Application Of Systemic Insecticides Research Articles

Review and Current Status of Systena frontalis (Coleoptera: Chrysomelidae): An Insect Pest Associated with Nursery Production Systems1

Abstract Systena frontalis (F.) (Coleoptera: Chrysomelidae) is an insect pest of nursery production systems throughout the Midwest, Southeast, and Northeast regions of the United States. The original scientific name was Galleruca frontalis F. before reclassification of the genus to Systena. There is minimal information in the scientific literature providing evidence that S. frontalis is native or an introduced species. In addition, the overwintering life stage is unknown. However, records indicate that S. frontalis is native to North America based on reports of this beetle being found in 5 provinces of Canada and 31 states in the United States. Records also indicate that the adult may be the overwintering life stage. Current management strategies implemented to reduce feeding damage caused by S. frontalis adults to container-grown nursery plants are associated with foliar spray applications of contact insecticides. However, applying contact insecticides to plant material in nursery production systems is labor intensive and not cost efficient. Application of systemic insecticides to the growing medium is a management strategy that nursery producers can use to reduce feeding damage caused by S. frontalis adults. Research demonstrates that the systemic insecticides dinotefuran and thiamethoxam protect container-grown nursery plants 45 d after application. Therefore, based on empirical, scientific-based research, applying systemic insecticides before S. frontalis adults are active provides practical and cost-effective plant protection from adult feeding damage during the growing season, thereby allowing nursery producers to grow, market, and sell container-grown nursery plants.

Residual Activity of Systemic Insecticides against Field-Collected Populations of Redheaded Flea Beetle (Coleoptera: Chrysomelidae), Systena frontalis, Adults under Laboratory and Greenhouse Conditions1

Abstract Systena frontalis (F.) is an insect pest of nursery production systems in the Midwest, Southeast, and Northeast regions of the United States. Adults feed on plant leaves and can reduce salability of container-grown nursery plants. Limited management options are available to protect plants from S. frontalis adult feeding damage. Insecticide spray applications to plant leaves are labor-intensive and not cost-efficient. Systemic insecticide applications to the growing medium may protect plants from S. frontalis adult feeding. In 2023, we conducted two laboratory and two greenhouse experiments to assess the residual activity of the systemic insecticides dinotefuran, thiamethoxam, and acephate against field-collected populations of S. frontalis adults. In the laboratory experiments, growing medium containing Itea virginica L. ‘Little Henry’ plants were treated with these three systemic insecticides. Twenty-five and 45 d after treatments were applied, leaves were collected and placed into petri dishes with a single S. frontalis adult. In the greenhouse experiments, Itea plants were placed into plastic observation cages. Eight S. frontalis adults were released into each cage with a single Itea plant. In the laboratory experiments 25 and 45 d after application of dinotefuran and thiamethoxam, the S. frontalis adults in the dishes with treated leaves had 66–90% mortality after 72 h. In the greenhouse experiments, dinotefuran and thiamethoxam protected Itea plants from S. frontalis adult feeding 45 d after application; 2.4 and 2.8 mm2 of leaf area were fed upon by S. frontalis adults. These results indicate that systemic insecticides can reduce feeding damage by S. frontalis adults on container-grown nursery plants.

Electrical signalling and plant response to herbivory: A short review

ABSTRACTFor a long time, electrical signaling was neglected at the expense of signaling studies in plants being concentrated with chemical and hydraulic signals. Studies conducted in recent years have revealed that plants are capable of emitting, processing, and transmitting bioelectrical signals to regulate a wide variety of physiological functions. Many important biological and physiological phenomena are accompanied by these cellular electrical manifestations, which supports the hypothesis about the importance of bioelectricity as a fundamental ‘model’ for response the stresses environmental and for activities regeneration of these organisms. Electrical signals have also been characterized and discriminated against in genetically modified plants under stress mediated by sucking insects and/or by the application of systemic insecticides. Such results can guide future studies that aim to elucidate the factors involved in the processes of resistance to stress and plant defense, thus aiding in the development of successful strategies in integrated pest management. Therefore, this mini review includes the results of studies aimed at electrical signaling in response to biotic stress. We also demonstrated how the generation and propagation of electrical signals takes place and included a description of how these electrical potentials are measured.

