Flower Mites

Flower mites may be the fastest living things on Earth. But you wouldn’t know it by looking at them. And they don’t exactly run. But they sure do move!

It’s easy to see the big things in your garden: trees, shrubs, vines, and raised beds. And we know there are countless tiny things in our gardens, as well. But flower mites are pretty unique, even at half the size of a grain of salt.

These nectar and pollen eaters hitch rides from one flower to the next with hummingbirds in a behavior known as phoresy.

We used to think that flower mites ran up a bird’s beak and grabbed hold of their host’s nostrils for the flight from one flower to another. We now know that the electrostatic field created by the motion of a hummingbird’s wings helps propel those tiny mites, much like the sock that sticks to a blanket coming out of the dryer.

Note: Research by Carlos Garcia-Robledo has shown that different flower mite species are attracted to specific frequencies related to the geometry, size, and vibration of their host. It’s a crazy world out there!

However they do it, mites also hop onto the bats, bees, beetles, butterflies, and moths that frequent your garden. As their ride pulls up to a flower, mites often have only a split second to decide if the current flower can feed them. Guess wrong and die. [You can see some amazing photos at the Audubon website.]

There are several different flower mite species, including Proctolaelaps, Rhinoseius, and Tropicoiseus. It should come as no surprise that flower mite dietary preferences tend to match their ride. Hummingbird flower mites prefer plants in the blueberry, coffee, ginger, onion, and pineapple families, and these are all big favorites of hummingbirds.

You can usually identify mite feeding with a hand lens after noticing leaf blistering, bronzing, galls, and stippling.

Some flower mites have a one-track mind. They feed on a single plant species all year. This is called monophagy. Other mites have a broader menu, following the bloom cycle of several flower species. This is called polyphagy. But how much nectar do flower mites eat? Does it really make a difference? I mean, these creatures are very small.

It turns out that the answer is yes. Sort of.

Nectar attracts pollinators and protectors. With less nectar, we would expect there to be less food for those pollinators and protectors, resulting in smaller harvests. And in some cases, we’d be right.

According to one study, excluding flower mites increased the availability of nectar by up to 49%! That’s huge in the world of nectar feeders. One would expect that heavy mite feeding would negatively impact the health of local pollinators by reducing their food supply. But the net result might surprise you.

Sometimes, flower mite feeding reduces pollination, resulting in smaller crops. But not always.

In some cases, flowers respond by producing more nectar. In other cases, pollinators work harder, visiting more flowers. By doing so, they actually increase pollination rates.

We have already discussed bulb mites, citrus bud mites, dryberry mites, European red mites, fig mites, spider mites, and more. For the most part, they are microscopic arachnids. Some are worse than others.

While flower mites do not technically carry plant diseases, they do carry the viruses and phytoplasmas responsible for aster yellows, various leaf spot diseases, and potato virus Y.

The bottom line on mites: how you respond to them depends on your tolerance level. If your plants are healthy, you don’t need to do anything about flower mites. If your plants are prone to the diseases mentioned above, you can spray the affected areas with insecticidal soaps or horticultural oil.