scholarly journals Temporal Dynamics of Brown Rot in Different Apple Management Systems and Importance of Dropped Fruit for Disease Development

2007 ◽  
Vol 97 (9) ◽  
pp. 1104-1111 ◽  
Author(s):  
I. J. Holb ◽  
H. Scherm
Keyword(s):  
Management System ◽  
Temporal Dynamics ◽  
Management Practice ◽  
Disease Incidence ◽  
Brown Rot ◽  
Tree Canopy ◽  
Apple Orchards ◽  
Progress Curve ◽  
Epidemic Development ◽  
Organic Orchards

Epidemic development of brown rot, caused by Monilinia fructigena, was monitored in integrated and organic apple orchards at two locations in eastern Hungary between 2002 and 2005 on three cultivars with early, midseason, and late ripening periods. Disease incidence and severity measures were affected significantly (P < 0.05) by management system (organic versus integrated) and cultivar, but there was no significant management system–cultivar interaction. Epidemics started 2 to 4 weeks earlier in organic orchards and on the early cv. Prima compared with integrated orchards and the late cv. Mutsu. Disease intensity increased markedly in the final 3 to 5 weeks before harvest and was considerably lower in integrated than in organic orchards. Final brown rot incidence on fruit in the tree was correlated with incidence on dropped fruit on the orchard floor (r > 0.75, P < 0.05), whereby the lag period from the appearance of the first symptomatic fruit on the ground to the occurrence of the first symptomatic fruit in the tree ranged from 2 weeks to 2 months, depending on the cultivar. The inflection point of the disease progress curve was attained first by fruit on the ground, followed successively by fruit in the lower, middle, and upper thirds of the tree canopy. This may indicate that dropped fruit that became infected early provided a source of inoculum for subsequent epidemics by serving as a bridge between sporulation from overwintered fruit mummies in the spring and the first fruit with sporulating lesions in the tree in midsummer. Removal of dropped fruit from the orchard floor resulted in a significantly lower disease incidence on fruit in the tree on all cultivars; thus, drop-removal may be useful as a brown rot management practice in apple orchards.

scholarly journals Analyses of temporal dynamics of brown rot development on fruit in organic apple production

2003 ◽  
Vol 9 (3-4) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Power Function ◽  
Yield Loss ◽  
Temporal Dynamics ◽  
Disease Incidence ◽  
Brown Rot ◽  
Mathematical Function ◽  
Apple Orchards ◽  
Apple Production ◽  
Fruit Disease ◽  
Fruit Harvest

In a two-year study, yield loss and temporal dynamics of brown rot development caused by Monilinia fructigena (Aderh. & Ruhl.) Honey were quantified and analysed in two organic apple orchards (Debrecen—Pallag and Debrecen—Józsa). The first infected fruits were observed at the beginning of August in both years and both locations, except for one occasion when the first infected fruit was found at the end of July. Temporal disease development was continuous up to harvest time in both years and locations. In the two years, pre-harvest yield loss on the trees amounted between 8.9% and 9.3% at Debrecen-Pallag and between 9.7% and 10.8% at Debrecen—Jozsa by fruit harvest. Incidence of infected fruits on the orchard floor ranged from 32.4% to 43.2% and from 53.3% to 61.9%, at Debrecen—Pallag and Debrecen—Józsa, respectively, by fruit harvest. Analyses of temporal disease progress showed that the best-fitted mathematical function was the power function in both orchards and years. Both parameters of the power function clearly demonstrated that incidence of brown rot on fruit increased faster on the orchard floor than on the tree. Moreover, the disease increase was faster at Debrecen—Józsa in most cases than at Debrecen—Pallag. Our results indicated that the strategy of disease management, the ripeness of the fruit and the presence of a wounding agent played an important role in the yield loss and in the temporal development of fruit disease incidence caused by M. fructigena in organic apple orchards. Biological and practical implications of the results are discussed.

scholarly journals Epidemiology of brown rot on two apple cultivars in an organic apple orchard

