Release Plots Research Articles

Establishment of the wasp Tetramesa romana for biological control of Arundo donax in northern California and the role of release plot manipulation

Arundo donax is a non-native, invasive large-statured grass of riparian systems in the southwestern USA, including the Sacramento and San Joaquin River watersheds of northern California and the Sacramento-San Joaquin Delta. In 2017, the shoot tip-galling wasp Tetramesa romana was released at nine sites, three in each region. Shoots in some release plots were manipulated prior to release by cutting to ground or pruning to 1 m height, while others were left uncut. One year later, exit holes made by emerging adult wasps were found at two of nine sites. Exit hole density per main shoot length was 16-fold higher on regrowth shoots in ground-cut plots than in uncut plots. An additional plot manipulation study at two other sites found that exit hole density per shoot length was 19-fold higher in plots that were double-cut (cut to ground and regrowth pruned) than in single-cut plots. By 2023, T. romana was established at eight sites spanning both river watersheds and their Delta with dispersal up to 6.5 km, based on dissection of shoots, multi-year counts of exit holes and galls, and trapping of adult T. romana with sticky traps. The abundance of T. romana may be limited in northern California by low annual heat unit accumulation. The results show that physical manipulation of host plants improves short-term establishment and demonstrate the importance of using multiple monitoring methods to determine long-term establishment.

Optimizing release strategies for red king crab stock enhancement: Effects of release timing

Red king crab, Paralithodes camtschaticus, was commercially important around Kodiak, Alaska, USA, in the 1960s and 1970s; however, the stock crashed in the late 1970 s and has remained closed since 1983. The lack of recovery inspired consideration of stock enhancement through the release of hatchery-reared juveniles as a means to bolster the wild population. We examined the effects of release timing on in situ survival of hatchery-reared red king crab by releasing juveniles in June, August, and September 2015 in Trident Basin, Kodiak. We monitored densities inside and outside of release plots for six months using quadrat counts to determine loss and emigration rates. Relative predation risk was determined using tethering experiments performed after each release, and predator densities were quantified using quadrat counts and predator transect counts. Initial mortality over the first 24 h was approximately 53%, and subsequent mortality rates decreased with month-of-release, likely due to a combination of larger size-at-release and seasonal changes in predation. Although predator density was consistent over time, relative predation risk of tethered crabs decreased with season, suggesting later releases may be beneficial. However, the extended hatchery rearing period needed for later releases presents other challenges, including cannibalism, and the potential for developing maladaptive traits. Stock enhancement programs must balance these trade-offs to maximize overall success. Early releases of small juveniles immediately after settlement may be optimal if large-scale hatchery communal rearing results in significant juvenile production loss and/or hatchery conditioning is impractical.

Comparison of Mini-Tablets and Pellets as Multiparticulate Drug Delivery Systems for Controlled Drug Release

Mini-tablets made into hard capsules or administered using special dosing units, as well as pellets in hard capsules or compressed into tablets, offer the advantages of multiparticulate drug delivery systems and are suitable for controlled drug release using polymer coatings. Four different kinds of solid drug preparations were manufactured and investigated concerning drug release. Inert pellets were coated with the model drug sodium benzoate and, in a second step, with the insoluble polymer ethylcellulose. The coated pellets were compressed into mini-tablets and into normal tablets. Another kind of mini-tablet was compressed from a sodium benzoate compression mixture and finally coated with ethylcellulose. The coating of the tablets was performed using fluidized bed technology. The sodium benzoate release plots of the coated pellets show a lag time and retarded release according first-order kinetics. The mini-tablets and normal tablets compressed from pellets release sodium benzoate according to first-order kinetics as well, but without the lag time due to distinct ethylcellulose layer destruction during tableting. The release is retarded with increasing ethylcellulose layer thickness on directly compressed mini-tablets. The different formulations of coated pellets, mini-tablets, and normal tablets offer a broad choice for variable drug release kinetics depending on the biopharmaceutical and pharmacological requirements.

Successful establishment, spread, and impact of the introduced parasitoid Spathius galinae (Hymenoptera: Braconidae) on emerald ash borer (Coleoptera: Buprestidae) populations in postinvasion forests in Michigan.

