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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Sclerotinia Leaf Drop of Lettuce - Testing New Fungicides and Formulations of Ronilan for Disease Control

Matheron, M. E., Matejka, J. C. 05 1900 (has links)
Leaf drop of lettuce, caused by the fungus Sclerotinia sclerotionunb is a sporadic but potentially destructive disease in Arizona During the 1988-89 lettuce season in western Arizona, different fungicides and formulations of materials were evaluated in the field for disease control. All tested compounds provided significant disease suppression and increased yields, provided that a sufficient rate of fungicide was applied. Ronilan and Rovral, the two fungicides currently registered for use on lettuce for Sclerotinia leaf drop, were the most effective fungicides in this test, performing significantly better than the two experimental materials. The SODF formulation of Ronilan provided significantly better disease control than the SOW formulation of the same compound.
22

Powdery Mildew of Cantaloupe - Testing New Fungicides for Disease Control

Matheron, M. E., Matejka, J. C. 05 1900 (has links)
Powdery mildew of cantaloupe, caused by the fungus Sphaerotheca fuliinea, is a perennial and often serious disease in Arizona. In 1989, potential new fungicides were evaluated for disease control in a field trial. All tested materials provided significant control when compared to untreated plants. Of the compounds tested only Bayleton currently is registered for use on cantaloupe. Rally, which performed extremely well in this test; should be available for use on cantaloupe in the near future.
23

Down Mildew of Broccoli - Effect of Fungicides on Disease Control and Crop Yield

Matheron, M. E., Matejka, J. C. 05 1900 (has links)
Downy mildew of broccoli, caused by the fungus peronowora parasitica, usually can be found on a yearly basis in broccoli fields in Arizona During the 1988-89 season, four different fungicides were evaluated in the field for disease control. All four materials significantly reduced the number of downy mildew lesions on treated broccoli leaves. Although significant disease control was achieved the average head weight was not significantly different when treated plants were compared with untreated plants. Light to moderate levels of downy mildew or late development of disease, as found in this trial, apparently do not require application of fungicides to prevent yield loss. Ridomil/Bravo and Bravo currently are registered for disease control, while SDS-59891 and Aliette are not registered for use on this crop.
24

1991 Virus Survey of Cantaloupe in Yuma

Butler, Marvin, Brooks, Dave, Watson, Mike 12 1900 (has links)
No description available.
25

Fungicides Evaluated for Control of Sclerotinia Leaf Drop of Lettuce in 1991 Field Test

Pier, J. W., Doerge, T. A., McCreary, T. 12 1900 (has links)
No description available.
26

Fungicides Evaluated for Control of Powdery Mildew of Cantaloupe in 1991 Field Trial

Matheron, M. E., Matejka, J. C. 12 1900 (has links)
Leaf drop of lettuce, caused by the plant pathogenic fungi Sclerotinia sclerotiorum and S. minor. occurs every year in some lettuce fields in Arizona. When environmental conditions are favorable, disease incidence and resulting crop loss can be significant. During the 1990-1991 lettuce season in western Arizona, different fungicides and rates of materials were evaluated in the field for disease control. All tested materials increased yields compared to not using any fungicide for disease control.
27

Fungicides Evaluated for Control of Rhizoctonia Bottom Rot of Lettuce in 1991 Field Trials

Matheron, M. E., Leonard, R., Major, G. 12 1900 (has links)
Bottom rot of lettuce, caused by the soil -borne fungus Rhizoctonia solani, can cause economic losses on early season lettuce harvested in November. First evidence of the disease is the appearance of brown, sunken, necrotic areas on the midribs of leaves touching the soil. Under favorable environmental conditions, the pathogen grows from leaf to leaf inside the head. If the fungus invades the leaves of the marketable head it and all similarly infected heads are left in the field resulting in economic losses. Field trials were established to evaluate the potential level of disease control obtainable by applying Ronilan or Rovral to lettuce beds immediately after thinning. No significant reduction in loss of marketable heads was observed in these trials, although there was a trend toward lower levels of bottom rot when either fungicide was in place.
28

Field Testing of Potential New Fungicides for Control of Powdery Mildew of Cantaloupe, 1993

Matheron, M. E., Matejka, J. C., Porchas, M. 09 1900 (has links)
Powdery mildew of cantaloupe in Arizona is caused by the plant pathogenic fungus Sphaerotheca fuliginea. The disease is usually found in some melon fields each year; however, the incidence and severity of the disease is quite variable. Disease development is favored by low relative humidity, moderate temperatures, and succulent plant growth. Potential new fungicides were evaluated for disease control in a field trial conducted in the spring of 1993. All tested materials provided significant control when compared to untreated cantaloupe plants. In this study, none of the compounds provided disease protection significantly superior to that demonstrated by Bayleton, the fungicide currently registered for use on cantaloupes.
29

Management of Sclerotinia Leaf Drop on Lettuce: Efficacy of Fungicides in 1996 Field Trial

Matheron, Michael E., Porchas, Martin 08 1900 (has links)
Leaf drop of lettuce is caused by the plant pathogenic fungi Sclerotinia minor and S. sclerotiorum. Cool and moist environmental conditions favor disease development. Potential new fungicides were evaluated in a field trial for management of this disease in 1996. For plots containing Sclerotinia minor, all compounds and rates tested significantly reduced the number of diseased heads compared to plots not treated with a fungicide. All treatments except Ronilan at the 0.5 lb. a. i./A rate yielded a significantly higher number of marketable heads compared to nontreated plots infested with S. minor. For plots containing S. sclerotiorum, all materials except the Ciba compound at the low and high rates decreased the number of diseased heads and increased the number of marketable heads compared to nontreated plots.
30

Field Testing of Potential New Fungicides for Control of Lettuce Diseases, 1993

Matheron, M. E., Matejka, J. C., Porchas, M. 09 1900 (has links)
Several diseases caused by plant pathogenic fungi can cause economic losses to lettuce growers in Arizona. Leaf drop of lettuce is caused by Sclerotinia minor and S. sclerotiorum, while downy and powdery mildew are caused by Bremia lactucae and Erysiphe cichoracearum, respectively. Cool and moist environmental conditions favor development of leaf drop and downy mildew, while warmer and dry weather is conducive for development of powdery mildew. Potential new fungicides were evaluated for control of these diseases during the winter of 1992-93. For leaf drop, two nonregistered materials, Fluazinam and Topsin M, controlled disease at least well as the standard registered fungicides. Fluazinam and Aliette provided equivalent control of downy mildew, while Fluazinam but not Aliene significantly reduced the severity of powdery mildew on lettuce.

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