Aerial Application Of Insecticides Research Articles

Efficacy of insecticide aerial spraying programs to reduce tree mortality during a spruce budworm outbreak (1967–1992) in the province of Quebec

Abstract Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in eastern North America. The main approach for protecting forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial insecticide applications in the global forest protection strategy, little is known about its real effects on tree mortality or the stand characteristics that may affect its long‐term efficacy. We evaluated the efficacy of the protection program that was implemented during the 1967–1992 outbreak in Quebec (Canada) in tree mortality reduction. We established 422 plots in eastern Quebec based upon the following parameters: insecticide application; stand composition; drainage quality; and stand age. Unprotected plots exhibited 18 to 44% greater tree mortality than protected plots. Insecticide efficacy was affected by drainage condition. Protected plots that established on sites with poor quality drainage exhibited 67.53% lower balsam fir (Abies balsamea) mortality than did unprotected plots. Stand age did not affect tree mortality. Insecticide application had no substantial effect on spruce mortality. Our study also found that the return on protection investment in terms of mortality reduction may decline after 7 years of aerial spraying, and that it is not necessary to achieve the target protection goal (50% foliage protection) every year to reduce host tree mortality. Our results may be useful for decision‐makers to decide where and when to apply insecticides during a spruce budworm outbreak and may help to determine the appropriateness of treating the forest on an annual basis depending upon the protection goals.

Effects of aerial adulticiding for mosquito management on nontarget insects: A Bayesian and community ecology approach

AbstractDiseases transmitted by mosquitoes are emerging across the globe in a broad range of urbanized, rural, and natural environments inhabited by their vector species. Because applications of insecticides remain the most effective, and often the only available tool to prevent or control mosquito‐borne disease outbreaks, their use and scope continue to expand. However, the effects of multiple insecticide applications targeting adult mosquitoes on nontarget insect communities remain poorly characterized. To remedy this knowledge gap, we conducted an evaluation of five aerial insecticide applications on insect communities in a natural environment near Salt Lake City, Utah. Employing a before–after–control–impact approach, we assessed abundance and community composition changes over the study period utilizing Bayesian and community ecology analytical methods. We observed no discernible effects on most insect taxa, and there were no changes in the overall insect community composition. The abundance of Diptera, Coleoptera, and Hemiptera declined in control and treatment sites, Odonata increased over the period of the study, and Hymenoptera and Lepidoptera remained similar, suggesting seasonal trends rather than treatment effects. The only consistently detectable treatment effect was on nonbiting midges (Diptera: Chironomidae), that are closely related to mosquitoes taxonomically and have similar body size and diel activity. Midge abundance declined by 79.9% (95% credible interval: 58.4–91.9). Overall posttreatment abundance decline of 62.2% (95% credible interval: 22.5–87.8) was also detected for leafhoppers (Hemiptera: Cicadellidae), but, these declines were inconsistent and may be attributed to natural variability rather than the treatment effect. Treatment frequency, location, life‐stage targeting, and application techniques may mitigate the effects of mosquito control on nontarget insects to allow protecting human health while limiting environmental impacts.

Can insecticide applications used to kill vector insects prevent pine wilt disease?

The aerial application of insecticides is a primary method used to prevent the spread of pine wilt disease by reducing the population density of Monochamus beetles, the vector insects of pine wood nematodes (PWNs). This study investigated the mortality of vector insects and the ratio of PWN-infected trees according to systemically remaining thiacloprid residues in Pinus densiflora. To do this, thiacloprid was sprayed on a nursery of 5-year-old P.densiflora in meshed cages. Then Monochamus alternatus adults carrying PWNs were placed into meshed cages 1 and 15 days post-treatment (T1 and T15 groups for thiacloprid spraying, and N1 and N15 groups for nonsprayed groups) and tree mortality was monitored. We also measured the thiacloprid residues in pine branches in each treatment. In pine trees, more thiacloprid residues were found in the T1 group than in the T15 group, but most M.alternatus adults died in the T1 and T15 groups and PWNs were detected in 51.3% of all recaptured beetles. In the 16th week after each treatment, the average tree mortalities in T1 and T15 were 0% and 16.7%, respectively, whereas mortality of ≈50-60% of all tested trees in the nonsprayed groups was observed. The current aerial application of insecticides may have a limitation in preventing PWN transmission from dying M.alternatus adults when they are exposed to low thiacloprid residues in pine trees.

