Steven P. Arthurs

Codling moth granulovirus: a comprehensive review

Abstract Codling moth (CM), Cydia pomonella (L), is regarded as the most serious insect pest of apple worldwide. A variety of problems associated with the traditional use of non-selective insecticides for its control include: untoward environmental effects, insecticide resistance, negative impacts on natural enemies, and safety for pesticide applicators and the food supply. Concerns about these consequences have increased the interest in and development of alternative means for CM control that have little or no impact on humans, beneficial organisms and sensitive ecosystems. An effective and selective alternative to chemical insecticides for CM control is the CM granulovirus (CpGV). The virus was first isolated in Mexico and subsequently studied and evaluated in Europe and North America. A variety of research including pathology, pathogenesis and histopathology of the virus, determination of virulence, development of production methods, field use, factors that influence efficacy, commercial development, formulation, and CM resistance to the virus has been conducted. Commercial products of CpGV are now produced in Europe and North America and used by orchardists worldwide. In this paper we present a comprehensive review of the CpGV literature and the role of the virus in integrated pest management.

Effect of Dose, Pre-mortem Host Incubation Temperature and Thermal Behaviour on Host Mortality, Mycosis and Sporulation of Metarhizium anisopliae var. acridum in Schistocerca gregaria

The effects of dose, pre-mortem host incubation temperature and thermal behaviour on mortality, mycosis and sporulation of Metarhizium anisopliae var. acridum in the desert locust, Schistocerca gregaria (Forskål) were assessed in the laboratory. While all factors were important in determining locust mortality rate, they had little influence on rates of mycosis and sporulation following host death. Mortality rates at constant incubation temperatures between 15 and 30°C broadly reflected the temperature-related vegetative growth profile of the fungus, with higher doses causing quickest mortality and generally high (> 80%) levels of dose-independent mycosis. At 35°C, locusts were able to suppress infection for several weeks, the effect of dose on mortality was less apparent and no mycosis was observed, despite being more amenable for basic pathogen development compared with 15°C. When locusts were presented with an intermittent cooler period (20/35°C), dose-dependent mortality was more rapid with relatively high (> 70%) dose-independent rates of mycosis. However, providing a thermal gradient of 25-50°C in place of 35°C, allowed locusts to suppress infection for some weeks and reduced mycosis rates slightly, demonstrating the therapeutic advantages of host thermoregulation. Despite this, there was little evidence that hosts could escape infection indefinitely, demonstrated by the rapid mortality and mycosis rates when the temperature was reduced to 30°C. The importance of dose and pre-mortem host incubation temperature for the conidial yield resulting from mycosed cadavers was assessed. Inoculating dose was unimportant and no consistent trend of the incubation conditions on conidial yield was found, suggesting these were also unimportant, as long as the pathogen could grow sufficiently well to kill the host. Implications for secondary cycling of the pathogen in the field are discussed.

Use of Entomopathogenic Nematodes (Steinernematidae) in Conjunction with Mulches for Control of Overwintering Codling Moth (Lepidoptera: Tortricidae)

Mulches were compared to test their utility for enhancing efficacy of entomopathogenic nematodes (EPNs) applied against over-wintering codling moth, Cydia pomonella (L.), larvae. Compared with bare...

Evaluation of Isaria fumosorosea (Hypocreales: Cordycipitaceae) for control of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

A laboratory bioassay was developed to evaluate strains of Isaria fumosorosea Wize, against Diaphorina citri. Up to 100% of adult psyllids were killed at concentrations between 106 and 107 blastospores/ml after 12 days, with derived LC50 values (at 7 days post treatment) between 1.4 × 105 and 2.0 × 106 blastospores/ml for strains ARSEF 3581, FE 9901 and Apopka-97. A significantly higher value (1.5 × 107) was obtained with a conidial formulation of Apopka-97. Average survival times were dosage dependent, i.e. between 10.2 days at 103 blastospores/ml and 3.5 days at 108 blastospores/ml. Rates of mycosis were also dosage dependent, with up to 100% sporulation on cadavers at 108 blastospores/ml but declining at lower concentrations. The Apopka-97 strain (commercially available as PFR-97) was tested against established D. citri infestations in potted citrus in greenhouse cages. Treatments at label rates reduced psyllid populations by approximately 50% over 3 weeks. The combination of PFR-97 with emulsifiable oils (0.25% v/v) did not increase psyllid mortality compared with either agent alone. Imidacloprid applied as a drench killed 100% of psyllids within 3 weeks. Subsequent greenhouse tests during humid conditions were hampered by natural dissemination of I. fumosorosea to untreated psyllids, suggesting that this fungus is spread by air movement and may be highly effective under very humid conditions. In later tests, a Cladosporium sp. rapidly colonised psyllid cadavers and leaf surfaces, but was not pathogenic in laboratory tests. Our studies confirm the potential of I. fumosorosea to be used in IPM strategies for D. citri that rely on other tactics, such as insecticidal oils and native or introduced biological control agents.