2013 ◽  
Vol 19 (1-2) ◽  
Author(s):  
I. J. Holb ◽  
J. Gáll
Keyword(s):  
Disease Incidence ◽  
Brown Rot ◽  
Logistic Function ◽  
Apple Orchard ◽  
Absolute Rate ◽  
Mathematical Functions ◽  
Monilinia Fructigena ◽  
Disease Progress ◽  
Progress Curve ◽  
Apple Cultivars

In a two-year-study, the temporal development of brown rot (Monilinia fructigena) on fruits was analysed in an organic apple orchard on an early (Prima) and one late (Idared) maturing cultivars at Debrecen-Józsa in Hungary. Out of five mathematical functions (linear, exponential, three-parameter logistic, Gompertz, Bertalanffy-Mitscherlich), the three-parameter logistic function gave the best fit to brown rot incidence of all cultivars in both years. Disease progress started at the end of June for cv. Prima and at the end of July for cv. Idared, then disease increased continuously from 6-8 weeks up to harvest in all cultivars. Descriptive disease variates derived from the three-parameter logistic function were used to analyse disease progress. These were: Yf, the final disease incidence; Y55, fruit incidence at day 55; Y95, fruit incidence at day 95; b and q, the relative and the absolute rate of disease progress, respectively; T1.5, the time when disease incidence reaches 1.5 %; M, the inflection point and AUDPC, area under disease progress curve. Descriptive disease variates were significantly different (P<0.05) for cv. Prima compared to cv. Idared, except for the relative and absolute rate of disease increase, b and q, respectively. The largest differences among cultivars were in the values of the AUDPC. Disease progress curves and descriptive disease variates were presented and the practical implications of the results were discussed.

Glasshouse and field screening of chickpea cultivars for resistance to Phytophthora megasperma f.sp. medicaginis

1991 ◽  
Vol 31 (5) ◽  
pp. 663 ◽  
Author(s):  
ML Dale ◽  
JAG Irwin
Keyword(s):  
Disease Incidence ◽  
Field Trials ◽  
Field Resistance ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Progress Curve ◽  
Susceptible Control ◽  
Epidemic Development ◽  
Compound Interest ◽  
Chickpea Cultivars

The resistance expressed by a range of chickpea cultivars to phytophthora root rot in glasshouse and field trials was examined. Van der Plank's compound interest equation was the most suitable transformation for providing parameters to describe epidemic development for most of the cultivars when compared to the simple interest equation by plotting residuals and coefficients of determination. The area under the disease progress curve (AUDPC) was significantly correlated with the final disease incidence (FDI), which was also significantly correlated with the apparent infection rate (r), but r and AUDPC were not significantly correlated. The AUDPC proved to be relatively indiscriminate in this study for selecting resistant cultivars, since the value for the susceptible control cultivar was high, and many cultivars therefore had statistically lower AUDPC values. Several cultivars (i.e. CQ1591, ICC7568 and 232-4) were resistant on the basis of both the FDI and r parameters in the field trial and considered worthy of further investigation. When the parameters FDI or r were used to categorise the disease reactions of cultivars in the field, only half of the 30 cultivars assessed showed similar responses in both the glasshouse and field trials. The glasshouse assay used here does not allow the detection of all potentially useful forms of field resistance, and further work is needed in the development of a glasshouse assay which gives an accurate representation of field response to Phytophthora megasperma Drechs. f. sp. medicaginis Kuan and Erwin.

scholarly journals Field Response of New Peanut Cultivar UF 91108 to Tomato Spotted Wilt Virus

Plant Disease ◽  
1997 ◽  
Vol 81 (12) ◽  
pp. 1410-1415 ◽  
Author(s):  
A. K. Culbreath ◽  
J. W. Todd ◽  
D. W. Gorbet ◽  
F. M. Shokes ◽  
H. R. Pappu
Keyword(s):  
Disease Incidence ◽  
Field Resistance ◽  
Individual Plant ◽  
Breeding Line ◽  
Oil Composition ◽  
Tomato Spotted Wilt ◽  
Progress Curve ◽  
Rating Method ◽  
Epidemic Development ◽  
Highly Correlated

