Performance of larval parasitoid,Bracon brevicornis on two Spodoptera hosts: implication in bio-control of Spodoptera frugiperda

Successful pest management using parasitoids requires careful evaluation of host-parasitoid interactions. Here, we report the performance of larval ecto-parasitoid wasp, Bracon brevicornis (Wesmael) on important agricultural pests, Spodoptera litura (Fabricius) and S. frugiperda (J.E. Smith). Biology of B. brevicornis was studied on different host instars under laboratory and cage setup. In no-choice assay, the parasitoid development was highest on fifth-instar S. litura larvae as the wasp laid?~?253 eggs with 62% hatching, 76% pupae formation and 78% adult emergence. Similarly, these parameters were highest on fifth instar S. frugiperda larvae (293 eggs, 57% hatching, 80% pupae formation, 70% adult emergence). In two-choice assay, B. brevicornis preferred fourth or fifth over third instar larvae of both hosts. Successful parasitism depends on host paralysis and suppression of host immunity. B. brevicornis interaction downregulated cellular immunity of both hosts as shown by reduced hemocyte viability and spreading. The percent parasitism rate of B. brevicornis was unaltered in the presence of host plant, Zea mays in cage study. 76 and 84% parasitism was observed on fifth-instar larvae of S. litura and S. frugiperda, respectively. We evaluated the performance of B. brevicornis as a biocontrol agent on S. frugiperda in maize field. Our results show 54% average reduction in infestation after release of B. brevicornis. Taken together, we report the performance of B. brevicornis on important insect pests for the first time in laboratory and field conditions. Our findings indicate that B. brevicornis is a promising candidate for integrated pest management.

     

Studies on performance of rice as influenced by drainage in Eastern India

Field experiments were conducted in WTCER research farm, Mendhasal and in the farmer's field at Bishwanathpur, Orissa, India, during two crop years to assess the performance of rice as influenced by drainage at different growth stages. In the first experiment, scented rice variety CR-689-113 was tested with drainage at different growth stages in the main plot and nitrogen levels in the sub plots. In the second experiment, rice variety Swarna was investigated and drainage at different growth stages was provided under the best nitrogen level. The results revealed that drainage at the tillering stage recorded significantly higher grain yield than drainage at all other crop stages. The grain yield of rice was found to be increased by 19–22% when drainage was provided at the tillering stage for an 8–10 day period relative to that of no drainage treatment. However, drainage at the panicle initiation stage recorded the lowest grain yield. Nitrogen at 60 kg ha^?1 resulted in higher grain yield. Crop growth rate and nitrogen use efficiency were found to be higher when drainage was given at the tillering stage.     

Free-radical scavenging properties of low molecular weight peptide(s) isolated from S1 cultivar of mulberry leaves and their impact on Bombyx mori (L.) (Bombycidae)

The mulberry leaves have been considered as a sole food source for silkworm, Bombyx mori (L.). In present work an attempt was made to investigate the role of low molecular weight peptide(s) isolated from mulberry leaves on silkworm rearing. Also we have tried to find out the role of free-radical scavenging activities of isolated peptide(s) on silkworm growth. Larval growth rate was found effective under the influence of peptide(s). Consumption rate of larvae after peptide(s) treatment on mulberry leaves was significantly enhanced over control. High antioxidant activity was found in Low molecular weight peptide(s) which have an effect on silkworm.     

Classification of yarn interlacement pattern in fabrics using least square support vector machines

The purpose of this paper is to suggest an effective and reliable tool that can read through fabric images in the quest of deciphering yarn interlacement patterns by means of Least-Square Support Vector Machines (LS-SVM). A LS-SVM based binary pattern recognition system is formulated for identifying two modes of yarn interlacements viz., warp over weft or warp under weft and accuracy of the classifier was assessed by k-fold cross validation techniques. A comparative study establishes that LS-SVM shows better result than the standard SVM while classifying yarn interlacement patterns in fabrics. The proposed method has the potential to classify yarn interlacement patterns with possibility of extending it to designdecoding of diverse fabrics.     

Effect of nitrogen nutrition of stock plants of Justicia gendarussa L. on the rooting of cuttings

The effect of the nitrogen nutrition of stock plants of Justicia gendarussa L. on the rooting of cuttings was studied in sand culture under high, medium and low levels of nitrogen.

Nitrogen starvation induced rooting. Exogenous application of the auxins IAA (indol-3yl-acetic acid), IBA (indol-3yl-butyric acid) and NAA (naphth-lyl-acetic acid) greatly increased the rooting response of cuttings from-stock plants grown with small amounts of nitrogen.

The root-promoting effect of a low nitrogen supply was associated with a retardation of growth in the stock plants from which the cuttings were made. High C/N (total available carbohydrates/total nitrogen) and P/N (total phosphorus/total nitrogen) ratios increased anthocyanin pigmentation in the shoot, and increased rooting cofactor activity in the tissues of cuttings. The phenolic compounds, ferulic acid, p-hydroxybenzoic acid and p-coumaric acid were present in the shoots of all three nutritional treatments and acted as important cofactors in the cuttings. In general, rooting cofactor activity was inversely related to nitrogen supply and the activity was highest under low nitrogen.