Toys or Tools? Utilization of Unmanned Aerial Systems in Mosquito and Vector Control Programs.

Organized mosquito control programs (MCP) in the United States have been protecting public health since the early 1900s. These programs utilize integrated mosquito management for surveillance and control measures to enhance quality of life and protect the public from mosquito-borne diseases. Because much of the equipment and insecticides are developed for agriculture, MCP are left to innovate and adapt what is available to accomplish their core missions. Unmanned aerial systems (UAS) are one such innovation that are quickly being adopted by MCP. The advantages of UAS are no longer conjectural. In addition to locating mosquito larval habitats, UAS affords MCP real-time imagery, improved accuracy of aerial insecticide applications, mosquito larval detection and sampling. UAS are also leveraged for applying larvicides to water in habitats that range in size from multi-acre wetlands to small containers in urban settings. Employing UAS can reduce staff exposure to hazards and the impact associated with the use of heavy equipment in sensitive habitats. UAS are utilized by MCP nationally and their use will continue to increase as technology advances and regulations change. Current impediments include a dearth of major UAS manufacturers of equipment that is tailor-made for mosquito control, pesticides that are optimized for application via UAS and regulations that limit the access of UAS to national airspace. This manuscript highlights the strengths and weaknesses of UAS within MCP, provides an update on systems and methods used, and charts the future direction of UAS technology within MCP tasked with public health protection.

Relative impacts of gypsy moth outbreaks and insecticide treatments on forest resources and ecosystems: An experimental approach

Abstract1. Gypsy moth outbreaks cause severe defoliation in Holarctic forests, both in North America where it is invasive, and in its native range in Eurasia. Defoliation can hamper timber production and impact ecological communities and processes. Aerial insecticide applications are regularly performed in outbreak areas to mitigate economic losses. These operations can be financially costly and harmful to non‐target species and may disrupt species interaction networks. However, replicated studies of the relative impacts of gypsy moth outbreaks and insecticide application on forest growth and animal communities are rare and have yet to be carried out in the species' indigenous range.2. Here, we review the pathways in which gypsy moth outbreaks and the chemical control of these outbreaks affect forest ecosystems. We then present an experimental design established in South Central Germany in early 2019, aiming to study the ecological and economic consequences of gypsy moth eruptions and insecticide application in oak forests. The study's full factorial design comprises forest stands at high and low defoliation risk, either treated with tebufenozide or left unsprayed, within 12 experimental blocks. Measurements of forest growth and structure, tree mortality, gypsy moth density, and composition of lepidopteran, bird, bat, ground beetle, and canopy arthropod communities will be conducted for several years.3. One‐year intensive monitoring of gypsy moth populations and damage across the selected sites showed substantial differences in population density between plots at high and low defoliation risk and high efficacy of tebufenozide in suppressing gypsy moth populations in treated plots. In the first year of the experiment, gypsy moth density and defoliation in predicted outbreak plots differed strongly, confirming the importance of using many replicates and blocking to control spatial heterogeneity. The experiment will be running continuously during the coming years to produce short‐ and medium‐term economic and ecological data to improve our understanding and management of gypsy moth outbreaks.

Ecological Legacy of DDT Archived in Lake Sediments from Eastern Canada.

