How many insects can boast their own international organization? That is the case for dragonflies and damselflies, both members of the order Odonata (meaning “toothed” – the dragonfly has serrated mandibles). The Worldwide Dragonfly Association is dedicated to sharing “research, conservation and public awareness” about these creatures. To that end, they publish two scientific journals and sponsor a biennial International Congress of Odonatology. Their mission? To explore and celebrate what they call an “ancient and beautiful order of insects with amazing behavior.”
“Beautiful” because of their eye-catching jewel-toned iridescence; their large, lacy, double-wing structure; and their long needle-like body and tail.
And “Amazing” because of their fanciful and agile flight patterns, made possible by the unique structure, musculature, placement, and mobility of their wings. In flight, an adult dragonfly can move instantly in any of six different directions: upward, downward, forward, backward, to the left, and to the right. And a seventh: the ability to remain stationary in space, using flight muscles that control each of the four wings separately.
There are subtle differences between dragonflies and damselflies. Dragonflies are generally larger, have heavier bodies, and are stronger fliers. Damselflies have slender bodies and are less powerful fliers. A key difference for identification is that dragonflies hold their wings horizontally both in flight and at rest, while most species of damselfly fold their wings over the abdomen when at rest. This article is primarily concerned with dragonflies.
The nimble, swift, and acrobatic flight of dragonflies, combined with their exceptional eyesight, ensures successful hunting. They have almost 360-degree vision due to their two huge compound eyes, which comprise nearly the entire bulk of the dragonfly head; each compound eye contains about 28,000 single eyes. Dragonflies are voracious insectivores, with an astonishing 95% success rate when capturing prey. They can consume about one fifth of their body weight in prey each day. They'll eat just about any insect, from tiny gnats and midges up to and including damselflies and smaller dragonflies. In fact, if they can't fly, they will die of starvation, because they scoop up prey with their forelimbs while in flight. Because they only eat flying insects, aphids (for example) are safe from their predation, but mosquitos are fair game: one dragonfly can eat from 30 to literally hundreds of mosquitoes daily.
Dragonflies have adapted to life everywhere on earth, inhabiting or visiting every continent except Antarctica, from sea level up to about 12,000 feet, although the number of different species decreases at the highest altitudes. Within the order Odonata, there are eleven dragonfly families, broken down further into 384 genera containing thousands of species. All dragonfly species require aquatic habitat in order to reproduce.
A dragonfly's life begins in fresh water. Mating is complex and multi-step; according to National Geographic the process involves the male self-inseminating, by “curling his body to transfer sperm from his primary genitalia, at the tip of his abdomen, to the secondary genitalia, just below the thorax. When he finds a receptive female, he grasps her behind her head with claspers at the tip of his abdomen, and the two fly off together. When they land, the female curls her abdomen under to meet his secondary genitalia, forming a ‘mating wheel' that can resemble the shape of a heart.” (Sometimes they will mate in the air.)
Immediately after mating and generally in the middle of summer, females lay their eggs by hovering over and dipping their abdomens into a patch of fresh water. These eggs will hatch in about a week. Depending on the species, dragonfly larvae (nymphs) can live in water for up to three years, consuming aquatic insects, mosquito larvae, or even other dragonfly larvae. A dragonfly nymph can go through six to 15 molts before becoming a fully formed adult dragonfly, which emerges in a fairly dramatic fashion: once it crawls out of the water, its exoskeleton breaks open to release the abdomen, which was nestled in like a telescope. Next, its four wings come out, and they dry and harden over the next several hours to days.
Sadly, some species of the beautiful, mesmerizing adults live only about a month, while others live up to a year, delighting us by zooming around our gardens, posing momentarily on garden stakes or plant stems, and hunting for their next meal.
Dragonflies have captured the imagination of humans for thousands of years, serving different roles depending on the culture. For some indigenous peoples of the American southwest, dragonflies had special status as medicine animals, with the power to effect transformation. For the Navajo, they symbolized pure water. In China dragonflies are seen as agents of change, so in feng shui practice the placement of a dragonfly image is thought to bring new insights and changes for the better. In Japan, dragonflies represent rebirth, courage, strength, and happiness.
In Europe, though, dragonflies have played a more sinister role. Some English vernacular names, such as "horse-stinger", "devil's darning needle", and "ear cutter", associate them with evil or injury. The north American colonists brought these beliefs with them, carrying across the ocean the superstition that dragonflies could stitch shut the mouths, and sometimes the eyes and ears, of lying children, scolding women, and cursing men. This belief is reflected in the common species name of “darner” (as in a needle used to darn socks).
