scholarly journals Late Growth Stages of Johnsongrass Can Act as an Alternate Host of Colletotrichum sublineola

2020 ◽  
Vol 21 (1) ◽  
pp. 60-62
Author(s):  
Ezekiel Ahn ◽  
Gary Odvody ◽  
Louis K. Prom ◽  
Clint Magill
Keyword(s):  
Growth Stage ◽  
Cross Infection ◽  
Growth Stages ◽  
Alternate Host ◽  
Favorable Conditions ◽  
Late Growth

Twenty-six johnsongrass cultivars, collected from seven U.S. states, were spray inoculated with spores of an isolate of Colletotrichum sublineola derived from sorghum. Inoculations were made when plants reached growth stages of 2 (four to five leaves), 3 (seven to eight leaves), and 6 (post panicle emergence). At the earlier stages the johnsongrass cultivars showed hypersensitive responses and small lesions; however, acervulus formation was not observed. When late growth stage johnsongrass plants were spray inoculated, acervulus formation was confirmed in 19 cultivars as early as 5 days postinoculation. Results obtained confirm that johnsongrass can act as an alternate host of C. sublineola under favorable conditions, and growth stages of johnsongrass may be an important factor for cross infection of C. sublineola between johnsongrass and sorghum.

scholarly journals Effect of Herbicides on the Management of the Invasive Weed Solanum rostratum Dunal (Solanaceae)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Jackline Abu-Nassar ◽  
Maor Matzrafi
Keyword(s):  
Growth Stage ◽  
Late Summer ◽  
Early Spring ◽  
Growth Stages ◽  
Weed Species ◽  
Invasive Weed ◽  
Solanum Rostratum ◽  
Stage 4 ◽  
Chemical Solutions ◽  
Late Growth

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.

Control of Early Watergrass (Echinochloa Oryzoides) and Late Watergrass (Echinochloa Phyllopogon) with Cyhalofop, Clefoxydim, and Penoxsulam Applied Alone and in Mixture with Broadleaf Herbicides

2006 ◽  
Vol 20 (4) ◽  
pp. 992-998 ◽  
Author(s):  
Christos A. Damalas ◽  
Kico V. Dhima ◽  
Ilias G. Eleftherohorinos
Keyword(s):  
Growth Stage ◽  
Leaf Growth ◽  
Application Rate ◽  
Early Growth ◽  
Rice Fields ◽  
Growth Stages ◽  
Early Growth Stage ◽  
Late Growth ◽  
Echinochloa Phyllopogon

Experiments were conducted to study the effect of application rate, growth stage, and tank-mixing azimsulfuron or bentazon on the activity of cyhalofop, clefoxydim, and penoxsulam against two morphologically distinctEchinochloaspecies from rice fields in Greece. Mixtures of penoxsulam with MCPA were also evaluated. Cyhalofop (300 to 600 g ai/ha) applied at the three- to four-leaf growth stage provided 62 to 85% control of early watergrass but 41 to 83% control of late watergrass averaged over mixture treatments. Control ranged from 37 to 80% for early watergrass and from 35 to 78% for late watergrass when cyhalofop was applied at the five- to six-leaf growth stage averaged over mixture treatments. Mixtures of cyhalofop with azimsulfuron or bentazon reduced efficacy on both species irrespective of growth stage or cyhalofop application rate compared with cyhalofop alone. Clefoxydim (100 to 250 g ai/ha) applied alone at the three- to four-leaf growth stage provided 98 to 100% control of early watergrass and 91 to 100% control of late watergrass; when clefoxydim was applied alone at the five- to six-leaf growth stage the control obtained was 91 to 100% for early watergrass and 79 to 100% for late watergrass. Mixtures of clefoxydim with azimsulfuron or bentazon reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Penoxsulam (20 to 40 g ai/ha) applied alone provided 94 to 100% control of both species at both growth stages. Mixtures of MCPA with penoxsulam reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Mixtures of penoxsulam with azimsulfuron or bentazon reduced efficacy only on late watergrass at the late growth stage.

