Abstract
The symptoms of crown infection of corn caused by Diplodia zeae include: a dark straw-brown discoloration of the tissues of the crown and lower internodes; prevalence of subepidermal pycnidia on the crown and around the aerial adventitious roots; disintegration and shredding of the internal tissue of the crown; intense brown discoloration of the nodal plates, and a dark brown decay of the mesocotyl which results in the loss of the primary root system. Crown infection occurred on 14 to 52 percent of the field corn in central Iowa in the years from 1930 to 1933. Practically every corn plant grown from Diplodia-infected seed may show crown infection at maturity. Infected seedlings which, by means of timely establishment of adventitious roots, do not die may be parasitized during the remainder of the growing season. The symptoms on plants grown from disease-free seed in Diplodia-infested soil are identical with those derived from infected seed. The pathogene grows through the soil to the mesocotyl where it becomes established in the wounds created by the emerging seminal roots. The crown may be invaded directly from the soil at the point of emergence of an adventitious root but the crown is usually invaded from the decayed mesocotyl. The pathogene progresses up the mesocotyl from this primary lesion and becomes established on the crown. The mycelium spreads internally to a limited extent during the growing season and rapidly involves the entire crown and lower nodes at maturity. Although Diplodia zeae spreads from the mesocotyl upward for several nodes, it is not systemic in the plant. Under field conditions it is generally restricted to the first internode above the roots. Crown infection has been induced by infesting steamed soil with infected crowns and stalks of plants which had over-wintered under field conditions. Diplodia zeae may live in a soil devoid of plant refuse but its development is hampered in mixed culture. The presence of the pathogene in ordinary soil from a corn field has been demonstrated by growing plants from disease-free seed in such soil collected in the spring. Invasion of the crown from infested soil is most severe at high soil moisture contents, but the development of the infected plants is severely reduced at either high or low moisture contents. The dry weight of plants growing at optimum soil moisture content was not reduced by crown infection. The dry weight of roots is reduced more than that of the tops of plants grown in infested soil. The dry weight of the tops, however, is significantly less than that of non-infected plants grown under soil moisture conditions approaching the maximum or minimum for growth. A light infection of a plant growing at low soil moisture may be almost as injurious to the plant as a severe infection where there is an abundant supply of water. The transpiration ratio of infected plants is increased at soil moisture contents favorable to reduction in dry weight. Plants grown from Diplodia-infected seed treated with a mercury dust had a higher percentage of crown infection than similar plants from untreated seed. Treatment of disease-free seed with the same dust decreased the amount of crown infection of plants growing under field conditions. The dust apparently inhibited the fungus without killing it in the seed. Plants protected in this fashion later suffer crown infection. The extent of crown invasion under given conditions depends upon the time of initial infection. Seed treatment of disease-free seed may delay mesocotyl invasion from infested soil and thereby decrease crown infection. Selfed lines of corn have different reactions to crown infection by Diplodia zeae under field conditions and furnish some remarkably resistant lines for genetical studies. Late crown infection is a significant phase of the parasitism of Diplodia zeae on corn. The pathogene may reduce the dry weight of the plant to half that of a normal plant under certain soil moisture conditions. Under the most favorable field conditions there is a reduction in yield.
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Claims 20
Claim · model-written summary
Crown infection had discoloration, pycnidia, tissue disintegration, and mesocotyl decay.
- Taxon
- corn
Zea mays subsp. mayst0 - Interactor
- Diplodia zeaee0pathogen
- Outcome
- symptoms of crown infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The symptoms of crown infection of corn caused by Diplodia zeae include: a dark straw-brown discoloration of the tissues of the crown and lower internodes; prevalence of subepidermal pycnidia on the crown and around the aerial adventitious roots; disintegration and shredding of the internal tissue of the crown; intense brown discoloration of the nodal plates, and a dark brown decay of the mesocotyl which results in the loss of the primary root system”
t0“corn”
Claim · model-written summary
Crown infection affected 14 to 52 percent of field corn in central Iowa during 1930–1933.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- Crown infectione0
- Value
- 14 to 52 percente0
- Setting
- central Iowae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crown infection occurred on 14 to 52 percent of the field corn in central Iowa in the years from 1930 to 1933”
t0“corn”
Claim · model-written summary
Practically every corn plant from infected seed may show crown infection at maturity.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- maturitye0
- Treatment
- Diplodia-infected seede0
- Outcome
- crown infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Practically every corn plant grown from Diplodia-infected seed may show crown infection at maturity”
t0“corn”
Claim · model-written summary
Infected seedlings surviving through adventitious roots may remain parasitized through the growing season.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- seedlingse0
- Outcome
- parasitized during the remainder of the growing seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Infected seedlings which, by means of timely establishment of adventitious roots, do not die may be parasitized during the remainder of the growing season”
t0“corn”
Claim · model-written summary
Plants from disease-free seed in infested soil showed symptoms identical to those from infected seed.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- Diplodia-infested soile0
- Outcome
- symptomse0
- Direction
- identicale0
- Comparator
- infected seede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The symptoms on plants grown from disease-free seed in Diplodia-infested soil are identical with those derived from infected seed”
t0“corn”
Claim · model-written summary
The pathogen grew through soil to the mesocotyl and established in wounds from emerging seminal roots.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- mesocotyle0
- Outcome
- established in the woundse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The pathogene grows through the soil to the mesocotyl where it becomes established in the wounds created by the emerging seminal roots”
t0“corn”
Claim · model-written summary
The crown was usually invaded from the decayed mesocotyl, though direct invasion from soil also occurred.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- crowne0
- Outcome
- crown is usually invaded from the decayed mesocotyle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The crown may be invaded directly from the soil at the point of emergence of an adventitious root but the crown is usually invaded from the decayed mesocotyl”
t0“corn”
Claim · model-written summary
Mycelium spread internally only to a limited extent during growth, then rapidly involved crown and lower nodes at maturity.
