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This article explores the symbiotic role of microorganisms (bacteria, fungi and protozoans) associated with xylophagous termites. Members of the subfamily Macrotermitinae belonging to the family Termitidae have evolved symbiosis with fungi, which belong to the genus Termitomyces. The function of Termitomyces varies for different termite groups depending on their feeding behaviour. In some termites, the primary function of Termitomyces fungi is the degradation of lignin to its simpler form and to make cellulose available to termites; however, these fungi also serve as nutrient rich food sources to other groups of termites. The subsequent breakdown of ingested cellulose in termite gut is further facilitated and controlled by the action of various groups of enzymes secreted by gut-borne microflora and micro-fauna. Understanding the function, significance and management of these diverse microbial symbionts associated with pestiferous higher termites may help in developing their effective bio-control.

Bioassay with Ocimum sanctum L. and Polygonum hydropiper L. leaf powders @ 5 g/ kg seeds revealed adult mortality of Sitophilus oryzae (L.) at 70.00% and 96.67%, respectively; with Callosobruchus chinensis (L.) these values were 66.67% and 93.33% at 10 DAT, respectively. The LD50 values of O. sanctum and P hydropiper leaf powders were 0.86 g/ kg and 1.69 g/ kg against S. oryzae and 1.01 g/ kg and 1.32 g/ kg against C. chinensis, respectively.

Leaves of Aegle marmelos Correa (Rutaceae) were extracted successfully with methanol (95%), ethyl alcohol (50 and 95%). These extracts were tested for their toxicity against eggs, larvae, protonymphs, deutonymphs and adults of Oligonychus coffeae (Nietner) (Tetranychidae: Acari) under laboratory conditions. In general, methanol extract was the most potent in terms of acaricidal activities against all life stages, followed by 95% ethyl alcohol and 50% ethyl alcohol extracts. The effect was stronger with increasing concentrations. The methanol extract effectively and significantly reduced the mite population in field trial, and its efficacy was comparable to synthetic pesticides and neem pesticides. With the availability and distribution of A. marmelos in and around tea growing areas of northeastern India, A. marmelos should be further developed as a potential plant-based acaricide for effective management of tea red spider mite.

Hemocytes of healthy (untreated) and Beauveria bassiana (Bals.-Criv.) Vuill.-treated nymphs and adults Periplaneta americana (L.) (Blattodea: Ectobiidae) were examined with phase contrast microscopy. The total hemocyte counts (THCs) and differential hemocyte counts (DHCs) were estimated and compared between the untreated and treated nymphs and adults; significant augmentation of THC was observed in the treated 3rd, 4th, 5th instars and adults at 6 h after treatment (HAT), compared to the untreated individuals, followed by its suppression. In addition to changes in the population dynamics of prohemocytes (PRs), plasmatocytes (PLs), granulocytes (GRs) and spherulocytes (SPs), their morphology was also affected. GRs, predominant hemocytes involved in cell-mediated defense, responded to the infection differently including the formation of fine pseudopodia–like cytoplasmic extensions and, they clumped together.

Rice hispa D. armigera is one of the most important constraints to crop production globally. It attacks the vegetative stages of summer rice causing 35-65% loss and post flooded transplanted rice causing 100% loss in yield throughout Assam and hence it is regarded as one of the major limiting factors in rice production in Assam. Beauveria bassiana (Bals.) Vuill. is a naturally occurring potent entomopathogenic fungus which has been successfully utilized for controlling many insect pests of rice including rice hispa. For developing a good formulation, Beauveria bassiana (Bals.) Vuill (Strain AAU-09) is mass cultured in the potato broth, rice gruel, coconut water, rice husk, sawdust and rice bran. It was seen that amongst the solid media ,rice husk in addition of 2% dextrose was the best in terms of spore production (6.25 x 107 conidia/ml) and pathogenecity (86.67%) to Dicladispa armigera (Olivier) (Coleoptera: Chrysomelidae) adults. Likewise, amongst the liquid media potato broth supplemented with synthetic chitin (2%), dextrose (2%) and peptone (2%) supported maximum spore production. Chitin is essential not only for spore production but also increasing the power of penetrating on cuticle.

