scholarly journals Relationships Between Reactions of Sweet Corn Hybrids to Stewart's Wilt and Incidence of Systemic Infection by Erwinia stewartii

Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 223-228 ◽  
Author(s):  
P. M. Michener ◽  
N. D. Freeman ◽  
J. K. Pataky
Keyword(s):  
Growth Stage ◽  
Sweet Corn ◽  
Systemic Infection ◽  
Control Measures ◽  
Growth Stages ◽  
Corn Hybrids ◽  
Systemic Movement ◽  
Erwinia Stewartii ◽  
Stewart's Wilt ◽  
Central Illinois

Relationships between the reactions of sweet corn hybrids to Stewart's wilt and the incidence of natural, systemic infection by Erwinia stewartii differed among trials in which the prevalence of Stewart's wilt differed. Systemic Stewart's wilt infection was assessed for 262, 296, and 245 hybrids planted in seven trials in central Illinois in June and July 1998, 1999, and 2000, respectively. Incidence of systemic infection was calculated in each trial for all hybrids in each of nine categories of Stewart's wilt reactions (i.e., 1 = resistant and 9 = susceptible). When mean incidence was about 5%, incidence ranged from about 1 to 8% on resistant to moderately susceptible hybrids, but incidence was nearly 30% on susceptible hybrids. When mean incidence ranged from 10 to 16%, the relationships between hybrid reactions and incidence were explained by exponential or polynomial regressions. Incidence was less than 10% for hybrids with resistant and moderately resistant reactions, and incidence was greater than 15% for moderately susceptible to susceptible hybrids. When mean incidence was near 50%, the relationship was linear. Incidence was about 18% for resistant hybrids and about 80% for susceptible hybrids. Incidence increased about 8% for each class of hybrid reaction from 1 to 9. The influence of resistance on the development of systemic infection at very early seedling growth stages also was evaluated in six greenhouse trials. A highly resistant hybrid, Bonus, was systemically infected in two of six greenhouse trials when seedlings were inoculated prior to the V3 growth stage; however, systemic infection was not as severe as on a susceptible hybrid, Jubilee. Systemic infection was more severe on Bonus when plants were inoculated at earlier growth stages between VE and V3. The resistant hybrid Bonus was not systemically infected when inoculated after the V4 growth stage except for one greenhouse trial when all Stewart's wilt ratings were higher than usual. Hybrid reactions to Stewart's wilt affected the incidence of systemic infection in field situations and they affected the growth stage at which resistance effectively prevented systemic movement of E. stewartii within plants in greenhouse trials. This information can be used to determine more effectively when to apply other control measures, such as insecticidal seed treatments.

scholarly journals Levels of Stewart's Wilt Resistance Necessary to Prevent Reductions in Yield of Sweet Corn Hybrids

Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1278-1284 ◽  
Author(s):  
Noah D. Freeman ◽  
Jerald K. Pataky
Keyword(s):  
Adverse Effects ◽  
Sweet Corn ◽  
Systemic Infection ◽  
Experimental Unit ◽  
Regression Equations ◽  
Corn Hybrids ◽  
Wilt Resistance ◽  
Leaf Stage ◽  
Erwinia Stewartii ◽  
Stewart's Wilt

Stewart's wilt reactions and yield of a total of 69 sweet corn hybrids were evaluated in trials in 1999 and 2000 in order to determine the level of Stewart's wilt resistance necessary to prevent reduction in yield of sweet corn hybrids. Plants at the 2- to 3-leaf stage were inoculated with Erwinia stewartii using the pinprick method. Stewart's wilt symptoms were rated from 1 to 9, and incidence of systemic infection was determined as a percentage for each experimental unit. Primary ears were harvested about 21 days after midsilk, and yield was measured as ear weight and number of marketable ears. Percent yield was calculated for each hybrid by dividing yield from inoculated treatments by yield from noninoculated treatments and multiplying by 100. Hybrid means for Stewart's wilt ratings in inoculated treatments ranged from 2.0 to 7.3. The relationships between percent yield and Stewart's wilt severity ratings were described best by curvilinear regressions, whereas percent yield decreased linearly with the incidence of systemic infection in 2000. Ear weights of hybrids with ratings below 3 or 3.5 were estimated from the regression equations to be within 95 or 92%, respectively, of those from noninoculated treatments of the same hybrid. The number of marketable ears from hybrids with ratings of 3 or below was estimated from the regression equations to be within 90% of those from noninoculated treatments of the same hybrid. A level of resistance that resulted in Stewart's wilt ratings below 3 or 3.5 corresponded to nonsystemic infection of most plants (i.e., incidence of systemic infection below 5 or 10%, respectively). The adverse effects of Stewart's wilt on ear weight and marketability appeared to be minor for sweet corn hybrids with levels of resistance that prevented or minimized systemic infection.

