A new approach to monitor and assess the damage caused by two-spotted spider mite (original) (raw)
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Spectral monitoring of two-spotted spider mite damage to pepper leaves
Remote Sensing Letters, 2012
Two-spotted spider mites (TSSM; Tetranychus urticae Koch) cause significant damage to crops and yields, in the field as well as in greenhouses. By feeding, TSSM destroy chloroplast-containing cells; this damage can be spectrally detected in the reflectance of the visible and near-infrared regions. This study focuses on hyperspectral reflectance data of greenhouse pepper (Capsicum annuum) leaves, obtained by integrated sphere. The reflectance data were transformed into vegetation indices allowing early TSSM damage detection by separation between leaf damage levels. One-way analysis of variance of coupled damage levels was applied to each of the vegetation indices. We concluded that early identification of TSSM greenhouse pepper leaf damage can be obtained by multispectral means. Furthermore, the proposed methods may identify the damage on the upper side of the leaves although the TSSM feed on the underside of leaves.
Remote Sensing Evaluation of Two-spotted Spider Mite Damage on Greenhouse Cotton
Journal of visualized experiments : JoVE, 2017
The objective of this study was to evaluate a ground-based multispectral optical sensor as a remote sensing tool to assess foliar damage caused by the two-spotted spider mite (TSSM), Tetranychus urticae Koch, on greenhouse grown cotton. TSSM is a polyphagous pest which occurs on a variety of field and horticultural crops. It often becomes an early season pest of cotton in damaging proportions as opposed to being a late season innocuous pest in the mid-southern United States. Evaluation of acaricides is important for maintaining the efficacy of and preventing resistance to the currently available arsenal of chemicals and newly developed control agents. Enumeration of spider mites for efficacy evaluations is laborious and time consuming. Therefore, subjective visual damage rating is commonly used to assess density of spider mites. The NDVI (Normalized Difference Vegetation Index) is the most widely used statistic to describe the spectral reflectance characteristics of vegetation canop...
Indian journal of entomology, 2020
A field experiment was conducted on parthenocarpic cucumber under net house conditions. during 2016-2017 and 2017-18, to study the population dynamics of spider mite Tetranychus urticae Koch. The eggs and other active stages were observed, which revealed that egg (21.2 and 25.5 eggs/ ten leaves) and active stages (15.2 and 18.8 active stage/ ten leaves) were at peak during 22 nd and 21 st standard meteorological week, respectively during 2017 and 2018. Correlation coefficients with weather parameters showed a significant and positive relationship between temperature-with r values for temp Max , temp Min and Temp Avg with 'r' values being 0.55, 0.60 and 0.59, respectively (significant at p= 0.01). Relative humidity (RH M and RH Avg) showed significant negative correlation (r =-0.59 and-0.51; significant at p= 0.01). The stepwise regression analysis revealed that Temp Min was the weather factor responsible in determining abundance of T. urticae and its buildup to the extent of 44%.
Detection and Classification of Pests in Greenhouse Using Image Processing
IOSR Journal of Electronics and Communication Engineering, 2013
The techniques of machine vision and digital image Processing are extensively applied to agricultural science and it have great perspective especially in the plant protection field, which ultimately leads to crops management. The paper proposes a software prototype system for early pest detection on the infected crops in greenhouse. Images of the infected leaf are captured by a camera with pan tilt and zoom and processed using image processing techniques to detect presence of pests. SVM classifier is used for classification. SVM classifier helps to detect the pests and in the classification of pest based on their features. Results show more precision in identifying the presence of pest at early stage.
Revista de la Facultad de Ciencias Agrarias UNCuyo
Argentina is the second largest peanut (Arachis hypogaea L.) exporter in the world. The main peanut pest in our country is the two-spotted spider mite (Tetranychus urticae Koch 1836). To date, there is no validated method to quantify this pest. The aim of this work was to develop and validate a logarithmic diagrammatic scale to assess damage by the two-spotted spider mite in peanut. In 2015-16, 200 leaflets were collected from a plot infested with the pest. Damaged leaf area (DLA) was calculated using SisCob software. Six-, seven-, eight- and nine-class scales were proposed. Mean values for each class and scale were obtained with 2-LOG. Leaflets were analyzed by 13 raters who used the four proposed scales. Precision and accuracy were determined by simple linear regression between the DLA and estimated damaged leaf area. Reproducibility was determined by linear regression between estimates of raters combined in pairs. The seven-class scale was the best validated one for all the param...
