Each month V.D. Kaviraj will answer questions about plants and plant problems. Kaviraj is one of the foremost pioneers of Agro-homeopathy and author of the book, Homeopathy for Farm and Garden.
Send your questions with sufficient detail and pictures when possible (JPG or GIF format) to firstname.lastname@example.org with the subject “Plant Doctor”.
Note: When I refer to treating plants with homeopathic remedies, this is the standard dosing procedure: Put 20 drops of a 6X potency in a litre of water. Succuss the bottle 50 times. Put this litre in the watering can, fill it up with 19 litres of tap water and stir. If the watering can is smaller, the amount of remedy put in must be proportionally smaller. Thus a 10 litre can needs only ½ litre and just 10 drops of the remedy. Apply the contents of the watering can to the roots of the plants to be treated.
Hello Dr. Kaviraj,
I have a small lemon tree in my yard that has not grown an inch since I bought it 4 years ago. It always had only 2 leaves. It may not like the soil. We live 5km from the sea and I think the place I am living was covered by sea water in ancient times.
What can I do to make it grow?
First of all, you may want to have a soil analysis done. If the soil was once under water – sea water at that – it may have a high salt-content. Depending how long ago – if over 50 years then you have little to worry, unless it is lower than sea-level. In that case, Natrum mur may do the trick in neutralising the effects of salt water. If on the other hand it is well above sea level, the best solution seems to me to give it a dose of Carbo veg. That should settle it nicely. Please keep us posted about the progress.
Since permethrin (main ingredient in tick killer for animals) comes
from the marigold, is there some way to make a salve, cream etc. from
this plant, so the animals are protected but safe from the poison.
Hi Mike, you can also make a wash with Calendula tincture, about 100 drops on a litre. Wash the dog with it on a regular basis and that should keep the ticks off. If you use a cream or salve, you will stick the hairs in the pelt together and they will lose their isolation property and possibly make your dig catch a severe cold.
Our evergreen tree seems to be losing needles. We’re in the N.E. part of the U.S. and the soil the tree is living in is somewhat acid. Do you have any thoughts o this?
Pine trees love acidic soils. They are pioneer plants on acidic soils and the pH will therefore have little to do with it. I suspect a borer under the bark or another parasite, good at hiding in cracks. After you inspect the tree – bring a magnifying glass because many pests are extremely small – you may find a pest and this can be combated with Thuja. Alternatively, it could be a fungus and then you look for spores or hyphen – small, extremely thin web-like threads that infest the places where the needles have gone. In that case, use Salicylic acid to combat it.
It pays to read this month’s article on fungal diseases (below), because it will enable you to identify many fungal diseases with greater ease.
Function of Fungi
Fungi may be beneficial or detrimental to plants, depending upon the type, and what they use as a food source. In general, fungi are composed of microscopic cells that usually grow as long threads called hyphae, pushing their way between soil particles, roots and rocks. Hyphae are usually only several thousandths of an inch thick. A single hypha can span in length of a few cells to many yards. A few fungi, such as yeast, are single cells.
Hyphae sometimes group into masses called mycelium or thick, cord-like “rhizomorphs” that look like roots. Fungal fruiting structures (mushrooms) are made of hyphal strands, spores, and some special structures like gills on which spores form. A single fungus can include many fruiting bodies scattered across an area as large as a baseball diamond.
Fungi perform important services related to water dynamics, nutrient cycling, and disease suppression. Along with bacteria, fungi are important as decomposers in the soil food web. They convert hard to digest organic material into forms that other organisms can use. Fungal hyphae physically bind soil particles together, creating stable aggregates that help increase water infiltration and soil water-holding capacity.
Soil fungi can be grouped into three general groups based on how they get their energy. Decomposersâ€”saprophytic fungiâ€”convert dead organic material into fungal biomass, carbon dioxide, and small molecules, such as organic acids. These fungi generally use complex substrates, such as the cellulose and lignin in wood, and are essential in decomposing the carbon ring structures in some pollutants. A few fungi are called “sugar fungi” because they break down the same substances as do many bacteria. Like bacteria, these fungi are important for immobilizing, or retaining, nutrients in the soil.
Mutualistsâ€”the mycorrhizal fungiâ€”colonize plant roots. In exchange for carbon from the plant, mycorrhizal fungi help make soluble phosphorus and bring soil nutrients (phosphorus, nitrogen, micronutrients, and perhaps water) to the plant. One major group of mycorrhizae, the ectomycorrhizae, grow on the surface layers of roots and are commonly associated with trees. The second major group of mycorrhizae are the endomycorrhizae, that grow within the root cells and are commonly associated with grasses, row crops, vegetables, and shrubs.
The third group of fungi, pathogens or parasites, cause reduced production or death when they colonize roots and other organisms. Root-pathogenic fungi cause major economic losses in agriculture each year.
Saprophytic fungi are commonly active around woody plant residue. Fungal hyphae have advantages over bacteria in some soil environments. Under dry conditions, fungi can bridge gaps between pockets of moisture with their tube-like hyphae, and continue to survive and grow. In arid rangeland systems, fungi pipe scarce water and nutrients to plants. Fungi are able to use nitrogen from the soil, allowing them to decompose surface residue, which is often low in nitrogen.
Soil fungi are aerobic organisms. Soil that becomes anaerobic for significant periods generally loses its fungal component. Anaerobic conditions often occur in waterlogged soil and in compacted soil.
Four separate assays that help determine the types of fungi in soil and their extent of colonization are included in the next section. They may be performed concurrently or at separate times.
Seeing Soil Fungi
Fungi participate in a wide variety of soil processes. Some are mycorrhizal, increasing the capacity of plant roots to absorb nutrients. Fungi also secrete chemical compounds that dissolve minerals, making nutrients available to other organisms. Basidiomycetes are also associated with the ability of a soil to suppress plant disease. Some actinomycetes produce compounds that act as antibiotics. Streptomycetes sp. was the original source of streptomycin. As a group, fungi also help bind together soil particles, creating the fluffy “tilth” that is very desirable for root growth.
We often think of fungi as the “mushrooms” that are visible above ground. These are only reproductive structures, analogous to apples. The actually body of a fungus is a mass of microscopic threadlike filaments called a mycelium. Each thread is called a hypha (pl. hyphae). The everyday functions of fungi, secreting enzymes and absorbing nutrients, are carried out by the hyphae. In some fungi, a segment of hypha may contain several nuclei, so a section of hypha is not quite the same as a cell. Forest soils from the PNW often contain hundreds or thousands of meters of hyphae!
In general, the more fungal hyphae found in a soil sample, the healthier the soil, and the more able to support plant life. Mycorrhizal fungi increase the capacity for plant roots to absorb nutrients, as they secrete chemical compounds that dissolve minerals, making nutrients available. Basidiomycetes are associated with the ability of a soil to suppress plant disease. Some actinomycetes produce compounds that act as antibiotics. As a group, fungi also bind together soil particles, creating fluffy “tilth” that is very desirable for root growth.
Types of Fungi Present in Soil
Wear a latex glove for this assay, so fungi from fingers don’t contaminate the sample. Place a thin slice of potato in a petri dish that has been lined with a moistened paper towel. Place a sample (a pinch) of site soil in the center of the potato slice, spreading it into a circle about 1 cm in diameter. Repeat this for 2 more potato slices, each in its own petri dish. Leave the petri dishes in a dark place, and do not disturb for 2-10 days. After that time, examine the potatoes for fungal growth. Four general appearances are listed below, along with the type of fungi most commonly associated with each: