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The present study aimed to evaluate the software CROPWAT 8.0 that is used for estimation of the crop water requirement forsugarcane. With these approach the net irrigation requirement of sugarcane is calculated and the monthly water requirement is calibrated to meet out the requirement. It includes a simple water balance model that allows the simulation of crop water stress conditions and estimation of yield reductions based on wellestablished methodologies. The use of modern irrigation techniques will go a long way in reducing water use and conservation. This will put wider areas under cultivation and potentially contribute to greater agricultural production. The results showed that the Net and Gross Irrigationare 1394 and 1991.5 mm, repectively. The crop water requirement of sugarcane in Coimbatore was estimated to be 1438.7 mm. [ABSTRACT FROM AUTHOR]

Two field experiments were conducted to assess the efficacy of the F9252 (bifenthrin 8% + clothianidin 10% SC) a synthetic pyrethroids and neonicotinoid combination ready mix formulation against white grub and sucking pests of groundnut at Tamil Nadu Agricultural University, Coimbatore during February to May 2016 and May - July 2017 using Groundnut variety TMV 7 in randomized block design (RBD). Applications of insecticides were made at the time of planting and at 30 days after sowing. Assessment of the phytotoxic effect of F9252 at X, 2X and 4X doses on groundnut crop was also evaluated. The results revealed that, the per cent plant mortality due to white grub infestation is less than 1 per cent at the plots treated with F9252 @ 100 + 125 g a.i. ha-1 and F9252 @ 80 + 100 g a.i. ha-1 at the time of harvest and it was 14.73 per cent in untreated control. The data on per cent control of sucking pests (aphids and thrips) indicated that highest per cent control was recorded in the treatments, F9252 at 100+125 g a.i. ha-1 and F9252 at 80+100 g a.i. ha-1 and these two treatments were comparatively superior to all other treatments. Based on per cent reduction of pest populations over untreated control the order of relative efficacy of the test insecticides in controlling the sucking pests were, F9252 @ 100 + 125 g a.i. ha-1 = F9252 @ 80 + 100 g a.i. ha-1 > F9252 @ 60 + 75 g a.i. ha-1 = clothianidin @ 125 g a.i. ha-1 = clothianidin @ 100 g a.i. ha-1 > phorate 10 G @ 2500 g a.i. ha-1 = chlorpyrifos 20 EC @ 225g a.i. ha-1 = bifenthrin @ 80 g a.i. ha-1. F9252 at 80 + 100, 160 + 200 and 240 + 300 g a.i. ha-1 did not cause any visual phytotoxic symptoms in both the season of experimentation. The groundnut pod yield was maximum in the F9252 @ 100 + 125 g a.i. ha-1 (83.10% increase over untreated control) and which was statistically on par with the yield of F9252 @ 80 + 100 g a.i. ha-1 (80.19% increase over untreated control). Hence, F9252 @ 80 + 100 g a.i. ha-1 is recommended to get maximum yield with effective control of groundnut pests in the comparatively low dose of insecticide exposure to the environment. [ABSTRACT FROM AUTHOR]

The experiment was conducted at Department of Seed Science and Technology, Coimbatore during 2019-20 to standardize the pellet size for mechanized sowing in foxtail millet. The seeds of foxtail millet (Setaria italica) were circumscribed by small amount of filler materials and adhesive to produce a globular unit of size and also supply nutrient to the plant. Pellet size in terms of seed size has been standardized by using TNAU pelleting powder as filler material and gum acacia as adhesive to suite the requirement of air assisted seed drill for precision sowing with minimum seed rate. Results showed that the pellet size of 3.1 mm was found to be optimum for mechanized sowing with seed drill and 11 layers of coating with filler material increases the seed size from 0.8 to 3.1mm. The seeds coated to 11 layers have recorded maximum germination (87%), root length(12.7 cm), shoot length (6.3 cm),vigour index (1656) with high speed of germination (6.5) at laboratory condition. [ABSTRACT FROM AUTHOR]

Ampelomyces is one of the most naturally occurring mycoparasitic fungi on powdery mildews. A detailed survey was conducted in major bhendi (Abelmoschus esculentus (L.) Moench) growing regions of Coimbatore district of Tamil Nadu to assess the incidence of powdery mildew disease. The results revealed that disease incidence ranged from 38.04 to 69.54 per cent. From the surveyed areas, ten isolates of Ampelomyces spp were isolated using water agar medium. All the isolates were identified by their morphological characters and microscopic studies. Initially, the mycelia were hyaline and septate in nature over a period of time the color of the matured colonies in various medium turned greyish white to brownish black. Most of the isolates showed radial, flat to the submerged growth pattern. The pycnidia of different isolates of Ampelomyces varied in their shape and were mostly ovoid, pyriform to globose in shape. The size of pycnidia varied from 56.24 - 74.20 × 50.23 - 63.81µm. The pycnidial production was found to be more in the isolates viz., AQB1 and AQB7. Pycnidiospores are unicellular and guttulate in shape. An in vitro mycoparasitic activity on detached leaves of bhendi and a detailed microscopic analysis of the interactions between mycoparasite and Eryisphe cichoracearum was documented. Fungicide application is one of the most effective methods to manage powdery mildew disease. However, the frequent use of these fungicide has many disadvantages like the development of resistance to pathogens, residual toxicity and environmental pollution. Hence, we search for an alternative means for disease management. The genus Ampelomyces is considered to be the potential biocontrol agent against the powdery mildew pathogens. [ABSTRACT FROM AUTHOR]