Effect of Application Timing on Rhizome Johnsongrass (Sorghum halepense) Control with DPX-V9360

Weed Science ◽  
1990 ◽  
Vol 38 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Timothy T. Obrigawitch ◽  
William H. Kenyon ◽  
Henry Kuratle
Keyword(s):  
Growth Stage ◽  
Field Studies ◽  
Early Growth ◽  
Effective Control ◽  
Growth Stages ◽  
Application Timing ◽  
Leaf Surfaces ◽  
Treated Leaf ◽  
Plant Emergence ◽  
Late Growth

Field, greenhouse, and laboratory studies were conducted to examine the effect of application timing on the activity of DPX-V9360 on rhizome johnsongrass. Field and greenhouse studies indicated that johnsongrass treated with postemergence applications of DPX-V9360 at late growth stages (>5 leaves) was controlled more effectively than when treated in early growth stages (<5 leaves). Johnsongrass control was optimized with split-postemergence applications (treatments applied at early and late growth stages) in field studies compared to a single postemergence application at either early or late growth stages. The pattern of translocation of 2-14C (pyrimidine)-labeled DPX-V9360 applied to a fully expanded johnsongrass leaf did not differ significantly between three different growth stages of 10-, 30-, and 60-cm height. Over 60% of the absorbed14C remained in the treated leaf. Most of the translocated14C moved out of the treated leaf within 3 days after application and distributed to the shoot in greater quantities than to the rhizomes. About 40% of14C-DPX-V9360 applied to the leaf surfaces of a tolerant species (corn) or susceptible species (johnsongrass) was absorbed into the leaf. Corn metabolized over 90% of absorbed DPX-V9360 within 20 h, while there was no perceptible metabolism of DPX-V9360 in johnsongrass leaves after 24 h. Late growth stage and split-postemergence applications appear to provide more effective control than early growth stage applications because of better control of regrowth (new shoot emergence from rhizomes after application) and because tillering and plant emergence are more nearly complete at application time.

scholarly journals Enhancing Water use Efficiency of Maize under Deficit Irrigation: the Case of Moisture Deficit Areas of Tigray, Ethiopia

2019 ◽  
pp. 1-6
Author(s):  
Kiflom Degef Kahsay ◽  
Kidane Welde Reda
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Irrigation Water ◽  
Deficit Irrigation ◽  
Growth Stage ◽  
Biomass Yield ◽  
Growth Stages ◽  
Use Efficiency ◽  
Late Growth

Maize (Zea Mays L.) is one of the most important food crops worldwide. In Ethiopia, it is one of the leading food grains selected to assume a national commodity crop to support the food self-sufficiency program of the country. Maize is fairly sensitive to water stress and excessive moisture stress. This is due to variation in sensitivity of different growth stages to water stress. The study was conducted to determine the water use efficiency of maize under deficit irrigation practice without significant reduction in yield and to identify crop growth stages which can withstand water stress. The experiment was conducted at the Alamata Agricultural Research center experimental site Kara Adishabo Kebele, Raya Azebo district. The experiment was laid out in randomized complete block design (RCBD) with three replications and six levels of irrigation water applications as possible treatments. Analysis was done to yield and water use efficiency of maize using R statistical software and the mean difference was estimated using the least significant difference (LSD) comparison. The highest grain (33.72qt/ha) and biomass yield (148.4qt/ha) was obtained from the 50% deficit irrigation at late growth. The maximum irrigation water use efficiency was obtained from both 50% deficit at all the four growth stages (0.5418 kg/ha) and at 50% deficit at late growth stage (0.446 kg/m3). And by comparing the grain yield obtained at the 50% deficit at late growth stage (33.72 qt/ha) and grain yield obtained at 50% deficit at all growth stages (23.34 qt/ha), the 50% deficit at late growth stage shows better result. The 50% deficit of crop water requirement did not affect the yield components (plant height & number of cobs per plant) of maze. Therefore applying irrigation water by reducing the crop water requirement by 50% at the late growth stage has a significant contribution for sustainable and efficient irrigation water utilization at moisture deficient areas without a significant loss on grain and biomass yield.

scholarly journals Identification of Wheat Yellow Rust Using Optimal Three-Band Spectral Indices in Different Growth Stages

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 35 ◽  
Author(s):  
Qiong Zheng ◽  
Wenjiang Huang ◽  
Ximin Cui ◽  
Yingying Dong ◽  
Yue Shi ◽  
...  
Keyword(s):  
Classification Accuracy ◽  
Growth Stage ◽  
Yellow Rust ◽  
Kappa Coefficient ◽  
Economic Losses ◽  
Growth Stages ◽  
Spectral Indices ◽  
Rust Disease ◽  
Late Growth ◽  
Different Growth Stages

