Area-wide Pest Management Programs Research Articles

Simulating migration of wind-borne pests: “Deconstructing” representation of the emigration process

Models capable of simulating both local population dynamics and long-range dispersal of wind-borne pests show promise as components of adaptive areawide pest management programs. Local life cycles and long-range wind-borne transport patterns, especially for small weak fliers, are relatively well-understood. However, modelling proximate causes of emigration from crop fields (and, hence, subsequent infestation of remote crop fields) remains a challenge. We present results of a robustness analysis (RA) in which we systematically “deconstructed” the representation of emigration in a recent model that forecasts regional infestations of North American sorghum (Sorghum bicolor) fields by the sugarcane aphid (Melanaphis sacchari). Results of RA suggested that forecasts of emigration timing were robust, whereas forecasts of emigration magnitude were not. For all deconstructed versions of the model, the time lag between initial infestation of a sorghum field and first emigration of aphids from that field was consistently (in ≈83% of the simulations) less than a week. However, total magnitude of emigration from any given sorghum field differed among model versions by as much as 4- or 5-fold, or by hundreds of thousands of aphids. Placing these RA results within the context of areawide aphid management, they suggest a shift in modelling priorities from further refinement of details representing local population dynamics and magnitudes of emigration events to accurate representation of the dispersion and deposition of migrating aphids. Since (1) forecasted time lags between initial infestation and first emigration were both robust to changes in representation of the emigration process and of short duration, and (2) time lags between a small initial infestation and populations reaching the lower action threshold for pesticide application also can be of short duration, forecasted magnitudes of emigration, in addition to being non-robust, were of marginal utility within an areawide forecasting context. (We hasten to note that details of the terrestrial portion of the aphid life cycle are of the utmost importance from the perspective of modelling local population increase and means of suppression, but that is not our focus here.) Placing our results within the broader context of simulating long-range migration of wind-borne pests as a component of adaptive areawide pest management programs, we advocate the systematic deconstruction of local-scale insect pest models as a matter of habit. Systematic deconstruction could identify robust simplifications that could facilitate linking local-scale models to existing atmospheric transport models, thus increasing transferability of local-levels models from one system to another.

Operational Parameters for the Aerial Release of Sterile Codling Moths Using an Uncrewed Aircraft System.

Simple SummaryPest management through the release of sterile codling moths from drones or uncrewed aerial vehicles (UAVs) represents an efficient method for distribution over orchards. In this study, moths released from greater altitudes were more broadly distributed and drifted more in strong winds compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates from aerially released insects were 40–70% higher compared to those released from the ground. We found that an uncrewed aircraft system (UAS) releasing insects from 35 m above the ground in release routes 50 m apart outperformed standard ground release methods. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.The codling moth is a serious pest of apples in most regions of the world where this fruit is produced. The sterile insect technique is one strategy used to control this pest and is employed as part of an area-wide integrated pest management program for the codling moth in British Columbia, Canada. Modified fixed wing aircraft are the most common method for the release of sterile insects in large area-wide pest management programs. However, aerial release with a full-size aircraft can be prohibitively expensive. We evaluated the use of small, uncrewed aircraft systems (UASs) for the release of sterile codling moths. Sterile codling moths released from greater altitudes were more broadly distributed and drifted more in strong winds, compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates for aerially released insects were 40–70% higher compared to those released from the ground. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.

Factors influencing efficacy of an area-wide pest management program in three urban forests

Managing exotic invasive pests like emerald ash borer can strain budgets and the capacity of cities to protect their urban forest. Area-wide management approaches, like SLAM (SL.ow A.sh M.ortality), can potentially protect trees at a greatly reduced cost. We tested this strategy in three urban forests in Indiana by treating 40 % of the ash trees with insecticides. While the urban SLAM approach reduced overall mortality of untreated ash trees, survivorship varied considerably between sites. SLAM was most successful (54 % survival) where initially < 10 % of the ash trees were moribund (canopy thinning > 30 %) and 40 % of all trees were treated with emamectin benzoate every two years. The approach was less successful (38 % survival) in a site with similar initial ash morbidity but where 15 % of trees were treated with emamectin benzoate and 25 % with annual applications of imidacloprid. In the third site, where 51 % of ash forest were initially moribund and 40 % of the ash trees were treated, only 23 % survived. Overall survival of treated ash trees declined by 18–22 %, and trees that were not moribund were most likely to survive. Although many treated trees that were initially moribund regained their health by the end of the project, this was not the case for untreated ash trees. Where SLAM was most successful, both untreated and treated white ash were more likely to survive than green ash trees. Untreated ash trees at all three sites were more likely to survive when closer to trees treated with emamectin benzoate, but not to those treated with imidacloprid. Our findings suggest that the SLAM approach can protect urban ash trees, but its success is strongly influenced by initial tree condition, species composition and proximity to treated ash trees.