Common names of dragonfly species found in northern California are excellent indications of their morphology and of their hunting and flying prowess. A list provided by the San Francisco Bay Wildlife Information website includes the following: Common Green Darner; Blue-eyed Darner; California Darner; Variegated Meadowhawk; Cardinal Meadowhawk; Western Pondhawk; Blue Dasher; Common Whitetail; Widow Skimmer; Eight-spotted Skimmer; Flame Skimmer; Wandering Glider; Spot-winged Glider; and Black Saddlebags.
These and many other dragonfly species will be featured at the next Worldwide Dragonfly Association's International Congress on Odonatology, being held this year on the Mediterranean island of Cyprus, June 25 through 30, 2023.
JOB OPPORTUNITY: UC Cooperative Extension has an opening for an individual who can provide administrative and program oversight to the Master Gardener Program, plus technical and educational training to support the creation and maintenance of gardening programs with UC CalFresh Nutrition Education Program clientele in Butte County. For more information and to apply for the Garden Education Coordinator position visit Jobs - Division of Agriculture and Natural Resources (ucanr.edu).
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
If the new leaves of your peach or nectarine tree become reddish, puckered and severely distorted, chances are that peach leaf curl is the culprit. This disease is caused by the fungus Taphrina deformans and is one of the most common disease problems for backyard peach and nectarine trees here in Butte County. In addition to disfiguring leaves, leaf curl can affect the blossoms, stems and fruit of infected trees. If it is severe enough, leaf curl can significantly weaken a tree and reduce fruit production. Leaf- curl-affected leaves fall off in spring, exposing the main limbs to sunburn injury. And sunburn injury facilitates flatheaded borer attacks, which often result in limb dieback.
The best way to avoid leaf curl is to grow resistant varieties of peaches and nectarines, so if you are planning to buy fruit trees, keep this in mind. Resistant peach varieties include Frost, Indian Free, Muir and Q-1-8. Although the Frost peach variety is very resistant to leaf curl, it must receive fungicide applications in its first two to three years of growth. Red Haven peach and most of the varieties derived from it are rated “tolerant” to leaf curl. On the other hand, Redskin peach and its cultivars are rated “susceptible to highly susceptible” to the disease. Kreibich is a nectarine variety that is resistant to leaf curl.
The most common fungicides available to the home gardener contain fixed copper. The active ingredient, copper, is listed as “metallic copper equivalent,” or MCE. The higher the MCE, the more effective the product will be. Thorough coverage (by spraying the trees until they are dripping) is essential for disease control. Be aware that repeated use of copper products can result in the buildup of copper in the soil, where it may become toxic to soil organisms. The synthetic fungicide, chlorothalonil, is the only non-copper fungicide available for managing leaf curl on backyard trees. When using pesticides, always read and follow the label for usage, rates, toxicity and proper disposal. Proper protective clothing and gear (including goggles) should be used when handling any pesticides.
When the symptoms of peach leaf curl appear on a tree in the spring, nothing can be done to control the disease at that time. Removing diseased leaves or shoots does not control the disease. If your tree has leaf curl now, be sure to treat it next winter to prevent more serious problems the following spring.
For more detailed information on this topic, see the University of California Integrated Pest Management Pestnote #7426: Peach Leaf Curl Management Guidelines--UC IPM (ucanr.edu).
JOB OPPORTUNITY: UC Cooperative Extension has an opening for an individual who can provide administrative and program oversight to the Master Gardener Program, plus technical and educational training to support the creation and maintenance of gardening programs with UC CalFresh Nutrition Education Program clientele in Butte County. For more information and to apply for the Garden Education Coordinator position visit Jobs - Division of Agriculture and Natural Resources (ucanr.edu).
If you didn't already prune your apricots at the end of last summer, please hold off a little longer.
Our area has a fungus called Eutypa that infects fresh pruning wounds when rainfall occurs 2 to 6 weeks after pruning. Eutypa causes limbs or twigs to die suddenly in late spring or summer, with their wilted leaves still attached. Infected bark has a dark discoloration with amber-colored gumming. A cross section of a twig or branch will reveal an irregular discolored brown where the fungus has invaded.