Historic forest management practices led to widespread aerial application of insecticides, such as dichlorodiphenyltrichloroethane (DDT), to North American conifer forests during ∼1950-1970. Lake basins thus may provide an important archive of inputs and aquatic responses to these organochlorines. We use dated sediment cores from five study lakes in multiple watersheds in New Brunswick (NB), Canada, to provide a regional paleo-ecotoxicological perspective on this potential legacy stressor in remote lake ecosystems. Peak sedimentary levels of p, p'- and o, p'-DDT (ΣDDT) and breakdown products ΣDDE (dichlorodiphenyldichloroethylene) and ΣDDD (dichlorodiphenyldichloroethane) generally occurred during the 1970s to 1980s. Sediments exceeded probable effect levels (PELs) by ∼450 times at the most impacted lake. Modern sediments in all study lakes still contained levels of DDT-related compounds that exceed PELs. For the first time, we show that aerial applications of DDT to eastern Canadian forests likely resulted in large shifts to primary consumers within several lake food webs, principally through lake-specific impacts on zooplankton community composition. Modern pelagic zooplankton communities are now much different compared to communities present before DDT use, suggesting that a regional organochlorine legacy may exist in the modern food webs of many remote NB lakes.

Positive Results of an Early Intervention Strategy to Suppress a Spruce Budworm Outbreak after Five Years of Trials

Spruce budworm (Choristoneura fumiferana Clem.; SBW) outbreaks are one of the dominant natural disturbances in North America, having killed balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea sp.) trees over tens of millions of hectares. Responses to past SBW outbreaks have included the aerial application of insecticides to limit defoliation and keep trees alive, salvage harvesting of dead and dying trees, or doing nothing and accepting the resulting timber losses. We tested a new ‘early intervention strategy’ (EIS) focused on suppressing rising SBW populations before major defoliation occurs, from 2014 to 2018 in New Brunswick, Canada. The EIS approach included: (1) intensive monitoring of overwintering SBW to detect ‘hot spots’ of low but rising populations; (2) targeted insecticide treatment to prevent spread; and (3) proactive public communications and engagement on project activities and results. This is the first attempt of area-wide (all areas within the jurisdiction of the province of New Brunswick) management of a native forest insect population. The project was conducted by a consortium of government, forest industry, researchers, and other partners. We developed a treatment priority and blocking model to optimize planning and efficacy of EIS SBW insecticide treatment programs. Following 5 years of over 420,000 ha of EIS treatments of low but increasing SBW populations, second instar larvae (L2) SBW levels across northern New Brunswick were found to be considerably lower than populations in adjacent Québec. Treatments increased from 4500 ha in 2014, to 56,600 ha in 2016, and to 199,000 ha in 2018. SBW populations in blocks treated with Bacillus thuringiensis or tebufenozide insecticide were consistently reduced, and generally did not require treatment in the subsequent year. Areas requiring treatment increased up to 2018, but SBW L2 populations showed over 90% reductions in that year. Although this may be a temporary annual decline in SBW population increases, it is counter to continued increases in Québec. Following 5 years of tests, the EIS appears to be effective in reducing the SBW outbreak.

Spatio-temporal impacts of aerial insecticide applications on West Nile virus vectors

