scholarly journals Biotic Yield Losses in the Southern Amazon, Brazil: Making Use of Smartphone-Assisted Plant Disease Diagnosis Data

2021 ◽  
Vol 12 ◽  
Author(s):  
Anna C. Hampf ◽  
Claas Nendel ◽  
Simone Strey ◽  
Robert Strey
Keyword(s):  
Spatial Distribution ◽  
Yield Loss ◽  
Disease Diagnosis ◽  
Plant Diseases ◽  
Brown Spot ◽  
Economic Losses ◽  
Yield Losses ◽  
Cotton Production ◽  
Automated Recognition ◽  
Study Results

Pathogens and animal pests (P&A) are a major threat to global food security as they directly affect the quantity and quality of food. The Southern Amazon, Brazil’s largest domestic region for soybean, maize and cotton production, is particularly vulnerable to the outbreak of P&A due to its (sub)tropical climate and intensive farming systems. However, little is known about the spatial distribution of P&A and the related yield losses. Machine learning approaches for the automated recognition of plant diseases can help to overcome this research gap. The main objectives of this study are to (1) evaluate the performance of Convolutional Neural Networks (ConvNets) in classifying P&A, (2) map the spatial distribution of P&A in the Southern Amazon, and (3) quantify perceived yield and economic losses for the main soybean and maize P&A. The objectives were addressed by making use of data collected with the smartphone application Plantix. The core of the app’s functioning is the automated recognition of plant diseases via ConvNets. Data on expected yield losses were gathered through a short survey included in an “expert” version of the application, which was distributed among agronomists. Between 2016 and 2020, Plantix users collected approximately 78,000 georeferenced P&A images in the Southern Amazon. The study results indicate a high performance of the trained ConvNets in classifying 420 different crop-disease combinations. Spatial distribution maps and expert-based yield loss estimates indicate that maize rust, bacterial stalk rot and the fall armyworm are among the most severe maize P&A, whereas soybean is mainly affected by P&A like anthracnose, downy mildew, frogeye leaf spot, stink bugs and brown spot. Perceived soybean and maize yield losses amount to 12 and 16%, respectively, resulting in annual yield losses of approximately 3.75 million tonnes for each crop and economic losses of US$2 billion for both crops together. The high level of accuracy of the trained ConvNets, when paired with widespread use from following a citizen-science approach, results in a data source that will shed new light on yield loss estimates, e.g., for the analysis of yield gaps and the development of measures to minimise them.

scholarly journals A Coordinated Effort to Manage Soybean Rust in North America: A Success Story in Soybean Disease Monitoring

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 864-875 ◽  
Author(s):  
E. J. Sikora ◽  
T. W. Allen ◽  
K. A. Wise ◽  
G. Bergstrom ◽  
C. A. Bradley ◽  
...  
Keyword(s):  
North America ◽  
Information Dissemination ◽  
Monitoring Program ◽  
Plant Diseases ◽  
Soybean Rust ◽  
Economic Losses ◽  
Disease Monitoring ◽  
Growth Stages ◽  
Yield Losses ◽  
Monitoring Programs