Changes in the Endophytic Bacterial Community of Brassica rapa after Application of Systemic Insecticides.

Insecticides not only control target pests but also adversely affect non-target communities including humans, animals, and microbial communities in host plants and soils. The effect of insecticides on non-target communities, especially endophytic bacterial communities, remains poorly understood. Two phases of treatments were conducted to compare the trends in endophytic bacterial response after insecticide application. Endophytic bacteria were isolated at 2 and 4 weeks after germination. Most insecticide treatments showed a declining trend in bacterial diversity and abundance, whereas an increasing trend was observed in the control. Therefore, insecticide use negatively affected non-target endophytic bacterial communities. Bacillus spp. was mostly dominant in the early stage in both insecticide treatment and control groups. Nevertheless, in the matured stage, mostly bacteria including Pseudomonas spp., Priestia spp. were dominant in groups treated with high insecticide concentrations. Therefore, plants can regulate and moderate their microbiome during their lifecycle depending on surrounding environmental conditions.

Efficacy of four systemic insecticides for reducing Nantucket pine tip moth (Rhyaciona frustrana) (Lepidoptera: Tortricidae) infestation levels and improving growth metrics in loblolly pines.

The Nantucket pine tip moth (NPTM) (Rhyacionia frustrana Comstock) is a native, regeneration pest of young loblolly pines (Pinus taeda L.), causing shoot dieback, tree deformity, and growth and volume declines. Soil applications of systemic insecticides may be an effective strategy to suppress NPTM populations. The study objective was to assess the efficacy of four systemic insecticide treatments (chlorantraniliprole, dinotefuran, fipronil, and imidacloprid) for two growing seasons in outplanted bareroot and containerized seedling trials. Response variables included NPTM infestation rates, along with tree height, groundline diameter, volume index, and stem form. Infestation rates significantly decreased for each systemic insecticide treatment during the first year compared to controls, although dinotefuran and imidacloprid provided season-long control in one trial. Chlorantraniliprole reduced NPTM infestation rates for two growing seasons in both trials. While imidacloprid treatments did not alter growth metrics except for one comparison, fipronil and dinotefuran treatments improved several growth metrics. Chlorantraniliprole consistently improved growth metrics throughout the study.

Transplant tray drench application of systemic insecticides for insect control on romaine lettuce, 2023

Transplant tray drench application of systemic insecticides for insect control on romaine lettuce, 2023

Some Significant Threats to Lychee Production and their Management Options in Bangladesh

Taher, M.A., M.M. Rahman, K.S. Islam and M.M. Uddin. 2023. Some Significant Threats to Lychee Production and their Management Options in Bangladesh. Arab Journal of Plant Protection, 41(2): 114-118. https://doi.org/10.22268/AJPP-041.2.114118 Lychee (Litchi chinensis Sonn.) production is severely hampered by pest infestations in Bangladesh. To help in management of three major lychee pests, namely, lychee fruit borer (Conopomorpha sinensis), lychee mite (Aceria litchi) and lychee leaf roller (Platypeplus aprobola), the efficacy of seven different insecticides were assessed in a commercial lychee orchard at Gopalpur, Tangail, Bangladesh, in two consecutive fruiting seasons. Lychee fruit infestations by the lychee fruit borers (>50%) reached a peak in early to late May and in late April by the lychee mites (>42%). Leaves and inflorescences infestations by the lychee mites (>14%) and lychee leaf rollers (10-33%) were high from February to March. Among the treatments, the mixture of imidacloprid and abamectin resulted in a maximum reduction of infestation over the control trees (98.08% by lychee fruit borer, 87.10% by lychee mite and 92.12% by lychee leaf roller). The highest cost-benefit ratio was achieved by applying Novastar 56 EC (bifenthrin + abamectin) (1:10.36) and ranked second in reducing infestations. Solo application of systemic insecticide and combination of systemic and contact insecticide were effective. The combination imidacloprid + abamectin was the most efficient in reducing the damage by the pests, and the mixture of bifenthrin and abamectin was the most cost-effective to control the selected pests. Keywords: Lychee fruit borer, lychee mite, lychee leaf roller, chemical controls, seasonal abundance

Comprehensive analyses of agrochemicals affecting aquatic ecosystems: A case study of Odonata communities and macrophytes in Saga Plain, northern Kyushu, Japan