If your apricot shows symptoms of Eutypa, remove the infected limbs at least 1 foot below any internal symptoms of the disease. The preferred control method is to prune during July and August after harvest, and, ideally, before the first fall rains. At that time, there will be less regrowth from pruning cuts. Treating wounds with paints or sealants is not satisfactory because it is difficult to treat all of the pruning wounds immediately after pruning is completed and many sealants frequently crack after application, letting in moisture and trapping it under the sealant.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
At this time of year, some nurseries start selling the egg cases of Chinese mantis as a biological control for the garden. These alien-looking insects are Praying Mantis and are harmless to humans, but have an insatiable appetite for aphids, caterpillars and other insects. They are masters of disguise, hiding amongst vegetation for camouflage and to stalk their prey. They will often attack and eat things larger than themselves: lizards, frogs, and even birds. They are not considered a beneficial bug because they not only eat bad bugs but also good bugs, so they are of little value in biological control.
The mantis (or mantid) is part of the mantidae family. There are about 2,000 species of mantises worldwide, most of which live in warmer, subtropical climates. But the United States is home to at least three mantis species: the Chinese mantis, which was introduced in the late 1800's or early 1900's; the European mantis, which is pale green and only half the size of the Chinese mantis; and the Carolina mantis, the only mantis species considered native to the U.S.
The mantis is related to the grasshopper, the cricket and the termite. It has two large bulbous compound eyes capable of seeing shapes and colors, a mouth designed to chew, and very distinct wings. Because the mantis has only one ear, located on the underside of its belly, it cannot discriminate the direction or frequency of sound, but it is able to detect ultrasound. This helps protect the mantis from being eaten by bats, which produce ultrasound.
Praying mantises mate in the autumn, and will sometimes eat their mates. The female carries her eggs for a time, then deposits them on a twig, stem, or fence with a spongy, “Styrofoam-like” substance she secretes. This substance forms a protective egg case in which the offspring develop over the winter. Praying mantises can grow to well over six inches. There are three distinct stages of growth from infancy to adulthood: egg, nymph, and adult. Once the egg hatches, the nymph appears. It resembles its mother except it is much smaller in size and wingless. These nymphs have an exoskeleton (a skeleton on the outside of the body). When the nymph becomes too large, it sheds the flexible exoskeleton and forms a new one. This process, called molting, can occur up to ten times, depending on the species of mantis. During the last molting, the mantises emerge with thin, transparent wings.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
Among the joys of a California spring are swaths of annual wildflowers blooming around the state. Here in Butte County good places to view this wildflower show include Upper Bidwell Park, Table Mountain, and Feather Falls Trail. Annual wildflowers have a life cycle that lasts just one year. Seeds germinate in the fall and winter rains (or with irrigation), roots and lower leaves grow through the winter, and plants begin to bloom in the early spring, with different species blooming into early summer. Seeds are formed and mature from late spring through summer and fall, then the mother plant dies. Seeds are spread by the mother plant, the wind, or animals, in time for the whole process to start over with the next rainy season.
If you have only a small number of seeds, you may want to cluster a few of them together in selected spots. Use a narrow strip of paper towel or toilet paper laid on the ground and misted with water. Spread a few seeds evenly on the paper before covering them lightly with soil and watering gently.
Weed seeds still remaining in the ground will germinate and grow along with your wildflowers and can overrun them if left unchecked. Stay vigilant with your weeding! Be sure you are able to tell the difference between weed seedlings and native wildflowers when you weed. Photos of juvenile wildflower leaves can be very helpful at this point. Some people sow a few seeds in labeled pots to use as a reference when they sprout. Remember that seeds growing in pots will need to be watered more often than those planted in the ground.
Although very large patches of wildflowers are beautiful when in bloom, they're a little less appealing when the plants dry up. Large patches are also hard to keep weed-free, although it can become easier with time. Many people add some herbaceous perennials or small shrubs to the patch to provide interest when the wildflowers are spent. It's much easier to maintain smaller patches or to plant just a few seeds in small spaces in a perennial bed or in between shrubs.
Harvests & Habitats Nursery in Chico sometimes has seeds from a few native wildflowers for sale. Floral Native Nursery, also in Chico, sells a native wildflower mix, a pollinator mix, and seeds from about a dozen different kinds of native wildflowers. Online sources of native seeds include Larner Seeds, Theodore Payne Foundation, and Seedhunt.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.