Survey of Fruit Flies (Diptera: Tephritidae) from 23 Species of Fruits Collected in Sleman, Yogyakarta

Fruit flies (Diptera: Tephritidae) are major pests of fruits and vegetables in many countries, including Indonesia. Knowledge of the fruit fly host range in a specific area is an important part of the area-wide pest management program to reduce the pest problem. The aim of this study was to extend and update the information on the host range of fruit flies in the Regency of Sleman, Yogyakarta. This area is one of the centers of fruit production, particularly snake fruit in Indonesia. Fruit sampling was conducted from August 2019 to February 2020 in four sub-districts in Sleman consisting of different types of agro-ecosystems. Fruit rearing was carried out in the laboratory followed by identification of the fruit and fruit flies that emerged to species level. From the 23 species of fruits belonging to 14 different families that were collected, the following 6 species of fruit flies emerged: Bactrocera dorsalis, B. carambolae, B. umbrosa, B. albistrigata, B. mcgregori, and Zeugodacus cucurbitae. Bactrocera dorsalis and B. carambolae utilized the widest range of hosts, 12 and 11 species of fruits, respectively. Syzygium cumini, Malpighia emarginata, and Phaleria macrocarpa were recorded for the first time as new hosts of B. carambolae in Indonesia. Additional data of B. dorsalis and B. carambolae infesting salak cv. pondoh is also reported.

Where do all the aphids go? A series of thought experiments within the context of area-wide pest management

Aphids are economically important wind-borne crop pests worldwide. Forecasting invasions poses the challenge of modelling both the terrestrial and aerial portions of their life cycle in temporally-variable, spatially-heterogeneous environments. Within the context of area-wide pest management, modelling migrations is particularly problematic. We present a series of thought experiments, using sugarcane aphids (Melanaphis sacchari) as a test case, in which we ponder the relative importance of accurate forecasting of magnitudes of migrations and initial infestations versus accurate forecasting of timing of initial infestations. Our results indicate the latter is more important. Within the context of area-wide pest management programs, this suggests improvement in forecasting models for windborne pests most likely will come from increased emphasis on the aeroecological portion of the pest life cycle.

Potential of a fly gut microbiota incorporated gel-based larval diet for rearing Bactrocera dorsalis (Hendel)

BackgroundThe Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is an important polyphagous pest of horticultural produce. The sterile insect technique (SIT) is a proven control method against many insect pests, including fruit flies, under area-wide pest management programs. High quality mass-rearing process and the cost-effective production of sterile target species are important for SIT. Irradiation is reported to cause severe damage to the symbiotic community structure in the mid gut of fruit fly species, impairing SIT success. However, studies have found that target-specific manipulation of insect gut bacteria can positively impact the overall fitness of SIT-specific insects.ResultsTwelve bacterial genera were isolated and identified from B. dorsalis eggs, third instars larval gut and adults gut. The bacterial genera were Acinetobacter, Alcaligenes, Citrobacter, Pseudomonas, Proteus, and Stenotrophomonas, belonging to the Enterobacteriaceae family. Larval diet enrichment with the selected bacterial isolate, Proteus sp. was found to improve adult emergence, percentage of male, and survival under stress. However, no significant changes were recorded in B. dorsalis egg hatching, pupal yield, pupal weight, duration of the larval stage, or flight ability.ConclusionsThese findings support the hypothesis that gut bacterial isolates can be used in conjunction with SIT. The newly developed gel-based larval diet incorporated with Proteus sp. isolates can be used for large-scale mass rearing of B. dorsalis in the SIT program.