The negative influence of agrochemicals (pesticides: insecticide, fungicide, and herbicide) on biodiversity is a major ecological concern. In recent decades, many insect species are reported to have rapidly declined worldwide, and pesticides, including neonicotinoids and fipronil, are suspected to be partially responsible. In Japan, application of systemic insecticides to nursery boxes in rice paddies is considered to have caused rapid declines in Sympetrum (Odonata: Libellulidae) and other dragonfly and damselfly populations since the 1990s. In addition to the direct lethal effects of pesticides, agrochemicals indirectly affect Odonata populations through reductions in macrophytes, which provide a habitat, and prey organisms. Due to technical restrictions, most previous studies first selected target chemicals and then analyzed their influence on focal organisms at various levels, from the laboratory to the field. However, in natural and agricultural environments, various chemicals co-occur and can act synergistically. Under such circumstances, targeted analyses might lead to spurious correlations between a target chemical and the abundance of organisms. To address such problems, in this study we adopted a novel technique, “Comprehensive Target Analysis with an Automated Identification and Quantification System (CTA-AIQS)” to detect wide range of agrochemicals in water environment. The relationships between a wide range of pesticides and lentic Odonata communities were surveyed in agricultural and non-agricultural areas in Saga Plain, Kyushu, Japan. We detected significant negative relationships between several insecticides, i.e., acephate, clothianidin, dinotefuran, flubendiamide, pymetrozine, and thiametoxam (marginal for benthic odonates) and the abundance of lentic Epiprocta and benthic Odonates. In contrast, the herbicides we detected were not significantly related to the abundance of aquatic macrophytes, suggesting a lower impact of herbicides on aquatic vegetation at the field level. These results highlight the need for further assessments of the influence of non-neonicotinoid insecticides on aquatic organisms.

Foliar application of systemic insecticides disrupts feeding behavior of the whitefly Bemisia tabaci MEAM1 and the transmission of tomato chlorosis virus in potato plants

The whiteflies of the Bemisia tabaci (Genn.) complex (Hemiptera: Aleyrodidae) are serious agricultural pests that cause severe losses to vegetable, ornamental and fiber crops, including potato plants, mainly as a vector of economically important viruses. Among the most important viruses affecting potato is tomato chlorosis virus (ToCV) (Closteroviridae: Crinivirus), which is semi-persistently transmitted by whiteflies of the genera Bemisia and Trialeurodes. Chemical control is the main method used to manage B. tabaci and ToCV; however, this whitefly is resistant to most commercially available insecticides, and some products may not effectively prevent the vector stylet activities associated with virus transmission. The effective management of B. tabaci is crucial to reduce the spread of vector-borne diseases, and to minimize economic losses. We evaluated the effects of the foliar spraying with the systemic insecticides acetamiprid, flupyradifurone and cyantraniliprole on the probing behavior of non-viruliferous and ToCV-viruliferous B. tabaci MEAM1 and ToCV transmission in potato plants. To evaluate ToCV transmission in greenhouse conditions, viruliferous whiteflies were released on potato plants at different time points (3, 24 and 72 h and 7 days) after insecticide spraying. The EPG assay showed that at 3 h after insecticide application, the probing behavior differed, depending mainly on the state of the insects (viruliferous or not), whereas 72 h after application, the probing behavior differed only on plants treated with acetamiprid and flupyradifurone, for both viruliferous and non-viruliferous whiteflies. ToCV transmission was reduced mainly in plants treated with flupyradifurone and acetamiprid, likely as a result of phloem activity disruption.

Limited Scope Risk Assessment for Nontarget Ground-Dwelling Arthropods From Systemic Insecticide Applications to Young Pines.