Rice is seemingly the most urgent nourishment crops providing a quarter of calories consumption. About 23 per cent of calories consumed by people around the world are from rice alone. Rice blast is one of the major constraints for rice production. It is not only one of the earliest known plant diseases, but also one of the most widespread in any region of the world where rice is grown. The fungus has a wide host range and infects more than 100 species. A total of six isolates of rice blast collected from different locations in Coimbatore and Erode districts. The isolates were confirmed phenotypically through morphological characters. The isolates were also confirmed through molecular methods. Characterization by morphological and molecular methods will, therefore, be helpful in identifying and managing rice blast precautionarily. [ABSTRACT FROM AUTHOR]

Triclosan (TCS) is an antibacterial and antimicrobial compound, which is considered as "Emerging Organic Contaminants" and highly toxic to living organisms even at very low concentrations. It is an endocrine disrupter with anti-androgenic and oestrogenic properties and reduces serum level of thyroid hormone. TCS has highly persistence in sludge and sludge applied soils through sewage due to anthropogenic activities. The present study was carried out to assess the concentration of TCS in sewage, sewage sludge and contaminated soils from sewage treatment plants (STPs) of Ukkadam, Coimbatore. The observed TCS concentration in raw and treated sewage was 9.2 mg L-1 and 5.79 mg L-1. The higher concentration of TCS was found in sludge sample (28.24 mg kg-1) and the concentration of TCS in sewage contaminated soils of Coimbatore was 1.65 mg kg-1. The plant samples collected from sewage irrigated lands of Coimbatore (Napier grass) also showed 0.019 mg kg-1 including samples of leaf, stem and root. The study showed the presence of TCS in sewage, sewage sludge, contaminated soils and plant samples that can be harmful to the environment. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is one of the least available of all essential nutrients in the soil and its concentration is generally below that of many other macronutrients. An experiment was conducted to study the phosphorus use efficiency (PUE) of the sorghum and blackgram in soils of varying calcium carbonate content using radiotracer phosphorus (32 P). The pot culture experiment was conducted during 2017-2018 at Radioisotope (Tracer) Laboratory, Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore. The treatment structure of the pot culture experiment comprised of four types of soils and two levels of phosphorous (control and recommended level of phosphorus as phosphoric acid) with sorghum and blackgram as test crop. The results of the pot culture experiment showed that the grain yield of sorghum and blackgram decreased with increasing calcareousness of the soil. Lowest grain yield recorded was 14.14 g pl-1 for sorghum and 2.20 g pl-1 for blackgram in strongly calcareous soil (S4). In both sorghum and blackgram non calcareous soil (S1) was recorded the highest total P uptake (101.24 mg pl-1), (37.07 mg pl-1) respectively. Among crops, blackgram recorded the highest per cent Pdff (69.71%) than the sorghum (24.31 %). The highest sorghum per cent Pdfs (100 %) was observed with control (T1) which differed significantly from P application (75.70%), in blackgram the highest per cent Pdfs in blackgram (67.35 %) was recorded in slightly calcareous soil (S2) and the lowest % Pdfs (60.04 %) was registered in strongly calcareous soil (S4). Mean Phosphorus Use Efficiency (PUE) showed significant difference in non-calcareous soil (27.13 %) followed by slightly calcareous soil (23.81%). The mean lowest efficiency was observed in strongly calcareous soil (19.41%). Blackgram recorded higher PUE than sorghum in all the soils. [ABSTRACT FROM AUTHOR]

Mercury is a global pollutant, highly toxic, is a non-essential element with no biochemical or nutritional function in the organisms and is ubiquitous in the environment. In order to elucidate the participation of plants in uptake of mercury an experiment was carried out to study the plant behavior on mercury contamination in the Department of Environmental sciences, Tamil Nadu Agricultural University, Coimbatore with amaranthus and marigold as test crops. Four different concentration of mercury were spiked to a soil along with control (without mercury). Relatively higher amount of Hg was found accumulating in the roots of Marigold (3.35 µg.g-1) and Amaranthus (3.35 µg.g-1) and the plants did not express any visual symptoms of toxicity. Regarding the partition of mercury in different plant parts, it ranked in the order of roots > shoots > leaves. Among the treatments 20 mg.kg-1 Hg recorded higher enzymatic activity in both the test crops. Marigold being a non-food chain crop can be recommended for Hg contaminated soils. [ABSTRACT FROM AUTHOR]

Sterility mosaic disease (SMD), the most devastating disease of pigeonpea (Cajanus cajan) is caused by Pigeonpea sterility mosaic virus (PPSMV) transmitted by the eriophyid mite Aceria cajani. PPSMV is known to exist as distinct isolated in different regions of India. The Coimbatore isolate of PPSMV was purified, characterized at molecular level and compared with the type isolate of Patancheru region (Andhra Pradesh state, India). While viral nucleic acid analysis, northern hybridization and RT-PCR showed similarity among these isolates, variation in the molecular weight of virus related protein was found to be responsible for characterizing Coimbatore isolate of PPSMV as a distinct one. [ABSTRACT FROM AUTHOR]