Chemical Application

What is chemical application and how can this benefit plant life?

Chemical application is applying chemicals to plants to aid them in recovering from insect infestation or from the disease that may be brought on by plant pathogens such as virus and bacteria.

Holly plant-chemical-application
A Holly Plant

Every gardener should know a bit about chemical application because knowledge is power and most importantly, it can save you a considerable amount of money.

Chemicals are dangerous and extreme caution should be taken when handling them. With over twenty-two years of experience in the field of landscape and gardening, I have had not only the opportunity but also the training for working with some of these chemicals.  It is very important to follow the manufacturers’ directions to the letter. The label is the law if you are to be successful in this field.

In my opinion, chemicals should be the last resort. Other practices or methods should be sorted out first before using chemicals and if these do not work, then chemicals should be considered starting with the least toxic.

For example, plants become stressed when their requirements are not met or when environmental factors are out of our control. When this happens disease or insects begin to take over and plants begin to fight for their life.

Following the plant requirements as outlined in my PLANT CARE section is an important part of the overall health and life of that plant. If one of these basic requirements are not being met, be assured that you are headed for trouble.

Landscape and gardening inspection

In my studies of chemical application, I have been taught to carry out periodic plant inspections. When you perform plant inspections on a weekly basis, once done properly you may discover problems from the onset and are able to deal with them before they get out of control.

Garden flowering plants-chemical-application
Garden Flowering Plants

As a result of these consistent inspections, pest problems can be quickly resolved by simply using a hand pruner to prune off a small part of that plant rather than not having an inspection program and that small problem becomes a major problem that spreads to other plants. As a result, the gardener now has to take drastic measures like having to apply chemicals in probably great amounts to bring the problems under control.

So now time and money become a factor when having a regular inspection program could have saved you from this whole ordeal. Now don’t get me wrong, I am not saying that chemicals may not be needed if you have an inspection program in place but what I am saying is an inspection program will go a long way in helping you keep problems at a minimum using fewer chemicals and probably the least toxic.

One thing I have learned over the years is we can never totally eradicate insects out of our landscape and gardens no matter how effective our inspection program may be. But what we can do however is to keep insects at an acceptable level where they will not be a threat to our landscape and garden plants.

This is just food for thought.

All about chemical insecticides

While we have established the fact that training is required to know all about chemicals and their uses, there are some chemicals that are considered to be environmentally friendly or safe and can be purchased by the homeowner for use in their home landscape and garden. These include Insecticidal Soap, Talstar, and Upstar,

The ones that are considered to be toxic or dangerous can only be purchased by a licensed professional trained chemical applicator. These include Cygon, Malathion, and Avid.

N.B. To become a professional chemical applicator you will be required to sit an exam.

Inorganic Insecticides

Chemicals can either be powdered which is water soluble (you mix with water) or granule (it comes in dry pellet form). Apply this chemical by spreading it evenly and then apply water to the active ingredients can be released.  The liquid form of insecticides only requires adding water once you have measured the amount of chemical to be applied according to the direction.

Other chemicals such as insecticidal soaps come already mixed in liquid form all you have to do is apply to plants. And then there is horticultural oil which is oil sprays. This insecticide works by coming in contact with the insect clogging their spiracles they breathe through when this happens the insects die.

These inorganic or synthetic (man-made) insecticides are not only a contact insecticide but some of them are also systemic (they can only kill insects as it is ingested).

Systemic once applied to the plants are absorbed into the plant system. The chemicals are transported throughout the entire plant. The insects, in turn, feed on the treated plant, ingesting the systemic insecticide. When this happens the insects die.

Microbial Insecticides

Research has shown that microbial insecticides are safe to use around humans and animals. Therefore homeowners can use this in their landscape and garden.

These insecticides contain BT (Bacillus thuringiensis). This insecticide works by paralyzing the insect’s nervous system. When this happens the insect dies.

Botanical Insecticide

These are made from plant extract. Botanical Insecticide may be toxic so caution should be taken when using it.  These insecticides work by paralyzing the insect’s nervous system.

Some botanical insecticides are Pyrethrum which is extracted from the Chrysanthemum flower. Pyrethrin is extracted from the Daisy,  Neem oils from the Neem tree and Citrus oil that is derived from citrus peels.

Garden plant design-chemical-application
Garden Plant Design


You may have mixed the right amount of chemical and applied it in the right way but to your surprise, you have not only eliminated the target pest but your plant leaves are burnt.

What went wrong. Well, the problem that you are facing is called phototoxicity or plant burn and there are many reasons why this happens.