Yellow rust, a widely known destructive wheat disease, affects wheat quality and causes large economic losses in wheat production. Hyperspectral remote sensing has shown potential for the detection of plant disease. This study aimed to analyze the spectral reflectance of the wheat canopy in the range of 350–1000 nm and to develop optimal spectral indices to detect yellow rust disease in wheat at different growth stages. The sensitive wavebands of healthy and infected wheat were located in the range 460–720 nm in the early-mid growth stage (from booting to anthesis), and in the ranges 568–709 nm and 725–1000 nm in the mid-late growth stage (from filling to milky ripeness), respectively. All possible three-band combinations over these sensitive wavebands were calculated as the forms of PRI (Photochemical Reflectance Index) and ARI (Anthocyanin Reflectance Index) at different growth stages and assessed to determine whether they could be used for estimating the severity of yellow rust disease. The optimal spectral index for estimating wheat infected by yellow rust disease was PRI (570, 525, 705) during the early-mid growth stage with R2 of 0.669, and ARI (860, 790, 750) during the mid-late growth stage with R2 of 0.888. Comparison of the proposed spectral indices with previously reported vegetation indices were able to satisfactorily discriminate wheat yellow rust. The classification accuracy for PRI (570, 525, 705) was 80.6% and the kappa coefficient was 0.61 in early-mid growth stage, and the classification accuracy for ARI (860, 790, 750) was 91.9% and the kappa coefficient was 0.75 in mid-late growth stage. The classification accuracy of the two indices reached 84.1% and 93.2% in the early-mid and mid-late growth stages in the validated dataset, respectively. We conclude that the three-band spectral indices PRI (570, 525, 705) and ARI (860, 790, 750) are optimal for monitoring yellow rust infection in these two growth stages, respectively. Our method is expected to provide a technical basis for wheat disease detection and prevention in the early-mid growth stage, and the estimation of yield losses in the mid-late growth stage.

scholarly journals Monitoring the Vertical Distribution of Maize Canopy Chlorophyll Content Based on Multi-Angular Spectral Data

2021 ◽  
Vol 13 (5) ◽  
pp. 987
Author(s):  
Bin Wu ◽  
Huichun Ye ◽  
Wenjiang Huang ◽  
Hongye Wang ◽  
Peilei Luo ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Vertical Distribution ◽  
Chlorophyll Content ◽  
Spectral Data ◽  
Growth Stage ◽  
Growth Stages ◽  
Growth Monitoring ◽  
Spad Value ◽  
The Vertical Distribution ◽  
Late Growth

Remote sensing approaches have several advantages over traditional methods in determining information on physical and chemical parameters, including timely data acquisition, low costs, and wide coverage. Thus, remote sensing is widely used in crop growth monitoring. Unlike vertical observations, multi-angular remote sensing technology can obtain the vertical distribution information of the central and lower leaves of a crop. Furthermore, applications of remote sensing on the vertical distribution of maize canopy components is complicated, and related research is limited. In the current paper, we employed multi-angular spectral data, measured by a self-designed multi-angular observation instrument at view zenith angles (VZAs) of 0°, 10°, 20°, 30°, 40°, 50°, and 60°, to explore the monitoring strategy and monitoring precision of the vertical distribution of chlorophyll content in the maize canopy. This was then used to determine the optimal monitoring method for the chlorophyll content (soil and plant analyzer development (SPAD) value) of each layer. The correlation between SPAD value and chlorophyll sensitivity indices at different growth stages was used as the basis for screening indices and VZAs. The correlation between the selected EPI (eucalyptus pigment index) and REIP (red edge inflection point) indices and chlorophyll content indicated view zenith angles (VZAs) of 0°, 30°, and 40° as optimal for the early growth stage monitoring of chlorophyll content in the 1st, 2nd, and 3rd layers, respectively. These values were associated with RMSEs of 4.14, 1.71, and 1.11 for EPI, respectively; and 4.61, 2.31, and 1.00 for REIP, respectively. In addition, a VZA of 50° was selected to monitor the chlorophyll content of the 1st, 2nd, 3rd, and 4th layers at the late growth stage, with RMSE values of 2.97, 3.50, 2.80, and 4.80 for EPI, respectively; and 3.16, 5.02, 4.55, and 7.85 for REIP, respectively. The results demonstrated the ability of canopy multi-angular spectral reflectance to accurately estimate the maize canopy chlorophyll content vertical distribution, with the VZAs of different vertical layers varying between the early and late growth stages.

