Very often, wind pollination augments pollination by pollinators. This is important information if you grow any of these anemophilous plants and want a harvest. Or if you have allergies.

Characteristics of wind-pollinated plants

This is one of those cases where you don’t know what you have until it’s gone. Most plants invest a lot of energy and resources into attracting pollinators. They produce chemicals with enticing aromas, construct flashy, intricate flowers, and crank out sugary nectar. Anemophilous plants don’t need to go to all that trouble. Even the size and stickiness of pollen grains are reduced in wind-pollinated plants. The pollen of these plants is so small that it can be captured by a bee’s electrostatic field. [There’s a lot of it flying around at certain times of the year.] That is why honey can contain ragweed pollen even though honey bees generally do not visit ragweed flowers. Bees do visit corn tassels and other grains.

Structurally, these plants tend to have long, exposed stamens and feathery stigmas. These are used to dispense and collect pollen, respectively.

If you are allergic to pollen, it’s most likely pollen from anemophilous plants.

Researching yesterday’s post on bacterial blight, I was astounded at the number of diseases caused by Pseudomonas. Pseudomonas [soo-doh-MO-nas] is a genus of bacteria that most of us gardeners end up fighting.

These bacteria are commonly found in plant debris, soil, and water. They also hide out in many  dicot seeds. But don’t worry, Pseudomonas only infects plants with leaves and stems. The rest of your garden is safe. *wink*

Pseudomonas plant pathogens

To date, more than 500 strains of Pseudomonas have been sequenced. Here is a list of the most common bacterial diseases caused by Pseudomonas:

• Angular leafspot
• Bacterial blight
• Bacterial brown spot
• Bacterial canker
• Bacterial dieback
• Bacterial leaf spot
• Bacterial soft rot
• Bacterial speck
• Citrus blast
• Halo blight
• Leaf spot
• Olive knot

 
Small dark spots appear and expand into odd-shaped dead areas in nearly all these diseases. It’s all downhill from there.

Pseudomonas isn’t all bad

As handy as it would be to say that all Pseudomonas are evil, it ends up that some of these soil bacteria help plants stay healthy. In fact, they practically make life possible on Earth. Life sure can be messy, eh?

Some Pseudomonas protect plant roots against disease-causing Fusarium fungi and Pythium oomycetes. They also protect against plant-eating nematodes. And other strains help activate disease resistance within wheat and other cereal crops. Some Pseudomonas can metabolize pollutants and are used in bioremediation.

Finally, Pseudomonas helps form most snowflakes and raindrops that fall on Earth.

Now you know.

Bacterial blight is not the same thing as common bacterial blight, which attacks legumes. To make matters worse, many people call another bean variety of blight ‘bacterial blight’. I know, it gets confusing. Let’s see if we can clarify some of this.

The cause of bacterial blight

Bacterial blight, also known as blossom blight or shoot blight, is caused by a bacterium called Pseudomonas syringae. There are over 50 different strains of this bacteria that cause plant disease. Common examples include bacterial canker, bacterial speck, citrus blast, and halo blight. Pseudomonas syringae is commonly found on the exterior surfaces of healthy plants. It is only when bacteria get inside, through wounds or natural openings, that the trouble starts.

Bacterial blight symptoms

Like the other diseases caused by this pathogen, the first symptom is water-soaked areas on leaves. These areas turn brown and mushy and often have yellow halos. If these spots occur early in a leaf’s development, leaf curling and twisting may also occur. Leaves may also start dying from the outer edge, with the infection moving inward toward the center. Twigs may exhibit black streaks, and it is common for infected blossoms, branch tips, and leaves to die. If infected twigs develop a shepherd’s crook shape, it’s probably fireblight.

Managing bacterial blight

Pseudomonas syringae is most commonly spread by wind and rain. Insects and your garden tools can also be part of the problem. You have to assume that the disease is present. These bacteria can survive in diseased plants, infected plant debris, and soil.

Once a plant is infected, you can try to save it by trimming 10 to 12 inches below infected areas, making sure to disinfect your pruners between each cut. You can dip them in a 10% bleach solution for 30 seconds, though bleach is hard on tools. You can also use bathroom cleaner or other spray disinfectants that contain at least 70% alcohol. Just be sure to give it a few minutes to work before making another cut. Infected plant material should be bagged and thrown in the trash right away.

Prevention is easier. To prevent bacterial blight from taking hold in your landscape, use these tips:

• Start with resistant varieties.
• Space plants out enough that they get some good airflow.
• Feed and water plants appropriately to help them stay healthy.
• Avoid overhead watering
• Do not work around plants when they are wet.

Fixed copper sprays may also help.