Integrated modelling of the life cycle and aeroecology of wind-borne pests in temporally-variable spatially-heterogeneous environment

Integrating population ecology and aeroecology is important for understanding dispersal dynamics of pest insects that depend on aerial habitats. Sugarcane aphid (Melanaphis sacchari) is an economic pest of sorghum in Asia, Africa, Australia, and South America and recently invaded North America, affecting over 90% of the continent’s sorghum production. Long-distance, wind-aided dispersal together with the ability to overwinter in the southernmost sorghum-producing areas appear responsible for their geographic spread in North America. We developed a spatially-explicit, individual-based, stochastic model that integrates the life cycle and aeroecology of sugarcane aphids to forecast regional infestations of sorghum fields. We parameterized and calibrated the model to represent environmental conditions and sorghum phenologies of the southern to central Great Plains of the USA where sorghum is cultivated. We validated the model by comparing simulated spatial-temporal patterns of aphid infestations to georeferenced field data on infestations collected as part of an extensive field project. We assessed potential usefulness of the model by analysing regional patterns of aphid infestations on sorghum simulated under climatic conditions recorded in the southern to central Great Plains in 2017.On a regional scale, the simulated northward advance of aphid infestations generally followed the seasonal development of sorghum, with the main invasion front moving northward from southern to central Texas, then northwest towards the panhandles of Texas and Oklahoma (northernmost and westernmost regions, respectively, of these states), and then northward again into central and western Kansas. Within this general regional trend, the stochastic nature of simulated infestations resulted in wide variation within each region with regard to time lags between the appearance of sorghum and initial infestation, which led to wide variation in infestation levels. The geographical distribution of simulated aphid infestation probabilities approximately mirrored the proportion of land cover in sorghum production, with a prominent infestation “hot spot” covering west-central Kansas and the panhandles of Texas and Oklahoma. Models capable of simulating both local population dynamics as well as long-range, multi-generational dispersal of wind-borne pests show promise as a component of adaptive areawide pest management programs.

Prevalence of naturally-occurring strains of Beauveria bassiana in populations of coffee berry borer Hypothenemus hampei on Hawai'i Island, with observations on coffee plant-H. hampei-B. bassiana interactions.

Beauveria bassiana (Bb) strain GHA is a major component of an areawide pest management program for coffee berry borer (CBB) in Hawai'i. Recent studies have aimed to provide comprehensive assessments of the efficacy of the Bb-spray component of these programs for economic analyses; however, evaluations have been complicated by activity of naturally-occurring strains of this pathogen infecting CBB. Investigations were therefore undertaken to characterize these strains, assess their natural epizootic potential, and account for their contribution to CBB population suppression. A number of field sites were encountered with no history of significant use of commercial Bb-based biopesticides and where strain GHA was not detectable. Sampling of these sites was conducted early in the coffee season. Greatest activity of wild-type Bb strains was observed on high-elevation farms (>500 m), where 24-42% of foundress beetles in green coffee berries were infected. In contrast, infection rates did not exceed 4% on farms at low elevations (<300 m). Rates of 23-29% infection, comparable to those on high-elevation farms, were recorded in a stand of feral coffee at 293 m elevation, but the coffee was completely shaded and ventilation restricted by a dense overstory of vegetation. Despite high activity of naturally-occurring Bb at some sites (primarily sites at high elevations with humid, moderate-temperature environments and dense pest populations), these fungi did not prevent CBB from exceeding the economic threshold for commercial spray applications. Nevertheless, the high natural epizootic potential of these fungal strains suggests strong potential for development as microbial biocontrol agents.

Sexual Competitiveness, Field Survival, and Dispersal of Anastrepha obliqua (Diptera: Tephritidae) Fruit Flies Irradiated at Different Doses.

