|
Spring is just around the corner--or so we hope. We all look forward to spring and all the freshness, the new tender foliage, and the beautiful flowers. Even just thinking of that first bloom from the rose bushes in the garden brings happiness to our hearts and smiles to our faces. But spring brings something else to our gardens that winter has minimized. Insects.
Beginning this year, we would like you to consider a new approach to your gardens and all the living creatures that dwell there. That approach is tolerance and integrated pest management. Agriculture uses the term "agricultural entomology," which applies an economic threshold--the point when it becomes more economically necessary to save a crop than to do nothing. That point is reached only when, without action, the entire crop could not be saved. But we're talking about our gardens, where the issue is actually more aesthetic than economic.
Our gardens are living ecosystems. You are probably unaware of much of that ecosystem , but it is integral and important, nonetheless. Use of pesticides is an escalation to the maximum sentence for an insect that is considered a pest. That pesticide may kill your pest, but it will also kill beneficial insects indiscriminately. And some of those beneficial insects are actually predators for the very pest you are targeting. Unfortunately, pesticides kill them all. So find out who your garden friends are, discover what they like to live on, breed on and feed upon. Add those plants to your garden, offering a welcome mat to the beneficial insects--and observe the decrease in the pest population, right before your eyes. There are many beneficial insects in your gardens. Ladybugs and their larvae are common, and so are the green lacewing larvae. Today, learn a new approach to the rose slug. He'll be in our gardens before we know it, if he isn't already.
The rose slug is a sawfly larva (note - that means that its presence will be a temporary one). In your garden, this variety of sawfly, actually a tiny wasp, is one of your garden friends. Once it becomes an adult it likes to feed on other soft-bodied insects and, like the bee, acts as a pollinator. So as an adult, this insect is a beneficial one for humans. Here's the rub--its larva, the rose slug, is seemingly the rose lover's worst enemy! Or is it the rose leaf lover's worst enemy?
The American Rose Society website informs us: "Rose slugs are the immature stages of primitive wasps called sawflies. Rose slugs look more like caterpillars than slugs. They are not slimy and do not have rasping mouthparts like true slugs. The young larva begins feeding as a skeletonizer on the underside of the leaves and as it matures, it chews large holes on the leaves."
Recommended control: rose slugs look like caterpillars but they are not; consequently insecticides for caterpillars, such as Bacillus thuringiensis, will not kill them. If there are only a few rose bushes infested with the rose slugs, pull the leaves off and kill any larvae found on the upper or lower surfaces of the leaves.
Just about any contact insecticide labeled for use on roses will kill the rose slugs. Try to use the least toxic one possible, because you don't want to kill beneficial insects in your garden. Spray oil products such as Green Light Rose Defense are the least toxic, but still effective when sprayed directly onto the rose slug. You should also spray the soil under the rose bushes, as the larvae pupate in the soil prior to overwintering. If the damage is very widespread, chemical control may be indicated. We recommend Bayer Shrub & Tree Full Year Insect Protection.
Every year, we all face a "crop" of rose slugs in our rose gardens. Spring will soon be upon us, and only time will tell what this year brings us. Many of us are huge rose lovers and have many shrubs and climbers in our gardens. But one comment we would like to make to those of you who are "zero tolerant" of the little guy chewing at your rose leaves...most of us aren't growing the rose for its leaf. We don't cut the rose from the bush, throw out the rose and rose buds, and put the leafy cane into a vase. Your rose shrub will be able to continue to photosynthesize with fewer leaves, or leaves with holes. Keep this in mind when you are making a decision about the IPM (Integrated Pest Management) level of rose slug control in your gardens. Remember that the adult sawfly is a beneficial insect.
|