Existing crop monitoring programs determine the incidence and distribution of plant diseases and pathogens and assess the damage caused within a crop production region. These programs have traditionally used observed or predicted disease and pathogen data and environmental information to prescribe management practices that minimize crop loss. Monitoring programs are especially important for crops with broad geographic distribution or for diseases that can cause rapid and great economic losses. Successful monitoring programs have been developed for several plant diseases, including downy mildew of cucurbits, Fusarium head blight of wheat, potato late blight, and rusts of cereal crops. A recent example of a successful disease-monitoring program for an economically important crop is the soybean rust (SBR) monitoring effort within North America. SBR, caused by the fungus Phakopsora pachyrhizi, was first identified in the continental United States in November 2004. SBR causes moderate to severe yield losses globally. The fungus produces foliar lesions on soybean (Glycine max) and other legume hosts. P. pachyrhizi diverts nutrients from the host to its own growth and reproduction. The lesions also reduce photosynthetic area. Uredinia rupture the host epidermis and diminish stomatal regulation of transpiration to cause tissue desiccation and premature defoliation. Severe soybean yield losses can occur if plants defoliate during the mid-reproductive growth stages. The rapid response to the threat of SBR in North America resulted in an unprecedented amount of information dissemination and the development of a real-time, publicly available monitoring and prediction system known as the Soybean Rust-Pest Information Platform for Extension and Education (SBR-PIPE). The objectives of this article are (i) to highlight the successful response effort to SBR in North America, and (ii) to introduce researchers to the quantity and type of data generated by SBR-PIPE. Data from this system may now be used to answer questions about the biology, ecology, and epidemiology of an important pathogen and disease of soybean.

scholarly journals Impact of Brown Spot Caused by Septoria glycines on Soybean in Ohio

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 820-826 ◽  
Author(s):  
Christian D. Cruz ◽  
Dennis Mills ◽  
Pierce A. Paul ◽  
Anne E. Dorrance
Keyword(s):  
Growth Stage ◽  
Yield Loss ◽  
Management Program ◽  
Brown Spot ◽  
Growth Stages ◽  
Yield Losses ◽  
Cultivar Development ◽  
Term Management ◽  
Different Levels

Brown spot, caused by Septoria glycines, is the most common foliar disease of soybean in Ohio, but its economic impact has not been assessed on modern cultivars. Therefore, the objectives of this study were to (i) evaluate the effect of S. glycines on soybean yield and (ii) evaluate the efficacy of strobilurin- and triazole-based fungicides on the control of brown spot. Yield loss associated with S. glycines was determined using weekly applications of chlorothalonil. The efficacy of azoxystrobin, pyraclostrobin, tebuconazole, and flutriafol alone and in combinations were also assessed using applications at the R3 and R5 growth stages at two locations over 3 years. Significantly different levels of brown spot developed following applications of chlorothalonil, with mean yield differences between treated and nontreated plots ranging from 196 to 293 kg/ha. Pyraclostrobin and azoxystrobin applied at the R3 growth stage significantly reduced final levels of brown spot; however, significant increases in yield occurred in only three of the six location-years. Triazoles, flutriafol and tebuconazole, applied at R3 or R5 did not significantly decrease levels of brown spot or impact yield. More data on the accurate timing of fungicides are still required to establish a long-term management program for this disease, and resistance to brown spot should be monitored in soybean cultivar development to prevent future yield losses.

scholarly journals Soybean Disease Loss Estimates for the Top 10 Soybean Producing Countries in 1994

Plant Disease ◽  
1997 ◽  
Vol 81 (1) ◽  
pp. 107-110 ◽  
Author(s):  
J. A. Wrather ◽  
T. R. Anderson ◽  
D. M. Arsyad ◽  
J. Gai ◽  
L. D. Ploper ◽  
...  
Keyword(s):  
Yield Loss ◽  
Management Strategies ◽  
Total Yield ◽  
Stem Canker ◽  
Brown Spot ◽  
Yield Losses ◽  
Control Research ◽  
Staff Research ◽  
Field Workers ◽  
Soybean Diseases

Soybean disease loss estimates were compiled for the 1994 harvested crop from the 10 countries with the greatest soybean production. The objective was to document the major soybean disease problems in these countries and any recent changes in the severity of individual soybean diseases. Total yield losses caused by Heterodera glycines in these 10 countries were greater than those caused by any other disease. Next in order of importance were stem canker, brown spot, and charcoal rot. The total yield loss due to disease during 1994 in these countries was 14.99 million metric tons, valued at $3.31 billion. Methods used to estimate soybean disease losses were field surveys, plant disease diagnostic clinic samples, variety trial data, information from field workers and university extension staff, research plots, grower demonstrations, and private crop consultant reports. Yield loss estimates due to a particular disease varied by country. For example, yield losses due to rust were reported from China and Indonesia, but no losses due to this disease were reported from any of the remaining eight countries. Soybean disease control research and extension efforts are needed to provide more effective preventive and therapeutic disease management strategies and systems to producers.