The most consumed and economically important beverage plant, tea (Camellia sinensis), and its pests have coevolved so as to maintain the plant-insect interaction. In this review, findings of different research groups on pest responsive tolerance mechanisms that exist in tea manifested through the production of secondary metabolites and their inducers are presented. The phytochemicals of C. sinensis have been categorized into volatiles, nonvolatiles, enzymes, and phytohormones for convenience. Two types of pests, namely the piercing-sucking pests and chewing pests, are associated with tea. Both the insect groups can trigger the production of those metabolites and inducers through several primary and secondary biosynthetic pathways. These induced biomolecules can act as insect repellents and most of them are associated with lowering the nutrient quality of plant tissue and increasing the indigestibility in the pest's gut. Moreover, some of them also act as predator attractants of particular pests. The herbivore-induced plant volatiles secreted from tea plants during pest infestation were (E)-nerolidol, α-farnesene, (Z)-3-hexenol, (E)-4,8-dimethyl-1,3,7-nonatriene, indole, benzyl nitrile (BN), linalool, and ocimenes. The nonvolatiles like theaflavin and L-theanine were increased in response to the herbivore attack. Simultaneously, S-adenosyl-L-methionine synthase, caffeine synthase activities were affected, whereas flavonoid synthesis and wax formation were elevated. Defense responsive enzymes like peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, ascorbate peroxidase, and catalase are involved in pest prevention mechanisms. Phytohormones like jasmonic acid, salicylic acid, abscisic acid, and ethylene act as the modulator of the defense system. The objective of this review is to discuss the defensive roles of these metabolites and their inducers against pest infestation in tea with an aim to develop environmentally sustainable pesticides in the future.Key points• Herbivore-induced volatile signals and their effects on neighboring tea plant protection• Stereochemical conversion of volatiles, effects of nonvolatiles, expression of defense-responsive enzymes, and phytohormones due to pest attack• Improved understanding of metabolites for bio-sustainable pesticide development.

The major objective of shifting from conventional to eco-friendly and sustainable agriculture is to minimize the load of chemical inputs. The replacement of chemical pesticides by biologicals is a prime step for achieving this objective. Entomopathogenic fungi (EPF) can act as effective management tools for insect and mite pest regulations without harming the biodiversity and environment. About 49 EPF species, predominantly from Deuteromycotina and Zygomycotina, have so far been commercially exploited world-wide as biopesticides, among which the most widely used species belong to genus Beauveria and Metarhizium. In India, a country of rich biodiversity, research on EPF has given rise to many products, out of which about 638 EPF formulations have so far been registered. Despite of huge resources and many advantages over conventional synthetic pesticides, EPF remain relatively underutilized in Indian agriculture. Biopesticides represent only around 2–3% of the overall pesticide market in India, a share that is expected to increase manifold in coming years. In this review, we provide an overview on promising EPF as bio-control agents of the key agricultural pests and also the scope for future studies for their better utilization.

The aim of the present study was to identify the hemocytes types of American cockroach, Periplaneta americana in Assam. Four major types of hemocytes found were Prohemocytes, Plasmatocytes, Granulocytes and Spherulocytes. The size of hamocyte cell types were carried out using Optical adapter (Narshi). Of these hemocytes, the largest size (29.60 ± 0.49 × 9.32 ± 0.30 μm) was recorded in Plasmatocytes.

The southern cattle tick, Rhipicephalus (Boophilus) microplus is one of the most important tick species affecting bovine wealth worldwide. Three uninterrupted generations of this species were observed under laboratory conditions (28±3 oC and 80±5% R.H.) using rabbit hosts. The average life cycle was determined as 65±8 days. Adult feeding period averaged 7.1±1.24 days. Pre-oviposition and oviposition periods averaged 4.1±1.3 days and 8.6±0.85 days, respectively. Pre-hatching periods averaged 21.03±2.99 days. Larval free-living and feeding to moulting periods averaged 3.5±0.75 days and 7.9±0.69 days, respectively. Nymphal feeding to moulting periods averaged 10.9±1.38 days. Weights of unfed and fed females averaged 1.26±0.29 mg and 120.32±45.6 mg, respectively and produced egg masses with average weights of 29.5±9.03 mg. Number of eggs per female averaged 1455.3±434.5 eggs with peak oviposition on the 3rd day. Average hatching rate was 83.5±2.94%, and the reproduction efficiency index averaged at 12.79±2.85. The conversion efficiency index averaged at 0.26±0.05 and the reproduction fitness index averaged at 10.68±2.4. Tick recovery rate averaged at 4.7%. A strong linear relationship was found between weights of engorged females and weights of egg masses (r = 0.83) and also between weights of engorged females and number of eggs laid (r = 0.82). This work aims to describe temporal and quantitative biological facts of R. (B.) microplus life cycles. Few studies have discussed R. (B.) microplus biology in quantitative terms, and these data can be useful in designing control plans or in epidemiological studies under laboratory conditions.

