Insect Pests Of Crops Research Articles

Development and evaluation of emulsifiable concentrate formulation containing Sophora alopecuroides L. extract for the novel management of Asian citrus psyllid.

Utilization of non-host plants semiochemicals to mediate insect behavior offers a promising opportunity for novel management of insect pests in field crops and fruits. Therefore, there is still a substantial opportunity for the development of natural prophylactic as an eco-friendly approach in the novel pest management programs. Sophora alopecuroides extract has been used as a natural pesticide in the control of agricultural and household pests, but the low persistence effect and rapid biodegradability limit its use on a wider scale in pest management programs. In this study, an emulsifiable concentrate formulation containing S. alopecuroides extract (SAE-EC) was developed with a simple procedure and evaluated for its ovicidal, antifeedant, and repellent effects against Diaphorina citri under laboratory and semi-field conditions. Our results indicated that SAE-EC at 15, 30, and 50mg/mL concentrations provide complete protection against psyllids for a period of 96h after application both under laboratory andsemi-field conditions, while the aqueous methanolic extract of S. alopecuroides loses its persistence 48h after application. Furthermore, the emulsifiable concentrate at 20 and 30mg/mL concentrations, only 15.97% and 31.97% of eggs were able to hatch, and at similar concentrations, 72.86% and 85.5% of honeydew secretion were reduced as compared to the control. SAE-EC at 30mg/mL concentration has not shown any phytotoxic symptoms on Murraya paniculata seedlings. Fourier transform infrared (FTIR) study revealed the presence of alkaloids in emulsifiable concentrate after 3months of its preparation placed under ambient temperature. Furthermore, the particle size and polydispersity index (PDI) of the emulsifiable concentrate were also confirmed by dynamic light scattering (DLS). Our finding indicated that emulsifiable concentrate formulation prolongs the persistence of S. alopecuroides extract and enhances its efficacy both under laboratory and semi-field conditions. It has been concluded that the emulsifiable concentrate formulation containing S. alopecuroides extract might be developed as an eco-friendly novel prophylactic against citrus psyllid.

Mapping of spatiotemporal distribution of Tibraca limbativentris Stal (Hem.: Pentatomidae) in flooded rice crop in Southern Brazil

The rice stem bug, Tibraca limbativentris Stal (Hem.: Pentatomidae), is one of the main insect pests in Brazilian rice crops. Knowledge of its spatiotemporal distribution can support the development of an effective sampling system and improve IPM strategies. This study aimed to map the spatiotemporal distribution of rice stem bug in flooded rice crop in Southern Brazil. Flooded rice crop was scouted for two seasons to estimate insect densities. Four occurrence categories were observed: no insect, only adults, only nymphs, and both phases. The relationship between phenological stages and insect categories was established. Interpolation (mapping) of occurrence categories of T. limbativentris was performed by multiquadric equations. In two seasons during the rice cycle, the results indicate that rice stem bug “adults” were the most abundant category until the mid-vegetative phase of the rice; “nymphs” were the most abundant from the end of vegetative phase; “adults+nymphs” occurred from the beginning of reproductive phase; there were no rice stem bugs in more than 66% of the area, as they were most concentrated near the edge of the crop. The information presented here provides further knowledge about T. limbativentris spatiotemporal dynamics that can be applied to improve IPM strategies, such as developing sampling plans and localized control measures at the edge of rice fields.

Effect of Insecticide Drench Applications on Western Flower Thrips, Frankliniella occidentalis, Pupae in Growing Media

