Systemic insecticides have long been available for commercial use by growers and on a limited basis for the homeowner… let’s take a quick look at systemics.
Simply put… plants absorb the systemic chemicals and transports the active ingredients throughout its tissues. The chemicals DO NOT harm the plant, but the plant can now fight off insect pests and invading organisms for an indefinite period.
What Is A Systemic Insecticide?
Plants absorb systemics chemicals much like it would absorb miracle-gro plant food. It then renders the plant’s parts, the roots, stems and leaves poisonous to invading organisms. Some systemics remain unchanged in the plant, others find themselves chemically altered before they become active poisons. A plant treated with a systemic no longer becomes a target for chemicals but becomes a participant in making conditions unfavorable to invaders.
How Do Systemics Enter Plants?
The chemical reaches the internal tissues by first passing through the millions of microscopic cells forming the surface of leaves, stems, roots or seeds unlike the neem oil insecticide.
How Do Systemics Move Within Plants?
Water and food-conducting tissues are the usual pathways through which these chemicals move over long distances.
For example, drenched soil around roots with a systemic compound, show up in the leaves and fruits. The reverse direction of movement also occurs.
Some systemics tend to move upward from the point of application accumulating in leaf margins, growing tips and storage organs. Others collect in underground parts.
Plants differ widely in their response to systemic chemicals. Compounds absorbed through the seed coat may kill organisms invading the seed or seedling plant.
How Do These Compounds Work?
These foreign chemicals absorbed by a plant may greatly influence its balance of physiological processes.
The effect may be to kill or discourage the pest as:
- It begins to feed or enter the plant
- It may rid the plant of an established pest
- It may counteract poisons produced by invading fungi or bacteria
- It may increase the natural resistance of the plant or retard the visible symptoms of disease.
Do Systemics Remain Active Indefinitely?
The effectiveness generally decreases the longer the chemical remains in the plant. This causes come from:
- Dilution of the systemic within the growing plant
- By a breakdown of the chemical by physiological processes within the plant
- By accumulation or congregating of the compound in certain restricted parts of the plant.
The plant’s first contact with systemic must provide the toxic level required to protect the plant from injury, or the reapplied as the plant develops.
How To Apply These Chemicals?
The most common methods to apply systemics:
- Foliar spray on the leaves
- Drenching the soil
- Treating the seeds
- Injected into the trunk or stem of plants
- Applied as a paste to the outside
Insect and Problems Being Solved by Systemics
The first use of systemic insecticides proved impractical. Sodium fluoroacetate absorbed by bean plants killed insects feeding on the leaves but also left the beans too poisonous as a food. Entomologists observing aphids found they did not infest wheat grown on soils high in selenium. The chemical was too toxic for safety at the levels required for insect control.
In the last 60 years the introduction of a new wide range of field-tested systemic chemicals, now control plant-feeding insects like spider mites.
In addition to killing insect pests species these systemics, generally are noninjurious to beneficial insect predators and parasites. By using these compounds full advantage of biological insect control may be realized.
What Types Of Diseases Controlled By Systemics?
In recent years the introduction of systemic fungicides now combat diseases of fungus, bacterial and virus origin as well as some deficiency troubles.
Fungus diseases controlled, or temporarily checked, include:
- Oak wilt
- Fusarium and verticillium wilts of certain plants
- Rhizoctonia root rots
- Grape black rot
- Early blight of tomato
- Bleeding canker of various trees
- Damping-off of seedling plants
- Some turf diseases
Bacterial diseases find themselves controlled using streptomycin preparations include:
- Halo blight and common blight of beans
- Fire blight of fruit trees
- Walnut blight
- Bacterial spot of tomato and pepper
- Soft rot and bacterial wilt of chrysanthemum
- Bacterial blight of celery
- Soft rot of philodendron
Others are being added every month.
Potentially the greatest use may be for root rots, wilts and viruses not successfully controlled at present. Several chemicals have prevented the development of these diseases but are not being widely used because of:
- Difficulty in application
- Not giving protection long enough for practical control
The commonly used organic fungicides maneb, captan, and others have limited systemic activity. The antibiotics, produced by living microorganisms like streptomycin are effective for certain diseases of fungus or bacterial origin.
What Are Future Prospects?
Despite problems and the “Green Movement”, future research should whittle down what appear to be insurmountable obstacles.
When we know more about the processes of absorption, movement and storage of chemicals in tissues, the reactions of systemic compounds which result in plant protection without injury, the doors which now guard the wide-spread use of systemics may be unlocked.
Let’s be patient and wait for scientists to do their research. This should be well worth waiting for.
Pesticides and Brain Cancer
At www.insidermedicine.ca they share a story on pesticides and their link to brain cancer. This offers another good reason we need to go natural. I always try to go handle any housebug problems using a natural solution. In case you are not familiar with a way to take care of pest control without using health hurting chemicals check out Neem Tree Oil… that’s about as natural as you can get!