Compatibility of Isaria fumosorosea (Hypocreales: Cordycipitaceae) Blastospores with Agricultural Chemicals Used for Management of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

Biorational insecticides are being increasingly emphasized for inclusion in integrated pest management programs for invasive insects. The entomopathogenic fungus, Isaria fumosorosea, can be used to help manage the Asian citrus psyllid with minimal impact on beneficial arthropods, but its effectiveness may be compromised by agrochemicals used to control concurrent arthropod pests and diseases. We evaluated the compatibility of I. fumosorosea blastospores with a range of spray oils and copper-based fungicides registered for use in citrus groves. Results of laboratory and greenhouse tests showed a range of responses of the fungus to the different materials, including compatibility and incompatibility. Overall, I. fumosorosea growth in vitro was reduced least by petroleum-based materials and most by botanical oils and borax, and some of the copper-based fungicides, suggesting that tank mixing of I. fumosorosea with these latter products should be avoided. However, equivalent negative effects of test materials on fungal pathogenicity were not always observed in tests with adult psyllids. We hypothesize that some oils enhanced adherence of blastospores to the insect cuticle, overcoming negative impacts on germination. Our data show that care should be taken in selecting appropriate agrochemicals for tank-mixing with commercial formulations of entomopathogenic fungi for management of citrus pests. The prospects of using I. fumosorosea for managing the invasive Asian citrus psyllid and other citrus pests are discussed.

Integrated Pest Management of Coffee Berry Borer: Strategies from Latin America that Could Be Useful for Coffee Farmers in Hawaii

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) is the primary arthropod pest of coffee plantations worldwide. Since its detection in Hawaii (September 2010), coffee growers are facing financial losses due to reduced quality of coffee yields. Several control strategies that include cultural practices, biological control agents (parasitoids), chemical and microbial insecticides (entomopathogenic fungi), and a range of post-harvest sanitation practices have been conducted to manage CBB around the world. In addition, sampling methods including the use of alcohol based traps for monitoring CBB populations have been implemented in some coffee producing countries in Latin America. It is currently unclear which combination of CBB control strategies is optimal under economical, environmental, and sociocultural conditions of Hawaii. This review discusses components of an integrated pest management program for CBB. We focus on practical approaches to provide guidance to coffee farmers in Hawaii. Experiences of integrated pest management (IPM) of CBB learned from Latin America over the past 25 years may be relevant for establishing strategies of control that may fit under Hawaiian coffee farmers’ conditions.

Efficacy of Codling Moth Granulovirus: Effect of Adjuvants on Persistence of Activity and Comparison With Other Larvicides in a Pacific Northwest Apple Orchard

Control of codling moth, Cydia pomonella (L), in conventional orchards has relied heavily on broad spectrum insecticides such as azinphos-methyl (Guthion®, Bayer CropScience, Research Triangle Park...

Implementing an Integrated Pest Management Program for Coffee Berry Borer in a Specialty Coffee Plantation in Colombia

Efforts to implement an integrated pest management (IPM) program for coffee berry borer Hypothenemus hampei (Ferrari) in a 110-ha coffee plantation in the Huila region of Colombia are discussed. Hands-on training was provided for farm staff and harvest workers managing production in >80 coffee lots. Participants attended workshops describing pest management strategies, based on prior research and recommendations of the National Coffee Research Center in Colombia (Cenicafe). The training program focused on cultural practices, i.e., efficient harvesting of mature berries to eliminate coffee berry borer habitats, along with establishing a comprehensive monitoring program to reduce chemical insecticides and encouraging use of a biological-based insecticide. Participants implemented postharvest techniques by screening harvested berries and pulp pits to physically exclude adult coffee berry borers. The rationale was that adopting new practices would enable growers to transition away from chemical insecticides. Results over 3 yr showed widespread adoption of cultural, physical, and biological control methods. Overall, the IPM program was considered successful because problems associated with insect damage on the coffee crop decreased, despite reductions in endosulfan/chlorpyrifos use, which declined from 250 liters in 2002 to 75 liters in 2003, and 0 liters in 2004. Concurrently, Beauveria bassiana increased from 20 kg in 2002 to 80 kg in 2004. Harvest workers improved their efficiency at removing potential coffee berry borer breeding sites (leaving only 6.5 mature berries per tree in 2004, down from 22.2 in 2002). The quality of parchment coffee beans increased (insect damage was 2.3% in 2002, 1.7% in 2003, and 0.7% in 2004) whereas the proportion of the harvest sold as high quality ‘specialty’ coffee increased from 50% to 86% over the same period.