scholarly journals Control of Stewart's Wilt in Sweet Corn with Seed Treatment Insecticides

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1104-1108 ◽  
Author(s):  
J. K. Pataky ◽  
P. M. Michener ◽  
N. D. Freeman ◽  
R. A. Weinzierl ◽  
R. H. Teyker
Keyword(s):  
Host Resistance ◽  
Seed Treatment ◽  
Sweet Corn ◽  
Flea Beetle ◽  
Field Trials ◽  
Seed Treatments ◽  
Corn Hybrids ◽  
Flea Beetles ◽  
Erwinia Stewartii ◽  
Stewart's Wilt

Corn flea beetles, Chaetocnema pulicaria, vector Erwinia stewartii (synamorph Pantoea stewartii), which causes Stewart's bacterial wilt of corn (Zea mays). A seed treatment insecticide, imidacloprid, killed flea beetles and reduced the number of feeding wounds and Stewart's wilt symptoms per leaf in greenhouse studies. The objective of our research was to evaluate the ability of imidacloprid and thiamethoxam seed treatments to control Stewart's wilt on sweet corn hybrids under field conditions with naturally occurring populations of the corn flea beetle. Six field trials were planted at four locations in 1998. Eleven field trials were planted at nine locations in 1999. The treatment design was a factorial of sweet corn hybrids and seed treatments. Stewart's wilt incidence ranged from 0 to 54% in the 1998 trials. Incidence of Stewart's wilt in nontreated plots of the susceptible hybrid Jubilee ranged from 2% at the 8-leaf stage to 77% 1 week after mid-silk in the 1999 trials. Seed treatment insecticides reduced the incidence of Stewart's wilt by ≈50 to 85% relative to nontreated controls. The level of control was ≈75 to 85% in seven trials planted before 1 June 1999, when incidence of Stewart's wilt on nontreated Jubilee ranged from 4 to 71%. The level of control was ≈50 to 70% in the three trials planted after 1 July 1999, when incidence of Stewart's wilt on nontreated Jubilee ranged from 44 to 73%. Although comparisons varied, the level of control gained from seed treatment insecticides was similar to the next higher level of host resistance. Seed treatment insecticides appear to control Stewart's wilt during very early growth of corn plants, when foliar applications of insecticides are ineffective and the effectiveness of host resistance varies depending on the proximity of flea beetle feeding sites to the plant's growing point.

scholarly journals Transmission of Erwinia stewartii from Plants to Kernels and Reactions of Corn Hybrids to Stewart's Wilt

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 167-172 ◽  
Author(s):  
P. M. Michener ◽  
J. K. Pataky ◽  
D. G. White
Keyword(s):  
Sweet Corn ◽  
F1 Hybrids ◽  
Enzyme Linked Immunosorbent Assay ◽  
Corn Hybrids ◽  
Food Grade ◽  
Kernel Infection ◽  
Dent Corn ◽  
The Mean ◽  
Erwinia Stewartii ◽  
Stewart's Wilt

Stewart's wilt reactions of 98 food-grade, white corn hybrids, 3 yellow dent corn hybrids, and 23 sweet corn hybrids and infection of kernels by E. stewartii were evaluated in 1998, 1999, and 2000. Stewart's wilt symptoms were rated from 1 (no appreciable spread of symptoms) to 9 (dead plants) following inoculation. The mean Stewart's wilt ratings for the food-grade, white corn and yellow dent corn hybrids were 1.9, 2.4, and 2.9 in 1998, 1999, and 2000, respectively. The mean Stewart's wilt ratings for the sweet corn hybrids were 3.8, 4.2, and 4.6 in 1998, 1999, and 2000, respectively. Hybrids with ratings less than 3 were classified as resistant. Hybrids with ratings between 3 and 4.5 were classified as moderate. Hybrids with ratings greater than 4.5 were classified as susceptible. Ears harvested from each row in 1998 and 1999 were assayed for E. stewartii using an enzyme-linked immunosorbent assay (ELISA)-based seed health test. Kernels from 16 hybrids were positive for E. stewartii in 1998. Kernels from 11 hybrids were positive for E. stewartii in 1999. Kernel infection by E. stewartii was affected considerably by the level of host resistance (i.e., reactions of seed parent plants). For hybrids classified as resistant, estimates of kernel infection were 0.024 and 0.0007% in 1998 and 1999, respectively. For hybrids with moderate reactions to Stewart's wilt, estimates of kernel infection were 0.19 and 0.07% in 1998 and 1999, respectively. For hybrids with susceptible reactions to Stewart's wilt, estimates of kernel infection were 11.6 and 7.8% in 1998 and 1999, respectively. Based on high levels of Stewart's wilt resistance in food-grade, white corn hybrids, and low rates of kernel infection by E. stewartii in resistant and moderate hybrids, there is an exceedingly low probability of introducing E. stewartii to areas where it does not occur by transmitting the bacterium in grain of the food-grade, white corn hybrids evaluated in this study. Although all of the kernels harvested in these experiments were produced as grain on open-pollinated F1 hybrids, the rates of kernel infection observed for hybrids with resistant, moderate and susceptible reactions to Stewart's wilt are applicable to seed produced on inbred lines with equivalent Stewart's wilt reactions.