Western flower thrips, Frankliniella occidentalis, is one of the most destructive insect pests of greenhouse-grown horticultural crops. The primary method of managing western flower thrips populations involves applications of insecticides; however, there is no information associated with the effect of the insect growth regulator, pyriproxyfen, or the entomopathogenic fungus, Isaria fumosorosea, on western flower thrips pupae in growing media. Therefore, four laboratory experiments were conducted to determine the effect of pyriproxyfen and I. fumosorosea applied as a drench to growing media on western flower thrips pupae. Expt. 1 evaluated the efficacy of pyriproxyfen and I. fumosorosea on western flower thrips pupae. Based on the results from Expt. 1, Expt. 2 assessed the effect of pyriproxyfen in two growing media (LC1 and BM1) on western flower thrips pupae. Expts. 3 and 4 determined the residual activity of pyriproxyfen in growing media on western flower thrips pupae 3, 5, 7, and 14 days after treatments were applied. The pyriproxyfen treatment resulted in a significantly lower estimated mean probability of western flower thrips adults captured on yellow sticky cards (17%) compared with the water control (59%), untreated check (88%), and two I. fumosorosea treatments (46% for 1.0 g and 41% for 2.0 g of Ancora) in Expt. 1. However, for the two growing media in Expt. 2, the estimated mean probability of western flower thrips adults captured on yellow sticky cards was not significantly different between the pyriproxyfen treatment (LC1 = 15%; BM1 = 12%) and the water control (LC1 = 41%; BM1 = 24%). For either the pyriproxyfen treatment or the untreated check, there was no evidence of a significant difference between the two growing media on the estimated mean probability of western flower thrips adults captured on yellow sticky cards. Furthermore, there was no evidence of any residual activity 3 days after drench applications of pyriproxyfen. The results of the study have demonstrated that drench applications of pyriproxyfen are not affecting survival of western flower thrips pupae.

Spatial and Temporal Dynamics of the Native Banana-Spotting Bug, Amblypelta lutescens lutescens (Hemiptera: Coreidae), in Avocado Crops in North Queensland, Australia.

The native banana-spotting bug, Amblypelta lutescens lutescens Distant, is a major polyphagous insect pest of many tropical and subtropical horticultural crops in Australia, including high-valued commodities such as avocado (Persea americana Mill. (Laurales: lauraceae)). The cryptic nature of A. l. lutescens makes it difficult to sample, and much about its ecology and behavior remains poorly understood. A lure based on the main components of the semiochemicals emitted by male A. l. lutescens, which is attractive to adult males, adult females, and nymphs, has been developed and incorporated into a trap, facilitating sampling of A. l. lutescens in the field. A 2-yr study investigated the spatial and temporal dynamics of the pest in two conventionally managed avocado (cv. Shepard) orchards using a grid (36 m × 36 m) of traps across each. In each year of the study, higher numbers of A. l. lutescens were recorded from October to June. In one field, spatial clustering of adults was detected in close proximity to an adjacent lime [Citrus aurantiifolia (Christm.) (Rutales: rutaceae) Swingle] crop that was not managed with insecticides during the study. Spatial clustering of nymphs was detected adjacent to native riparian vegetation in the other field. The results suggest that source populations of A. l. lutescens could originate from neighboring crops that host A. l. lutescens and from riparian vegetation. Focused sampling of trees at the interface with these vegetation types could lead to early pest detection, timely suppression, and therefore improved pest management.

Effect of Thermotherapy on the Acquisition of Candidatus Liberibacter Asiaticus by the Asian Citrus Psyllid (Hemiptera: Liviidae)

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the most detrimental insect pest of citrus crops due to its role as a vector of Candidatus Liberibacter asiaticus (Las), the bacterial causal agent of huanglongbing, also known as citrus greening disease. Trees infected with Las decline rapidly and fruit production decreases until eventual tree death. Few treatment options for infected trees are available for disease management. A technique called “thermotherapy” is under development to reduce bacterial titers in infected trees; however, the effect of these treatments on the transmission cycle of Las is not known. Field and laboratory assays were conducted to determine whether thermotherapy treatment reduced Las acquisition by D. citri. Trees in the field were treated with a mobile heat treatment system. Potted trees in the laboratory were treated in a steam chamber. We monitored acquisition rates in D. citri following thermal treatment of Las-positive Citrus sinensis (L.) (Rutaceae). Psyllid acquisition and Las titer in thermotherapy-treated trees were compared with untreated Las-positive and untreated Las-negative trees. Our results confirmed the efficacy of whole-tree thermotherapy on Las in potted citrus trees. In contrast, thermotherapy did not significantly reduce plant Las titers or acquisition of Las by D. citri under field conditions. These results suggest that further development of field application methods is needed to determine the utility of thermotherapy as a tool for huanglongbing management.