Effects of Drip Irrigation on Photosynthetic Characteristics of Leaves and Bracts in Cotton at Late Growth Stage

2015 ◽  
Vol 41 (1) ◽  
pp. 100 ◽  
Author(s):  
Chao ZHANG ◽  
Dong-Xia ZHAN ◽  
Ya-Li ZHANG ◽  
Hong-Hai LUO ◽  
Ling GOU ◽  
...  
Keyword(s):  
Drip Irrigation ◽  
Growth Stage ◽  
Photosynthetic Characteristics ◽  
Late Growth

scholarly journals Growth Stages Classification of Potato Crop Based on Analysis of Spectral Response and Variables Optimization

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3995 ◽  
Author(s):  
Ning Liu ◽  
Ruomei Zhao ◽  
Lang Qiao ◽  
Yao Zhang ◽  
Minzan Li ◽  
...  
Keyword(s):  
Growth Stage ◽  
Spectral Response ◽  
Classification Model ◽  
Growth Stages ◽  
Potato Field ◽  
Spectral Bands ◽  
Svm Model ◽  
Selection Algorithms ◽  
Potato Crops

Potato is the world’s fourth-largest food crop, following rice, wheat, and maize. Unlike other crops, it is a typical root crop with a special growth cycle pattern and underground tubers, which makes it harder to track the progress of potatoes and to provide automated crop management. The classification of growth stages has great significance for right time management in the potato field. This paper aims to study how to classify the growth stage of potato crops accurately on the basis of spectroscopy technology. To develop a classification model that monitors the growth stage of potato crops, the field experiments were conducted at the tillering stage (S1), tuber formation stage (S2), tuber bulking stage (S3), and tuber maturation stage (S4), respectively. After spectral data pre-processing, the dynamic changes in chlorophyll content and spectral response during growth were analyzed. A classification model was then established using the support vector machine (SVM) algorithm based on spectral bands and the wavelet coefficients obtained from the continuous wavelet transform (CWT) of reflectance spectra. The spectral variables, which include sensitive spectral bands and feature wavelet coefficients, were optimized using three selection algorithms to improve the classification performance of the model. The selection algorithms include correlation analysis (CA), the successive projection algorithm (SPA), and the random frog (RF) algorithm. The model results were used to compare the performance of various methods. The CWT-SPA-SVM model exhibited excellent performance. The classification accuracies on the training set (Atrain) and the test set (Atest) were respectively 100% and 97.37%, demonstrating the good classification capability of the model. The difference between the Atrain and accuracy of cross-validation (Acv) was 1%, which showed that the model has good stability. Therefore, the CWT-SPA-SVM model can be used to classify the growth stages of potato crops accurately. This study provides an important support method for the classification of growth stages in the potato field.

scholarly journals Effect of Growth Stage on Susceptibility of Grape Berry and Rachis Tissues to Infection by Phomopsis viticola

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 517-520 ◽  
Author(s):  
O. Erincik ◽  
L. V. Madden ◽  
D. C. Ferree ◽  
M. A. Ellis
Keyword(s):  
Growth Stage ◽  
Grape Berry ◽  
Growth Stages ◽  
Phomopsis Viticola ◽  
Over Time

Intact ‘Seyval’ grape clusters in the greenhouse and ‘Catawba’ clusters in the field were inoculated with conidia of Phomopsis viticola at seven Eichorn-Lorenz growth stages between 12 (prebloom) and 35 (véraison) in 1998. Five pots (10 clusters) were used per inoculation, and the experiment was repeated three times. Also, 10 to 20 randomly selected Catawba clusters were inoculated in the field for each of three replications at each growth stage. Studies were repeated in 1999. In addition, Chambourcin clusters were also inoculated at four growth stages in the greenhouse in 1999. Results obtained in the greenhouse and field during both years and for all cultivars indicate that berry and rachis infections can occur at all growth stages between 12 and 35 with no evidence of decreasing susceptibility over time. Results disagree with some literature reports that indicate that berry infection occurs primarily during bloom and shortly after bloom, and susceptibility decreases as fruit matures.

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