The Nantucket pine tip moth (NPTM) [Rhyacionia frustrana (Comstock)], a native regeneration pest on young loblolly pines (Pinus taeda L.), negatively impacts pine growth. An emerging management approach is to apply systemic insecticides to seedlings to reduce NPTM damage. These systemic insecticide applications generally occur once, perhaps twice, during the first few years of loblolly pine growth. However, these applications could lead to unintended environmental consequences to nontarget organisms. The purpose of this study was to assess potential nontarget effects from four systemic insecticide applications by assessing ground-dwelling arthropod trap catch, with a focus on collembolan trap catch and genera richness. Loblolly seedlings (24 seedlings per plot) at three sites in southeast Georgia were treated with either chlorantraniliprole, dinotefuran, fipronil, or imidacloprid or left untreated as a control. Arthropods were collected with pitfall traps that were deployed for 5 d in July, August, and September 2019, 7-9 mo after treatment. Ground-dwelling arthropod trap catch, arthropod order trap catch, collembolan trap catch, and collembolan genera richness did not vary among insecticide treatments and the untreated control in this mid-term insecticide risk assessment. While no significant effects of insecticide treatment were observed, ground-dwelling arthropod trap catch, collembolan trap catch, and collembolan genera richness differed among collection times. This study was the first of its kind in a young pine stand setting and is an important first step to understanding risk in these settings. Information on nontarget risks of management practices informs growers of the level of environmental risk associated with systemic insecticides.

Stem application technique for sucking pest management in cotton at tribal area of Andhra Pradesh

Cotton is one of the most important fibre and cash crop in tribal area at Visakhapatnam district of Andhra Pradesh and plays a major share in the agricultural economy of the country. Nearly 65 per cent of cotton area is under rainfed and mainly in the plain and High altitude tribal areas of the district. Sucking pests of leaf hopper, white fly, thrips, mealy bugs, mites, redcotton bugs and aphids are becoming more serious, inviting indiscriminate use of pesticides in Bt cotton growing areas. Sucking pest incidence was controlled by the stem application of systemic insecticides viz., monocrotophos 1:4 ratio at 20 days after sowing and imidacloprid 200 SL with 1:20 ratio at 40 and 60 days after sowing. Within three days of application the population of sucking pests was reduced. This technique is being demonstrated and documented for two years at 20 locations in tribal farmers fields of Visakhapatnam district. Stem application in cotton showed better performance by reducing sucking pests damage of aphids (1.89%), leaf hoppers (3.57%), white fly (5.86%), thrips (4.31%), mealy bugs (5.09%), red cotton bug (6.82%) and mite (8.31%) along with more number of bolls and kapas yield in demo plots when compared to the farmers practice aphids (16.16%), leaf hoppers (27.32%), white fly (37.29%), thrips (18.42%), mealy bugs (36.87%), red cotton bug (7.90%) and mite (25.43%). On an average both years cotton kapas yield (2111kg/ha) under Front Line Demonstrations (FLDs) were higher by 19.76 per cent as compared to farmer’s practices. Results from the study showed that farmers realized additional net income of Rs.17, 260 due to increased cotton kapas yield by 19.76 per cent with reduction of cost of cultivation by Rs.3300, it could be attributed in reduction of manual labour requirement for stem application and also increase in yield.

Mustard Aphid and Crop Production

Mustard aphid, Lipaphis erysimi (L.) Kaltenbach (Homoptera: Aphididae) is the most notorious, cosmopolitan louse-like and obligate ectoparasite, which causes a bulk of the qualitative and quantitative loss of rapeseed-mustard crops. This article reviews the general overview of biology, damages, and the management of mustard aphids. Biologically, L. erysimi adults are soft bodies, varying in color mostly yellowish-greenish, small to medium-sized, globular, pear-shaped, manifesting wing dimorphism based on the resource availability. Plasticity in reproductive mode either sexually or asexually stimulated as an adaptive response to cope with seasonal fluctuations, maximizes the chance of survival from predators being outnumbering. Mustard aphid infested host plant in three major ways, firstly by sucking the plant phloem through stylets, the needle-like piercing-sucking mouthparts which manifest injury like curling and yellowing of the leaf, stunting and drying up of the plants. Secondly, by excreting a sticky substance (honeydew) on which 'sooty mold' growth, which blocks the process of photosynthesis. Thirdly, it causes secondary plant injury by transmission and dissemination of viruses including turnip mosaic viruses. The appearance, multiplication, and disappearance of mustard aphid are largely regulated by weather variations. Its prolific multiplication greatly thrives by cool, wet, and cloudy weather. The mustard aphid can be eschewed more so if the crop is sown before 20th October. Applications of the recommended dose of fertilizers, irrigation, resistant varieties are some cultural practices to cope with the aphid population. Natural enemies are effective and impressive nowadays for crop protection. Ladybird beetles viz., Cocciniella septempunctata, Hippodamia variegata, and Cheilomones vicina are active predators of this pest. Chemical control includes the application of systemic insecticides below the ETL (Economic Threshold Level). Some major insecticide includes are Imidacloprid 17.8% @ 0.25 ml/l, Thiamethoxam 25 WG @ 0.2g/l and Dimethoate 30EC @ 1 ml/l of water.
 Int. J. Appl. Sci. Biotechnol. Vol 8(3): 310-317

