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.

Seed damage and sources of yield loss by Sitodiplosis mosellana (Diptera: Cecidomyiidae) in resistant wheat varietal blends relative to susceptible wheat cultivars in western Canada

2014 ◽  
Vol 146 (3) ◽  
pp. 335-346 ◽  
Author(s):  
M.A.H. Smith ◽  
I.L. Wise ◽  
S.L. Fox ◽  
C.L. Vera ◽  
R.M. DePauw ◽  
...  
Keyword(s):  
Yield Loss ◽  
Market Value ◽  
Western Canada ◽  
Feeding Damage ◽  
Yield Losses ◽  
Wheat Varieties ◽  
Sitodiplosis Mosellana ◽  
Seed Damage ◽  
Kernel Weights ◽  
Wheat Midge

AbstractSpring wheat varieties with the Sm1 gene for resistance to wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were compared with susceptible wheat (Triticum Linnaeus; Poaceae) with respect to sources of yield loss and reduction in market value from wheat midge feeding damage. Four resistant varietal blends (90% Sm1 wheat plus 10% susceptible refuge) and four susceptible cultivars were grown in replicated experiments at eight locations in western Canada. Frequencies and 1000-kernel weights of undamaged and midge-damaged seeds were assessed before harvest by dissecting samples of ripe spikes, and after harvest in samples of cleaned grain. Spike data were used to estimate yield losses from reduced weight of damaged seeds and loss of severely damaged seeds (⩽8 mg) at harvest. Among midge-damaged seeds in spikes, few were severely damaged in resistant varietal blends, whereas most were severely damaged in susceptible cultivars. Cleaned, harvested grain of resistant varietal blends and susceptible cultivars had similar frequencies of midge damage and were assessed similar market grades. The primary benefit of midge-resistant wheat was reduced yield loss due to seed damage by wheat midge larvae. Resistant wheat did not protect against loss of market grade, but market value could increase due to larger yields.

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.

YIELD LOSSES IN CANOLA CAUSED BY ADULT AND LARVAL FLEA BEETLES, PHYLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE)

1986 ◽  
Vol 118 (4) ◽  
pp. 319-324 ◽  
Author(s):  
G.K. Bracken ◽  
G.E. Bucher
Keyword(s):  
Yield Loss ◽  
Flea Beetle ◽  
Soil Core ◽  
Feeding Damage ◽  
Yield Losses ◽  
Flea Beetles ◽  
Temporal Aspects ◽  
Field Plots ◽  
Effect Of Feeding ◽  
Adult Flea

AbstractThe temporal aspects of the effect of feeding damage to canola seedlings by adult flea beetles on yield were determined by protecting plants in 0.836-m2 field plots from beetle attack with screen cages for varying periods. Yield was reduced most when plants were damaged during stages 1.0–2.2, 5–10 days after germination, but was not reduced when they were damaged after reaching stages 2.3–2.4, 20 days after germination. Plots exposed to attack for periods greater than 5 days before protection had smaller yields and fewer plants than plots protected from the time of germination for 5 or more days before exposure to flea beetle attack. Yield losses caused by larvae were measured by growing plants inside field cages to stage 2.3–2.4 before exposing them to feral adults to establish larval populations; yields of plots treated subsequently with drenches of carbofuran to kill larvae were then compared with yields of untreated plots. A yield loss of 5% was observed at larval densities of 0.16/cm2, estimated from soil core samples and captures of adults in emergence cages. The results confirm that continuous protection of canola during and after germination is superior to post-germination protection and suggest that activities of flea beetle larvae reduce yield.

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 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 Pre-harvest field application of enhanced freshness formulation reduces yield loss in orange

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jaspa Samwel ◽  
Theodosy Msogoya ◽  
Abdul Kudra ◽  
Hosea Dunstan Mtui ◽  
Anna Baltazari ◽  
...  
Keyword(s):  
Yield Loss ◽  
Sweet Orange ◽  
New Technology ◽  
Significant Negative Correlation ◽  
Field Application ◽  
Yield Losses ◽  
Factorial Experiments ◽  
Marketable Yield ◽  
Pest Damage ◽  
Marketable Fruit