The sterile insect technique (SIT) is used in area-wide pest management programs for establishing low pest prevalence and/or areas free of fruit flies (Diptera: Tephritidae). The aim of this technique is to induce high levels of sterility in the wild population, for this the released insects must have a high sexual competitiveness and field dispersal. However, radiation decreases these biological attributes that do not allow it to compete successfully with wild insects. In this study the sexual competitiveness, field survival and dispersal of Anastrepha obliqua (Macquart; Diptera: Tephritidae) irradiated at 0, 40, 50, 60, 70, and 80 Gy were evaluated in laboratory. A dose of 60 Gy produced 98% sterility, whereas doses of 70 and 80 Gy produced 99% sterility. Sexual competitiveness was assessed in field cages, comparing males irradiated at 0, 50, 60, 70, and 80 Gy against wild males for mating with wild fertile females. Males irradiated at 50 and 60 Gy achieved more matings than those irradiated at 70 and 80 Gy. Wild males were more competitive than mass-reared males, even when these were not irradiated (0 Gy). There was no effect of irradiation on mating latency, yet wild males showed significantly shorter mating latency than mass-reared males. Female remating did not differ among those that mated with wild males and those that mated with males irradiated with different doses. The relative sterility index (RSI) increased from 0.25 at 80 Gy to 0.37 at 60 Gy. The Fried competitiveness index was 0.69 for males irradiated at 70 Gy and 0.57 for those irradiated at 80 Gy, which indicates that a 10 Gy reduction in the irradiation dose produces greater induction of sterility in the wild population. There were no significant differences in field survival and dispersal between flies irradiated at 70 or 80 Gy. Reducing the irradiation dose to 60 or 70 Gy could improve the performance of sterile males and the effectiveness of the SIT. Our results also distinguish between the effects of irradiation and mass-rearing on the performance of sterile males.

Effects of green manure cover crops on Spodoptera litura (Lepidoptera: Noctuidae) populations.

Spodoptera litura (F.) is an important pest of numerous agro-economic crops, including green manure cover crops. In Taiwan, sesbania (Sesbanin roxburghii Merr.), sunn hemp (Crotalaria juncea L.), and rapeseed (Brassicae campestris L. variety chinensis) are the most popular green manure crops; sesbania and sunn hemp are commonly planted in warm seasons, whereas rapeseed is grown in the winter. In this study, life-table data for S. litura reared on these three green manures were collected to evaluate their roles as refuges of this pest. The net reproductive rate, intrinsic rate of increase, and finite rate of increase of S. litura were the highest when reared on sesbania (1428.1 offspring, 0.2327 d(-1), 1.2621 d(-1)), followed by sunn hemp (778.4 offspring, 0.2070 d(-1), 1.2300 d(-1)) and rapeseed (737.6 offspring, 0.2040 d(-1), 1.2263 d(-1)). The high growth rates on these green manure crops show that they can serve as potential breeding sites for S. litura. Population projection demonstrated the rapid growth of S. litura on sesbania, sunn hemp, and rapeseed as well. Because most growers have traditionally ignored pest management in green manure fields, the mass emergence of S. litura in these fields may cause unexpected infestations in nearby vegetable, corn, and peanut crops. This study shows that the use of green manures as sources of nutrients should be critically reassessed and an area-wide pest management program should be instituted by taking the population of S. litura in green manure fields into consideration.

Cereal aphid movement: general principles and simulation modelling

Cereal aphids continue to be an important agricultural pest, with complex lifecycle and dispersal behaviours. Spatially-explicit models that are able to simulate flight initiation, movement direction, distance and timing of arrival of key aphid species can be highly valuable to area-wide pest management programmes. Here I present an overview of how knowledge about cereal aphid flight and migration can be utilized by mechanistic simulation models. This article identifies specific gaps in knowledge for researchers who may wish to further scientific understanding of aphid flight behaviour, whilst at the same time provides a synopsis of the knowledge requirements for a mechanistic approach applicable to the simulation of a wide range of insect species.Although they are one of the most comprehensively studied insect groups in entomology, it is only recently that our understanding of cereal aphid flight and migration has been translated effectively into spatially-explicit simulation models. There are now a multitude of examples available in the literature for modelling methods that address each of the four phases of the aerial transportation process (uplift, transport in the atmosphere, initial distribution, and subsequent movement). I believe it should now be possible to draw together this knowledgebase and the range of modelling methods available to simulate the entire process: integrating mechanistic simulations that estimate the initiation of migration events, with the large scale migration modelling of cereal aphids and their subsequent local movement.Electronic supplementary materialThe online version of this article (doi:10.1186/2051-3933-1-14) contains supplementary material, which is available to authorized users.

