C. 2. How does the Foliar Food Web affect plants?

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Foliar organisms create a protective layer on leaves, stems, blossoms, fruit and any above-ground just as happens in the soil, around roots.

This dynamic, living system on the aboveground parts of plants is constantly impacted by rain, wind, heat, sunlight, and pollution. Often disease can gain a foothold after some disturbance harms the community of beneficial, plant-surface dwelling organisms.

Understanding foliar health requires knowing:

1. what organisms should be present (community analysis),
2. how many are present (total biomass of each group), and
3. how many should be functioning (active biomass).

Healthy Leaves, Soil, or any System requires:

1. Organisms that cycle nutrients into the right forms at the right rates need to be present on the foliage in the right diversity, in the right number, in the right places (growing on the exudates plant surface release) with the right level of activity,
2. Organisms to prevent disease-causing organisms from being able to find a foot-hold on leaf or plant surfaces,
3. Organisms that cause plant stomates to open and remain open longer so nutrients added with the microbes will be pumped into the leave surfaces more rapidly, when the plant is supplying foods to make microbial activity occur,
4. Organisms to degrade toxic materials, especially air-borne pollutants,

Aren't organisms present in the soil, or on leaves, or in compost just automatically?

NO, they are not. Consider all the toxic chemicals human beings release on a daily basis. Consider air pollution. If air pollution is killing human beings, think of the damage to smaller, less well-protected individuals. Dust, and toxic pesticides and salts are being poured out onto soil, onto plant surfaces, each day. Natural disturbances (freeze, thaw, wet, dry, fire, and compaction) can kill critical organisms as well. We need to learn the impact of all disturbances, whether human-generated or natural occurrences. We need to learn how to replace, encourage and select for the presence of the appropriate organisms.

If nature kills organisms through natural disturbance, we need to know how to return to what is needed for the crops we want, just as we need to know how to return the organisms to what is needed after we use any chemical, for whatever reasons. It would be better not to let disturbance kill the organisms we want, but sometimes, we just don’t have any choice. We have to learn how to nurture the right biology and bring it back.

If anything has been harmed or reduced, or put out-of-balance, the appropriate organisms must be returned to the plant surfaces if they have been harmed or reduced in diversity or biomass. If the organisms that perform these benefits are missing, they need to be replaced.

The foliar food web will not contain the higher level predators. In unusual disease or pest outbreaks, such as ants farming aphids on foliage, it may be necessary to discourage the ants from this behavior by adding some ant-pathogenic fungi into their nests, or adding the fungi to the tea brew so the ants pick up the fungus and take it home with them on their feet.

Foliar pests can be discouraged by the smell, the taste, or the tackiness of the leave surface that foliar compost tea brews leave behind. The precise mechanism needs to be determined for why this works.

Bacteria are typically the dominant microbe on leaves, twigs, branches, blossoms and bark. Decomposer or saprophytic fungi are also present. Both bacteria and fungi use the exudates produced by the plant, by algae or lichen growing on plant surfaces or deposited by through-fall or other deposition processes. Maintenance of the proper coverage of organisms on the leaf surfaces is critical to maintaining disease suppression in the foliage of any plant.

How can the Soil and Foliar Food Web be assessed?

Methods have been developed that allow the numbers, types and activity of each important group in the soil and on plant surfaces to be quickly assessed. The kinds of assessments used are:

• Number of individuals or biomass of each group
• Type of organisms present and who is dominant
• How active the organisms are
• Relation of soil organisms to plant available nutrients

All of these methods need to be performed by direct microscopy, not by plate counts, enzyme assays, or other in-direct assessment methods.

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