P. D. Kamala Jayanthi

Modulatory Effect of Citrate Reduced Gold and Biosynthesized Silver Nanoparticles on α-Amylase Activity

Amylase is one of the important digestive enzymes involved in hydrolysis of starch. In this paper, we describe a novel approach to study the interaction of amylase enzyme with gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) and checked its catalytic function. AuNPs are synthesized using citrate reduction method and AgNPs were synthesized using biological route employing Ficus benghalensis and Ficus religiosa leaf extract as a reducing and stabilizing agent to reduce silver nitrate to silver atoms. A modulatory effect of nanoparticles on amylase activity was observed. Gold nanoparticles are excellent biocompatible surfaces for the immobilization of enzymes. Immobilized amylase showed 1- to 2-fold increase of activity compared to free enzyme. The biocatalytic activity of amylase in the bioconjugate was marginally enhanced relative to the free enzyme in solution. The bioconjugate material also showed significantly enhanced pH and temperature stability. The results indicate that the present study paves way for the modulator degradation of starch by the enzyme with AuNPs and biogenic AgNPs, which is a promising application in the medical and food industry.

Influence of Polyandry on Clutch Size of the Predatory Coccinellid, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae)

ABSTRACT The influence of different polyandrous situations on clutch size was determined in the predatory coccinellid, Cryptolaemus montrouzieri Mulsant, as a measure of female reproductive fitness. The study revealed that single female beetles each held with 3 mates under a continuous mating situation laid significantly more eggs (6.93/ day) than females each similarly held either with 2 males or with 1 male. However, correlation analysis revealed a highly significant negative correlation (r = -0.60**) between the progression of days and clutch size with 3 mates. The number of multiple matings and clutch size also decreased over time compared to other treatments. The implications of these results are discussed.

Age, body size and sex-related feeding response of the predatory coccinellid Cryptolaemus montrouzieri Mulsant

The objective of this study was to determine the effect of age, body size and sex on feeding rate of the predatory coccinellid Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae). The body size of the adult C. montrouzieri did not influence the feeding rate in either sex and the large body size was more common in both sexes. A significant increase in feeding (4.64 mealybugs/ day) and excretion (47.91 excreta deposits/ day) was observed in females compared with males (2.47 mealybgs/ day and 25.78 excreta deposits/ day, respectively) under mated conditions. The feeding rate throughout adulthood showed an inverse trend with age in both sexes and the curvilinear relationship explained much of the variability in the feeding response in relation to age. The feeding differences in relation to age, body size as well as sex of adult C. montrouzieri are discussed in detail.

Natural mycosis of mango leafhoppers (Cicadellidae: Hemiptera) by Fusarium sp.

Mango leafhoppers that feed on inflorescences and young shoots of mango (Mangifera indica L.) were found mycotized under natural conditions in Bangalore, India. Isolation and characterisation of the etiological agents by sequencing of the Translation Elongation Factor-1α gene, revealed 99% identity with the plant pathogenic fungus Fusarium proliferatum. This is an early report on the Fusarium associated entomopathogenicity in different mango leafhopper species.

Predicting the oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae) trap catch using artificial neural networks: a case study

The oriental fruit fly Bactrocera dorsalis (Hendel) is a very serious pest of fruit trees, causing enormous economic losses globally. The present study examines the capability of an artificial neural network (ANN) with a Quasi-Newton (QN) algorithm to predict a fruit fly trap catch and compare the results with those of a traditional regression model. MATLAB 7.0 was used to develop ANN programming and the fortnightly measurement of 14 input variables (abiotic along with biotic variables) provided the database for analysing the ANN model. An input model using a total of 14 identified input nodes with a selected QN-ANN structure (14-25-20-1) gave an optimum result. In general, the present study showed that an ANN could be used to estimate fruit fly trap catch with enhanced accuracy (R2 = 0.92; root mean square error (RMSE) = 23.75; Nash-Sutcliffe efficiencies = 0.99) over traditional regression models (R2 = 0.76; RMSE = 30.28; Nash-Sutcliffe efficiencies = 0.76). This finding helps the region-specific fruit fly monitoring and management programmes that lack long-term historic data.

Morphological diversity of trichomes and phytochemicals in wild and cultivated eggplant species

An attempt was made to understand the diversity of trichomes both at morphological and chemical levels in wild (Solanum viarum, S. mammosum, S. indicum, S. gilo, S. torvum) and cultivated eggplant (S. melongena) species. Cultivated and wild eggplant species have morphologically and chemically diverse trichomes. The presence of specific type of trichomes, their densities and chemical composition varied across species. The wild species viz., S. viarum and S. mammosum have seven (Type II to VIII) morphologically distinguishable types of trichomes including two types of glandular trichomes (Type VI, VII) as against uniform occurrence of branched stellate trichomes (Type VIII) alone in cultivated species. Differences among the phytochemicals viz., phenols and flavonoid levels were also observed across the eggplant species and type of trichomes.

Evaluation of synthetic oviposition stimulants to enhance egg collection of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Tephritid flies are pests of horticultural importance throughout the globe. The oriental fruit fly, Bactrocera dorsalis (Hendel), is particularly feared because it attacks many commercial fruits and vegetables causing huge economic losses. The sterile insect technique (SIT) can be an effective, target-specific and economically feasible control method. However, implementation of SIT depends on mass production of high-quality insects. Production of superior quality eggs is of foremost importance in insect mass production. However, present protocols make use of fruit juices or fruit domes that attract saprophytic insects or microorganisms, reducing the quality of eggs. Furthermore, fermentation of juices is known to decrease oviposition efficiency, and daily sanitation of oviposition devices is required. Here, in a laboratory-scale study, we evaluate the effectiveness of four synthetic oviposition stimulants (OS) of B. dorsalis for egg production in dual choice tests, using oviposition devices similar to those used in mass rearing. Results indicated that γ-octalactone, benzothiazole, octen-3-ol and ethyl tiglate significantly increased egg laying compared to controls (water). Of these, γ-octalactone was particularly effective and elicited a 263-fold increase in oviposition on treated oviposition devices compared to control. Our findings demonstrate the potential of using OSs to improve the efficiency and cost effectiveness of mass production of B. dorsalis.

The leaf beetle, Tricliona nr nigra Jacoby (Coleoptera: Chrysomelidae), a new pest damaging pomegranate, Punica granatum

This is the first report on occurence of the leaf beetle, Tricliona nr nigra (Coleoptera: Chrysomelidae) from India infesting pomegranate, Punica granatum L. Preliminary observations on general biological aspects and feeding damage of T. nr nigra have been conducted. The beetles occurred in large numbers and the nature of damage was mainly through surface scraping.

Study of inheritance of feeding potential in natural populations of predatory coccinellid Cryptolaemus montrouzieri Mulsant using isofemale strains

The ability to feed on the prey is of great concern for the predatory insects, especially with regard to predatory coccinellid, Cryptolaemus montrouzieri Mulsant, which is mass reared and released into the field in large numbers to control the target pests. The variability associated with feeding potential is partly influenced by the genetic background of the insects and partly due to the environment, but the genetic basis of this trait is not yet fully understood in C. montrouzieri. The aim of this study was to identify the genetic basis of variation and heritability of this quantitative trait in natural populations of C. montrouzieri through isofemale heritability and parent–offspring regression. The regression analyses indicated that there was a significant linear relationship between progeny and their mothers for feeding potential.

Damage potential and seasonality of the sapodilla bud borer Anarsia achrasella (Lepidoptera: Gelechiidae) in India

The gelechid bud borer Anarsia achrasella (Latreille) has become an increasingly serious pest of sapodilla Manilkara zapota Van Royen in India. The objective of the present study was to estimate the pest damage potential and determine the influence of abiotic factors and plant phenology on the pest incidence. The results indicate that each larva of A. achrasella could damage up to 36.9–46.6 buds before reaching pupation. Correlation analysis indicates that the pest incidence is not influenced by plant phenology and that the effect of abiotic factors is minimal. Of all weather parameters studied, only minimum temperature and wind speed correlated significantly with bud borer infestation. The linear and non-linear analyses showed that, in the case of minimum temperature, polynomial model order (2) Y = 0.4108x2 − 11.95x + 92.329 was found to explain 46% of the variability in bud borer incidence. However, in the case of wind speed, none of the tried models could explain variability in A. achrasella incidence beyond 53%. The implications of these results are discussed.RésuméEn Inde, le géléchide foreur de bourgeon, Anarsia achrasella (Latreille) est devenu un ravageur de plus en plus important de la sapotille Manilkara zapota Van Royen. L’objectif de cette étude est d’estimer les pertes potentielles et de déterminer l’influence des facteurs abiotiques et de la phénologie de la plante sur les dégâts. Les résultats montrent que chaque larve de A. achrasella peut endommager entre 36,9 et 46,6 bourgeons avant d’effectuer sa nymphose Une analyse de corrélations indique que l’incidence du ravageur n’est pas influencée par le stade phénologique de la plante et que les facteurs abiotiques sont peu importants. Parmi tous les facteurs climatiques étudiés seules la température minimale et la vitesse du vent sont corrélées avec le niveau d’infestation. Les analyses de corrélations linéaires et non linéaires montrent que lorsque la température est minimale, le modèle polynomial d’ordre (2) Y = 0.4108x2 − 11.95x + 92.329 explique 46% de la variabilité de l’incidence du foreur. Toutefois, dans le cas de la vitesse du vent, aucun modèle ne peut expliquer la variabilité de l’incidence de A. achrasella au-delà de 53%. Les implications de ces résultats sont discutées.