Solvent extracts of leaves of Chromolaena odorata, a widely distributed neo-tropical shrub having insecticidal properties, was tested for its safety to Trichogramma japonicum, a popular egg parasitoid of lepidopteran pests of rice, which revealed that extract toxicity could be arranged as petroleum ether < water < methanol < acetone < chloroform in terms of safety to adults causing 28.3% < 40.0% < 43.3% < 53.3% < 65.0% adult mortality at 1.0% concentration after 24 hours of treatment. Respectively, the LC50 values of solvent extracts were 7.98%, 5.20%, 3.65%, 1.62% and 0.02%. Petroleum ether, water and methanol extracts of C. odorata at 1% concentration were ranked as harmless, however, remaining extracts were moderately harmful to the egg parasitoid even after 24 hrs of treatment.

Toxicity study of Chromolaena odorata (L.) King & H. Rob. (Asteraceae) leaf powder @ 25 g/kg along with Beauveria bassiana (Bals.) Vuill. (Deuteromycetes) @12.5 g/kg revealed 100 and 50 adult mortality of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Tribolium castaneum (Herbst), (Coleoptera: Tenebrionidae) at 20 days after treatment; C. odorata @100 g/kg gave highest mortality of 29.67% in the 1st instar larvae of Corcyra cephalonica (Stainton) (Galleriidae: Lepidoptera) at 20 days after treatment. Thus C. odorata leaf powder was found to be having insecticidal and repellency properties.

The golden-yellow silk fibres obtained from Antheraea assama Westwood (Lepidoptera: Saturniidae) reared on leaves of three different host plants belonging to the family Lauraceae, were studied to evaluate their characteristic physico-chemical properties. The host plants, Machilus bombycina king, Litsaea polyantha A. Juss and Litsaea citrata Roxby, significantly influenced silk length, width, sericin and amino-acid contents of the fibres. The contents of the predominant amino-acids; glycine (10.55 μg), aspartic (5.43 μg) and serine (7.15 μg), were higher in fibres obtained from cocoons of A. assama fed on M. bombycina, while alanine (9.46 μg) was higher in the fibres of cocoons obtained from the other two host plants. The breaking load (17.791 g) and tenacity (3.562 g/d) were higher in cocoons from the host plant M. bombycina. The X-ray diffraction patterns showed the amorphous nature of the fibres obtained from the cocoons of A. assama fed on L. polyantha and L. citrata, while fibres obtained from cocoons from M. bombycina showed amorphous bands with little tendency to two dimensional order. Above all, the natural golden yellow hue of the fibre, which is one of the most important and commercially valuable added properties of this particular silk variety, was better retained in the fibres extracted from cocoons of A. assama larvae reared on M. bombycina.

Male Dicladispa armigera (Olivier) took an active role in initiating copulation, approached the female from the front, and mounted directly onto the dorsal surface of her elytra. Male and female D. armigera mated irregularly almost until death, an average of 67.60 ± 0.97 times. The average duration of copulation was 2.14 h.

The effect of nutrients (peptone, dextrose, maltose, NaCl), stickers (Tween-80 & TritonX-100) and spreaders such as oil (coconut oil, groundnut oil, mustard oil, sunflower oil), sunscreen lotion and detergents (soap, teepol) on biological parameters of Beauveria bassiana and its efficacy against larvae of Cnaphalocrocis medinalis. Three concentrations for each nutrients (0.75, 1.5% 3.0%), stickers (0.01, 0.023 & 0.03%), oil and lotion (0.025, 0.1 & 0.5%) and detergents (0.025, 0.05 & 0.1%) were tested. The combination of all the nutrients at 0.75% concentration, Tween 80 @ 0.1% and coconut oil @ 0.5% showed the best result in respect to conidial density (177.33x10⁷ conidia/ml), germination (94.9%) and mortality (90.4%) of C. medinalis.