Event Abstract Back to Event Spatio-temporal impacts of aerial insecticide applications on West Nile virus vectors Karen M. Holcomb1, 2*, Robert C. Reiner3 and Christopher M. Barker2, 4 1 University of California, Davis, Davis Arbovirus Research and Training (DART) Lab, Department of Pathology, Microbiology, and Immunology, United States 2 Pacific Southwest Center of Excellence in Vector-Borne Diseases (PacVec), United States 3 Institute for Health Metrics and Evaluation, United States 4 University of California, Davis, Davis Arbovirus Research and Training (DART) Lab, Department of Pthology, Microbiology, and Immunology, United States Aerial applications of pesticides that target adult mosquitoes are widely used for minimizing transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of efficacy for reducing the abundance of infectious mosquitoes vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment. To overcome the limitations of assessing the efficacy of single aerial spray events and capture the spatio-temporal population structure and dynamics, we fitted generalized additive models to mosquito surveillance data from CO2-baited traps in Sacramento and Yolo counties, California from 2006-2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex tarsalis and Culex pipiens in the absence of aerial spraying. Estimates for the magnitude and duration of reduction in relative abundance for each species following aerial spray events were obtained from the model. One week post-treatment, aerial sprays reduced Cx. pipiens by an estimated mean of 39.0% (95% CI: 19.7-55.1%) and Cx. tarsalis populations by an estimated mean of 40.1% (95% CI: 20.5-55.1%). Reductions persisted over several weeks for both species, with longer population suppression for Cx. tarsalis compared to Cx. pipiens. Repeated aerial spraying over multiple weeks was more effective at maintaining reductions in Cx. pipiens populations than in Cx. tarsalis populations. Taken together, our results indicate that aerial adulticides are effective for rapid and sustained reduction of West Nile virus vectors, and further research will consider whether these effects also result in reduced infection prevalence in the same areas. Acknowledgements We would like to thank Ruben Rosas, Marcia Reed, and Gary Goodman from Sacramento-Yolo Mosquito & Vector Control District for providing trapping and aerial spray data used in this study. KMH acknowledges funding support from the Floyd & Mary Schwall Fellowship in Medical Research at UC Davis, and KMH & CMB acknowledge support from the Pacific Southwest Center of Excellence in Vector-Borne Diseases funded by the U.S. Centers for Disease Control and Prevention (Cooperative Agreement 1U01CK000516). Keywords: Mosquito Control, Culex mosquitoes, generalized addtive model, surveillance, West Nile virus Conference: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data, Davis, United States, 8 Oct - 10 Oct, 2019. Presentation Type: Student oral presentation Topic: Spatio-temporal surveillance and modeling approaches Citation: Holcomb KM, Reiner RC and Barker CM (2019). Spatio-temporal impacts of aerial insecticide applications on West Nile virus vectors. Front. Vet. Sci. Conference Abstract: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data. doi: 10.3389/conf.fvets.2019.05.00097 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2019; Published Online: 27 Sep 2019. * Correspondence: Mx. Karen M Holcomb, University of California, Davis, Davis Arbovirus Research and Training (DART) Lab, Department of Pathology, Microbiology, and Immunology, Davis, United States, kmholcomb@ucdavis.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Karen M Holcomb Robert C Reiner Christopher M Barker Google Karen M Holcomb Robert C Reiner Christopher M Barker Google Scholar Karen M Holcomb Robert C Reiner Christopher M Barker PubMed Karen M Holcomb Robert C Reiner Christopher M Barker Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Chemical control in forest pest management

AbstractChemical insecticides have been an important tool in the management of forest insect pests in Canadian forests. Aerial application of insecticides began in the 1920s and expanded greatly after World War II with the widespread adoption of DDT primarily for the suppression of spruce budworm,Choristoneura fumiferanaClemens (Lepidoptera: Tortricidae), and other defoliating insects. Significant progress was made in the development of new chemical insecticides and formulations including fenitrothion and tebufenozide, as well as technology for the application of insecticides against various insect pests. However, widespread opposition to the use of chemical insecticides in forest management has led to significant reductions in the number of insecticides registered for use in Canadian forests. Developments in the past 20 years have focussed on new insecticides, formulations, and technologies that seek to limit the impacts on non-target organisms and subsequent ecosystem effects. These developments have resulted in significant improvements in the management of traditional management targets, such as the spruce budworm (Choristoneura fumiferana(Clemens); Lepidoptera: Tortricidae) but also the management of invasive species, especially wood-boring beetles (Coleoptera: Buprestidae, Cerambycidae).

Field assessment of novaluron for sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), management in Louisiana sugarcane

On-farm field experiments were conducted in 2004 and 2007 to assess the suitability of novaluron, a chitin synthesis inhibitor, for sugarcane borer, Diatraea saccharalis (F.), management in Louisiana sugarcane ( Saccharum spp. hybrids). Aerial insecticide applications reproducing commercial production practices were made when D. saccharalis infestation levels exceeded a recommended action threshold. In addition to decreased D. saccharalis infestations, 6.3 – 14.5-fold reductions in end of season injury, expressed as the percentage of bored sugarcane internodes, were observed in plots treated with novaluron. D. saccharalis control in novaluron plots was equivalent to ( P > 0.05) or better ( P < 0.05) than that achieved with tebufenozide, an ecdysone agonist that has been extensively used for over a decade on sugarcane. With a numerical trend of a 3.1-fold decrease in percent bored internodes, the pyrethroid gamma-cyhalothrin seemed less effective than the biorational insecticides in protecting sugarcane against D. saccharalis. Using continuous pitfall trap sampling, no measurable ( P > 0.05) decreases in predaceous and non-predaceous soil-dwelling non-target arthropods were associated with insecticides. However, numerical trends for decreases in immature crickets associated with novaluron and gamma-cyhalothrin were recorded in 2007. Our data suggest that novaluron will fit well in Louisiana sugarcane integrated pest management.

