We have all had plants die on us.  Sometimes the cause is obvious — a big chunk chewed out of the plant, or so many bugs they kill the plant.  Other times, the cause is not so obvious.  Then it is often a disease that killed the plant.

Types of Diseases

I am not foolish enough to try to cover every disease that attacks a plant.  I will, however, try to discuss the types of organisms that infect plants and how to identify them.  It is much easier to combat a disease if you know the general organism you are dealing with.  You have these choices:

• Viruses
• Bacteria
• Fungi
• Nematodes

See, even guessing, you have a one in four chance of being right.  Things are looking up already.

Viruses

Viruses are the same sorts of things that give humans colds and the flu.  You can spread them by using tools on one plant and then using the same tools on another plant without sterilizing them.  The same goes for your gardening gloves.  Be aware of this if you have a sick plant — use different gloves and sterilize your tools before moving on.

Bacteria

Bacteria are spread most often by splashing water.  For example, when you turn on the hose and let it run full stream to water a flower bed, the rushing water splashes dirt on the plants.  That dirt contains bacteria that can infect the plant.

Fungi

Fungi prefer damp, mild weather.  The spores are spread on the wind or in the water.  Equipment can also spread it.  Powdery mildew is an example of fungi.

Nematodes

Nematodes are small, wormlike things that feed on the roots of a plant.  Root-knot nematode is the most common of these in the home garden.

Preventing Diseases

The best way to combat all of these problems is to water appropriately, fertilize appropriately, and plant varieties of plants that are immune to the diseases common in your area, if possible.  A healthy plant is much more likely to fight off a problem, just as a healthy person can fight off a cold.  It is also important to rotate your crops so that you do not plant vegetables from the same family in the same spot for at least 24 months.  That keeps bacteria or viruses in the soil from having a ready food supply of their favorite vegetable.

Trellis Vines

If you can, train vegetables up on a trellis, even ones such as cucumbers and other crops that are not usually caged.  This means air can circulate better and the fruit does not contact the ground.  Clean fruit is not only healthier, it is nicer to deal with at harvest time.

Nematodes

Nematodes are hard to deal with.  It is best to plant resistant varieties of plants.  If you can’t, rotate in resistant plants every other year to help keep the nematode numbers down.

Treating Sick Plants

Each state has a plant diagnostic lab where you can submit a specimen and have the disease diagnosed.  They do charge, however.  Many times your county extension agent can help for free.

Want to learn to garden? My first attempt at gardening ended up in failure. The weeds took over and squeezed the vegetables out. I was very frustrated by this waste of good seed, time, and money. So I became a master gardener and spent a lot of time helping other people avoid or overcome problems in their garden. 

In order to help others garden successfully, I have written a book, Vegetable Gardening from the Ground Up, available in an ebook or a paperback from Amazon. It is also in Kindle Unlimited.