Pest Complex of Horticultural Crops in District Ghizer (Gilgit-Baltistan), Pakistan: A Baseline Survey

Agriculture is the main source of livelihood of the farming community of Gilgit-Baltistan especially district Ghizer. Wheat and other horticultural commodities are grown as cash crops in the district, however, productions have severely been suffered because of insect-pests and diseases. Being a remote area and lack of infrastructural facilities from field to markets, a major part of produce is being wasted. Earlier to this, no particular survey has been conducted regarding pests of concerns in the district, which is now dire need of time. Therefore, the current study was planned to document the basic information regarding insect-pests of horticultural crops of this area and provide basis to formulate programs for environment friendly and sustainable pest management strategies to enhance crop productivity and make farming profitable for farmers. In current survey, the main emphasis was to record the insect-pests and diseases that have become a great concern to farmers and environment of not only district Ghizer but also over all Gilgit- Baltistan province. Survey was confined to horticulture crops and some other major agronomic crops grown by local farmers on their farms. The overall results of this survey revealed that apple codling moth, apricot moth, white grub, cut worm, fruit flies and mealy bug were major insect-pests of horticultural crops which needed to be controlled on priority basis. The developmental needs of farming community required extensive trainings and first-hand knowledge on crop production, good agricultural practices and crop protection techniques. This document will provide basic information for formulating sustainable agriculture strategies in future.

Assessing Anaerobic Soil Disinfestation as a Control Tactic for Delia radicum (Diptera: Anthomyiidae) in California Brussels Sprouts.

Fumigants are often the primary material used to manage plant disease agents, soil-borne arthropods, and weeds in California agriculture, particularly in the absence of crop rotation. However, some fumigants have come under increased regulatory scrutiny and are therefore no longer available for use. We tested two biologically based preplant crop-protection fumigant alternatives for their effectiveness in reducing populations of Delia radicum (L.), a soil-borne insect pest of cole crops. Laboratory and field tests compared pest survival in untreated control soil with survival under anaerobic soil disinfestation (ASD), which is induced by incorporating a carbon source (rice bran or grape pomace) and subsequently saturating the soil with water. We also measured and compared the effects of standard grower practices (fumigation), ASD and biofumigation (mustard seed meal incorporated before planting), and untreated control soils on fly abundance, pupal survival, and root damage in Brussels sprout fields. In both laboratory and field studies, D. radicum pupal survivorship was reduced in ASD-treated soils relative to control soils. Pupal survivorship of Musca domestica (L.) (Diptera: Muscidae), which was used as a proxy for D. radicum in some field experiments, was also reduced in ASD- and biofumigation-treated soils, when compared with untreated control soils. These results indicate that fumigant alternatives may provide useful insect pest management opportunities for compatible cropping systems.

Deciphering host-parasitoid interactions and parasitism rates of crop pests using DNA metabarcoding

An accurate estimation of parasitism rates and diversity of parasitoids of crop insect pests is a prerequisite for exploring processes leading to efficient natural biocontrol. Traditional methods such as rearing have been often limited by taxonomic identification, insect mortality and intensive work, but the advent of high-throughput sequencing (HTS) techniques, such as DNA metabarcoding, is increasingly seen as a reliable and powerful alternative approach. Little has been done to explore the benefits of such an approach for estimating parasitism rates and parasitoid diversity in an agricultural context. In this study, we compared the composition of parasitoid species and parasitism rates between rearing and DNA metabarcoding of host eggs and larvae of the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera, Noctuidae), collected from millet fields in Senegal. We first assessed the detection threshold for the main ten endoparasitoids, by sequencing PCR products obtained from artificial dilution gradients of the parasitoid DNAs in the host moth. We then assessed the potential of DNA metabarcoding for diagnosing parasitism rates in samples collected from the field. Under controlled conditions, our results showed that relatively small quantities of parasitoid DNA (0.07 ng) were successfully detected within an eight-fold larger quantity of host DNA. Parasitoid diversity and parasitism rate estimates were always higher for DNA metabarcoding than for host rearing. Furthermore, metabarcoding detected multi-parasitism, cryptic parasitoid species and differences in parasitism rates between two different sampling sites. Metabarcoding shows promise for gaining a clearer understanding of the importance and complexity of host-parasitoid interactions in agro-ecosystems, with a view to improving pest biocontrol strategies.