Managing cabbage seedpod weevil in canola using a trap crop—A commercial field scale study in western Canada

Cabbage seedpod weevil is a relatively new pest of canola (oilseed rape) in the Prairie Ecozone of western Canada. In some years, in southern Alberta, farmers have had to resort to costly aerial insecticide applications to protect their canola crops. In this study, we evaluated perimeter trap cropping as a strategy to manage weevils in large commercial fields of canola. A total of 11 experimental fields (with perimeter trap crops) and nine conventional fields without trap crops were studied from 2000 to 2003. Field perimeters of Brassica rapa planted at the same time as the main crop of B. napus flowered ∼1 week earlier and effectively concentrated weevil populations that were sprayed with insecticide. The perimeter trap crop kept weevil populations below threshold levels in the main crops when fields were large and square (1600m×1600m). However, further research is required to develop management tools that augment the efficacy of trap crops in situations where fields are small or narrow (<400m wide), especially when populations are several times the economic threshold. Pod damage was less than 12% in the main crops of experimental fields where only the trap crops were sprayed which was comparable to that of conventionally managed fields. The savings in chemical insecticides, labor and time, as well as possible integration with other IPM strategies such as biocontrol, make perimeter trap cropping an important tool for cabbage seedpod weevil management.

Control of River Blindness in West Africa: Case History of Biodiversity in a Disease Control Program

The elimination of river blindness (onchocerciasis) in West Africa has been one of the most successful public health and economic development programs yet conducted. Control was based on aerial application of insecticides to control the aquatic, larval stages of black flies in the Simulium damnosum complex and distribution of ivermectin-based drugs to reduce incidence of the filarial worm, Onchocerca volvulus, that may ultimately result in blindness. Control efforts were long-term (1974–2003), extensive (with as many as 50,000 km of river miles being treated weekly for 12 years or longer), and far-reaching (distribution of drugs to almost 7 million people in 11 West African countries). The challenges and success of the program were strongly related to biodiversity: the vector S. damnosum is actually a complex of several species and subspecies, which vary in their competence in disease transmission; the filarial worm O. volvulus has different forms that vary in their virulence and incidence of producing blindness in humans; maintenance of the biodiversity of the non-target riverine fauna was a prime concern of both the control program and the donor countries that supported it; the main insecticide used to control the black fly vector was derived from a bacterium Bacillus thuringensis israelensis; and the drug used in controlling the filarial worm was derived from a soil-dwelling Streptomyces fungus. Long-term biomonitoring studies indicate that environmental damage (e.g., loss of sensitive taxa) incurred was reversed when insecticide applications ceased.

Impact of Spray Volume and Wetting Agent on Efficacy of Aerial Insecticide Applications to Man-Age First-Generation European Corn Borer Larvae in South Dakota, 1997

Abstract Field plots were established in central South Dakota near Letcher to evaluate aerially applied insecticide treatments for control of first-generation ECB larvae. The field was planted on 11 May at a rate of 20,400 kernels per acre. The study was carried out to determine the impact of Silwet™ wetting agent and spray volume on the effectiveness of Warrior 1 EC insecticide. Pre-treatment counts revealed an average of 2 ECB larvae (ca. 50% each of 2nd- and 3rd-instars) existed per plant. A strip-plot ex-perimental design was used, and each strip contained 4 replicates. Sampling was conducted within a 32-row subplot (30.5 m by 100 m) for each treatment area. Insecticides were applied on 13 Jul at whorl (ca. 2 d before tasseling) stage in 15.2-m swaths at a speed of 110 mph using a Piper Brave aircraft. A Crop Hawk system was mounted on the aircraft to monitor and regulate spray flow through CP™ nozzles at 25 psi. Treatments consisted of Warrior 1 EC at 0.025 lb (AI)/acre in a spray volume of 2 or 5 gpa. Additionally, each of these spray volumes was evaluated with or without Silwet™ (wetting agent), and all were compared with an untreated control. Approximately one month after insecticide applications (8 Aug), 40 plants in each plot were randomly selected, split vertically and examined for ECB cavity (tunneling) damage. The number and length of ECB cavities were recorded and analyzed using the ANOVA procedure and means were compared by LSD.