Spathius galinae is a larval parasitoid native to the Russian Far East that was approved for release in the United States in 2015 for biological control of the emerald ash borer (EAB), Agrilus planipennis, an invasive beetle from Asia responsible for widespread mortality of ash trees (Fraxinus spp.) in North America. From 2015 to 2017, 1,340-1,445 females of S. galinae along with males were released into each release plot, paired with a nonrelease control plot (1-12.5 km apart), at 6 postinvasion forested sites containing abundant pole-sized ash trees in Michigan. By 2018, S. galinae had spread to all but one control plot. Based on the first year that S. galinae was found in trees in each control plot and the distances of those trees to the parasitoid release point within each site, we estimated that S. galinae spread at 3.7 (±1.9) km per year after its initial releases in 2015. The proportion of sampled trees with S. galinae broods, brood densities within sampled trees, and parasitism of EAB larvae increased sharply in both control and release plots after the last field releases in 2017, with the highest parasitism rates (42.8-60.3%) in 2020. Life table analysis showed that S. galinae alone reduced EAB's net population growth rate by 35-55% across sites from 2018 to 2020. These results demonstrate that S. galinae has established an increasing population in Michigan and now plays a significant role in reducing EAB populations in the area.

Drivers of survival of translocated tortoises

AbstractTranslocation of animals, especially for threatened and endangered species, is a currently popular but very challenging activity. We translocated 158 adult Agassiz's desert tortoises (Gopherus agassizii), a threatened species, from the National Training Center, Fort Irwin, in the central Mojave Desert in California, USA, to 4 plots as part of a long‐distance, hard‐release, mitigation‐driven translocation to prevent deaths from planned military maneuvers. We monitored demographic and behavioral variables of tortoises fitted with radio‐transmitters from 2008 to 2018. By the end of the project, 17.72% of tortoises were alive, 65.82% were dead, 15.19% were missing, and 1.27% were removed from the study because they returned to Fort Irwin. Mortality was high during the first 3 years: >50% of the released animals died, primarily from predation. Thereafter, mortality declined but remained high. After 10.5 years, survival was highest, 37.50% (15/40), on the plot closest to original home sites, whereas from 2.56% to 23.68% remained alive on the other 3 release plots. Surviving tortoises settled early, repeatedly using locations where they constructed burrows, compared with tortoises that died or disappeared. Models of behavioral and other variables indicated that numbers of repeatedly used locations (burrows) were a driver of survival throughout the study, although plot location, size and sex of tortoises, and distance traveled were contributors, especially during early years. Because >50% mortality occurred, we considered this translocation unsuccessful. The study area appeared to be an ecological sink with historical and current anthropogenic uses contributing to habitat degradation and a decline in both the resident and released tortoises. Our findings will benefit design and selection of future translocation areas.

The Release of Trichogrammatoidea armigera parasitoid for the Parasitization of Helicoverpa armigera Eggs in Maize

Background: Helicoverpa armigera (Hübner) is a common polyphagous pest on corn cob. H. armigera that is controllable through Trichogrammatoidea armigera (Nagaraja) parasitoid release. Successful inundated release of parasitoids depends on parasitization and parasitoid dispersal. Methods: The experiment consisted of 2 parasitoid release plots and 1 no release plot. T. armigera parasitoid was released twice, at 45 DAP and 52 DAP (Day after planting) in the middle of the experimental plot. The dose of parasitoid released during the corn generative phase was 1000 individuals per 254 m2 (~ 40000/ha). Evaluation was carried out by collecting the eggs of H. armigera 3 days after release at radius 1, 3, 6 and 9 m in all cardinal directions from the release point. Result: The release of parasitoids increased the eggs parasitization of H. armigera in 45 DAP tot he tune of 51.91% and 52 DAP was 38.57%. The wind direction did not affect the parasitoid movement which is active and almost uniform in all cardinal directions. Parasitoid movement was slightly similar in all distances and cardinal directions. The distribution of parasitoids reached 9 m from 40 release points ha-1 in colonies. T. armigera parasitoids were grouped hence, the monitoring in corn was carried out systematically.

Dopamine Release Impairments Accompany Locomotor and Cognitive Deficiencies in Rotenone-Treated Parkinson's Disease Model Zebrafish.

In this work, we carried out neurochemical and behavioral analysis of zebrafish (Danio rerio) treated with rotenone, an agent used to chemically induce a syndrome resembling Parkinson's disease (PD). Dopamine release, measured with fast-scan cyclic voltammetry (FSCV) at carbon-fiber electrodes in acutely harvested whole brains, was about 30% of that found in controls. Uptake, represented by the first order rate constant (k) and the half-life (t1/2) determined by nonlinear regression modeling of the stimulated release plots, was also diminished. Behavioral analysis revealed that rotenone treatment increased the time required for zebrafish to reach a reward within a maze by more than 50% and caused fish to select the wrong pathway, suggesting that latent learning was impaired. Additionally, zebrafish treated with rotenone suffered from diminished locomotor activity, swimming shorter distances with lower mean velocity and acceleration. Thus, the neurochemical and behavioral approaches, as applied, were able to resolve rotenone-induced differences in key parameters. This approach may be effective for screening therapies in this and other models of neurodegeneration.

Releases of the parasitoid Pachycrepoideus vindemmiae for augmentative biological control of spotted wing drosophila, Drosophila suzukii

Spotted wing drosophila, Drosophila suzukii, is native to East Asia but has become a major pest of soft-skinned fruit crops in its invaded range in the Americas, Europe and North Africa. Control efforts are complicated by the seasonal movement of D. suzukii into crops from non-crop or untreated-crop habitats. Biological control may help to suppress D. suzukii populations. However, surveys have found that few parasitoid species attack D. suzukii in North America and Europe, with low levels of parasitism by the pupal parasitoids Trichopria drosophilae and Pachycrepoideus vindemmiae and little or no parasitism by larval parasitoids. Augmentation of these resident pupal parasitoids may be a sustainable tool for D. suzukii management. Most augmentation efforts to date have focused on T. drosophilae, although P. vindemmiae is the more abundant and widespread species in North America. In this study, we tested whether augmentative releases of P. vindemmiae could help control D. suzukii in caneberry hoop houses in Minnesota, Oregon and California. Results were inconsistent. Most trials showed no detectable post-release effects on parasitism or D. suzukii levels, although one trial in Oregon did show elevated parasitism levels in release plots. Larger releases of P. vindemmiae may be needed when D. suzukii numbers are high, or to overcome the effects of suboptimal conditions and/or dispersal.

N-eicosane/multilayer graphene composite phase change materials for electro-thermal conversion and storage

Phase change materials (PCMs) have many promising potentials for thermal energy conversion, storage, and utilization. However, several technical bottlenecks must to be solved such as poor thermal conductivity and leakage of liquid during the phase transition process. In this work, the n-eicosane (C20) was incorporated into the multilayer graphene (MLG), and the C20/MLG composite PCMs were fabricated through vacuum impregnation. The chemical stability, microstructure, and thermal behaviors of composites were characterized in detail. The DSC analysis shown that the C20/MLG composites have a latent heat value of 136.6–212.5 J g−1 for melting with excellent crystallinity over 98%. The influence of MLG on thermal behavior was investigated and discussed. By adding 45 wt% MLG, the thermal conductivity of C20/MLG45 (1.112 W m−1 K−1) was 4.85 times that of C20 (0.289 W m−1 K−1), and the thermal storage and release plots indicated the MLG considerably promoted the heat transfer performance of composites. The outstanding transient temperature response of C20/MLG45 was recorded by the thermal infrared imager. Moreover, the C20/MLG45 can effectively convert electricity to latent heat. The results of electro-thermal conversion measurement shown the electro-latent heat storage efficiency of C20/MLG45 can exceed 59.9% at 1.9 V. In conclusion, the composite C20/MLG45 have potentials in thermal energy storage applications including electro-thermal conversion and storage, building energy conservation and electrical power peak shifting.

Assessing the Potential of Inoculative Field Releases of Telenomus remus to Control Spodoptera frugiperda in Ghana.

Simple SummaryThe fall armyworm (FAW) is a serious threat to maize production in Africa following its outbreak in 2016. Fortunately, some beneficial insects that could control FAW are already present in Africa, including Telenomus remus which parasitizes FAW eggs. Telenomus remus has been used in South America for biological control of FAW for several decades. Though T. remus is already present in Africa, little is known about its potential to be used for augmentative biological control of FAW under ecological conditions and agricultural systems in Africa. This study contributed to addressing this knowledge gap by conducting replicated field release trials of T. remus for FAW control in large maize plots in Ghana. In the major and minor rainy seasons, T. remus parasitized up to 33% and 100% of FAW egg masses, respectively, in the release plots. However, similar effectiveness of T. remus was recorded in non-treated control and farmers’ plots located at 150–400 m distance from release plots, indicating high dispersion of the parasitoid. A single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus, and could be considered in IPM strategies against FAW.In response to the threat caused by the fall armyworm to African maize farmers, we conducted a series of field release studies with the egg parasitoid Telenomus remus in Ghana. Three releases of ≈15,000 individuals each were conducted in maize plots of 0.5 ha each in the major and minor rainy seasons of 2020, and compared to no-release control plots as well as to farmer-managed plots with chemical pest control. No egg mass parasitism was observed directly before the first field release. Egg mass parasitism reached 33% in the T. remus release plot in the major rainy season, while 72–100% of egg masses were parasitized in the minor rainy season, during which pest densities were much lower. However, no significant difference in egg mass parasitism was found among the T. remus release plots, the no-release control plots and the farmer-managed plots. Similarly, no significant decrease in larval numbers or plant damage was found in the T. remus release fields compared to the no-release plots, while lower leaf and tassel damage was observed in farmer-managed plots. Larval parasitism due to other parasitoids reached 18–42% in the major rainy season but was significantly lower in the minor rainy season, with no significant differences among treatments. We did not observe significant differences in cob damage or yield among the three treatments. However, the lack of any significant differences between the release and no-release plots, which may be attributed to parasitoid dispersal during the five weeks of observation, would require further studies to confirm. Interestingly, a single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus and, thus, merits further investigation in the context of developing IPM strategies against FAW.

Poloxamer 407‐based Floating Hydrogels for Intravesical Instillation: Statistical Optimization Using Central Composite Design, Gel Erosion, and Drug Release

Poloxamer 407 (POL) is widely used as a thermosensitive hydrogel for intravesical instillation. When POL hydrogel is instilled in the bladder, several problems, including urinary tract obstruction, are observed. To overcome this problem, a POL‐based floating hydrogel (PFH) system was developed. Sodium bicarbonate (BC) was used as a floating agent. PFH was optimized using a central composite design with two independent variables (X1 [POL concentration, 42.43%] and X2 [BC concentration, 5.23%]) and three response factors (Y1 [floating time, 240.33 s], Y2 [duration time, 270 min], and Y3 [viscosity, 110.39 Pa.s]). In gel erosion and drug‐release studies in vitro, the remaining PFH fraction decreased exponentially with time, while gemcitabine release was biphasic and surface erosion‐controlled. A plot of drug release versus gel erosion showed good linearity. Visual observation for floating, gel duration, and dye release supported the time‐course behaviors of the PFH, indicating its usefulness in intravesical instillation.

Bioefficacy of Rhynocoris longifrons (St\xe5l) (Heteroptera: Reduviidae) against multiple cotton pests under screen house and field conditions

Rhynocoris longifrons (Hemiptera: Reduviidae) is a generalist predator of many cotton insect pests. The hiding behaviour of this predator, which is one of the key factors of predation success, was investigated under screen house conditions. Moreover, we evaluated its biocontrol potential against Aphis gossypii (Hemiptera: Aphididae), Dysdercus cingulatus (Hemiptera: Pyrrhocoridae), Phenacoccus solenopsis (Hemiptera: Pseudococcidae), and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) under screen house and field conditions. Results showed that R. longifrons life stages preferred to hide under small pebbles in the screen house tests. All the R. longifrons life stages showed a biocontrol potential against the four insect pests under screen house conditions. However, their biocontrol potential had not varied in relation to day and night hours. Augmentative releases of R. longifrons were carried out for two seasons such as South-west monsoon, 2011 and post-monsoon, 2012. The augmentative release of R. longifrons reduced significantly insect pests on cotton. In fact, the release of this predator in cotton fields was capable to reduce the population of H. armigera (50%), P. solenopsis (28%), D. cingulatus (18.8%), and A. gossypii (11.8%) during the rain fed condition (south-west monsoon season). During irrigated condition (post-monsoon season), populations of D. cingulatus were reduced by 26%, than P. solenopsis (20.6%), and A. gossypii (16.8%). Except ants, no negative impact was reported on other natural enemies present in the cotton field. Significantly higher crop yield and cost benefit ratio was observed in the predator release plots indicating that R. longifrons can be used in an integrated pest management program for multiple cotton pests.

