by Judy Kautz, OSU Extension Master Gardener
Have you noticed the webs beginning to emerge in trees across our state? Fall webworms are starting to make their appearance, and they certainly cause our trees to look unsightly. But do webworms actually harm the trees or are they just a blight on the landscape?
Webworms, or Hyphantria cunea, usually appear on trees in the fall, causing unsightly nests and severe leaf damage. The webworm caterpillar is about an inch long with a black to reddish head and light yellow to greenish body with a mottled stripe of two rows of black and tufts of long whitish hairs. Adults appear as white moths with dark spots on the wings.
Webworm adults are white moths with black spots on their wings.
Webworms are a common occurrence across Oklahoma, but some years they are more noticeable than others. There may be several generations per season and their preferred species are pecan and persimmon trees. However, you may also find them on other trees including hickory, walnut, mulberry, redbud, American elm, cottonwood and even bald cypress.
Webs from the webworm may look unattractive, but they usually do not impact a tree's health. Your tree may be totally defoliated by the caterpillars one year and have enough stored energy through photosynthesis to come back next season. Even then, the long-term impact on the tree is minimal.
The webs themselves are created by a group of worms for protection as barriers from their own natural enemies, like arthropod predators, parasites and birds. Soon the worms will begin to fall from the webs and begin the next stage of their lives, pupating in the soil.
Webworms group together encased in webs to protect themselves from natural predators.
It’s a good idea to remove worms from younger trees, especially those less than two years old. Simply run your hand or a stick down the branch to remove the webs, or prune the branch out. Be sure to dispose of the worms and webs you remove from the trees.
There are also a variety of readily available sprays to help with those webs you cannot reach. You need to use a sprayer with enough pressure to penetrate the webbing. This ensures the spray comes in contact with the caterpillars. Bacillus thuringiensis, commonly referred to as (Bt), is a good spray to use. It only targets the caterpillars and does not harm beneficial insects like honey bees or other pollinators. You may also use other more broad ranging insecticides but be sure to closely follow all label instructions.
There are some who use a propane torch attached to a long pole to burn out the webs. Controlling fall webworms using a torch is extremely dangerous! Especially in our dry conditions, you may very well set the entire tree on fire and that could prove disastrous to your landscape or worse. Avoid this method entirely!
Here is the safest and most effective method of eliminating webworms: Prune the tree in the spring and spray with dormant oil spray. Dormant oil has low toxicity and is readily available in any local garden supply store. It is particularly effective because it attacks and kills overwintering eggs. Do make sure to clean up any leaf debris to remove these overwintering pupation populations as well.
Webworms are truly unsightly, but remember. Webs will eventually succumb to the elements. They only stay attached until wind and rain wash them away!
Fall webworms are beginning to show up in Oklahoma landscapes.
Do you have a gardening problem? You can easily obtain help from the Cleveland County Extension Office. Call (405) 321-4774 and ask to speak to a master gardener or simply come to the extension office. Bring your problem plant and you will certainly be helped with your issue!
by Judy Kautz, OSU Extension Master Gardener
As gardeners, we all know that there are benefits of having good bugs in our yards, and it seems that bugs are plentiful this year, since the heat came on early. However, most insects, spiders and other bugs are beneficial and we really do want them in our gardens! Here are details on these critters and why they can help!
First, among the hundreds of thousands of species of the Coleoptera (beetles) and Hemiptera (true bugs) insect orders are many predatory creatures which dine on their plant-eating relatives. Tiger, soldier, ground and ladybird beetles, along with assassin and pirate bugs are just a few of these beneficial creatures you should welcome in your garden as residents because they eat “bad bugs”. For example, the ladybird beetle’s favorite meal is aphids, which we definitely do not want on our plants!
The assassin bug provides great benefits in your garden by eating insect pests.
Bees are another beneficial species we want to keep around, because all of them are pollinators; they are largely responsible for the successful development of seeds, nuts, berries, fruits and other plant foods which feed both people and wildlife. You will also want to welcome wasps and ants as well; as avid predators, they constantly patrol and pick our gardens clean of pests. Also, only female wasps sting and that is usually because their nests have been threatened.
Butterflies and moths are attractive and wonderful to see in the landscape as they flutter about sporting beautiful colors. They are also important pollinators; even better, their caterpillars attract birds into our yards. Did you know that over 95 percent of backyard birds rely on caterpillars as a primary food source for their young. So, attracting these insects to your garden means that you will have more birds, which also eat insects.
Spiders can be scary-looking, but they are actually some of the most helpful garden invertebrates; although they are often hated or feared, they consume many insects. All spiders are predatory and hunt using a variety of techniques. For example, the orb-weaver garden spider uses skillfully woven webs. Tarantulas and trap-door spiders use ambush to catch their prey, and the wolf and jumping spiders use the method of stalking.
The orb-weaver may look dangerous, but is completely harmless and keeps pests down in your garden.
Dragonflies and damselflies offer a double threat in your yard. These aerial acrobats as adults feed on many flying insects, from mosquitos to biting flies and gnats. As larvae, they inhabit water and devour larvae of these same pests. Did you know that adult dragonflies can consume hundreds of mosquitoes in one day? They are valued as predators, since they help control populations of harmful insects. Adult dragonflies do not bite or sting humans, though nymphs are capable of delivering a painful but harmless bite.
There are three bugs you do not want in your garden, though. First, discourage mosquitos from your yard, as they spread diseases; eliminating stagnant water and cleaning clogged gutters will help to prevent them. Fire ants, introduced in Alabama over 100 years ago, are proliferating! They have a very painful sting and they have displaced many native ant species. Be sure to avoid their large mounds, and call an exterminator to remove them. Finally, because of our deer population here in Oklahoma, ticks can really create a problem in your landscape, because they spread diseases, and ticks are particularly bad this year. To fight them, avoid areas of tall grass and mow pathways in your garden. Also, wear long pants that are tucked into socks and be sure to check yourself and your pets after outdoor time.
Call an exterminator if you have fire ants in your yard!
To encourage beneficial insects, what can you do to attract them? First, plant native species which can support 60 percent more native insects that exotic ornamental plants. Second, don’t be too tidy; a natural garden design will provide hiding and hibernation spots, as well as food and places to nest. Finally, reduce the amount of pesticides you use; while they can be a useful tool, ultimately they kill all insects including the beneficial ones you want to promote in your yard!
As you prepare and enjoy your gardens this year, think twice about stepping on or spraying that spider, wasp or caterpillar! You will reap big benefits in the long run!
Welcome to Dishing the Garden Dirt!