Effect of Isaria Fumosorosea (Hypocreales: Cordycipitaceae) and Lysiphlebus Testaceipes, (Hymenoptera: Braconidae) on the Brown Citrus Aphid: Preliminary Assessment of a Compatibility Study

Recently, a strain of Isaria fumosorosea Wize (.Ifr) (= Paecilomyces fumosoroseus [Luangsa-ard et al. 2005]), (Hypocreales: Cordycipitaceae) was discovered in a Florida citrus grove infecting the Asian citrus psyllid, Diaphorina citri Kuwayama (Meyer et al. 2008). Also, laboratory studies have demonstrated that Ifr may be effective against several commercially important pests of citrus (Poprawski et al. 1999; Avery et al. 2009; Hoy et al. 2010; Hunter et al. 2011). Therefore, the use of Ifr (PFR 97TM 20% WDG, Certis USA, Columbia, Maryland), approved in 2011 by EPA for use in commercial citrus, may offer a potential tool for balancing citrus pest management with consum er demands for organic citrus produce. The brown citrus aphid (BCA), Toxoptera citri cidus Kirkaldy (=T. citricida [Nieto Nafria et al. 2005]), (Hemiptera: Aphididae) was discovered in Florida in 1995 and is recognized as a serious pest of citrus capable of vectoring citrus triseza virus (Halbert & Brown 1996; Michaud 1998; Roy & Brlansky 2009). Under optimal conditions, na tive natural enemies provide good management of BCA, although these are easily disrupted by insecticide applications (Michaud 1998; 2002). Presently, the aphids population is managed in part by the parasitoid Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae) (Evans & Strange 1997). This generalist aphid parasitoid Lysiphlebus testaceipes, native to Florida and the Americas, is an effective biocontrol agent of BCA (Evans & Strange 1997). The objectives of our study were to assess the impact of Ifr on the mor tality of BCA populations as well as the parasit ism and emergence rates of L. testaceipes. BCA and Carrizo citrus (a trifoliate hybrid: Washington navel x trifoliate orange) were ob tained from the Sub-Tropical Insect Research Unit, USDA Horticulture Research Laboratory in Fort Pierce, Florida. For the experiment, 5 car rizo citrus seedlings (25-30 cm tall) were placed in each of four separate nylon mesh-covered cages (35 x 35 x 35 cm) and each infested with 4 alate BCA (20 per cage). A second infestation was made after 9 days. Cages were maintained in a growth room at 24.0 ± 1 °C, 45.0 ± 1 % RH and 16:8 h (L:D) photoperiod. Two weeks later, 10 L. testa ceipes adults were added to two of the cages. After an additional 4 days, one cage with and without L. testaceipes was treated with Isaria fumosoro sea (Ifr) suspension (PFR 97TM 20% WDG) at 107 CFU/ml using Nalgene® (Nalge Nunc Interna tional, Rochester, NY) aerosol sprayer. The ger mination of PFR 97TM blastospores was 96% using the technique of Avery et al. 2009. The remaining 2 cages were sprayed with an equal volume of wa ter. Parasitoids were temporarily removed from all cages prior to spraying to eliminate potential drowning and were replaced with an additional 5 to compensate for handling stress. Two replicates of the same study were conducted on different dates.

Evaluation of Entomopathogenic Fungi Against Chilli Thrips, Scirtothrips dorsalis

Abstract Commercial strains of entomopathogenic fungi were evaluated for control of chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), an invasive pest of ornamental and vegetable plants in the Caribbean and southeastern United States. In laboratory assays, LC50 values against adult S. dorsalis were 5.1 × 104 CFU/mL for Beauveria bassiana GHA, with higher values 3.1 × 105 for Metarhizium brunneum F52 and 3.8 × 105 for Isaria fumosorosea Apopka 97. Second instars were comparatively less susceptible to all isolates, ostensibly due to moulting, with LC50 values of 1.1 × 108, 7.0 × 105, and 9.9 × 105 CFU/spores per mL for GHA, F52, and Apopka 97 strains, respectively. In greenhouse cages, compared with controls, three applications of mycoinsecticides and other biorational insecticides at 7 to 14 day intervals reduced overall S. dorsalis populations on pepper plants Capsicum annuum cv. California Wonder: spinosad reduced populations by 94–99%, M. brunneum F52 by 84–93%, B. bassiana GHA by 81–94%, I. fumosorosea PFR-97 by 62–66%, and different horticultural oils by 58–85%. The proportion of marketable fruit was significantly increased by M. brunneum F52, B. bassiana GHA, and 2% SuffOil-X treatments. Slightly lower levels of control were observed in nursery tests with ornamental rose shrubs, Rosa sp. Red Double Knock Out®, during hot sunny conditions. Four applications reduced thrips populations over 10 weeks: spinosad by an average of 91%, M. brunneum F52 by an average of 81%, B. bassiana GHA by an average of 62%, SuffOil-X by an average of 50%, and I. fumosorosea PFR-97 by an average of 44%. The data show that mycoinsecticides can be used in management strategies for low to moderate populations of S. dorsalis and provide resistance management tools for the limited number of insecticides that are effective against this pest.