無人ヘリコプター散布によるカンキツのカメムシ類防除

無人ヘリコプター散布によるカンキツのカメムシ類防除

Aerial Application of Insecticides for Control of First Generation European Corn Borer, 1995

Abstract The cornfield was located in Cedar County, northwest of the town of Hartington, NE. Two treatments and an untreated check were arranged in a strip plot design with one replication. Six black headed egg masses were infested onto 30 marked plants (3, ten plant subsamples) per treatment on 6 Jul. A Cessna 188 Ag Truck was used to make the applications on 13 Jul. On 18 Aug, all artificially infested plants were disected from tassel to ground and examined for corn borer cavities. Data were analyzed using analysis of variance procedures. Treatment means were separated using LSD procedures.

Aerial Insecticide Applications for Control of First-Generation European Corn Borer Larvae in South Dakota, 1994

Abstract A corn field near Beresford, SD, was chosen to evaluate aerially-applied chemical and biological insecticide treatments for control of first-generation ECB larvae. Pretreatment counts indicated a light, but uniform infestation of ECB larvae in 42% of plants sampled. Stadial composition consisted of 13, 32, 38, and 17% 1st-, 2nd-, 3rd-, and 4th-instar larvae, respectively. A strip-plot experimental design was used. Each strip contained 4 replicates. Individual treatment plots were 40 m (41 rows) by 122 m. Insecticides were applied on 29 Jun at whorl (ca. 10 d prior to tasseling) stage. All insecticide treatments were applied at 8.0 lb formulated product/acre in 20-m swaths using a Cessna Ag Truck aircraft. A Duke metering system mounted on the aircraft was used for insecticide calibration and application procedures. Approximately 1 month following treatment (28 Jul), 40 plants in each plot were randomly selected, split vertically and examined for cavity (tunnelling) damage. The number and length of cavities were recorded and analyzed using SAS’s General Linear Models (GLM) procedure with means being compared by DMRT.

Spray deposits from aerial insecticide spray simulant applications to a coniferous plantation in low and high wind speeds

Aerial insecticide applications were made on a jack pine plantation in low and high wind speeds, using a fixed-wing aircraft equipped with rotary atomizers. A 16 ha area with an average canopy height of 6.5 m was sprayed with a suspension of fluorescent particles in tripropylene glycol monomethyl ether at 0.42 l ha −1, using a 65 m swath width. The spray was released from 18 m above ground and had a volume median diameter of 41 μm. Wind speeds at release height were 1.2 and 4.5 m s −1 in trials 1 and 2, and the air layers between canopy top and spray release height were stable and unstable respectively. Average drop counts per conifer needle from trials 1 and 2 were significantly different at 0.91 and 1.92, and foliar deposits at 4 and 6 m were significantly greater in the high wind trial. Drop counts per needle increased with height and the count ratios at 2, 4, and 6 m were 1:2:4 and 1:3:10 in trials 1 and 2. Drop count distributions on needles from different heights showed significant differences and a larger proportion of needles received drops in the high wind trial, implying the potential for improved insecticide efficacy. Drop densities (cm −2) on Kromekote ground cards from trials 1 and 2 were significantly different at 3.26 and 1.85, implying substantially reduced contamination of the understorey in high winds. Drop sizes were similar, with average volume and number median diameters of 71 and 45 μm. Drop sizes on Kromekote combs placed in the canopy were also similar in both trials, with average volume and number median diameters of 49 and 21 μm. The results indicate an excellent opportunity for improving on-target spray deposits and efficacy while reducing understorey contamination from silvicultural insecticide applications, as well as their cost and temporal constraints.