Preplant 1,3-D treatments test well for perennial crop nurseries, but challenges remain

Preplant fumigation with methyl bromide commonly is used in open-field perennial crop nurseries in California for control of plant-parasitic nematodes, pathogens and weeds. Because this fumigant is being phased out, alternatives are needed to ensure the productivity of the perennial crop nursery industry as well as the ornamental, orchard and vineyard production systems that depend on clean planting stock. As part of the USDA Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives, several perennial crop nursery projects were conducted in California from 2007 to 2011 to test and demonstrate registered alternative fumigants and application techniques that maximize performance and minimize environmental impacts. The project was designed to evaluate shank application and soil surface sealing methods intended to reduce aboveground emission and improve soil performance of 1,3-dichloropropene, a leading methyl bromide alternative for nurseries. In these garden rose and tree nursery experiments, 1,3-dichloropropene treatments performed well regardless of application techniques. In this article, we highlight recent research and discuss the significance and remaining challenges for adoption of methyl bromide alternatives in this unique nursery stock production system.

OUTLOOK: Specialty crops and methyl bromide alternatives: Taking stock after 7 years

finding alternatives to Outlook Specialty crops and methyl bromide alternatives: taking stock after 7 years Greg T. Browne Research Plant Pathologist, Crops Pathology and Genetics Research Unit, USDA-ARS, Department of Plant Pathology, University of California, Davis S Jack Kelly Clark pecialty crop farms and nurseries in Califor- nia, Oregon and Washington provide local and world markets with abundant fruit, nut and vegetable crops and planting stock. These op- erations thrive due to dedicated human investment and the availability of precious combinations of soil, climate and water resources. California alone produces 99% of the U.S. almond and walnut crops and 90% of the strawberry crop, and it supplies 99% or more of U.S. almond, raisin, table grape and walnut exports. Combined, California, Oregon and Washington account for roughly 32% of the U.S. floriculture crop value, 44% of the nursery crop value and 78% of the fruit and nut crop value. Pest-free nursery stock We all have a large stake in the availability of and productive specialty crops. Research increasingly documents soils are vital their benefits to our health. They are a livelihood, to efficient use directly or indirectly, for many of us. As a society, of land, water, energy and we have contributed collectively to key infrastruc- fertilizer resources tures, such as water resource developments for for specialty crops irrigation and the land-grant college system with such as almonds and grapes. its associated teaching, research and extension Above, an almond functions. Indisputably, ample food production, orchard in bloom. including specialty fruits, nuts and vegetables, is a key measure of national and global security. California Agriculture journal thanks Yet specialty crop farming faces the faculty chairs for this special col- serious challenges. Especially in lection: Greg Browne, Research Plant California, urban growth is remov- Pathologist, USDA Agricultural Research ing farmland irreversibly. Also, Service (USDA-ARS) and Department water resources can be allocated of Plant Pathology, UC Davis, and away from agriculture, and some Brad Hanson, Cooperative Extension specialty crop pest management Specialist, University of California, practices, such as soil fumigation, Davis. We also thank the USDA-ARS are requiring intensive regulation to Pacific Area-Wide Pest Management Program for Integrated Methyl Bromide ensure public safety. Alternatives for helping defray the In 2006, preplant soil fumigation cost of this issue and the upcoming with methyl bromide, an effective October–December 2013 edition. pest management practice used ex- tensively in production of billions of dollars of high-value specialty crops annually, was being phased out due to its contributions to ozone depletion in the stratosphere. Further, the immedi- ate alternatives to methyl bromide, mainly a few other soil fumigants, were on “shaky ground” due to their own environmental challenges. That year, the U.S. Department of Agriculture (USDA) launched the Pacific Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives (PAW-MBA). The program drew growers, nursery representatives, regulatory officials and scientists from California, Oregon and Washington to work together as a multidisciplinary team in response to the methyl bromide phase-out. Scientists from the USDA Agricultural Research Service, University of California, California Department of Pesticide Regulation, Oregon State University and Washington State University, along with public and private stakeholders, all were vital to development and implementation of the program. The PAW-MBA sought to: 1) optimize avail- able “next-best” fumigant alternatives to methyl bromide soil treatments and 2) foster development of non-fumigant alternatives. Specific needs of the targeted production systems (i.e., perennial and annual nursery crops, strawberries, almonds and stone fruits, walnuts and grapes) as well as over-arching environmental challenges (e.g., hu- man health and safety; air, soil and water quality; efficient use of environmental resources) would be accommodated. In the absence of methyl bromide, specific needs varied among the different production systems. Field nurseries needed alternatives to manage weeds (effective herbicides were not available) and nematodes (certification requires nursery stock to be nematode-free) over 1- to 2-year plant pro- duction cycles, and there was little flexibility for non-fumigant alternatives. In contrast, orchardists had less need to control weeds and more pressing needs to manage soilborne pathogen complexes (including but not limited to nematodes) over 15- to 30-year production cycles. Compared to field nurs- eries, orchard, vineyard and strawberry produc- ers had more flexibility to explore non-fumigant alternatives. All of the PAW-MBA specialty crop systems shared the imperative to minimize non-target fu- migant emissions to the atmosphere. Fumigants are hazardous, volatile, broad-spectrum biocides and are regulated accordingly at federal, state and county levels to keep bystanders safe and minimize http://californiaagriculture.ucanr.edu • JULY–SEPTEMBER 2013

