What is eating my Knockout roses?
Your knock out roses appear to have suffered from roseslug sawfly feeding. The roseslug sawflies are most frequently active mid-May through early June. They cause windowpaning damage on the leaves. This occurs when the sawfly consumes most of the leaf but leaves behind the upper epidermis which becomes frosted as it dries out. Eventually it dries out and drops off the leaf, and a smooth-edged hole remains. As the sawfly becomes larger, they may chew through the entire leaf or consume large sections of the leaf. Turn the leaf over and see if there are any small pale green ‘caterpillar looking’ insects on the underside. If there are, then you still have active sawfly larvae. If there are no insects on the underside of the leaves, then they are done feeding at least for now. We have a couple species in our area and one of them has multiple generations a year. This means they may be back later and your roses should be watched for further signs of feeding. An insecticide used for treating roseslug sawflies has the active ingredient called spinosad. There are a couple different products on the market that have this, and an application when larvae are feeding will provide control. There could be other insects present and if there are questions about those, I’d suggest bringing in a sample to the New Castle County Extension office on Wyoming Road.
Treating Knock Out Roses for Pests Organically
The biggest problem most people encounter with a knock out rose is trying to prevent insects from destroying them. Preventing pests from destroying plants presents a problem for organic gardeners as they cannot use chemicals that damage the soil. This article will examine how you can reduce or eliminate the insects that are preying on your plants using organic pesticides and alternative plant treatments.
The Knock Out Rose has a couple of common pests that attack it. Aphids are drawn by the sweet smelling blossoms and stick around to eat the leaves, and Japanese beetles are particularly fond of the plants as well. There are other insects to be wary of, but these two are the major pests you will have to deal with. Dealing with these pests can be time consuming, but with a little time and attention it can be accomplished.
There are not many organic pesticides available. In nature, repelling a harmful pest is more common than killing it. Of the organic pesticides available, only Neem oil is recognized as being effective against a wide range of insect pests. There are other organic pesticides on the market but none have the success of Neem oil. In most cases, you can achieve as much benefit from using other plants as you can from any sort of pesticide. Ladybugs are another option. Ladybugs feed on aphids so try both attracting them and planting them in the area. You can order them online or pick them up from your local garden center.
Care and Feeding
Taking care of a rose bush means giving it proper care and feeding. Additionally, you can reduce the effects of pests if you intersperse knock outs with sweet alyssum to draw predator insects away from your prize plants. Marigolds are another plant known as an insect repellent and are often used in gardens for that very purpose. But a healthy knock out is probably the best defense and that can be done by treating the soil, not by planting new plants.
Plant and Soil Care
One of the best all-purpose fertilizers for organic gardening is cottonseed meal. It contains more vital plant nutrients than either bone meal or fish meal and is high in all three macro-nutrients as well as the other necessary minerals and metals. If your soil is healthy, it is more attractive to predator insects which help to keep your pest problem at a minimum. Additionally, healthy soil gives the plant more energy to fight off infection and the damage to your roses caused by pests.
If all else fails, you can pick your knock outs clean. Pick off insects and place them in a paper bag. It may take quite a while, but this is the healthiest and safest method. Many people save the insects they remove and mix them into a water solution. This solution is then sprayed back on the leaves of the plants, and many gardening experts believe that this mixture will repel other bugs of the same types as as used in the solution. The idea is that the odors of dead bugs causes other to avoids coming into the perceived danger zone.
Using these tips for treating knock out rose pests will keep them blooming for years to come. It’s to time to sit back, relax, and enjoy their beauty.
A strange phobia makes people feel panicked or ill at the sight of holes, and new research hints at the cause.
In people who suffer from trypophobia, the sight of soap bubbles, aerated chocolate, or other objects with clusters of holes can cause migraines, panic attacks, hot sweats and a racing heart. The fear may stem from a visual resemblance to poisonous animals, according to a new study.
Trypophobia is “the most common phobia you have never heard of,” said study researcher Geoff Cole, a psychologist at the University of Essex, in England, who suffers from the fear himself.
Though many people have complained of it on the Internet, few studies have investigated the phenomenon. In one study, Cole and his colleagues found that 16 percent of participants showed signs of trypophobia. In his new study, one sufferer described the reaction to hole clusters: ” can’t really face small, irregularly or asymmetrically placed holes, they make me like, throw up in my mouth, cry a little bit, and shake all over, deeply.”
Even so, the phobia is not recognized as a disorder by the recently updated mental health manual, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
Cole’s team wanted to know if trypophobic objects shared a common visual feature, so they compared 76 images of objects on a trypophobia website with 76 images of holes not associated with the phobia.
The images of trypophobic objects had high contrast at midrange “spatial frequencies” — repetitive spatial features of an image — compared with the nontrypophobic images.
They had the same visual structure as stripes, which can sometimes trigger migraines.
One trypophobic participant provided a clue to understanding the strong aversion to certain hole patterns: He reported having this same negative reaction to seeing a blue-ringed octopus, one of the world’s most poisonous animals.
To investigate whether poisonous creatures could be causing the phobia, Cole and his colleagues analyzed images of the blue-ringed octopus, the deathstalker scorpion, the king cobra snake and other poisonous snakes and spiders, finding that they all had high contrast at midrange frequencies, too.
Trypophobics’ repulsive reaction to clusters of holes may be a side effect of an evolutionary adaptation to avoid poisonous animals, the researchers believe. “We think that everyone has trypophobic tendencies even though they may not be aware of it,” Cole said in a statement. “We have an innate predisposition to be wary of things that can harm us.”