Safening Influence of LAB 145 138 on Nicosulfuron, Terbufos and Bentazon Interactions in Sweet Corn (Zea mays)

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 339-344 ◽  
Author(s):  
Darren K. Robinson ◽  
David W. Monks ◽  
James D. Burton
Keyword(s):  
Zea Mays ◽  
Seed Treatment ◽  
Growth Stage ◽  
Yield Loss ◽  
Sweet Corn ◽  
Leaf Growth ◽  
Growth Stages ◽  
Height Reduction ◽  
Reduced Height ◽  
Previously Treated

LAB 145 138 (LAB) was evaluated as a safener to improve sweet corn tolerance to nicosulfuron applied POST alone or with terbufos applied in the planting furrow or bentazon applied POST. To ensure enhanced injury for experimental purposes, nicosulfuron was applied at twice the registered rate alone or mixed with bentazon at the six- to seven-leaf growth stage of corn previously treated with the highest labeled rate of terbufos 15 G formulation. LAB applied as a seed treatment (ST) or POST at the two- to three-, four- to five-, or six- to seven-leaf growth stages reduced height reduction and yield loss from nicosulfuron applied POST in combination with terbufos applied in-furrow. LAB applied POST at the four- to five-leaf growth stage was most effective in preventing injury from this treatment, with yield reduced only 8% compared with 54% from the nicosulfuron and terbufos treatment. LAB applied POST at the eight- to nine-leaf growth stage did not alleviate injury. With the nicosulfuron, terbufos, and bentazon combination, LAB applied POST at the three- to four- or six- to seven-leaf growth stages decreased height reduction and yield loss caused by this combination, with LAB at the three- to four-leaf growth stage being most effective.

scholarly journals SWEET CORN INBREDS WITH PARTIAL RESISTANCE TO NORTHERN LEAF BLIGHT AND STEWART'S WILT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1067a-1067 ◽  
Author(s):  
A. C. Meyer ◽  
J. K Pataky ◽  
J.A. Juvik
Keyword(s):  
Partial Resistance ◽  
Sweet Corn ◽  
Leaf Blight ◽  
Exserohilum Turcicum ◽  
Northern Leaf Blight ◽  
Dent Corn ◽  
Erwinia Stewartii ◽  
Stewart's Wilt ◽  
Corn Inbred ◽  
Moderately Resistant

Approximately 200 sweet corn inbred lines were screened for two years for resistance to northern leaf blight, caused by Exserohilum turcicum, and Stewart's wilt, caused by Erwinia stewartii. Inbreds with the best levels of partial resistance to races 1 and 2 of E. turcicum included IL11d, IL676a, IL677a, IL685d, IL766a, IL767a and IL797a. Inbreds with the best partial resistance to E. stewartii included IL126b, IL676a, IL767a, IL772a, IL774g, IL797a, IL798a and M6011. Several of these resistant and moderately resistant inbreds had common ancestors; however, inspection of pedigrees suggested that resistance was derived from Puerto Rican, Bolivian, and other tropical sources and/or dent corn. Thus, many of the sweet corn inbreds may carry different genes for resistance and can be used for the development of populations with improved resistance.

scholarly journals Effect of Temperature Regime and Growth Stage Interaction on Pattern of Virus Presence in TSWV-Resistant Accessions of Capsicum chinense

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1199-1204 ◽  
Author(s):  
Salvador Soler ◽  
M. José Díez ◽  
Fernando Nuez
Keyword(s):  
Temperature Regime ◽  
Growth Stage ◽  
Systemic Infection ◽  
Plant Introduction ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Growth Stages ◽  
Leaf Stage ◽  
Temperature Regimes ◽  
Wilt Virus

We studied the resistance to tomato spotted wilt virus in plant introduction accession (PI)-151225 and PI-159236 under Mediterranean climatic conditions. Two temperature regimes were utilized, corresponding to early and late cultivation cycles. Inoculations were made at 2- and 4-leaf stages to determine the effect of early infection. The existence of interaction between temperature regime and developmental stage was also studied. When plants of both PIs were maintained at 30/18°C (day/night), all plants at both growth stages when inoculated developed systemic infection. At 25/18°C, only those plants inoculated at 2-leaf stage became systematically infected; however, those inoculated at the 4-leaf stage behaved as resistant. Thus, there was an interaction between temperature regime and growth stage. There is potential for using this type of resistance in areas with mild climates, providing seedling infections are avoided.