Epidemics of spotted wilt, caused by tomato spotted wilt tospovirus (TSWV), were monitored in field plots of the new runner-type peanut (Arachis hypogaea) cv. UF 91108, in advanced breeding line F 84 × 9B-4-2-1-1-2-b2-B, in runner-type peanut cvs. Southern Runner and Florunner, and in Virginia-type cv. NC-V11 at two locations in 1994 and 1995. Epidemics of spotted wilt were suppressed in UF 91108 compared to the standard runner-type cv. Florunner. Final disease incidence, standardized area under the disease progress curve values, and final disease intensity ratings were lower in UF 91108 than in Florunner and were similar to those in the moderately resistant cv. Southern Runner. Results indicate that new cv. UF 91108 represents a new potential tool for management of spotted wilt in peanut production areas of the southeastern United States. UF 91108 is the first peanut cultivar in which an oil composition of approximately 65% oleic acid is combined with a moderate level of field resistance to TSWV. Epidemics of spotted wilt also were suppressed in breeding line F 84 × 9B-4-2-1-1-2-b2-B. Across the four tests, the effects of NC-V11 on epidemic development, final incidence, and spotted wilt intensity ratings were not consistent relative to the other genotypes. Use of final disease intensity ratings provided separation of the genotypes similar to use of final incidence of spotted wilt. Assessment values by these two methods were highly correlated. In three of four experiments, final disease intensity ratings were more closely correlated with pod yield than was final incidence. The new intensity rating method described in this paper requires much less time and effort than determining disease incidence and may be a practical alternative to individual plant assessment for characterization of genotype responses to TSWV.

scholarly journals Epidemic Development of Bacterial Blight on Rice Carrying Resistance Genes Xa-4, Xa-7, and Xa-10

Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1337-1340 ◽  
Author(s):  
I. Oña ◽  
C. M. Vera Cruz ◽  
Rebecca J. Nelson ◽  
Jan E. Leach ◽  
T. W. Mew
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Xanthomonas Oryzae ◽  
Diseased Leaf ◽  
Near Isogenic Lines ◽  
Bacterial Blight Resistance ◽  
Progress Curve ◽  
Diseased Leaf Area ◽  
Epidemic Development

Epidemic development of bacterial blight caused by Xanthomonas oryzae pv. oryzae on three near-isogenic lines (IRBB lines) carrying bacterial blight resistance genes Xa-4 (IRBB4), Xa-7 (IRBB7), and Xa-10 (IRBB10) was studied in two farmers' fields located in Calauan and Mabi-tac, Phillipines, during 1993, 1994, and 1995. The plots were planted continuously during dry and wet seasons, with disease assessments done during the wet seasons, when weather was conducive to bacterial blight development. Disease incidence (number of hills infected) and severity (diseased leaf area) were assessed and area under the disease progress curve (AUDPC) values were computed. Mean disease incidence and severity in Calauan (AUDPC = 3,241.5 and 716.7, respectively) were significantly higher than in Mabitac (AUDPC = 2,431.2 and 558.0, respectively). In Calauan, AUDPC values for disease incidence and severity on IRBB4, IRBB10, and IR24 did not differ significantly during the three years of testing. In Mabitac, the AUDPC values for disease incidence and severity were not significantly different among IRBB4, IRBB10, and IR24 in 1993 and in 1995. However, in 1994, disease incidence (AUDPC = 3,037.7) and severity (AUDPC = 891.0) on IRBB4 were significantly lower than on IRBB10 and IR24. Bacterial blight was lowest on IRBB7 at both sites and throughout 1993 to 1995, indicating that this genotype is effective in suppressing the disease even with the presence of an indigenous virulent population of X. oryzae pv. oryzae.

scholarly journals Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  
Keyword(s):  
United States ◽  
Disease Resistance ◽  
Leaf Spot ◽  
Field Experiments ◽  
Disease Incidence ◽  
The United States ◽  
Yield Potential ◽  
Cercospora Arachidicola ◽  
Breeding Lines ◽  
Progress Curve

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

scholarly journals Spatial Distribution of Green Mold Foci in 30 Commercial Mushroom Crops