Negative impact of Novaluron on the nontarget insect Bombyx mori (Lepidoptera: Bombycidae)

Due to increased use of agrochemicals and growing concerns about ecotoxicology, the development of new insecticides, moving away from those with neurotoxic and broad spectrum effects towards insecticides that are safer for the environment and nontarget beneficial species, has been a research priority. Novaluron stands out among these newer insecticides, is an insect growth regulator that is used for the control of insect pests in crops grown close to mulberry plantations. Mulberry serves as food for the silkworm Bombyx mori, which is a nontarget insect of great economic importance to silk production. We investigated the lethal and sublethal effects of Novaluron on the development of B. mori. Larvae were segregated into experimental groups: the control groups (CGs) and the treatment groups (TGs), which were treated with the Novaluron concentration of 0.15 mL/L. Following exposure, we analyzed: larval mortality, changes in the insect life cicle and cytotoxic effects on the midgut cells. This is the first report about the Novaluron’s effects on B.mori. We detected rupture in the integument, complete cessation of feeding, late development, incomplete ecdysis and production of defective cocoons. After 240 h of exposure, there was 100% mortality in TG larvae exposed in the 3rd instar and 20% mortality from larvae exposed in the 5th instar. Cytotoxic effects was observed, such as dilation of cells, emission of cytoplasmic protrusions, extreme rarefaction of the cytoplasm and nuclei, dilation of the endoplasmic reticulum in addition to changes in mitochondria, the presence of large digestive vacuoles and intercellular spaces and the presence of active caspase. Novaluron exposure impairs the midgut and may affect the physiological functions of this organ. Novaluron additionally compromises several phases of insect development, indicating the importance of toxicology studies that utilize different life stages of nontarget species to evaluate the safe use of insecticides.

The Potential Global Distribution and Voltinism of the Japanese Beetle (Coleoptera: Scarabaeidae) Under Current and Future Climates

Japanese beetle, Popillia japonica (Newman), is a severe invasive insect pest of turf, landscapes, and horticultural crops. It has successfully colonized much of the United States and has recently established in mainland Europe. The distribution and voltinism of P. japonica will undoubtedly change as a consequence of climate change, posing additional challenges to the management of this species. To assess these challenges, a process-oriented bioclimatic niche model for P. japonica was developed to examine its potential global distribution under current (1981-2010) and projected climatic conditions (2040-2059) using one emission scenario (representative concentration pathway [RCP] 8.5) and two global climate models, ACCESS1-0 and CNRM-CM5. Under current climatic conditions, the bioclimatic niche model agreed well with all credible distribution data. Model projections indicate a strong possibility of further range expansion throughout mainland Europe under both current and future climates. In North America, projected increases in temperature would enable northward range expansion across Canada while simultaneously shifting southern range limits in the United States. In Europe, the suitable range for P. japonica would increase by 23% by midcentury, especially across portions of the United Kingdom, Ireland, and Scandinavia. Under the RCP 8.5 scenario, cumulative growing degree-days increased, thereby reducing the probability of biannual life cycles in northern latitudes where they can occur, including Hokkaido, Japan, northeastern portions of the United States, and southern Ontario, Canada. The results of this study highlight several regions of increasing and emerging risk from P. japonica that should be considered routinely in ongoing biosecurity and pest management surveys.