Profile of Coffee Crops and Management of the Neotropical Coffee Leaf Miner, Leucoptera coffeella

The Neotropical coffee leaf miner is a key coffee pest and in the state of Bahia, one of the major coffee-producing states in the country. The insect finds favorable conditions for its development, causing production losses and intensive use of insecticides. Thus, the objective of the study was to analyze aspects of the profile of coffee crops and the management of the leaf miner, including the use of insecticide for the western and highland regions of Bahia. Data were obtained through questionnaires applied to coffee growers and/or production technicians and included information on the total area, area with coffee, and native vegetation, type of cultivation, cultivars, pest monitoring, methods of control and use, insecticide rotation, and doses used. Descriptive statistical analysis, principal component analysis (PCA), and canonical correlations indicated differences between farm size, and areas with coffee and native vegetation. Chemical pest control prevails as a management strategy in all farms. The results are important for managing the coffee leaf miner while providing an overview and diagnosis of insecticide use in coffee production in the state of Bahia. An increase in the application of systemic insecticides took place in recent years, similarly (same active ingredients) among most coffee growers. This fact increases the risk of selecting populations resistant to insecticides, compromising the management of the leaf miner in the regions.

Effects of systemic insecticides on the population dynamics of the dragonfly Sympetrum frequens in Japan: Statistical analyses using field census data from 2009 to 2016

Since the mid-1990s, populations of the common Japanese dragonfly Sympetrum frequens in rice fields have declined severely. Application of systemic insecticides—especially fipronil—to nursery boxes of rice seedlings is suspected to be the main cause of the decline. However, until now there have been insufficient population data to test the causality. We conducted a dragonfly survey from 2009 to 2016 in four prefectures of Japan and compiled the data to enable the comparison of population growth rates along five main census routes over the years. We also estimated the use ratio of each insecticide applied to nursery boxes in rice fields (i.e., the area exposed to insecticide as a ratio of the total rice field area) by prefecture. We then statistically analyzed the effects of the insecticides on the dragonfly’s population growth rates, taking into account the potential confounding factors based on current knowledge. There was a significant negative association between the annual increase in use ratio of the sum of systemic insecticides (e.g., fipronil, imidacloprid, and chlorantraniliprole) and the annual population growth rate of S. frequens. This association suggests that systemic insecticide use affected the decrease in population density of the dragonfly, although some agronomic factors need to be further examined as potential confounders.

Application of Loop-Mediated Isothermal Amplification in an Early Warning System for Epidemics of an Externally Sourced Plant Virus.

Restricting Turnip yellows virus (TuYV) spread in canola (Brassica napus) crops often relies upon the application of systemic insecticides to protect young vulnerable plants from wide-scale green-peach aphid (GPA; Myzus persicae) colonization and subsequent virus infection. For these to be applied at the optimal time to ensure they prevent epidemics, growers would need to be forewarned of incoming viruliferous aphid migration and colonization. This study was conducted to field validate a loop-mediated isothermal amplification (LAMP) protocol designed to detect TuYV in aphids caught on traps and develop an early warning system for TuYV epidemics. Double-sided yellow sticky traps were deployed at 30 sites sown with canola over a two-year period in the south-west Australian grainbelt. Using LAMP, the percentage (%) of trap sides with TuYV-carrying aphids was measured and related to TuYV infection incidence in the adjacent crop. When TuYV was detected in aphids on >30% trap sides in a six-week period from pre-emergence to GS15 (five-leaf stage), TuYV reached >60% crop incidence by GS30 (beginning of stem elongation). Whereas, TuYV detection in aphids on ≤15% trap sides during this period was associated with ≤6% TuYV incidence by GS30. Furthermore, when large numbers of aphids, including GPA, were caught during this period but no TuYV was detected in them, minimal TuYV spread (≤5%) occurred in the crop by GS30. Therefore, the LAMP TuYV protocol can be used in an early warning system for TuYV epidemics by providing detection of initial viruliferous aphid migration into a canola crop before they establish colonies throughout the crop and spread virus. This would enable proactive, non-prophylactic, and thereby more effective systemic insecticide applications to minimize seed yield and quality losses due to early season TuYV infection.