Kinetics and mechanisms of Zn2+ release from antimicrobial food packaging based on poly (butylene adipate-co-terephthalate) and zinc oxide nanoparticles

Intended for use in the food packaging field, active PBAT/ZnO bionanocomposite films were successfully prepared by solvent casting and characterized by several techniques. The antibacterial performance of these nanomaterials was evaluated against three bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis), and a Zn2+ ions liberation study was also carried out, focusing thus their potential and effectiveness in food packaging industry application. The viability curves of PBAT/ZnO samples against the three bacterial strains showed a considerable decrease in bacteria’s number, confirming therefore the high antibacterial performance of these nanocomposite films, against both of Gram-positive and Gram-negative bacteria, whereas the Zn2+ release profiles have approved a long-term controlled release during a time period exceeding 45 days. Furthermore, the kinetic modeling of Zn2+ ions release plots indicates a good fit with Higuchi and Korsmeyer–Peppas models, and describing therefore the combination of three physicochemical phenomena: dissolution, diffusion and degradation, as mechanism inducing thus the controlled Zn2+ ions release.

Sterically stabilized recombined HDL composed of modified apolipoprotein A-I for efficient targeting toward glioma cells

Reconstituted high density lipoprotein (rHDL) has been regarded as a promising brain-targeting vehicle for anti-glioma drugs under the mediation of apolipoprotein A-I (apoA-I). However, some stability issues relating to drug leakage and consequent reduced targeting efficiency in the course of discoidal rHDL (d-rHDL) circulating in blood hinder its broad application. The objective of the study was to develop a novel stabilized d-rHDL by replacing cholesterol and apoA-I with mono-cholesterol glutarate (MCG) modified apoA-I (termed as mA) and to evaluate its allosteric behavior and glioma targeting. MCG was synthesized through esterifying the hydroxyl of cholesterol with glutaric anhydride and characterized by FI-IR and 1H NMR. d-rHDL assembled with mA (termed as m-d-rHDL) presented similar properties such as minute particle size and disk-like appearance resembling nascent HDL. Morphological transformation observation and in vitro release plots convinced that the modification of cholesterol could effectively inhibit the remolding of d-rHDL. The uptake of m-d-rHDL by LCAT-pretreated bEND.3 cells was significantly higher than that of d-rHDL, thereby serving as another proof for the capability of m-d-rHDL in enhancing targeting property. Besides, apoA-I anchoring into m-d-rHDL played a critical role in the endocytosis process into bEND.3 cells and C6 cells, which implied the possibility of traversing blood brain barrier and accumulating in the brain and glioma. These results suggested that the modification toward cholesterol to improve the stability of d-rHDL is advantageous, and that this obtained m-d-rHDL revealed great potential for realization of suppressing the remolding of d-rHDL in the brain-targeted treatment of glioma for drug delivery.

Amino acid–intercalated layered double hydroxide core @ ordered porous silica shell as drug carriers: Design and applications

Abstract

PREPARE AND EVALUATE MUCOADHESIVE FORMULATIONS OF LAMIVUDINE WITH BETTER CONTROLLED/ SUSTAINED DRUG RELEASE PROFILE

The aim of present study was to formulate & evaluate the mucoadhesive sustained release formulations of lamivudine and to fulfill this aim, two mucoadhesive formulations Gels and Tablets were prepared by using three different polymers: HPMC K15, poloxamer 407 & carbopol 934. Three mucoadhesive gel and nine tablet formulations were prepared and evaluated for various parameters. All three gels were able to give sustained release up to 12 hours. Tablet formulations, F1 to F5 failed to fulfill the aim. Only F6, F7, F8 & F9 formulations were selected, as all gave sustained release up to 12 hours, except F6, which gave sustained release profile only till 7 hours. From the drug release plots, it was concluded that the type of polymer and concentration of polymer have distinct effect on in vitro drug release profile and all the formulations follow first order mechanism with anomalous diffusion or non-fickian diffusion, except carbopol gel and poloxamer tablets. Carbopol gel follows zero order release rate with super case II transport and poloxamer tablets (F6) follow higuchi with non-fickian diffusion. It is concluded that mucoadhesive formulations of lamivudine can be prepared for sustaining its release. And the successful outcome of the present study also encourage for further studies to assess the ability of the mucoadhesive formulations of lamivudine in providing an effective sustained and safe therapy for AIDS.

