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Sreedevi G.,Indian Central Research Institute for Dryland Agriculture | Prasad Y.G.,Indian Central Research Institute for Dryland Agriculture | Prabhakar M.,Indian Central Research Institute for Dryland Agriculture | Rao G.R.,Indian Central Research Institute for Dryland Agriculture | And 2 more authors.
PLoS ONE | Year: 2013

Temperature-driven development and survival rates of the mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) were examined at nine constant temperatures (15, 20, 25, 27, 30, 32, 35 and 40°C) on hibiscus (Hibiscus rosa-sinensis L.). Crawlers successfully completed development to adult stage between 15 and 35°C, although their survival was affected at low temperatures. Two linear and four nonlinear models were fitted to describe developmental rates of P. solenopsis as a function of temperature, and for estimating thermal constants and bioclimatic thresholds (lower, optimum and upper temperature thresholds for development: Tmin, Topt and Tmax, respectively). Estimated thresholds between the two linear models were statistically similar. Ikemoto and Takai's linear model permitted testing the equivalence of lower developmental thresholds for life stages of P. solenopsis reared on two hosts, hibiscus and cotton. Thermal constants required for completion of cumulative development of female and male nymphs and for the whole generation were significantly lower on hibiscus (222.2, 237.0, 308.6 degree-days, respectively) compared to cotton. Three nonlinear models performed better in describing the developmental rate for immature instars and cumulative life stages of female and male and for generation based on goodness-of-fit criteria. The simplified β type distribution function estimated Topt values closer to the observed maximum rates. Thermodynamic SSI model indicated no significant differences in the intrinsic optimum temperature estimates for different geographical populations of P. solenopsis. The estimated bioclimatic thresholds and the observed survival rates of P. solenopsis indicate the species to be high-temperature adaptive, and explained the field abundance of P. solenopsis on its host plants. © 2013 Sreedevi et al.

Prabhakar M.,Indian Central Research Institute for Dryland Agriculture | Prasad Y.G.,Indian Central Research Institute for Dryland Agriculture | Vennila S.,National Center for Integrated Pest Management | Thirupathi M.,Indian Central Research Institute for Dryland Agriculture | And 3 more authors.
Computers and Electronics in Agriculture | Year: 2013

Phenacoccus solenopsis Tinsley, a native of North America, is a widespread exotic mealybug infesting cotton, Gossypium spp. in several countries. Monitoring of this pest is generally undertaken through regular field surveys, which is labour intensive, time consuming and error prone. Alternately, radiometry is a reliable technique for rapid and non-destructive assessment of plant health. Thus, a study was conducted to characterize reflectance spectra of cotton plants with known mealybug infestation levels (grade-0 is healthy and grade-4 is severe), and seek to identify specific narrow wavelengths sensitive to mealybug damage. Reflectance measurements were made in the spectral range of 350-2500nm using a hyperspectral radiometer. Significant differences were found in green, near infrared and short wave infrared spectral regions for plants with early stages of P. solenopsis infestation, and for plants showing higher grades of infestation these differences extended to all the regions except blue. A significant reduction in total chlorophyll (12.83-35.83%) and relative water content (1.93-23.49%) was observed in the infested plants. Reflectance sensitivity analysis of the hyperspectral data revealed wavelengths centered at 492, 550, 674, 768 and 1454nm as most sensitive to mealybug damage. Mealybug Stress Indices (MSIs) were developed using two or three wavelengths, tested using multinomial logistic regression (MLR) analysis and compared with other indices published earlier. Results showed that the MSIs were superior (R2=0.82) to all other spectral vegetation indices tested. Further, the proposed MLR models corresponding to each MSIs were validated using two independent field data sets. The overall percent correct classification of cotton plants into different mealybug damage severity grades was in the range of 38.3 and 54.9. High classification accuracy for grade-1 (81.8%) showed that models are capable of early detection of mealybug damage. Results of this study could suggest potential usage of remote sensing in monitoring spatial and temporal distribution of the solenopsis mealybug, and thereby enable effective planning and implementation of site-specific pest management practices. © 2013 Elsevier B.V.

Rumbos C.I.,University of Thessaly | Khah E.M.,University of Thessaly | Sabir N.,National Center for Integrated Pest Management
Australian Journal of Crop Science | Year: 2011

Fifty two local Greek tomato (Solanum lycopersicum) cultivars and accessions and ten commercial nematode-resistant tomato cultivars and rootstocks were evaluated under controlled environmental conditions for resistance against the root-knot nematode Meloidogyne javanica. All tested local tomato cultivars and accessions were susceptible to M. javanica. Conversely, the commercial root-knot nematode-resistant tomato cultivars significantly reduced galling and egg mass production of M. javanica. Depending on the inoculum level (200 or 400 second stage juveniles (J2) per plant), the tested tomato rootstocks showed a different response to M. javanica. When plants were inoculated with 200 M. javanica J2 a significantly lower number of galls and egg masses was recorded for all tested rootstocks in comparison to that of the control 6 weeks after inoculation. Plant inoculation with 400 M. javanica J2 resulted in reduced root galling on the non-grafted rootstock Multifort 6 weeks after inoculation, whereas a significantly lower gall index was recorded for all non-grafted rootstocks and the grafted rootstocks Multifort and Unifort 12 weeks after inoculation.

Sabir N.,Indian Agricultural Research Institute | Sabir N.,National Center for Integrated Pest Management | Singh B.,Indian Agricultural Research Institute
Indian Journal of Agricultural Sciences | Year: 2013

Protected cultivation of high value vegetables and cut-flowers has shown tremendous potential during the last decade or so. With the progress of liberalized economy and the advent of newer technologies in agriculture, protected cultivation opens up avenues in agriculture hitherto not seen. These technologies are not only creating avenues at higher level but also to the growers with the smaller landholdings as the higher productivity levels retain economic relevance to agriculture. Protected cultivation is in a way precise, progressive and parallel agriculture encompassing virtually all facets of agriculture and rather under additional scrutiny of technical relevance to situations and grower and market economics. Since protected cultivation is a vast assembly of diverse aspects of agriculture, this review is an effort to bring its current status in global arena covering various components of this important and emerging field of horticulture. Apart from the status, technological components and methodologies, review also discusses principal vegetables like tomato, cucumber, capsicum and lettuce in brief, besides a good amount of treatise on key pests and plant protection strategies in greenhouses.

Birah A.,Central Agricultural Research Institute | Birah A.,National Center for Integrated Pest Management | Simhachalam P.,Central Agricultural Research Institute | Ganeshan S.,Central Agricultural Research Institute | And 2 more authors.
Indian Journal of Agricultural Sciences | Year: 2014

Fruit flies belonging to the family Dacinae, are biologically interesting and economically very important group of Diptera, as are known to infest a wide range of plant species especially fruits and vegetable crops. The present work was aimed for molecular profiling of fruit fly (Bactrocera sp) which is abundantly found in South Andaman. Though number of Bactrocera species has been reported to exist in these islands, Bactrocera cucurbitae is the most serious pest of cucurbit plants. Bactrocera sp is widely spread all over the world causing 85 -100 % damage to vegetable and fruits. Taxonomical diagnosis based on morphological characters could not discriminate them and all were found to be similar morphologically. During the course of this investigation, efforts were made to assess genetic similarities among these collections by using RAPD-PCR involving nine primers. The dendrogram of all primers depicted two major clusters which were having 60% similarity within as well as species. This shows a bright possibility of the use of RAPD-PCR in molecular profiling and identification of Bactrocera species of Andaman Islands.

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