Basisporium dry rot of corn

Basisporium gallarum was first found on corn from Bulgaria in 1911 by Bubak and by Arzberger in Ohio in 1913. Coniosporium gecevi Bubak is identical with Basisporium gallarum Moll. The common name of Basisporium dry rot is suggested for the disease caused by this organism. The dry rot of corn, caused by this fungus, was very prevalent in Iowa in 1923, causing an average damage to the crop of 9.1 percent, while in a few fields from 50 to 60 percent of the ears were infected. The damage consists of moldy and light ears, reduced stand and weak plants the succeeding year. Heavy precipitation in August and September, when the crop is maturing, favors the development of the disease. Studies to date indicate that Basisporium dry rot is markedly dependent upon excessive moisture conditions when the crop is maturing, for its destructive development. Basisporium gallarum attacks the shanks, husks and stalks of corn. The shanks particularly are weakened and break easily. On the ears the fungus is visible at the butt and base of the kernels. The black spores of the fungus can be readily seen with the unaided eye. The kernels are affected in varying degree, some only slightly, while in others the embryo is killed. The spores germinate poorly or not at all in water. They germinate readily in tomato or orange juice. Such juice neutralized to litmus failed to produce germination. Plant tissues in the same atmosphere with the drop cultures also stimulate germination. This action is due to the CO2 given off by the tissues. Carbon dioxide in small amounts produces a like effect. \u27fhe maximum, optimum and minimum temperatures for spore germination are 35° C., 25° C., and 15° C., respectively. The optimum temperature for mycelial growth is 25° C., tho good growth takes place between 20° C. and 35° C.-40° C. and 10° C. inhibit growth. Sporulation may take place between 20° C. and 35° C. The fungus readily winters over in its conidial stage. Basisporium gallarum grows well on a wide range of media, but prefers especially media rich in nitrogenous material. On the corn kernel, the fungus destroys the embryo before it does the starchy endosperm. Corn is most susceptible to attack during time of germination of the seed and late stages of maturity. Inoculation of growing roots and stalks yielded negative results. Basisporium dry rot does not spread readily in cribbed corn. In 1923 early varieties became generally infected while late varieties remained free

Notes on Some North American Conifers Based on Leaf Characters

Leaf characters, unlike stem characters, are as a rule subject to such variations that they form an unreliable basis of comparison between plants. Conifer leaves on the contrary, because of their simplicity as compared with other leaves, show a large degree of uniformity, particularly in those characters seen in cross section

Studies on the crown rust of oats

During some seasons crown rust of oats (Puccinia coronata Corda) becomes a serious limiting factor in successful oat production in Iowa. It is not uncommon to have this rust occur in epidemic form one year and the following year to have only a small amount of the disease present. Up to the present time the various factors which influence the growth, development and epidemiology of this rust have not been definitely studied

The comparative resistance of varieties of oats to crown and stem rusts

Numerous instances of the production of disease-resistant crops may be noted in this and other countries, but comparatively little work has been done on the problem of resistance of oats to stem rust (Puccinia grarninis Pel\u27s.) and crown rust (P. coronata Corda.) Many of the published records on the rust resistance of oats are observations covering but a single season and too often with no determination of the species of rust present. The use of resistant varieties, however, appears . to be the most hopeful method of combating these rusts. This paper is chiefly an account of studies conducted to determine which of the existing varieties are resistant to either or both of the rusts mentioned above

The Barberry Bush and Black Stem Rust of Small Grains

During the season of 1916 the cereal crop of the middle west suffered another severe epidemic of black stern rust {Pucclnla graminis). It is estimated that this disease caused a loss of $110,000,000 in the wheat growing districts of Minnesota, North and South Dakota, and Nebraska. In the four principal spring wheat growing provinces or Canada the damage was placed at$100,000,000. Altho Iowa did not suffer as severely as adjoining states on the north, yet the damage was probably not less than $5,000,000. Unquestionably, these severe losses are in a large measure responsible for the present high cost or food stuffs. The protection of the cereal crops from this rust Is or importance, not only to the farmer who grows the grain, but also to every bread consumer

Relation of the barberry to stem rust in Iowa

It has been definitely known since 1865 that the European barberry is the alternate host of stem rust (Puccinia graminis); yet the exact relation of this shrub to the annual appearance of stem rust of our grains and grasses is not well understood. Tulasne brothers (18) (1847), de Bary (1) (1865) and others rarely described and figured the morphology of teleutosporic germination. They gave little consideration, however, to the questions as to what environmental conditions influence such germination and the production, dissemination, viability and growth of the sporidia—conditions that have a fundamental bearing on serious attacks of stem rust

Don't Blame Me

Sketch/Farce (?) Written for actors Arthur Denton, Gus Bluett and Nelle Fleming. Text including song. The text is possibly complete but this is not yet established beyond doubt

Collisionless evaporation from cluster elliptical galaxies

We describe a particular aspect of the effects of the parent cluster tidal field (CTF) on stellar orbits inside cluster Elliptical galaxies. In particular we discuss, with the aid of a simple numerical model, the possibility that collisionless stellar evaporation from elliptical galaxies is an effective mechanism for the production of the recently discovered intracluster stellar populations. A preliminary investigation, based on very idealized galaxy density profiles (Ferrers density distributions), showed that over an Hubble time, the amount of stars lost by a representative galaxy may sum up to the 10% of the initial galaxy mass, a fraction in interesting agreement with observational data. The effectiveness of this mechanism is due to the fact that the galaxy oscillation periods near equilibrium configurations in the CTF are comparable to stellar orbital times in the external galaxy regions. Here we extend our previous study to more realistic galaxy density profiles, in particular by adopting a triaxial Hernquist model.Comment: 6 pages, 2 figures. To appear on "Lecture Notes in Physics", proceedings of the Workshop on "Galaxies and Chaos. Theory and Observations", Athens (September 16-19, 2002), G. Contopoulos and N. Voglis, ed