relatively new invasive pest of small fruits in many temperate regions worldwide. Adult females possess large, serrated ovipositors that allow penetration into partially ripe and ripe fruit. Larvae render fruit unmarketable and cause economic losses. Monitoring and management tactics have focused on...

An update on current research on spotted wing drosophila, ’Drosophila suzukii’ in Florida

Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive pest that was introduced into Florida in 2009. Spotted wing drosophila survives well under Florida’s climatic conditions. In 2014, losses to berry crops in Florida were estimated at $35 million. Losses are due to maggot-infested fruit, which is unaccept...

The lesser mealworm, Alphitobius diaperinus (Panzer), damages poultry barns, vectors poultry diseases, inhibits poultry weight gain, and consumes poultry feed. Management of the pest is a challenge because of its resistance to several insecticides, difficulty in treating infestations that can be concealed in locations within barns, and the high pop...

This EDIS publication is an alternate version of a page published first on the Featured Creatures website. The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are intended for the use of interested laypersons with some knowledge of biology as well as a...

Exclusion fencing represents a potentially useful management tool for key insect pests in broccoli but may also affect other invertebrates that have important roles in agroecosystems. Because beetles (Coleoptera) are generally abundant and diverse in agriculture and some species (i.e., members of the Carabidae and Staphylinidae) are important for b...

Horticultural practices may impact invertebrates in agroecosystems, particularly natural enemies. Impacts can be better understood by grouping organisms functionally or using morphological traits in addition to taxonomic determinations. We compared the effects of mulch type (compost, pine needles, unmulched) and weeding strategy (weeded, unweeded)...

Since its first detection in Florida in 2009, the spotted wing drosophila has spread to over 30 fruit-producing counties in the state. Surveys of this pest from 2012–2015 indicate that the pest is active throughout the year with peak activity from April to June when blueberry and blackberry production is highest. As a result, losses have almost dou...

Drosophila suzukii Matsumura is a recent invasive fruit pest in North and South America and Europe, causing pre-harvest damage and significant economic losses to crops. Little is known about biological control of D. suzukii; here we report the predatory capability of Dalotia (Atheta) coriaria Kraatz, a commercially available control agent against s...

A critical density of four third-instar larvae per 900 cm2 for European chafer, Rhizotrogus ( Amphimallon ) majalis (Razoumowsky), in winter wheat, Triticum aestivum L . , was derived from small-plot greenhouse and field experiments conducted under favorable crop growing conditions at several Ontario and Michigan locations from 2001–2003. On averag...

Molecular gut-content analysis allows determination of pest predation by field-collected predators. Ground beetles (Coleoptera: Carabidae) common in lowbush blueberries may consume blue-berry spanworm, Itame argillacearia (Packard) (Lep-idoptera: Geometridae), and blueberry flea beetle, Altica sylvia Malloch (Coleoptera: Chrysomelidae), providing p...

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a recent invasive pest of fruit crops in North America and Europe. Carpophagous larvae render fruit unmarketable andmaypromote secondary rot-causing organisms. To monitor spread and develop programs to time application of controls, further work is needed to optimize trap design and trapping p...

Ground beetles common in temperate agroecosystems are predators of crop pests, including slugs (Gastropoda: Pulmonata). Salad green production in greenhouses during autumn and spring can be limited by damage due to slugs and other pests. Introducing ground beetles to greenhouses may help reduce damage and improve yields. In the laboratory, while ar...

Blueberry maggot, Rhagoletis mendax Curran (Diptera: Tephritidae), is the most important pest of blueberries in eastern North America. Insecticide use in fruit-bearing lowbush blueberry fields could be reduced with management strategies focused on vegetative fields. We assessed fly distribution and fruit infestation levels where fruit-bearing and v...

Spotted wing drosophila, Drosophila suzukii, is a globally invasive pest of soft-skinned fruit. Females oviposit into ripening fruit and larvae cause direct destruction of tissues. As many plant essential oils are permitted food additives, they may provide a safe means of protecting fruit from D. suzukii infestation in both conventional and organic...

Generalist predators provide an agroecosystem service if they consume plant pests. Ground beetles (Carabidae) that are common during spring in lowbush blueberry fields were tested as predators of blueberry spanworm and blueberry flea beetle using molecular analysis of gut contents. A ~600 bp fragment of the cytochrome oxidase I mtDNA was sequenced,...

Scientific Note J. ent. Soc. Ont. 144: 125–130 Zaprionus indianus gupta (diptera: drosophilidae) was described in india (gupta 1970) (Fig. 1) but is suspected to be native to the afrotropical Region (Chassagnard and kraaijveld 1996). In the New World, it was first found in late 1998 in São Paulo, Brazil and has since spread rapidly throughout South...

Agriculture relies on ecosystem services, such as biological control of pests, for economic success and sustainability. Commercially managed lowbush blueberries are an important crop in eastern North America, but pest control by natural enemies has not been well studied. In this paper we address questions about consumption of two blueberry pests by...

The Carabidae (Coleoptera) are a diverse family of beetles with almost 300 species identified in Nova Scotia, Canada. Carabid beetle communities have been studied in several agricultural systems, but not wild blueberries, an important crop in eastern Canada. In the interest of potentially developing conservation biological control programs in wild...

Biological control of insects by predators may be indirectly influenced by management practices that change the invertebrate community in agroecosystems. In this study we examined effects that mulching and weeding have on predatory beetles (Carabidae and Staphylinidae) and their potential prey in a highbush blueberry field. We compared beetle commu...

Control of blueberry maggot, Rhagoletis mendax Curran, typically is achieved with insecticides targeting adult flies before females oviposit in ripening fruit. Management strategies targeting other life stages have received less attention. We tested effects of compost or pine needle mulches on emergence of blueberry maggot flies under laboratory an...

Ground beetles (Carabidae) are important in agroecosystems because they may regulate pest populations. Carabids have been investigated in horticultural crops, but there are few studies in highbush blueberries. Mulching is used in highbush blueberries for weed control, moisture retention, and fertilization, but its impact on ground beetles is largel...

Mulching can be beneficial for organic highbush blueberry production, but its effects on insect pests have received little attention. For pests that pupate in soil, depth may affect pupation success due to differences in temperature and moisture, mortality factors such as predation, or efficacy of controls such as insecticidal soil drenches. We exa...

Insects of potential benefit to agriculture may respond to farming practices by increasing in abundance and diversity. In this study, we investigated effect of compost (from papermill biosolids) or pine needle mulch versus no mulch and weeding versus no weeding in plots in highbush blueberries near Rawdon, Nova Scotia, Canada. Pitfall traps were us...

A new aleocharine rove beetle, Pella glooscapi Klimaszewski & Majka, sp. n., from Nova Scotia, Canada, is described and illustrated. Data on bionomics and distribution are provided. A short diagnosis, description, colour body image, and black and white genital images are also provided. It appears to be closely related to P. criddlei (Casey). Pella...

After greenhouse and outdoor microplot experiments, a critical density of two third instars per microplot for third instars of European chafer, Rhizotrogus (Amphimallon) majalis (Razoumowsky), in corn, Zea mays L., was derived. On average, the number of missing or damaged plants increased approximately 8% from zero to two larvae per 900 cm2. Furthe...

Thesis (M.Sc.)--University of Guelph, 2004. Includes bibliographical references.