Even people who don’t fear such hole patterns rated the trypophobic images as less comfortable to look at, said Cole, who added that he cured his own trypophobia by looking at the images so often he became desensitized to them.
To see how ingrained trypophobia might be, Cole’s team is now studying how images of everyday objects, like watches, can be manipulated to make people prefer them more or less.
The study was detailed in the journal Psychological Science.
Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.
George WeigelRoseslugs are the likely culprit in these holes in rose leaves.
Q: Over the past few months, many of my outdoor flowering plants have developed holes (large and small) in the leafy areas of the plants. I’ve attempted to research the reason for this but to no avail. I’ve tried various insecticides but the problem still exists. Can you shed any light on what the problem might be? I’ve looked under the leaves, stems, etc., and can see no insects that may be causing this. Some of the plants affected are: geraniums, sweet potato vine, asters, hostas, lilies, mums and roses.
A: You’ve probably had visits from an assortment of insects since most insects come and go as the season progresses and most only target one or a few plant types. I don’t think you’re dealing with just one particular bug. You could’ve had budworms on the geraniums, lacebugs on the asters and roseslugs on the roses, for example.
Two common reasons why you might not be catching bugs red-handed (or red-legged, as the case may be): 1.) Some insects feed only or mainly at night, and 2.) Some insects are hard to see because of their small size or because they fly away when a possible predator (i.e. you) comes near.
Holes in the leaves are usually the work of bugs, although leaf diseases sometimes kill spots or patches in the leaves, leading to the dry tissue falling out and resembling chewing damage. (A disease masquerading as bug damage is one explanation why insecticides wouldn’t be working.)
For insecticides to stop a problem, you first have to use an insecticide that’s effective against the particular bug you’re trying to kill. Then the product has to be applied thoroughly enough to do an effective job and applied at the right time.
Soaps and horticultural oil, for example, are effective when you directly hit the bug. They’ll probably do little to control, say, a night-feeding bug.
Or if you apply the right insecticide but do it after the bug has moved on or morphed into another stage in its life, it’ll have no impact.
One way to tell if your effort worked is that new growth won’t have holes. Then again, the bug problem might have passed naturally and you wouldn’t have seen any new damage anyway.
I know it all sounds complicated, and actually, it is. It’s very difficult, especially for young or new gardeners, to diagnose the correct bug and figure out what to apply when.
On the bright side, most damage is cosmetic and temporary. Very few bugs kill plants.
Also on the bright side, bug problems vary from year to year. Just because you have a bad year with something (or some things) one year doesn’t mean you’ll be dealing with that level of trouble every year.
My philosophy is that I’ll put with cosmetic damage, pick off or cut off unacceptable damage and replace plants that either die or get bug-attacked year in and year out.
I’ve found there are too many good plants that are relatively bug-resistant that I’d rather switch to them instead of investing a lot of effort, money and spray on ones that aren’t doing well.
If you’re determined to grow certain things and just want to stop bugs before they do damage, it’s pretty much a case-by-case deal. What stops slugs from chewing your hosta won’t keep budworms off the geraniums.
I’ve got a variety of diagnostic and bug-ID resources listed on my web site under the Links and Resources section at this link: http://georgeweigel.net/links-and-resources. Some of the resources show pictures to help you zero in on the exact problem.
Penn State Master Gardeners and most garden centers also are happy to look at damaged leaves and diagnose what probably caused it. Master Gardeners station themselves at some libraries, garden shows and the West Shore Farmer’s Market (among other places), and they field calls at county Extension offices.
Roses Have Holes In Leaves: Why Do My Roses Have Holes In The Leaves
Do your rose leaves have holes in them? This happens more often than you might think. While finding roses with holes can be frustrating, there are a number of reasons this can occur and most quite fixable. Read on to learn more about what to do when leaves on rosebushes have holes.
Why Do My Roses Have Holes in the Leaves?
Holes, rips or tears in rosebush leaves can be caused in different ways. In some cases, the wind whips the foliage so hard that the leaves will get puncture wounds in them from their own thorns. Small pea-sized hail will also cause holes, rips or tears in the foliage. Larger hail stones can totally defoliate a rosebush and break off canes as well.
Most often, when leaves on rosebushes have holes, insect pests are to blame. Here are the most common culprits:
Cutter bees will make half-moon shaped notches in the leaves of some rosebushes. With cutter bee damage, I just leave them alone and treat it like a badge of honor. Cutter bees do a lot of good and having them choose some of my roses to make their nesting materials with is a small price to pay. While they can do considerable damage to many leaves, the rose will grow back, just keep it well watered and put some Super Thrive in the water to help them deal with the stress and shock.
Some beetles like to punch holes in the foliage of rosebushes to suck out the juices as a means of nourishment. The same is true of some rose slugs (sawfly larvae), but they usually will not stop at a few holes. Instead, these pests end up devouring or skeletonizing the entire plant. Spraying the rosebushes with a good insecticide that has the culprit listed will help to gain control of the situation. The rose leaves with damage to them may be removed if desired, but again, affected rosebushes will usually bring forth new foliage that will perform better.
Rose chafers can also cause this type of damage but will usually attack the blooms as well. Caterpillars are another common pest of roses. Their damage usually presents as numerous irregular areas near the center of the leaves, or entire leaves eaten. Most of these can be hand picked off and dropped into a bucket of water. Likewise, the use of Bacillus thuringiensis is another nontoxic approach for them.
Remember to take the time to truly inspect your rosebushes on a regular basis, as catching any problem early goes a very long way to a timely cure!