The cuttings taken from plants grown under different levels of nitrogen interacted differentially with the exogenously applied auxins.     

Feed Formulation Using Linear Programming for Fry of Catfish,Milkfish, Tilapia,Asian Sea Bass,and Grouper in India

Nutritional profiles of 25 feed ingredients available in India were selected and compiled. Their costs were ascertained from Cochin (SW), Tuticorin (SE), and Bhubaneswar (NW), where fish/shrimp farming is traditionally practiced. Least-cost feed formulations (using the linprog toolbox in Matlab software) were attempted for catfish, milkfish, tilapia, and grouper fry specifying levels of four critical limits: Ca/P ratio, digestible energy (DE), 10 amino acid levels (where data was available), and 10 ingredients, totaling 26 constraining limits to the model. Feeds formulated for catfish fry cost US$0.066 kg^?1 at Bhubaneswar, US$0.117 kg^?1 at Tuticorin, and US$0.153 kg^?1 at Cochin, with poultry by-product meal and hydrolyzed feather meal as the major ingredients; limiting amino acids in these feeds were methionine and phenylalanine. Feeds formulated for milkfish fry cost US$0.110 kg^?1 at Cochin, US$0.108 kg^?1 at Tuticorin, and US$0.072 kg^?1 at Bhubaneswar; the limiting amino acids in this case were histidine and threonine. The cost of feeds for tilapia fry was US$0.207 kg^?1 at Cochin, US$0.369 kg^?1 at Tuticorin, and US$ 0.114 kg^?1 at Bhubaneswar; the limiting amino acid was methionine. Feed formulae for fry of Asian sea bass had an LP solution containing only five ingredients for all three places. The feed formula was the same for Cochin and Bhubaneswar market prices, and the total cost of ingredients was US$0.274 kg^?1 and US$0.142 kg^?1, respectively. At Tuticorin market prices, the feed formula cost was US$0.397 kg^?1. The feed formulae for grouper fry at Bhubaneswar and Tuticorin market prices had the same three ingredients costing US$0.114 kg^?1 and US$0.321 kg^?1, respectively, whereas feed formula for Cochin market price consisted of four ingredients costing US$0.280 kg^?1.     

Enzyme‐producing bacteria isolated from fish gut: a review

Digestion of food depends on three main factors: (i) the ingested food and the extent to which the food is susceptible to the effects of digestive enzymes, (ii) the activity of the digestive enzymes and (iii) the length of time the food is exposed to the action of the digestive enzymes. Each of these factors is affected by a multitude of secondary factors. The present review highlights the experimental results on the secondary factor, enzymatic activity and possible contribution of the fish gut microbiota in nutrition. It has been suggested that fish gut microbiota might have positive effects to the digestive processes of fish, and these studies have isolated and identified the enzyme‐producing microbiota. In addition to Bacillus genera, Enterobacteriaceae and Acinetobacter, Aeromonas, Flavobacterium, Photobacterium, Pseudomonas, Vibrio, Microbacterium, Micrococcus, Staphylococcus, unidentified anaerobes and yeast are also suggested to be possible contributors. However, in contrast to endothermic animals, it is difficult to conclude the exact contribution of the gastrointestinal microbiota because of the complexity and variable ecology of the digestive tract of different fish species, the presence of stomach and pyloric caeca and the relative intestinal length. The present review will critically evaluate the results to establish whether or not intestinal microbiota do contribute to fish nutrition.     

Host and virus effects on reversion in cassava affected by cassava brown streak disease

The phenomenon of virus‐infected plants naturally recovering health is known as ‘reversion’, and is a type of resistance mechanism exploited in some crop plants for disease control. Various parameters were investigated that affect reversion from cassava brown streak disease (CBSD) in three cassava varieties (Albert, Kaleso and Kiroba) that differ in levels of resistance to the disease. Cassava plants were inoculated by grafting with two virus species (Ugandan cassava brown streak virus, UCBSV and Cassava brown streak virus, CBSV) that cause CBSD, and the plants grown from them were subsequently assessed for reversion. The rate of reversion depended on the cassava variety, virus species, and the length and position of the stem cuttings used. A significantly high proportion of progenies were virus‐free (reverted) for the resistant variety Kaleso (64·1% for UCBSV and 54·9% of CBSV), compared to the tolerant variety Kiroba (56·7 and 45·5%) and the susceptible control Albert (38·9 and 35·1%). The highest number of virus‐free plants was generated from short 10 cm long cuttings (e.g. 60·1% for Kaleso for CBSV) compared to 20 cm long stem cuttings (e.g. 21·4% for Albert). Cuttings taken from upper stems of diseased plants produced most virus‐free progenies compared to middle and lower parts. More than 50% virus‐free plants were obtained in the resistant and tolerant varieties. This is a highly valuable finding and could be exploited for developing strategies to control the current CBSD epidemic in eastern and central Africa.