- Taxon
- cornZea mays subsp. mayst0
- Organ / stage
- crown and lower nodese0
- Outcome
- mycelium spreads internallye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mycelium spreads internally to a limited extent during the growing season and rapidly involves the entire crown and lower nodes at maturity”
t0“corn”
Claim · model-written summary
Diplodia spread several nodes upward but was not systemic, generally remaining below the first internode in the field.
- Taxon
- cornZea mays subsp. mayst0
- Interactor
- Diplodia zeaee0pathogen
- Outcome
- not systemic in the plante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although Diplodia zeae spreads from the mesocotyl upward for several nodes, it is not systemic in the plant. Under field conditions it is generally restricted to the first internode above the roots”
t0“corn”
Claim · model-written summary
Infesting steamed soil with overwintered infected crowns and stalks induced crown infection.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- infesting steamed soil with infected crowns and stalkse0
- Outcome
- Crown infectione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crown infection has been induced by infesting steamed soil with infected crowns and stalks of plants which had over-wintered under field conditions”
t0“corn”
Claim · model-written summary
Crown invasion from infested soil was most severe at high soil moisture.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- high soil moisture contentse0
- Outcome
- Invasion of the crowne0
- Direction
- most severee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Invasion of the crown from infested soil is most severe at high soil moisture contents”
t0“corn”
Claim · model-written summary
Infected plant development was severely reduced at high or low soil moisture.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- high or low moisture contentse0
- Outcome
- development of the infected plantse0
- Direction
- severely reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the development of the infected plants is severely reduced at either high or low moisture contents”
t0“corn”
Claim · model-written summary
At optimum moisture, crown infection did not reduce plant dry weight.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- crown infectione0
- Outcome
- dry weight of plantse0
- Direction
- not reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The dry weight of plants growing at optimum soil moisture content was not reduced by crown infection”
t0“corn”
Claim · model-written summary
Root dry weight was reduced more than top dry weight in infested soil.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- infested soile0
- Outcome
- dry weight of rootse0
- Direction
- reduced moree0
- Comparator
- topse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The dry weight of roots is reduced more than that of the tops of plants grown in infested soil”
t0“corn”
Claim · model-written summary
Top dry weight was significantly lower than in noninfected plants near growth moisture limits.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- dry weight of the topse0
- Direction
- less thane0
- Comparator
- non-infected plantse0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The dry weight of the tops, however, is significantly less than that of non-infected plants grown under soil moisture conditions approaching the maximum or minimum for growth”
t0“corn”
Claim · model-written summary
Infection increased the transpiration ratio at soil moisture levels that reduced dry weight.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- infected plantse0
- Outcome
- transpiration ratioe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The transpiration ratio of infected plants is increased at soil moisture contents favorable to reduction in dry weight”
t0“corn”
Claim · model-written summary
Mercury dust treatment of infected seed raised crown infection relative to untreated infected seed.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- mercury duste0
- Outcome
- percentage of crown infectione0
- Direction
- highere0
- Comparator
- untreated seede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants grown from Diplodia-infected seed treated with a mercury dust had a higher percentage of crown infection than similar plants from untreated seed”
t0“corn”
Claim · model-written summary
Mercury dust treatment of disease-free seed decreased crown infection in field plants.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- same duste0
- Outcome
- amount of crown infectione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of disease-free seed with the same dust decreased the amount of crown infection of plants growing under field conditions”
t0“corn”
Claim · model-written summary
Selfed corn lines differed in field reaction to crown infection and included resistant lines.
- Taxon
- cornZea mays subsp. mayst0
- Material
- Selfed lines of corne0
- Interactor
- Diplodia zeaee0pathogen
- Outcome
- different reactions to crown infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Selfed lines of corn have different reactions to crown infection by Diplodia zeae under field conditions and furnish some remarkably resistant lines for genetical studies”
t0“corn”
Claim · model-written summary
Under favorable field conditions, crown infection reduced corn yield.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- yielde0
- Direction
- reductione0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under the most favorable field conditions there is a reduction in yield”
t0“corn”
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.