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 71-76 ◽  
Author(s):  
D. J. Royse ◽  
K. Boomer ◽  
Y. Du ◽  
M. Handcock ◽  
P. S. Coles ◽  
...  
Keyword(s):  
Cultural Practices ◽  
Disease Incidence ◽  
Spatial Distributions ◽  
Trichoderma Spp ◽  
Nutrient Supplementation ◽  
Green Mold ◽  
Factors Influencing ◽  
Airborne Contamination ◽  
Epidemic Development ◽  
Surface Covering

Statistical analyses were performed on spatial distributions of mushroom green mold foci caused by Trichoderma spp. in 30 standard Pennsylvania doubles (743 m2 production surface) selected at random from over 900 total crops mapped. Mapped production houses were divided into four tiers of six beds each with 16 sections per bed (total = 384 sections per double). Each section contained approximately 2 m2. Green mold foci were mapped according to presence or absence in each section as they became visible during the course of the mushroom production. There was a trend toward higher disease incidence at the ends of the doubles, although this was not consistent from level to level. Spatial analysis revealed that green mold foci were more likely to occur in neighboring sections along the beds rather than above, below, or across from each other. Cultural practices that were associated with movement along the beds, i.e., nutrient supplementation, spawning, bed tamping, surface covering, etc., were considered the most likely factors influencing the incidence of green mold in spawned compost. Airborne contamination was considered a less likely source of inocula contributing to epidemic development. Sanitation practices that reduce spore loads along the beds are expected to provide the greatest degree of green mold control.

scholarly journals Epidemiology of Mango Malformation in Guerrero, México, with Traditional and Integrated Management

Plant Disease ◽  
1999 ◽  
Vol 83 (3) ◽  
pp. 223-228 ◽  
Author(s):  
D. H. Noriega-Cantú ◽  
D. Téliz ◽  
G. Mora-Aguilera ◽  
J. Rodríguez-Alcazar ◽  
E. Zavaleta-Mejía ◽  
...  
Keyword(s):  
Wind Speed ◽  
Integrated Management ◽  
Disease Incidence ◽  
Mangifera Indica ◽  
Spore Density ◽  
Cost Rate ◽  
Average Maximum ◽  
Fusarium Sp ◽  
Epidemic Development ◽  
Benefit Cost

The temporal progress of malformation (MM) of mango (Mangifera indica) was studied from 1993 to 1995 with three management technologies applied to commercial plantations in North Guerrero, Mexico. Management influenced shoot production and thus determined the dynamics of epidemics. Environmental factors also affected disease incidence, particularly through an apparent effect on inoculum dispersal. In general, integrated management (IM), consisting of pruning, acaricide, and fungicide sprays, resulted in slower rates of epidemic development, lower levels of initial and final disease, and lesser areas under the disease progress curves. In the first cycle, IM increased yield per tree by 51% in relation to high technology (HT) and 74% in relation to lower traditional technology (LT), representing a benefit-cost rate of 2.8 and 3.3, respectively. Change of malformation incidence was correlated positively with the number of macroconidia of Fusarium sp. trapped in the canopy (r = 0.90, P = 0.0001) and wind speed (r = 0.83, P = 0.0001); both variables lagged over a 4-month period. The greatest change in malformation occurred during the main vegetative flush, which occurred 3 to 6 months after picking the fruit (May). The accumulated proportion of diseased shoots was correlated with the following variables measured over a 1-week period: average maximum daily temperature (r = -0.68, P = 0. 01), average temperature per hour (r = -0.59, P = 0.04), average number of hours with relative humidity ≥60% (r = -0.82, P = 0.001), and wind speed (r = 0.94, P = 0.0001). In general, the greatest spore density was found during the rainy season, with a morning periodicity showing the highest correlation with wind speed (r = 0.812, P = 0.0001). F. subglutinans was isolated consistently from diseased (86%) and asymptomatic (5%) vegetative and flowering shoots.