*Spraying during high temperatures or when it is too hot can work against you. The compounds that make up these chemicals which are exposed to direct heat causes a negative reaction. That’s why it is important to spray in the morning when it is cool.

*Another reason why plants may burn when applying chemicals are combining chemicals that are not compatible. In other words, seeking to mix several different chemicals to combat pest problems. You can mix chemicals but only those that are compatible. That’s why it is so important to follow the manufacturer’s directions. If the label does not call for a particular chemical to be mixed with another then don’t do it.

*Plant burn can also happen when the water that you are mixing the chemicals in, has impurities. Water that has salt can have an adverse effect on plants when mixed with chemicals.

*Lastly, there is mixing the chemicals at higher rates. Remember to follow the manufacturer’s direction. If direction says this amount, then it’s that amount and no more.


Fungicides are chemical compounds that are used to eliminate fungi. Within our landscape and garden, we are sometimes faced with having to deal with these disease-carrying organisms.

Action should be taken as soon as possible to correct this problem or the disease will spread to the other parts of the plant causing plant life to decline and if the problem persists the plant will eventually die.

So in this section, we will be looking at ways to eliminate fungi and how we can put programs in place to minimize their activity.

Fungi may become active due to one or two reasons it may be because of poor maintenance practices or it may have come about because of environmental factors.

An example of an environmental factor may include, seasons, where there are heavy rainfalls to the point where soil becomes saturated or waterlogged and does not dry out, to the point where plants are sitting in water for days.

Fungi are reproduced by wind carrying and spreading their spores. There are also insects that carry these disease organisms, spreading them from plant to plant.

Or it may have come about because of poor maintenance practices. Such as placing plants too close together so there is no proper air circulation or because of a lack of proper drainage for plants especially potted plants.

A fungus can also be spread by using an infected tool transferring the disease from plant to plant.

Signs of fungi infections

Signs of fungi infections include wilt, rust, rotted tissue, scabs, moldy coating, blotches, or in some cases a foul smell because of rotted tissue.

Preventative measures

We may not have complete control over these disease-carrying organisms but there are some practices that we can put in place to counter-attack their spread and limit their activity.

Types of fungicides

There are two types of fungicides that are used to combat fungi. First, you have CONTACT and then you have the SYSTEMIC.

Contact fungicides

Contact fungicides, when applied to the surface of the plant leaf acts as a barrier inhibiting the germination of fungal spores that invade the plant. Contact fungicide must be applied to the plant before it is infected in order for it to be effective.

Systemic fungicides

Systemic fungicides are fungicides once applied to the plant works itself into or is absorbed into the plant. Once this happens the chemical is transported throughout the entire plant to fight off the plant’s infection.

Fungicide application

Like insecticides and herbicides, fungicides should be mixed and applied according to the label. Remember the label is the law so follow the label to the letter if success is to be achieved.

The final word

All chemicals should be stored away from children and pets in a cool dry area including those that are safe to use around humans and animals.

Even when using the environmentally safe ones proper protection should be taken like rubber or disposable gloves, respirators and safety goggles.

chemical suits are for chemicals that are least to very toxic and is applied by a trained chemical applicator.

When chemical containers are empty, fill the containers with water to get the rest of the residue out of it. This residue can also be used to treat plants. Place the empty container in a plastic bag, making sure to tie the bag well enough so that children don’t have access to the containers. Place the container in a properly secure garbage container.

And remember our plants are depending on us to keep them healthy and growing.


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About the author

+ posts

Norman loves being in the garden, both at home and for his job....
he is 'Natures Little helper' being outdoors, growing his vegetables and flowers from an early age.
Now having spent over 22 years in the profession he want to give some of his knowledge to others...
his vast array of hints and tips you will find scattered over this site will help you no end growing plants in your garden.

4 thoughts on “Chemical Application”

  1. The website it’s self is well presented and there is a lot of information and the content is well presented this is a slight problem I can find tho and that is you title the garden of eden you might want to sort it out so the letters are all together that is the first thing that I noticed.

  2. It is really important to use any garden chemicals in a safe manner. I agree with you that garden inspection can save time and money. But sometimes when a real problem hits, garden chemicals,can protect your investment of time and money. I am really glad that you stress environmentally friendly and safe choices like Insecticidal Soap, Talstar and Upstar,
    I garden in a community garden where one gardener’s pests become all gardener’s pests, so using preventive measures are almost always necessary. When they are I always use safe choics. Thanks for the great info!

    • Good evening Diana sorry that I am responding so late, Thanks for the follow I am glad that I could help and that you agreed with me. Have a good day. and please do tell others about my website, thanks again, God bless.


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