Could tree density play a role in managing Citrus Huanglongbing epidemics?

Citrus Huanglongbing (HLB) management relies on adoption of preventive measures including the use of healthy nursery trees, area-wide control of the vector Diaphorina citri, and eradication of symptomatic trees. Cultural practices including tree density could contribute to HLB management. We investigated the role of tree density on the incidence of HLB using a historical dataset from commercial orchards in Sao Paulo State, Brazil. The HLB incidence from 2013 to 2015 was compared through 495 blocks of different tree ages (3 to 13 years old), tree localization within the farm (edge or non-edge), and tree densities (from 220 to 714 trees·ha−1) according to the tree spacing used. Diaphorina citri was controlled rigorously in all commercial blocks using drench applications of systemic insecticides and foliar sprays of contact insecticides. The results indicated that cumulative HLB incidence was predominantly lower at higher tree densities. In addition to vector control and removal of HLB-symptomatic trees, planting of trees in high densities may reduce the proportions of HLB-infected trees, thereby contributing to improved profitability for farmers in HLB-endemic sites. In particular, this management practice should be applied at the edges of farms.

UV-irradiation and leaching in water reduce the toxicity of imidacloprid-contaminated leaves to the aquatic leaf-shredding amphipod Gammarus fossarum.

Systemic neonicotinoid insecticides such as imidacloprid are increasingly applied against insect pest infestations on forest trees. However, leaves falling from treated trees may reach nearby surface waters and potentially represent a neonicotinoid exposure source for aquatic invertebrates. Given imidacloprid's susceptibility towards photolysis and high water solubility, it was hypothesized that the leaves' toxicity might be modulated by UV-irradiation during decay on the forest floor, or by leaching and re-mobilization of the insecticide from leaves within the aquatic ecosystem. To test these hypotheses, the amphipod shredder Gammarus fossarum was fed (over 7 d; n = 30) with imidacloprid-contaminated black alder (Alnus glutinosa) leaves that had either been pre-treated (i.e., leached) in water for up to 7 d or UV-irradiated for 1 d (at intensities relevant during autumn in Central Europe) followed by a leaching duration of 1 d. Gammarids' feeding rate, serving as sublethal response variable, was reduced by up to 80% when consuming non-pretreated imidacloprid-contaminated leaves compared to imidacloprid-free leaves. Moreover, both leaching of imidacloprid from leaves (for 7 d) as well as UV-irradiation reduced the leaves' imidacloprid load (by 46 and 90%) thereby mitigating the effects on gammarids' feeding rate to levels comparable to the respective imidacloprid-free controls. Therefore, natural processes, such as UV-irradiation and re-mobilization of foliar insecticide residues in water, might be considered when evaluating the risks systemic insecticide applications in forests might pose for aquatic organisms in nearby streams.

Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015: Table 1

Sweetpotato whitefly, also known as silverleaf whitefly is a serious of pest of curcubit vegetables in southwest Florida. Feeding can result in loss of yield and fruit quality due to silverleaf disorder but watermelon growers can experience catastrophic losses from watermelon vine decline caused by squash vein yellowing virus transmitted by B. tabaci . We prepared three raised beds 32 inches wide on 6-ft centers and 430 ft long for this trial on 22 Jan at the Southwest Florida Research and Education Center in Immokalee FL. Two drip tapes with 8-inch emitter spacing and flow rate of 0.67 gpm/100 ft were laid on each bed which was then covered with whiteface polyethylene film and fumigated with 300 lbs/acre Pic-Clor 60 EC (chloropicrin 56.7% + 1-3 dichloropropene 37.1%) injected through …

Systemic Control of Nantucket Pine Tip Moth (Rhyacionia frustrana Scudder in Comstock, 1880) Enhances Seedling Vigor, Plantation Establishment, and Early Stand-Level Productivity in Pinus taeda L.