Acyrthosiphon pisum (pea aphid).

2021 ◽  
Author(s):  
Melaku Wale
Keyword(s):  
Acyrthosiphon Pisum ◽  
Yield Loss ◽  
Economic Losses ◽  
Virus Spread ◽  
Feeding Damage ◽  
Yield Losses ◽  
Severe Damage ◽  
Major Pest ◽  
Sooty Moulds ◽  
Economic Pest

Abstract A. pisum is a major pest of pea, lucerne and clover. Severe damage can occur to peas due to direct feeding and virus spread. Direct feeding on pea results in sap being removed from terminal leaves and the stem. Heavy infestations on pea can cause stunting, deformation, wilting and even death. Plants smaller than 15 cm can easily be killed by aphid infestations, although plants bigger than 15 cm usually suffer only relatively minor damage due to direct feeding. Aphids can also feed on pods, causing them to curl, shrink and only partially fill. Direct feeding therefore leads to yield loss and reductions in crop quality. Bommarco (1991) calculated economic losses in pea through a number of seasons due to A. pisum; with observed yield losses of up to 230 kg/ha. Although direct feeding damage is significant, this aphid is primarily an economic pest on pea due to its ability to transmit viruses. Broad beans and a range of other bean crops can also suffer yield losses, through similar direct feeding impacts, from heavy infestations of A. pisum. On peas and beans, A. pisum secretes honeydew from its siphunculi, which can coat plants, reducing photosynthetic efficiency and resulting in the growth of unsightly sooty moulds.

Optimizing chloroacetamide application timing in dicamba-resistant cotton production systems for control of glyphosate-resistant Palmer amaranth

2021 ◽  
pp. 1-23
Author(s):  
John T. Buol ◽  
Lucas X. Franca ◽  
Darrin M. Dodds ◽  
J. Anthony Mills ◽  
Janice L. DuBien ◽  
...  
Keyword(s):  
Yield Loss ◽  
Biomass Yield ◽  
Production Systems ◽  
Management Program ◽  
Palmer Amaranth ◽  
Yield Losses ◽  
Cotton Production ◽  
Single Application ◽  
Application Timing ◽  
Late Season

A chloroacetamide herbicide by application timing factorial experiment was conducted in 2017 and 2018 in Mississippi to investigate chloroacetamide use in a dicamba-based Palmer amaranth management program in cotton production. Herbicides used were S-metolachlor or acetochlor, and application timings were preemergence, preemergence followed by (fb) early postemergence, preemergence fb late postemergence, early postemergence alone, late postemergence alone, and early postemergence fb late postemergence. Dicamba was included in all preemergence applications, and dicamba plus glyphosate was included with all postemergence applications. Differences in cotton and weed response due to chloroacetamide type were minimal, and cotton injury 14 d after LP application was less than 10% for all application timings. Late-season weed control was reduced up to 30 and 53% if chloroacetamide application occurred PRE or LP only, respectively. Late-season weed densities were minimized if multiple applications were used instead of a single application. Cotton height was reduced by up to 23% if a single application was made LP relative to other application timings. Chloroacetamide application at any timing except PRE alone minimized late season weed biomass. Yield was maximized by any treatment involving multiple applications or EP alone whereas applications PRE or LP alone resulted in up to 56 and 27% yield losses, respectively. While no yield loss was reported by delaying the first of sequential applications until EP, foregoing a PRE application is not advisable given the multiple factors that may delay timely POST applications such as inclement weather.

scholarly journals Estimating Yield and Economic Loss from Constriction Canker of Peach