Nano/microfibers of EVA copolymer obtained by solution blow spinning: Processing, solution properties, and pheromone release application

ABSTRACTPheromones have been used for monitoring and control of insect pests in crops, reducing the use of pesticides. However, among obstacles for this technology to be more useful, is the control and time to release. In this way, this work aims the evaluation of the release of pheromones using micro/nanofibers of ethylene–vinyl acetate (EVA) produced by blow spinning. Solutions with 0.5–15 wt % EVA were prepared based on the solubility parameter of the copolymer. Fibers were obtained from solutions in the semidiluted concentration regime. Synthetic sex pheromones from the oriental fruit moth, Grapholita molesta and citrus leafminer Phyllocnistis citrella were incorporated into the micro/nanofibers. The morphology and structure of these fibers were evaluated employing field emission scanning electron microscopy and wide‐angle X‐ray diffraction. The fibers sizes (95–426 nm) were dependent on the feed rate of the solution. As a result, pheromone release has occurred linearly over 10 weeks, as determined by thermogravimetry analysis. The solubility parameter influences the amount incorporated in the fiber and the rate of pheromone release. The proposed fiber/pheromone system is interesting since it reduces the use of actives and can be used in several planting cycles and reused. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47647.

Characterization of inheritance and preliminary biochemical mechanisms of spirotetramat resistance in Phenacoccus solenopsis Tinsley: An economic pest from Pakistan

Phenacoccus solenopsis is an economically important insect pest of different agronomic and horticultural field crops. In Pakistan, the cotton crop was severely attacked by P. solenopsis during 2007 and since then a varied group of insecticides are used by farmers to manage this pest. As a result, insecticide resistance has become a barrier in control of P. solenopsis. The current study was designed to explore the basics of genetics, realized heritability and possible genetic mechanisms of resistance against spirotetramat in P. solenopsis. Before selection, the wild population (Wild-Pop) showed 5.97-fold resistance when compared with lab-reared susceptible strain (Susceptible Lab-Pop). The P. solenopsis was selected with spirotetramat to 21 generations, called Spiro-SEL Pop, which showed 463.21-fold resistance as compared with the Susceptible Lab-Pop. The values of LC50 for F1 (Spiro-SEL Pop ♂ × Susceptible Lab-Pop ♀) and F1 (Spiro-SEL Pop ♀ × Susceptible Lab-Pop ♂) populations were statistically similar and values of dominance level were 0.42 and 0.54, respectively. Reciprocal crosses between Susceptible Lab-Pop and Spiro-SEL Pop showed that resistance was of autosomal in nature with incomplete dominant traits. According to the fit test, monogenic model estimation of the number of genes, which are responsible for the development of spirotetramat resistance in a population of P. solenopsis, showed that multiple genes are involved in controlling the resistance levels in tested strains of P. solenopsis. The value of heritability for resistance against spirotetramat was 0.13 in P. solenopsis. Our results suggested the presence of a metabolic-based resistance mechanism associated with the monooxygenases in P. solenopsis, while testing the synergism mechanism. These results will provide the baseline to design an effective control strategy to manage P. solenopsis in the field.

Phytotoxicity of tracer 120SC on greenhouse-grown rose (Rosa sp.) flowers

Tracer 120SC is effective against several insect pests of different crops, but it may be phytotoxic. The objective of this study was to quantify the phytotoxic effect of Tracer 120SC on rose. Phtotoxicity of Tracer 120SC was tested at three rates. A single application of Tracer 120SC caused acute phytotoxic damage to leaves, shoots and flower stalks at all tested rates. Two to three days after spraying symptoms were observed on 32.2 to 52.0% of sprayed shoots, with severity of 26 to 38%. Damage on individual shoots without flower buds varied between 21.1 and 37.6%. Similarly, the proportion of damaged leaves per flower stalk ranged from 57.8 to 62.3%. Flower damage was highest of any tissue, with 79.5 to 90% of tissue exhibiting phytotoxic symptoms. Taken together all flower stalks exhibited damage and were not marketable.

A new segmentation algorithm based on evolutionary algorithm and bag of words model

Crop disease and insect pest detection and recognition using machine vision can provide precise diagnosis and preventive suggestions. However, the complexity of agricultural pest and disease identification based on traditional bag of words (BOW) models is high and the effect is general. This paper presents a histogram quadric segmentation algorithm based on an evolutionary algorithm to observe the features (colour, texture) of disease spots and to learn from the guided filtering algorithm. This process aims to obtain the precise positions of disease spots in images. Dense-SIFT, which can extract features and spatial pyramid, which can map image features to high-spatial-resolution space, are simultaneously applied in the recognition of crop diseases and insect pests in the BOW model. The experimental results show that the new segmentation algorithm can effectively locate the positions of disease spots in corn images and the improved BOW model substantially increases the recognition accuracy of crop diseases and insect pests.