Second Generation European Corn Borer Control with Aerial Application of Insecticides, 1992

Abstract Insecticides were aerially applied to natural ECB populations in 2 fields near Indianola, IA, using an Ag-Cat airplane. Treatments were replicated 3 times in each field in a RCBD. All liquid formulations were applied in 1.0 gal of water per acre. Pretreatment counts of egg masses on 10 Aug indicated 11 egg masses per 100 plants in Field 1 and 19 egg masses per 100 plants in Field 2. Insecticides were applied on 16-17 Aug; the 2nd application for the split Penncap-M treatment was made on 31 Aug. Treatments were evaluated on 24-25 Sep by splitting stalks, ear shanks, and removing the husks from 10 plants in the center row of each plot (center of the spray swath) and counting live larvae. Yields were taken from the center 4 rows (Field 1) or 6 rows (Field 2) of each plot with a combine. Yields were measured on a truck scale (Field 1) or with a weigh wagon (Field 2) and samples were adjusted to 15.5% moisture and number 2 corn. Yield plot sizes ranged from 0.35-0.64 acre (Field 1) and 0.4 acre (Field 2). Yield data were not collected from replication 2 in Field 2 because of a hybrid change that split the plots. Data were analyzed by using PROC ANOVA or PROC GLM procedures of SAS. Mean separation was accomplished using Fisher’s protected LSD procedure (P = 0.10).

Aerial Application of Insecticides for Second Generation European Corn Borer Control, 1993

Abstract Insecticides were aerially applied to natural ECB populations in 2 fields near Pleasantville, IA, using an Ag-Cat airplane. Treatments were replicated 3 times in each field in a randomized complete block design. Liquid formulations were applied in one gallon of water per acre. Pretreatment counts of egg masses on 12 Aug indicated 7 egg masses per 50 plants in Field 1 and 23 egg masses per 50 plants in Field 2. Plant stage on this date was brown silk (Field 1) and green silk (Field 2). Insecticides were applied on 19 Aug; the 2nd application for the split Penncap M treatment was made 31 Aug. Treatments were evaluated on 2 and 4 Oct by splitting stalks, ear shanks, and removing the husks from 10 plants in the center row of each plot (center of the spray swath) and counting live larvae. Yields were taken on 4 Oct from the center six rows (Field 1) and on 14 Oct from the center 4 rows (Field 2) of each plot with a combine. Yields were measured with a weigh wagon, adjusted to 15.5% moisture and number 2 corn, and converted to bu/acre. Yield plot sizes were 0.35 acre (Field 1) and 0.52 acre (Field 2). Data were analyzed by using PROC ANOVA or PROC GLM procedures of SAS. Mean separation was accomplished using Fisher’s protected LSD procedure (P = 0.10).

Aerial Application of Insecticides for Control of Second Generation European Corn Borer, 1991

Abstract Insecticides were aerially applied to 2 fields near Indianola, IA, using a Cessna 188 Ag-Truck. Treatments were replicated 3 times in each field in a RCB. On 25 Jul, field counts indicated 60 egg masses per 100 plants in Field 1 and 9 egg masses per 100 plants in Field 2. Insecticides were applied on 29 Jul; the 2nd application for the split Penncap M treatment was made on 9 Aug. Ten consecutive stalks in each plot were split on 29 Aug and the number of live larvae counted. Yields from each plot were taken from Field 1 by collecting corn ears from 35 ft of row (2 adjacent rows of 17.5 ft near the original 10 split stalks) on 19 Sep. Because of the unevenness of the plant population, ear yield per plant served as the basis for yield estimation. Ears were weighed, adjusted to 15.5% moisture, and extrapolated to bu/acre based on 22,000 plants per acre. Yields in Field 2 were taken with a combine on 30 Oct. The center 4 rows of each plot (approximately 0.55 acre) were harvested, weighed, and adjusted to 15.5% moisture. Yields were converted to bu/acre based on field measurements taken with a measuring wheel. Data were analyzed by using PROC ANOVA or PROC GLM procedures of SAS. Mean separation was accomplished using Fisher’s protected LSD procedure.