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 941-946 ◽  
Author(s):  
Norman Lalancette ◽  
Dean F. Polk
Keyword(s):  
Yield Loss ◽  
Disease Incidence ◽  
Economic Loss ◽  
Control Measures ◽  
Economic Losses ◽  
Crop Loss ◽  
Friedman Test ◽  
Yield Losses ◽  
Yield Level ◽  
Total Crop

Constriction cankers, caused by Phomopsis amygdali, girdle and kill fruiting twigs which results in a direct crop loss. To quantitatively determine this loss from 1996 to 1998, the number of fruit lost per infected shoot was estimated as a function of disease incidence in 21 severely infected orchards in New Jersey. For each cultivar in 1997 and 1998, the distribution of fruit sizes at harvest and prices at shipping were used to calculate total crop value for typical expected yields. Economic loss was then calculated from yield loss and crop value estimates. The overall percent yield loss mean across all sites and cultivars, unadjusted for fruit remaining on infected shoots, was 22.2, 30.7, and 23.7% for 1996, 1997, and 1998, respectively. The frequency of these losses were not normally distributed, and the nonparametric Friedman test indicated that yield loss was significantly different among years. Assuming the remaining fruit on infected shoots were harvested, yield losses for 1997 and 1998 were 28.5 and 21.0%, which translated into average economic losses of $4,009 and 2,803/ha, respectively, for an expected yield level of 14,010 kg/ha. These loss values justify control measures for management of constriction canker in severely infected orchards.

scholarly journals Citrus Diseases Exotic to Florida: Citrus Tristeza Virus– Stem Pitting (CTV-SP)

EDIS ◽  
2006 ◽  
Vol 2006 (7) ◽  
Author(s):  
Kuang-Ren Chung ◽  
Ronald H. Brlansky
Keyword(s):  
Citrus Tristeza Virus ◽  
Plant Diseases ◽  
Production Costs ◽  
Brown Spot ◽  
Economic Losses ◽  
Citrus Diseases ◽  
Florida Citrus ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus is susceptible to a large number of diseases caused by plant pathogens. Economic losses due to plant diseases can be severe, but fortunately, not all pathogens attacking citrus are present in Florida. Major citrus diseases currently present in Florida include: Alternaria brown spot, blight, citrus canker, greasy spot, melanose, Phytophthora-induced diseases (foot and root rot, brown rot), postbloom fruit drop (PFD), scab, and tristeza. An exotic, destructive disease called citrus greening (Huanglongbing) has recently been found in Florida. Any exotic diseases, if introduced, will increase production costs and decrease profitability for Florida growers. Exotic diseases affect the viability of the industry or the varieties that could be profitably grown. Background information for each exotic citrus disease will be presented in a series of fact sheets to: 1) provide a basis for evaluating exotic pathogens that may pose potential risks to Florida citrus; and 2) create a decision-making framework to prevent their introduction and spread. This paper will discuss Citrus tristeza virus-Stem Pitting (CTV-SP) disease. This article is written based on the materials used for the Workshops of the Exotic Citrus Pathogen Threat Project led by Drs. S. M. Garnsey and H. W. Browning, and approved for publication.

scholarly journals A new somatic cell count index to more accurately predict milk yield losses

2017 ◽  
Vol 60 (4) ◽  
pp. 373-383 ◽  
Author(s):  
Janez Jeretina ◽  
Dejan Škorjanc ◽  
Drago Babnik
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Milk Yield ◽  
Somatic Cell Count ◽  
Yield Loss ◽  
Early Stage ◽  
Economic Losses ◽  
Yield Losses ◽  
Daily Milk Yield ◽  
Daily Milk