Abstract Background Orange (Citrus sinensis L.) production in Tanzania is constrained by several pre-harvest factors that include pests. Hexanal, sprayed as Enhanced Freshness Formulation (EFF) is a relatively new technology that has been reported to reduce pre-harvest loss in fruits. However, the effects of hexanal on pre-harvest yield loss of orange are not known. We studied the effects of hexanal as EFF on yield losses of three sweet orange cultivars namely, Early Valencia, Jaffa, and Late Valencia. Factorial experiments tested the effects of EFF concentration, variety, and time of EFF application on number of dropped fruit, percentage of non-marketable fruit and incidence of pest damage. Results Results showed significant negative correlation (p < 0.001) between EFF and the percentage of dropped fruit, non-marketable yield, and incidence of pest damage. An increase in hexanal concentration by 1%, is expected to reduce number of dropped fruit by 50, percentage of non-marketable by 35.6, and incidences of pest damage by 36.5% keeping other factors constant. Results also show significant association (p < 0.001) between time of hexanal application and non-marketable yield. Percentage of dropped fruit is expected to increase by 1 for each day away from harvest, keeping other factors constant. Conclusion Pre-harvest application of hexanal as EFF can significantly reduce number of dropped fruits, percentage of non-marketable fruit and incidence of pest damage.

scholarly journals The impact of cultivar resistance and fungicide treatment on mycotoxin content in grain and yield losses caused by Fusarium head blight in wheat

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Yield Loss ◽  
Joint Effect ◽  
Yield Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Fungicide Treatment ◽  
The Impact

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

scholarly journals Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Jill Alms ◽  
Sharon A. Clay ◽  
David Vos ◽  
Michael Moechnig
Keyword(s):  
Loss Function ◽  
Growth Stage ◽  
Yield Loss ◽  
Corn Yield ◽  
Yield Losses ◽  
Herbicide Resistant ◽  
Growing Seasons ◽  
Previous Season ◽  
Control Volunteer ◽  
Soybean Plants

The widespread adoption of glyphosate-resistant corn and soybean in cropping rotations often results in volunteer plants from the previous season becoming problem weeds that require alternative herbicides for control. Corn yield losses due to season-long volunteer soybean competition at several densities in two growing seasons were used to define a hyperbolic yield loss function. The maximum corn yield loss observed at high volunteer soybean densities was about 56%, whereas, the incremental yield loss (I) at low densities was 3.2%. Corn yield loss at low volunteer soybean densities was similar to losses reported for low densities of velvetleaf and redroot pigweed, with 10% yield loss estimated to occur at 3 to 4 volunteer soybean plants m−2. Several herbicides, including dicamba with or without diflufenzopyr applied at the V2 growth stage of volunteer soybean, provided > 90% control, demonstrating several economical options to control volunteer glyphosate-resistant soybean in glyphosate-resistant corn. Reevaluation of control recommendations may be needed with commercialization of other genetically modified herbicide-resistant soybean varieties.

scholarly journals Quantification of Avoidable Yield Losses in Oilseed Brassica Caused by Insect Pests

2011 ◽  
Vol 51 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Jagdev Kular ◽  
Sarwan Kumar
Keyword(s):  
Seed Yield ◽  
Yield Loss ◽  
Insect Pests ◽  
Block Design ◽  
Maximum Yield ◽  
The Other ◽  
Yield Losses ◽  
Eruca Sativa ◽  
Mustard Aphid ◽  
Randomized Block Design

Quantification of Avoidable Yield Losses in OilseedBrassicaCaused by Insect PestsA six year field study was conducted from 2001-2002 to 2006-2007 at Punjab Agricultural University, Ludhiana, India to study the losses in seed yield of differentBrassicaspecies (B. juncea, B. napus, B. carinata, B. rapaandEruca sativa) by the infestation of insect pests. The experiment was conducted in two different sets viz. protected/sprayed and unprotected, in a randomized block design, with three replications. Data on the infestation of insect pests, and seed yield were recorded at weekly intervals and at harvest, respectively. The loss in seed yield, due to mustard aphid and cabbage caterpillar, varied from 6.5 to 26.4 per cent.E. sativasuffered the least loss in seed yield and harboured the minimum population of mustard aphid (2.1 aphids/plant) and cabbage caterpillar (2.4 larvae/plant). On the other hand,B. carinatawas highly susceptible to the cabbage caterpillar (26.2 larvae/plant) and suffered the maximum yield loss (26.4%).

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