PESTICIDES IMPORT, USE, CONSUMPTION AND RESIDUE STATUS AMONG FOOD CROPS IN NEPAL: A REVIEW

Insubstantial options for chemical pest management compelled farmers to use synthetic pesticides against crop insect pests that created vicious circle of increasing high-dose-pesticides applications in agriculture sector. The study was carried out to understand prevailing situation of pesticides uses and their state regulation status. Secondary data were obtained from Plant Protection Division, Plant Management and Registration Division, and FAOSTAT for drawing inferences and trend analysis. Chemical pest management commenced from using Paris green, Gamaxone, Nicotine sulphate and Chlorinated hydrocarbons in 1950s to 117 chemically defined pesticides including bio-pesticides and bio-rational compounds of 2186 formulations from 1960s to 2018 has made obvious changes in pest management scenario in the country. Per hectare pesticide consumption in Nepal is 396.0 gram (a.i.) while in commercial vegetable sector its consumption is as high as 1,600 gram a.i. per hectare. Option dearth but farmers’ reliability only in chemical applications in pest management in crop fields has resulted in repercussion of vicious circle of compelled higher dose pesticide applications in crops. Obvious result is scores of multitudes of pesticides crowded in market in the country. Above all, problems of pesticide residues in food grains and green vegetables are emerging.

Modelling and Forecasting of Greenhouse Whitefly Incidence Using Time-Series and ARIMAX Analysis

Greenhouse whitefly (Trialeurodes vaporariorum) is a major insect pest of greenhouse crops. To prevent the damage caused by whiteflies, farmers control the population of whiteflies by spraying pesticides in a regular basis. However, pesticides are costly and may affect the environment and health of farmers. To provide a more efficient way for applying pesticides, this research aims to develop a model for predicting the possible increase in whitefly population in greenhouses using autoregressive integrated moving average (ARIMA) and ARIMA with exogenous variables (ARIMAX). The data used in this work were collected using wireless imaging devices that can monitor the number of whiteflies trapped on sticky paper traps using an automatic insect counting algorithm. The wireless imaging devices were installed in a greenhouse that grew tomato seedlings, which is one of the host plants of whiteflies. The ARIMA and ARIMAX models were compared by setting different combinations of input data. Particularly, ARIMA includes only the whitefly count while ARIMAX includes the whitefly count and environmental data. Based on preliminary testing, the minimum number of input data was found to be at around 60 days to 90 days. ARIMAX was found to be the best model with input data including the increase in whitefly counts, temperature and humidity. In average, the RMSE for 7-day forecasting of the proposed method was found to be around 1.30. To assist farmers in decision-making for pesticide application scheduling, four levels of increase in whitefly count were defined such as Normal, Moderate, High, and Critical, which were determined using K-means clustering algorithm, and testing results on a testing dataset show an F1-scores of 0.86 and 0.42 for Normal and Moderate levels of daily increase in whitefly count.

Farmers’ indigenous knowledge and management of insect pests in Maize and Tomato crops at West Hararghe Zone, Oromia Region, Ethiopia

The survey involved 207 purposely selected farmers (Key Informants (KI) and Focus Group Discussion (FGD) who were interviewed using structured questionnaires. Majority of the farmers estimated that the insects, the most serious pest infesting maize and tomato crops, mainly were army worm, maize stalk borer, and African ball worm on maize and spider mite, white fly, and African ball worm on tomato crop. Averagely from all the study areas, more than 25.9% of the farmers make use of cultural control method when comparing with chemical insecticides. Only 12.0% had access to chemical insecticides in controlling of insect pests of both the crops. Most of discussants traditionally used by adding various particles like ash, urea, soils and botanical extracts such as tobacco, garlic, Datura (banji), green pepper and also soap particles (66.6 and 18.5% from Darolebu and 29.7 and 4.7% from Chiro districts), respectively. From all the study areas, 26.40% respondents were used mechanically by the removal of infested plants in the fields. But 14.3% of respondents were not used any traditional methods.

Exploration on Strengthening Treatment Method of Integral Stressed Bridge under Special Load

Based on the characteristics and current situation of crop diseases and insect pests, this paper analyzes the problems of farmers’ lack of awareness of prevention and control, blind introduction of quarantine pests that lead to the spread of quarantine pests, and lack of advanced pest control technology in the prevention and control of crop diseases and pests. , For reference and reference.

Development and Survival of Lygus hesperus (Hemiptera: Miridae) Nymphs Under Constant and Variable Temperatures.

Thermal environments of the arid western United States are often harsh compared with the ranges of temperatures favorable for development and survival of crop insect pests. In cotton [Gossypium spp. (Malvales: Malvaceae)], new irrigation practices such as deficit irrigation may impact populations of pest and beneficial arthropods by temporarily altering temperature profiles within the plant canopy. Most information regarding the temperature-dependent development and survival of an important cotton pest, the western tarnished plant bug (Lygus hesperus Knight), is derived from constant temperature studies. We examined the development and survival of L. hesperus nymphs under constant (±0.2°C) and variable (±8°C) temperature regimes at daily mean temperatures of 15, 22, and 29°C. Under the low temperature (15°C), stadium lengths and duration of the nymphal stage were shorter when temperatures were variable compared with a constant temperature. No differences in development times were observed between regimes at the medium temperature (22°C). Except for the first stadium, development times under the high variable temperature regime were longer compared with the high constant regime (29°C). Nymph survival was unaffected by temperature regime except at the lowest temperature, where daily thermal fluctuations substantially improved survival compared with the constant conditions. These results suggest that temporarily increased crop canopy temperatures caused by altered irrigation schemes are unlikely to substantially reduce the growth of L. hesperus populations. However, enhanced nymphal development and survival under low variable temperatures likely contribute to the survival of overwintering L. hesperus in the absence of acute, low-temperature mortality.

Integrated Pest Management Efforts for Eco-friendly Agricultural Production in Nepal: A Perspective

World-wide, Integrated Pest Management (IPM) has been considered one of the eco-friendly and powerful tools to manage crop pests. In Nepal, it has been adopted for more than two decades with its highest success in various crops. As dissemination and up-scaling tools to this approach, Farmers Field School (FFS) is being launched in numerous farming communities. The basic notion of initiation of this program was to mitigate and combat the negative consequence created by chemical pesticides while controlling insect pests in crops. In Nepal, it started in 1997 through a FAO Technical Cooperation Project (TCP). This article summarizes IPM activities ever since TCP to Second Phase of IPM Program (2008-2013) launched by the Government of Nepal with the support of Norwegian government. Until, 2012/013, altogether 3772 FFSs were conducted by PPD and FAO initiatives and 99751 farmers graduated in IPM Program, while 1175 farmers trained as IPM FFS Facilitators. More than 5000 farmers groups benefited from yearlong IPM FFS. Medium level agricultural technicians, government Officers from different disciplines and 25 participants from Council for Vocational Education and Training Centre (CTEVT) were trained as IPM Master Facilitators. IPM policy and participatory system of IPM product certification system were drafted however; they could not be finalized during the project period. Support for Master Degree studies and Bachelor degree mini-thesis were provided to students of various Agriculture Education Institution. Curricula developed for yearlong IPM FFS in different crops were adopted by CTEVT and other Institute in their academic programs. In the the later phase of project, emphasis was towards the institutionalization of the outcomes into regular program of the Government with a modified approach of bio pesticide production, plant clinics and networking. The program ignited and stressed largely on the socio-technical empowerment to the farmers and technicians. Initiation on the marketing of IPM products was also one of the outputs. This should be linked with increasing use of bio pesticides to the healthy food production so that environmentally damaging chemical pesticides may be reduced from the country.