The population abundance of the two-spotted spider mite, Tetranychus urticae that infest cucumber plants in upper-Egypt was investigated during spring plantations of 2015 and 2016 season. Data showed that the population of the spider mite population varied in its density during the entire season of both seasons with a peak number occurrence the end of season (May 30), when plant age was 90 day-old when temperature and relative humidity were in moderate levels. Also, this study revealed that the cucumber plants highly impacted by the pest in addition to the few number of predators were observed during these seasons. The abiotic factors, e.g. temperature, relative humidity, and the plant age, more likely to induce the infestation than the biotic factors (predators). Accordingly, further studies are needed to examine the factors affecting the population of this pest. This study may be useful for determining the timing of the control program for T. urticae that infest cucumber plants during spring plantations.
Systematic and Applied Acarology, 2019
Cultivating resistant host plants has been considered as an important strategy for sustainable pest management of mites. The current study was conducted to evaluate the response of 43 cucumber (Cucumis sativus L.) cultivars against two important tetranychid species, two-spotted spider mite (Tetranychus urticae Koch.) and strawberry spider mite (Tetranychus turkestani Ugarov & Nikolski). The experiment was implemented in a Randomized Complete Block design (RCB) with 43 treatments replicated 4 times in a greenhouse during 2015-2016. Two main evaluation criteria, cultivar injury rate (from 1 to 5) and number of eggs/female/day (EFD) on each cultivar, were used to compare responses. The results revealed that the highest number of eggs/female/day (EFD) for both mites was observed on Taha cultivar (9.0±0.40 and 9.5±0.28 for T. urticae and T. turkestani, respectively). The highest injury rate was also observed on this cultivar (4.8±0.26 and 5.0±0.0 for T. urticae and T. turkestani, respect...
International Journal of Acarology, 2010
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Environmental Entomology, 2009
The twospotted spider mite, Tetranychus urticae Koch, is among the most economically important pests in strawberries (Fragaria spp.). As T. urticae feeds, it ingests mesophyll cells that contain pigments essential for physiologic function and alters radiant energy use of the leaf tissue, severely compromising plant health and productivity. In our study, diffuse reßectance spectroscopy in the visible and near infrared (VNIR) portions of the spectrum was used to identify speciÞc spectral regions altered by T. urticae feeding and to quantitatively assess T. urticae density. During the 2006 Ð2007 growing season, 80 strawberry leaßets with varying levels of T. urticae infestation were collected. Spectral classiÞcation of both mite density (continuous) and mite density class (categorical) were developed. Spider mite density classes were low infestation (0 Ð20 mites/leaßet), moderate infestation (20 Ð50 mites/leaßet), and high infestation (Ն50 mites/leaßet). Continuous spectral prediction for leaf infestation was developed using partial least squares (PLS) regression. ClassiÞcation trees were used to train spectra to categorical levels of infestation. Both models were calibrated with 67% of the samples, and accuracy was evaluated using the remaining 33%. Categorical validation accuracy was 81%, with odds ratios for correctly predicting extreme categories (low and high) of 33 and 47.7, respectively. Continuous validation efÞciency was also high, with an r 2 between predicted and observed of 0.85 and a root-mean-squared error (RMSE) of 12.2 mites per leaf. Developing a spectral pest monitoring system would provide a diagnostic tool allowing early and effective intervention for precision management of T. urticae in strawberry. KEY WORDS spider mites, precision pest management, visible and near infrared spectra, Fragaria spp.
Journal of Applied and Natural Science
Field trials were conducted to assess the damage potential of two-spotted spider mite (Tetranychus urticae Koch) on cucumber (Cucumis sativus Linnaeus). Young cucumber plants were artificially infested with different densities of T. urticae (5, 10, 15 and 20 mites/ grown up leaf) while uninfested plants acted as control. Post infestation, the plants differed in their support to mite density in accordance with initial infestation density and observation period. Grown up leaves were found to be the most susceptible to mite infestation (5.86 mites/ sq. cm leaf). The number of feeding (chlorotic) patches on cucumber leaves significantly increased from 1.38/sq cm at a pre-count of 5 mites per grown up leaf to 1.71/sq cm leaf at a pre-count of 20 mites as compared to no patch recorded in control. Highly significant negative correlation was recorded between mite population and photosynthetic pigments. Total chlorophyll, chlorophyll-a, chlorophyll-b and carotenoids decreased to a maximum of...