Establishment is a vulnerable and expensive stage of stand development in intensively managed pine plantations. We evaluated the capacity of establishing loblolly pine (Pinus taeda L.) plantations to increase productivity by systemic control of Nantucket pine tip moth (Rhyacionia frustrana Scudder in Comstock, 1880). In January 2009, four genotypes of improved genetics loblolly pine were planted in whole-plot treatments of herbaceous competition control at an upper coastal plain (UCP) site and phosphorus fertilization at a lower coastal plain (LCP) site, and split-plot treatments of tip moth control. Trees were monitored for tip moth infestation levels, vigor, survival, and stand-level biomass production for 2 years. During this time, tip moth infestation levels were very high at both sites, averaging 69% at UCP and 70% at LCP. However, levels averaged only 8% at UCP and 39% at LCP in treatments that included applications of systemic insecticides at planting. At LCP, biomass production averaged 2,159 kg ha 1 after 2 years. Protection from tip moth increased LCP biomass by 11% averaged across genotypes and 20 –30% for the most responsive genotypes. At UCP, 2-year pine biomass production was much lower at 114.5 kg ha 1 and was increased 150% by protection from tip moth. At UCP, there was a strong effect of genetics whereby one genotype experienced very high mortality (mean of 30%) attributed to meteorological conditions of the establishment year; however, this was greatly decreased (17%) by protection from the interacting stress of tip moth damage. We conclude that systemic control of tip moth using imidacloprid soil tablets has the potential to greatly enhance pine plantation establishment success and early productivity in areas of heavy pest pressure, which may compound through stand development.

침투이행성 농약의 토양처리 후 토마토잎에서의 잔류에 의한 꿀벌 독성

꿀벌에 대한 급성독성이 강한 침투이행성 농약을 대상으로 토양처리 후 흡수이행에 의해 나타나는 꿀벌(Apis mellifera)에 대한 영향을 조사하고자 꿀벌 엽상잔류독성시험을 수행하였다. 본 연구에서는 침투이행성 농약인 dinotefuran 입제와 imidacloprid 입제 그리고 clothianidin 입제를 토마토 정식시 3가지 처리량으로 토양에 파구처리를 하였다. 처리 후 경과시간에 따라 잎을 채취하여 잎에서의 잔류농도를 분석하였고 꿀벌에 노출시켜 꿀벌치사율을 조사하였다. Dinotefuran 입제 처리구의 꿀벌 독성은 7일 이후 꿀벌치사율이 100%로 나타났고 17일 이후 감소하였다. Imidacloprid 입제의 경우 꿀벌 최대치사율이 44~72%로 낮았으나 그 영향은 18일까지 지속된 후 감소하였고 clothianidin 입제는 처리 후 7일에 꿀벌치사율이 100%이었으며 14일 이후 점차 감소하였다. 시험농약 처리 후 경과시간에 따른 잎의 잔류 경향성과 각 시험농약에서 꿀벌의 치사율은 유사한 경향성을 보였으며, 토마토의 생장이 활발한 14일 이후에는 토마토 잎에서의 잔류량이 점차 감소하였고, 실제 사용량 처리시 21일 이후에는 엽상잔류에 의한 꿀벌의 영향도 확연하게 감소하였다. Residual toxicity test to honeybee was conducted to evaluate an indirect effects on honeybee after planting hole application of systemic insecticides which were highly toxic to honeybee (Apis mellifera). In this study, It was applied three application rates in the planting hole by three systemic insecticides, dinotefuran GR, imidacloprid GR and clothianidin GR at planting time of tomato. Residual analysis of foliage was carried out after periodic sampling the foliage and investigated the effects of exposed honeybee on the tomato foliage. The honeybee mortality by dinotefuran residues on the foliage was shown almost 100% at 7 days after treatment and decreased 17 days after treatment. The maximum mortality of honeybee by imidacloprid residues on the foliage was 44 ~ 72%. But the effect of pesticide lasted for 18 days and then decreased. The honeybee mortality by clothianidin residues on the foliage was 100% at 7 days after treatment and decreased 14 days after treatment. A tendency of the honeybee mortality and residue in foliage showed a similar character as time goes by. The residues in tomato foliage decreased gradually after 14 days by vigorous growth of tomatoes and the toxic effect of honeybee was significantly decreased after 21 days in actual usage of the treatment.