scholarly journals Rates of Transmitting Erwinia stewartii from Seed to Seedlings of a Sweet Corn Hybrid Susceptible to Stewart's Wilt

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 1031-1035 ◽  
Author(s):  
P. M. Michener ◽  
J. K. Pataky ◽  
D. G. White
Keyword(s):  
Sweet Corn ◽  
Natural Infection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Adult Plant ◽  
Plant Seed ◽  
Transmission Rates ◽  
Infected Seed ◽  
Erwinia Stewartii ◽  
Stewart's Wilt ◽  
Corn Hybrid

Rates of transmitting Erwinia stewartii from seed to seedlings were estimated from field grow-outs of seedlings grown from seed infected with E. stewartii. Infected seed were produced in 1998, 1999, and 2000 on a Stewart's wilt-susceptible sweet corn hybrid, Jubilee. Seedlings were inoculated repeatedly with pinprick inoculators and suspensions of E. stewartii were injected into ear shanks of the primary ears of each adult plant. Seed from inoculated plants were harvested and bulked. Single kernels were assayed for E. stewartii to estimate the proportion of kernels infected with E. stewartii. Estimates of E. stewartii-infection were 15.6 ± 4.3, 49.4 ± 3.9, and 12.5 ± 2.4% for seed produced in 1998, 1999, and 2000, respectively. Approximately 61,800 seedlings were grown in DeKalb, IL in 1999 and 83,400 and 60,000 seedlings were grown in Plover WI in 2000 and 2001, respectively, from infected seed lots produced the previous year. Approximately 10,000, 12,200, and 29,400 seedlings of susceptible sweet corn hybrids also were grown each year from commercial seed produced in Idaho where Stewart's wilt does not occur. Based on estimates of kernel infection in each seed lot and plant populations in each grow-out trial, about 9,600, 41,200, and 7,500 seedlings were grown from infected kernels in 1999, 2000, and 2001, respectively. Seedlings at the two- to three-leaf stage were examined for symptoms of Stewart's wilt. Infected plants were confirmed by microscopic observations of bacterial ooze and by enzyme-linked immunosorbent assay. When data were combined from all three trials, 59 of approximately 58,300 seedlings grown from infected seed were infected with E. stewartii based on symptoms of Stewart's wilt and E. stewartii-positive leaf tissue samples. Of these 59 seedlings, 22 probably were infected from seed-to-seedling transmission of E. stewartii and 37 probably were the result of natural infection due to the presence of flea beetles in DeKalb in 1999. Twenty-two infected seedlings from 58,300 infected kernels corresponds to a seed-to-seedling transmission rate of 0.038%. This rate of seed-to-seedling transmission of E. stewartii is substantially lower than seed transmission rates reported in the first half of the twentieth century; however, it is similar to seed-to-seedling transmission rates reported from other recent research.

scholarly journals Yield and Quality of Huitlacoche on Sweet Corn Inoculated with Ustilago maydis

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 782-785 ◽  
Author(s):  
M.E. Valverde ◽  
P. Fallah Moghaddam ◽  
M.S. Zavala-Gallardo ◽  
J.K. Pataky ◽  
O. Paredes-Lopez ◽  
...  
Keyword(s):  
Zea Mays ◽  
Growth Stage ◽  
Sweet Corn ◽  
Ustilago Maydis ◽  
Harvest Time ◽  
Corn Hybrids ◽  
Gall Tissue ◽  
Yield And Quality ◽  
Optimal Harvest

Ear gall development was evaluated after inoculating sweet corn (Zea mays L.) hybrids with Ustilago maydis (DC) Corda by injecting sporidial suspensions into silk channels when silks had emerged ≈3 to 6 cm from ear shoots. Gall incidence was ≈35% in two inoculation trials. About 0.5% of the noninoculated control plants was infected. Gall weight increased ≈250% to 500% between 14 and 21 days after inoculation, reaching a maximum of ≈280 to 600 g. Gall tissue was nearly 100% black and had lost its spongy integrity 19 to 21 days after inoculation, when mycelial cells formed powdery teliospores. A 1- or 2-day harvest window during which huitlacoche yield and quality were optimized corresponded to the time at which 60% to 80% of the gall tissue was black. The optimal huitlacoche harvest time varied among hybrids from 17 to 19 days after inoculation, but we suspect that optimal harvest time varies from ≈15 to 24 days after inoculation, depending on the growth stage at which the host is inoculated and the environmental conditions following inoculation. Differences among sweet corn hybrids in gall incidence, gall size, and coverage of mature galls by husk leaves were observed and could be used to select sweet corn hybrids that are well suited for producing huitlacoche.

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