Marigold (Tagetus sp.) is a commercially exploited flower crop and is having a prominent place in ornamental horticulture. Agriculture is having a large impact on human economics and the emergence of red spider mite, Tetranychus urticae as a serious pest of marigold is a major concern. It leads to an economic yield reduction in crops depending on cropping seasons and agro-climatic conditions. Once it is established in an area, it is hard to get rid of it due to its high fecundity, dispersal techniques, short life cycles, rapid development of resistance to acaricides and adaptability to various ecological conditions. There is an urgent need to create awareness for this acarine and its behaviour for its timely management. This review gives a complete picture of the two spotted spider mite, Tetranychus urticae, including its pests, biology, population dynamics, effect of environment and the damage it causes to marigold crop. Awareness through this documentation will open new scope for its early detection on marigold crop.

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Background: African marigolds an important medicinal and ornamental plant is grown throughout the world. The two spotted red spider mite, Tetranychus urticae is one of the most destructive pests of the crop. Methods: Estimation of various minerals and stress measures of T. urticae infested and non infested leaves was performed in two seasons namely summer and winter under both screen house and field conditions. ANOVA was analysed under two factorial Completely Randomized Design. Mite population per leaf was correlated with each biochemical measures and statistical significance of data was analyzed. Result: Significantly lower nitrogen, phosphorous and potassium content was recorded in infested (2.01, 0.307, 1.509% dry weight) leaves as compared to uninfested leaves (2.93, 0.387, 1.874% dry weight) respectively. Summer season reported higher per cent loss in mineral content as compared to the winter season. The content of total phenol and proline was significantly more in infested leaves (18.75 mg/g, 57.07 µ/100 g) as compared to the uninfested leaves (11.42 mg/g and 47.50 µ/100 g). The per cent increase of phenol and proline ranged from (43.90 and 20.81%) in summer and (42.90 and 17.45%) in winter, respectively.

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Awareness about healthy organic food is increasing, leading to research on contaminants/pollutants and their effect on aquatic fauna and mankind. The effect of zinc sulphate on the growth performance of White leg shrimp, Litopenaeus vannamei (Boone) was evaluated under six doses viz; 0.5, 1, 2, 4, 6, and 8 mg/l in in vitro study conducted from June to October 2021.  The results revealed that higher doses of zinc sulphate showed toxicity against L. vannamei. The weight (3.12gm), length (8.95cm), weight gain per shrimp (4.11g), average daily weight gain (0.032), and specific growth rate (1.1g) were significantly (5%) lower at the higher dose (8mg/l) of zinc sulphate than control 11.73g, 16.22cm, 19.75g, 0.156g, and 2.20g respectively. With an increase in zinc sulphate dose from 0 mg/l in control to 8 mg/l, survival of shrimp decreased from 100 % to 7%. The Lethal concentration (LC50) for zinc sulphate treatments was recorded at 0.71 ppm for shrimp. The water quality parameter pH (7.17-8.09), dissolved oxygen (6.13-7.58mg/l), hardness (4000-4772mg/l), and total alkalinity (162-231mg/l) were in an optimum range. The variation in Nitrite- Nitrogen, Nitrate- Nitrogen and Ammonical-Nitrogen (0-0.018, 0-0.4, 0-0.018mg/l) were within a permissible range. Thus, the present study revealed that zinc had a negative potential effect on L. vannamei at higher concentrations and may lead to serious economic loss to farmers if ignored.