Abstract. Intramammary infection and clinical mastitis in dairy cows leads to considerable economic losses for farmers. The somatic cell concentration in cow's milk has been shown to be an excellent indicator for the prevalence of subclinical mastitis. In this study, a new somatic cell count index (SCCI) was proposed for the accurate prediction of milk yield losses caused by elevated somatic cell count (SCC). In all, 97 238 lactations (55 207 Holstein cows) from 2328 herds were recorded between 2010 and 2014 under different scenarios (high and low levels of SCC, four lactation stages, different milk yield intensities, and parities (1, 2, and  ≥  3). The standard shape of the curve for SCC was determined using completed standard lactations of healthy cows. The SCCI was defined as the sum of the differences between the measured interpolated values of the natural logarithm of SCC (ln(SCC)) and the values for the standard shape of the curve for SCC for a particular period, divided by the total area enclosed by the standard curve and upper limit of ln(SCC)  =  10 for SCC. The phenotypic potential of milk yield (305-day milk yield – MY305) was calculated using regression coefficients estimated from the linear regression model for parity and breeding values of cows for milk yield. The extent of daily milk yield loss caused by increased SCC was found to be mainly related to the early stage of lactation. Depending on the possible scenarios, the estimated milk yield loss from MY305 for primiparous cows was at least 0.8 to 0.9 kg day−1 and for multiparous cows it ranged from 1.3 to 4.3 kg day−1. Thus, the SCCI was a suitable indicator for estimating daily milk yield losses associated with increased SCC and might provide farmers reliable information to take appropriate measures for ensuring good health of cows and reducing milk yield losses at the herd level.

scholarly journals Climatic Causes of Maize Production Loss under Global Warming in Northeast China

2020 ◽  
Vol 12 (18) ◽  
pp. 7829
Author(s):  
Yanling Song ◽  
Hans W. Linderholm ◽  
Yi Luo ◽  
Jinxia Xu ◽  
Guangsheng Zhou
Keyword(s):  
Global Warming ◽  
Low Temperatures ◽  
Northeast China ◽  
Yield Loss ◽  
Climatic Factors ◽  
Heavy Rain ◽  
Maize Yield ◽  
Plant Diseases ◽  
Yield Losses ◽  
Adaptation To Climate Change

Maize (Zea mays L.) is one of the most important staple crops in Northeast China, and yield losses are mainly induced by climate anomalies, plant diseases and pests. To understand how maize yield loss is affected by global warming, daily precipitation and temperatures, together with provincial agricultural data sets, were analyzed. The results showed that the accumulated temperature, an important factor in agricultural productivity, increased by 5% in 1991–2017, compared to 1961–1990, and that the frequency of low temperatures decreased by 14.8% over the same time period. An increase in drought by 21.6% was observed from 1961–1990 to 1991–2017, caused by decreased growing-season precipitation by −4 mm/decade. In addition, days with heavy rain in August and September increased slightly in Northeast China. In general, maize growth responded positively to the increased thermal conditions; in 1961–1990, 22.7% of observed maize yield-loss cases were due to low temperatures, but only 10% in 1991–2017. However, during the same time, the number of drought-induced yield loss cases increased from 27.3% to 46.7%. Moreover, yield loss cases caused by heavy rainstorms increased from 4.5% to 13.3%, indicating that heavy rainstorms have become an increasing threat to agriculture in Northeast China over the last three decades. In total, at least 70% of cases of provincial yield losses in Northeast China over the last three decades could be attributed to climatic factors. The frequency of climate hazards has changed under global warming, resulting in new challenges for agriculture. While drought and low temperatures were the primary causes for climate-induced yield losses before the 1990s, negative impacts from extreme events, mainly drought but also heavy precipitation, have increased in the last three decades, associated with global change. Farmers, agricultural scientists, and government policy makers could use these results when planning for adaptation to climate change.

scholarly journals First report of Stemphylium lycopersici causing leaf spot on Polygonatum kingianum in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Jianxin Chen ◽  
Yuqian Wei ◽  
Zejia Lv ◽  
Qingli Han ◽  
Yuan Zheng ◽  
...  
Keyword(s):  
Plant Protection ◽  
Early Stage ◽  
Strong Support ◽  
Morphological Characteristics ◽  
Plant Diseases ◽  
Brown Spot ◽  
Economic Losses ◽  
Brown Pigment ◽  
New Host ◽  
Stemphylium Lycopersici