Activity patterns and body temperature (T b ) and its maintenance were investigated in the 5th instar larvae of Antheraea assama Westwood (Lepidoptera: Saturniidae). These larvae thermoregulate by finding and utilizing favourable microenvironments and by restricting their activities to suitable times of the day. Further convective cooling, facilitated by a raised posture also serves to ameliorate T b . Regression analysis suggests that environmental temperature is the major determinant of T b along with solar radiation (SR) and wind (W)

Performance of Antheraea assama Westwood, a multivoltine sericogenic insect, as a commercial silk producer varies during different seasons in Assam, India. This study was done to determine seasonal variation of larval period, body weight, lipid reserves, water content, blood volumes, and quantitative hemocyte compositions of the fourth (penultimate) and fifth (ultimate) instars of this species during the winter, spring, summer, and autumn. Larval period was longest (51.50 ± 0.25 d) during winter (December-February) and shortest (25.00 ± 0.29 d) during summer (May–July). Greatest larval dry body weight (19.40% and 16.77% of fresh body weight of the fourth and fifth instars, respectively) occurred during winter and autumn (October-February) whereas larvae reared during spring and summer (March-August) were characterized by lowest body weight. Similar patterns of variation of lean dry weights, lipid reserves, and total hemocyte counts were also observed. Correspondingly, spring- and summer-reared larvae showed significantly higher levels of blood volume and total water as well as cellular and gut water content in comparison with those reared during the autumn and winter seasons. This study shows that lipid reserves may enable survival of larvae during seasonal adversity.

The site of sex pheromone production in female Supella longipalpa (F.) was localized to the fourth and fifth abdominal tergites. Behavioral assays of males with hexane extracts of various female body parts showed that these tergites were significantly more attractive than any other region of the body. Both behavioral and electroantennogram assays confirmed that the fourth and fifth tergites contained significantly more sex pheromone than any other tergites. Cuticular pores occur on all tergites, but their density is highest on the lateral margins of the fourth and fifth tergites. Each pore is connected via a long duct to modified epidermal cells, suggesting that these structures are involved in pheromone production and in its release while the female engages in calling behavior.

Globally, 1031 species of arthropods are associated with the intensively managed tea Camellia sinensis (L.) O. Kuntze monoculture. All parts of the plant, leaf, stem, root, flower, and seed, are fed upon by at least one pest species, resulting in an 11%–55% loss in yield if left unchecked. There has been heavy use of organosynthetic pesticides since the 1950s to defend the plant against these pests, leading to rapid conversion of innocuous species into pests, development of resistance, and undesirable pesticide residues in made tea. As a result of importer and consumer concerns, pesticide residues have become a major problem for the tea industry. Integrated pest management (IPM) may help to overcome the overuse of pesticides and subsequent residues. We review the advances made in our understanding of the biology and ecology of major insect and mite pests of tea, host plant resistance, cultural practices, biocontrol measures, and need-based application of botanicals and safer pesticides to understand the present status of IPM and to identify future challenges to improvement.

The compatibility of Beauveria bassiana (Bals.-Criv.) Vuill. with Chromolaena odorata (L.) King & H. Rob. (Asteraceae) was evaluated in vitro. Aqueous and solvent extracts of leaves of C. odorata at concentrations of 0.1, 0.5 and 1% were evaluated on the growth, conidial density and germination of B. bassiana by using the poisoned food technique. The extracts exhibited varying effects on growth of the fungus ranging from toxicity to inhibitory action, which increased with increase in the concentrations. The reduction percentage of radial growth of B. bassiana over control was found to be significantly less with the aqueous extracts of C. odorata. Inhibitory action was found to be highest (96.93%) with the chloroform extracts at 1% concentration. Similarly, as the concentrations increased from 0.1 to 1%, there was a significant reduction in the conidial density and germination in all the test concentrations. Based on the findings, the order of compatibility based on percentage reduction of radial growth is as follows: water > petroleum ether > methanol > acetone > chloroform. Hence, the aqueous extracts of C. odorata at 0.1% concentration can be integrated along with B. bassiana in any biointensive pest management programme.

Morphology of haemocytes of healthy and Beauveria bassiana (Bals.) Vuill.-infected Dicladispa armigera (Olivier) adults was examined in a phase contrast microscope to characterize them into different types. The total haemocyte count (THC) and the differential haemocyte count (DHC) were also estimated. Four types of haemocytes were identified: prohaemocyte, plasmatocyte, granulocyte and spherulocyte. In the healthy adults, the THC varied between 5055 and 5950/mm3, out of which 85% were composed of granulocytes and plasmatocytes. As B. bassiana infection time increased, THC decreased and was associated with a significant concomitant increase in granulocytes and a decrease in prohaemocytes. Granulocytes reacted in various ways, including disintegration of the plasma membrane, formation of fine pseudopod-like cytoplasmic extensions and finally clumping of cells. Granulocytes and plasmatocytes were the predominant haemocytes involved in all the cell-mediated defence reactions.