Effects of Application Method and Rate on Control of Sclerotinia Blight of Peanut with Iprodione and Fluazinam1

2001 ◽  
Vol 28 (1) ◽  
pp. 28-33 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson
Keyword(s):  
Disease Control ◽  
Disease Incidence ◽  
Maximum Yield ◽  
Wide Band ◽  
Yield Response ◽  
Application Method ◽  
Sclerotinia Blight ◽  
Progress Curve ◽  
Application Methods ◽  
Yield Responses

Abstract Two trials with iprodione and three trials with fluazinam were conducted to assess the effects of application method and rate on the control of Sclerotinia blight of peanut with fungicide. In order to concentrate the fungicides near the crown area where the disease causes the most damage, applications were made through a canopy opener with a single nozzle centered over the row to achieve a 30.5-cm-wide band (canopy opener), and through a single nozzle centered over the row to achieve a 46-cm-wide band (band). Broadcast applications were compared to these methods at rates of 0, 0.28, 0.56, and 1.12 kg/ha on the susceptible cultivar Okrun. Sclerotinia blight was severe, with &gt; 70% disease incidence and &lt; 2000 kg/ha yield for the untreated controls in each trial. Linear reductions in area under the disease progress curve (AUDPC), but not final disease incidence, with iprodione rate were significant (P &lt; 0.05) for all methods of application. However, the rate of decrease did not differ among application methods. Linear increases in yield with rate of iprodione were greater for canopy opener compared to the band or broadcast applications. Only a 50% reduction in AUDPC and a maximum yield of &lt; 2700 kg/ha was achieved with iprodione using the best method. At the maximum rate of 1.12 kg/ha, fluazinam provided &gt; 75% disease control and &gt; 4000 kg/ha yield for all application methods. Differences in disease control and yield among application methods only occurred at the 0.28 and 0.56 kg/ha rates of fluazinam. Reductions in AUDPC with fluazinam rate were quadratic for all application methods, but AUDPC values were less for the canopy opener and band methods at 0.28 and 0.56 kg/ha compared to the broadcast methods. The yield response to rate for broadcast applications of fluazinam was linear. However, predicted yield responses to fluazinam rate were quadratic for the band and canopy opener methods and approached the maximum response at 0.84 kg/ha. Targeting fungicide applications using the band and/or canopy opener methods was beneficial for fluazinam at reduced rates. Disease control with iprodione was not adequate regardless of application method.

scholarly journals Native insect pollinators in Apple orchards under different management practices in the Kashmir Valley

2013 ◽  
Vol 1 (1) ◽  
pp. 29
Author(s):  
Muzaffar Ahmad Ganie ◽  
Amit Kumar Pal ◽  
Nazeer Ahmad
Keyword(s):  
Management System ◽  
Management Practices ◽  
Early Spring ◽  
Management Systems ◽  
Apple Orchards ◽  
Kashmir Valley ◽  
Hand Pollination ◽  
The Family ◽  
Insect Pollinators ◽  
Family Contribution

It is now clear that over use of pesticides and intensive management of orchards can lead to drastic declines in apple pollinator abundance and crop failures. During the period of study a grower’s survey was conducted to know about knowledge of farmers on native insect pollinators, pollinator management practices, their perceptions of the importance and utility of native pollinators, and their attitudes regarding pesticide application. Despite of having significant knowledge of managed pollination, only few farmers (2%) adopted supplementary methods of pollination (renting honey bee colonies, hand pollination etc.). In Pulwama, 60% of farmers had knowledge about native insect pollinators and 40% did not have any idea of native pollinators and in case of Shopian, the figures were fifty-fifty i.e. 50% had knowledge about native insect pollinators and 50% were unaware. During the period of investigation, native insect pollinators were sampled from different apple orchards under different management systems in early spring during apple flowering. A total of 17 species of insect pollinators belonging to 11 families and 3 orders_ Hymenoptera, Diptera and Lepidoptera registered their occurrence at all the studied apple orchards of the Kashmir Valley. At all the study sites i.e. apple orchards under different management systems, family Halictidae and Empididae registered their presence as dominant groups. The % family contribution of the former at different orchard types decreased with increase in the intensity of the management system and the % family contribution of the later however, showed a direct relationship with the management system found, i.e. the more intense the system, the more abundant was the group. Other groups in general did not show any greater differences in abundances at different sites studied.

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