Polygonatum kingianum, a member of the Liliaceae, is valued in traditional medicine and as a vegetable food crop. In July 2019, more than 50% of P. kingianum growth was suppressed in several field nurseries in Simao, Mojiang, Jingdong and Lancang County, Puer City, China. At the early stage of infection, symptoms manifested as a small circular brown spot. As the lesion matured, the spot gradually enlarged, forming an oval to irregular lesion with reddish-brown and dark green borders. In serious cases, the leaves were withered, and became brittle with cracks. The infected plants were collected from six major fields. The tissues of diseased leaves were soaked in 75% ethanol for 10 s, 0.1% mercuric chloride for 2 min, rinsed with sterilized water, and placed on potato dextrose agar (PDA) at 25℃ for 7 days. On PDA, four strains were isolated, and the colony was gray to dark yellowish-brown, flocculent, regular with concentric growth rings. Strain PKLS06 produced a dark red to brown pigment in the agar medium. On lesions, the conidiophores were solitary or in fascicles, straight or slightly curved, brown, with a conical apex, with three to five septa. The conidiogenous cells were pale-brown and swollen at the apex. On PDA, spores were solitary, oblong, bluntly rounded or sometimes with a point at the apex, with two to five transverse septa and one to two longitudinal septa with contractions at the main transverse septum. Morphological characteristics were consistent with published descriptions of Stemphylium lycopersici (Kee et al. 2017; Xie et al. 2018). For molecular identification, rDNA internal transcribed spacer (ITS) and the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene were amplified and sequenced (ITS accessions: MW243098, MW243099, MW243100, MW243101; gpd accessions: MW246803, MW246804, MW246805, MW246806) using published primers (White et al. 1990; Câmara et al. 2002). A phylogenetic tree was developed by Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian inference (BI). These four isolates fall into the S. lycopersici clade with strong support and all isolates were distinguished clearly from other species. Pathogenicity tests were performed using these four isolates. Each isolate was cultured on PDA and shake-cultured in V-8 juice broth (Nasehi et al. 2014). Conidia were resuspended in sterilized water (1×106 conidia/mL) and inoculated on intact leaves with injury of 1-year-old P. kingianum. The plants were incubated at 25℃ with a 12 h photoperiod and 90% humidity. A small spot began to appear after 3 days, and symptoms were similar to the those observed in the nursery after 10 days. Interestingly, the pathogenicity of strain PKLS06 was relatively weaker. Control plants treated with sterile water showed no disease symptoms. Re-isolated strains had the same morphological characteristics and the same ITS and gpd sequences as the original isolates, thus fulfilling Koch’s postulates. S. lycopersici, an important pathogen, is widely distributed, and can cause a variety of plant diseases. It is noteworthy that the disease was observed on a plant in the Liliaceae, expanding the host range of S. lycopersici, which previously was reported to primarily infect plants in the Solanaceae. Based on the results presented above, P. kingianum is a new host plant of S. lycopersici in China. This disease is a threat for nursery production of P. kingianum, leading to a reduction in yields and economic losses. References Kee, Y. J., et al. 2017. Plant Disease 102 (2): 445–446 Xie, X. W., et al. 2019. Canadian Journal of Plant Pathology-Revue Canadienne De Phytopathologie 41 (1): 124–128 White, T. J., et al. 1990. PCR Protocols: A Guide to Methods and Applications PCR Protocols: A Guide to Methods and Applications 18: 315–322 Câmara M. P. S., et al. 2002. Mycologia 94 (4): 660–672 Nasehi A., et al. 2014. Archives of Phytopathology & Plant Protection, 47 (14): 1658-1665.

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