WSR-88D doppler radar detection of corn earworm moth migration

Corn earworm (Lepidoptera: Noctuidae) (CEW) populations infesting one crop production area may rapidly migrate and infest distant crop production areas. Although entomological radars have detected corn earworm moth migrations, the spatial extent of the radar coverage has been limited to a small horizontal view above crop production areas. The Weather Service Radar (version 88D) (WSR-88D) continuously monitors the radar-transmitted energy reflected by, and radial speed of, biota as well as by precipitation over areas that may encompass crop production areas. We analyzed data from the WSR-88D radar (S-band) at Brownsville, Texas, and related these data to aerial concentrations of CEW estimated by a scanning entomological radar (X-band) and wind velocity measurements from rawinsonde and pilot balloon ascents. The WSR-88D radar reflectivity was positively correlated (r2=0.21) with the aerial concentration of corn earworm-size insects measured by a scanning X-band radar. WSR-88D radar constant altitude plan position indicator estimates of wind velocity were positively correlated with wind speed (r2=0.56) and wind direction (r2=0.63) measured by pilot balloons and rawinsondes. The results reveal that WSR-88D radar measurements of insect concentration and displacement speed and direction can be used to estimate the migratory flux of corn earworms and other nocturnal insects, information that could benefit areawide pest management programs. In turn, identification of the effects of spatiotemporal patterns of migratory flights of corn earworm-size insects on WSR-88D radar measurements may lead to the development of algorithms that increase the accuracy of WSR-88D radar measurements of reflectivity and wind velocity for operational meteorology.

Experiences with the Large-Scale Operation of the Biogents Sentinel™ Trap

We obtained 160 Biogents Sentinel traps (BGS-traps) to monitor adult mosquito populations for the Area-wide Pest Management Program for the Asian tiger mosquito (Aedes albopictus) in New Jersey. We deployed between 90 and 110 BGS-traps weekly from May through October of 2008, 2009, 2010. and 2011. Here we detail our experience: challenges with acquisition, defects in construction, as well as actions taken to correct problems we found and preempt them in the future. Further, we describe the impact of these problems on our research and provide a cost analysis of repairs.

Government Success in Partnerships: The USDA-ARS Areawide Ecologically Based Invasive Annual Grass Management Program

L ong-term research about complicated pest man- agement issues creates incremental knowledge that systematically solves problems. But once knowledge is well-enough advanced to dramati- cally improve the success of pest management, it is of little value unless that knowledge and technology are transferred to the intended users. Furthermore, the implementation of such technologies on a eld-by- eld level will have little impact on pest issues that cross regions, states, and some- times countries. Since the mid-1990s, the US Department of Agriculture–Agricultural Research Service (USDA- ARS) has funded an Areawide Pest Management program to address both of these issues. DOI: 10.2458/azu_rangelands_v34i4_smith

Evaluation of Methyl Eugenol and Cue-Lure Traps With Solid Lure and Insecticide Dispensers for Fruit Fly Monitoring and Male Annihilation in the Hawaii Areawide Pest Management Program