Condiciones edáficas, abundancia y riqueza de hongos ectomicorrizógenos comestibles

Los hongos ectomicorrizógenos (HECM) favorecen la movilización nutrimental y el transporte del agua entre el sustrato y los árboles, por lo que la asociación ectomicorrícica es fundamental para el buen desarrollo de los ecosistemas forestales. Para establecer los efectos de las propiedades edáficas en la riqueza y abundancia de las poblaciones de HECM, se compararon cuatro tipos de prácticas silvícolas: corta de regeneración, de aclareo (primera y segunda) y de liberación. Se delimitaron y georreferenciaron 10 parcelas de monitoreo, en bosques bajo aprovechamiento del municipio Zacatlán, Puebla. La riqueza y la abundancia fúngica se evaluaron en 2015 y 2016; en este último, se hizo el muestreo y análisis del suelo. Se obtuvieron diferencias significativas entre años para la abundancia en la segunda corta de aclareo y en la de liberación, así como entre las cortas de aclareo que responden al periodo entre el año de intervención y el de muestreo. El porcentaje de materia orgánica y de arena registraron una correlación positiva con la abundancia, en contraste con K, Ca, Mn y Mg, que fueron negativas entre tratamientos, y no se obtuvieron diferencias para pH y la riqueza de especies; sin embargo, Lactarius indigo, Boletus aestivalis y Tylopilus sp. solo se recolectaron en rodales con valores de 5.76 a 5.93, en las parcelas de cortas de aclareo y liberación. Los resultados muestran que las prácticas silvícolas afectan el área basal arbórea alterando las propiedades químicas y físicas del suelo, lo que a su vez incide sobre la abundancia de esporomas.

Potential Impacts of Emerald Ash Borer Biocontrol on Ash Health and Recovery in Southern Michigan

Emerald ash borer (EAB) is an invasive beetle that kills native North American ash species, threatening their persistence. A classical biological control program for EAB was initiated in 2007 with the release of three specialized EAB parasitoids. Monitoring changes in the health and regeneration of ash where EAB biocontrol agents have been released is critical for assessing the success of EAB biocontrol and predicting future changes to the ash component of North American forests. We sampled release and control plots across southern Michigan over a three-year period to measure ash health and recruitment to begin assessing the long-term impact of EAB biological control on ash populations. We noted a reduced mortality of larger trees between 2012 and 2015 in release plots compared to control plots and increases in ash diameter, but our results were otherwise inconsistent. Ash regeneration was generally higher in release plots compared to control plots but highly variable among sites, suggesting some protection of ash saplings from EAB by parasitoids. We conclude that EAB biocontrol is likely to have a positive effect on ash populations, but that the study duration was not long enough to definitively deduce the long-term success of the biocontrol program in this region.

Electrochemical Measurement of Dopamine Release and Uptake in Zebrafish Following Treatment with Carboplatin.

Post-chemotherapy cognitive impairment, also known as 'chemobrain,' is a neurological condition in which cognitive function is impaired as a result of cancer chemotherapy treatment. In this work, we used fast-scan cyclic voltammetry (FSCV) to measure electrically evoked dopamine release and uptake in whole brain preparations from zebrafish that have been treated with carboplatin, an agent associated with chemobrain. We administered carboplatin by addition to the fish's tank water or their food. One week of treatment with 100 μM carboplatin in the water was needed to significantly impair dopamine release (∼40 % of control); however, only one day of treatment through the zebrafish's food was needed to cause a similar impairment. Atomic absorption spectroscopy measurements suggested that administration through food resulted in higher initial levels of carboplatin compared to water administration, but water administration resulted in an increase over time. Uptake, determined by modeling stimulated release plots, was unaffected. These results are consistent with our previous findings of diminished neurotransmitter release in rats and support a role for zebrafish in chemobrain-related studies.

Assessment of crop loss due to leafhopper, (Empoasca kerri Pruthi) in pigeonpea

An experiment was conducted at Agriculture Research Station, Kalaburagi, Karnataka, India during kharif, 2015-16 to understand the effect of differential population of leafhoppers, on growth and yield parameters of pigeonpea under field conditions with seven level of population load. Maximum of 26.16 hoppers/3 leaves were found at 12 pairs release plot which was at par with 10 pairs (22.21) and 8 pairs (24.96) released which were statistically significant. The average hopper count @ 4 and 6 pairs released plots were 13.14 and 16.15 per 3 leaves respectively and were at par among themselves and significantly higher than 2 pairs release and lower than 8 pairs release plots. This was a clear indication that the differential population of leafhopper had impact in reduction of growth and yield parameters with. Reduction in yield to the tune of 3.12, 5.29, 10.05, 17.99, 24.63 and 31.91 % at 2, 4, 6, 8, 10 and 12 pairs released plots, respectively. From the present investigation it was clear that the 5.59 to 5.77 leafhoppers aggregated in top leaf at 90 to 120 days aged crop of medium duration variety will cause 10 per cent reduction in yield.