Methyl eugenol (ME) and cue-lure (C-L) traps with solid lure dispensers were deployed in areas with low and high populations of oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), respectively. In low-density areas, standard Jackson traps or Hawaii Fruit Fly Areawide Pest Management (AWPM) traps with FT Mallet ME wafers impregnated with dimethyl dichloro-vinyl phosphate (DDVP) or AWPM traps with Scentry ME cones and vapor tape performed equally as well as standard Jackson traps with liquid ME/C-L and naled. Standard Jackson traps or AWPM traps with FT Mallet C-L wafers impregnated with DDVP or AWPM traps with Scentry C-L plugs with vapor tape performed equally as well as standard Jackson traps with a lure-naled solution. In high density areas, captures with traps containing FT Mallet wafers (ME and C-L) outperformed AWPM traps with Scentry cones and plugs (ME and C-L) with DDVP insecticidal strips over a 6-mo period. Captures of B. dorsalis and B. cucurbitae with wafers containing both ME and raspberry ketone (FT Mallet MC) were equivalent to those containing separate lures. From a worker safety and convenience standpoint, FT Mallet ME and C-L wafers with DDVP or Scentry plugs, with or without DDVP vapor tape, are more convenient and safer to handle than standard liquid insecticide formulations used for monitoring and male annihilation programs in Hawaii, and for detections traps used on the U.S. mainland. Furthermore, the FT Mallet MC wafer might be used in a single trap in place of two separate traps for detection of both ME and C-L responding fruit flies.

Landscape composition modulates population genetic structure ofEriosoma lanigerum(Hausmann) onMalus domesticaBorkh in central Chile

Landscape genetics have been particularly relevant when assessing the influence of landscape characteristics on the genetic variability and the identification of barriers to gene flow. Linking current practices of area-wide pest management information on pest population genetics and geographical barriers would increase the efficiency of these programs. The woolly apple aphid, Eriosoma lanigerum (Hausmann), an important pest of apple orchards worldwide, was collected on apple trees (Malus domestica Borkh) from different locations in a 400 km north-south transect trough central Chile. In order to determine if there was population structure, diversity and flow were assessed. A total of 215 individuals from these locations were analysed using Inter Simple Sequence Repeat (ISSR) markers. Four ISSR primers generated a total of 114 polymorphic loci. The percentage of molecular variation among locations was 18%. As the algorithm used by structure may be poorly suited for inferring the number of genetic clusters in a data set that has an IBD relationship, the number of genetic clusters in the samples was also analyzed using a Bayesian clustering method implemented in software Baps version 4.14. We inferred the presence of four genetic clusters in the study region. Clustering of individuals followed a pattern explained by some geographical barriers. Using partial Mantel tests, we detected barriers to gene flow other than distance, created by a combination of main rivers and mountains. Although landscape genetics are rarely used in pest management, our results suggest that these tools may be suitable for the design of area-wide pest management programs.

Effectiveness of Corn Rootworm (Coleoptera: Chrysomelidae) Areawide Pest Management in South Dakota

Diabrotica barberi Smith & Lawrence and Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) are serious pests of maize, Zea mays L. To reduce the amount of toxicants released into the environment, the Agricultural Research Service implemented a 5-yr (1997-2001) areawide pest management program in five geographic locations, including one in South Dakota. The objective was to use integrated pest management tactics to suppress adult Diabrotica populations over a broad geographic area by using aerially applied semiochemical-baited insecticides. Suppressed populations theoretically should reduce oviposition, limit larval feeding damage to maize roots, and result in fewer beetles emerging in subsequent years. We used emergence cages, sticky traps, and CRW lure traps to monitor adult D. barberi and D. v. virgifera populations. We sampled for Diabrotica eggs, and we determined damage to maize roots. We sampled in several maize fields (control) located near the areawide site. The baited insecticides were effective in reducing adult populations 1 and 2 wk after application, and most remained low for the duration of the maize growing season. Fewer beetles were captured in both sticky and lure traps in the areawide site than in the control site. With a few exceptions, egg counts, adult emergence, and maize root damage were similar between the areawide and control sites; however, maize roots had greater fresh weight in the control site. Although not all goals were accomplished, when considering the amount of toxicant released into the environment, using semiochemical-baited insecticides to suppress adult pest Diabrotica populations seems to be an effective areawide management tool.

Optimal pest management: A reproductive pollutant perspective

Regarding pests as reproductive pollutants, pest management can be considered as an optimal stock management problem similar to that faced in fishery and forestry. Taking this view, an optimal control model with N heterogeneous farmers sharing a mobile pest is developed to investigate the conventional pest management tactic on a farm-by-farm basis and the innovative area-wide pest management tactic on a regional basis. The study results indicate that area-wide pest management (APM) is superior to farm-by-farm pest management in the presence of pest movement. We proceed to examine the stability of the cooperative solution under APM by formulating the pest management problem as a repeated game of infinite duration. The results suggest that a one-off pest suppression campaign can be a practical strategy for initiating APM programs.