Need Help - Bugs are Killing my Knockout Roses
Hi, I just joined the forum today. I need some advice. My husband and I bought six knockout rose plants last year. We know very little about them but, are interested in learning how to care for them properly. We love roses and heard that knockout roses are fairly low maintenance. I'm not sure if that is true or not. The plants did well last year but, this year we seem to have a swarm of little black bugs that we can't get rid of. They are killing the rose bushes and leaving big holes in the leaves. I've googled the different type of pests that like roses but, none of the photos I have found seem to be resemble what are on our plants. Out of desperation, I bought two products to spray/use on the them. I just looked outside and see there are still bugs on the bushes (although not nearly as many today). My husband sprayed a multi-purpose fungicide, insecticide, miticide 3 in 1 product on the plants yesterday. I took a picture of one of the bugs. Can someone tell me what it is and how to get rid of them? They are ruining my plants. Thanks in advance for any help or advice you can provide.
~Lisa C.
Comments (13)
gardengal48 (PNW Z8/9)
7 years ago
Lisa C
7 years agoRelated Discussions
Double knockout roses got disease, need help
Comments (6)I did live in the burbs in Houston for almost a decade, and if I see your gardening area correctly, the rose is planted right next to a cement slab. (And the weepholes in the brick wall in back of the rose?) The problem is, or at least may be, that the slab may be affecting the pH of the soil. And that pH may be affecting nutrient uptake by your roses. (Also there may be some chemical treatments done to the perimeter of your house before you moved in. First, call the Texas County extension agent and ask him or her about getting a soil test for that specific soil (forget about any suggestions that you should take samples from all over your yard, that's for grass growers). Also ask that the test check for nutrients in the soil....See MoreNeed help with my knockout roses
Comments (11)Hi Derek, I'm just north of Cullman...about midway between Birmingham & Huntsville. We've had the same extremely hot & dry June and extremely rainy July here. I don't think the weather extremes themselves should have hurt 3 year old KOs. Also would be surprised if a drainage issue is just now causing a problem since we've had lots of extremely rainy periods in the last 3 yrs...but there could be a new sinkhole, soil shift, etc, so worth checking the soil below to make sure. Very possibly could be something eating the roots as Michael suggested. My roses are currently being devoured by thousands of Japanese Beetles...started early June this year and still going strong...but you would notice the beetles on your bushes, and best I can tell from your pictures, that isn't JB damage. It could be leftover winter damage or canker damage from early spring. I had canker issues worse than I've ever experienced this spring and more winter damage to my roses than I can remember, too. I pruned most out early in the season, but did leave canes that had some damage, but looked like they might recover. Most of those are now dying since the heat set...weren't strong enough to handle it. You might not have noticed a canker spot low on a cane that otherwise looked healthy this spring, but that could now be cutting off energy to it....See Morekill poison ivy that wraps around KnockOut Rose
Comments (13)Roses can absorb RoundUp from the soil i.e. overspray is not the only way glyphosate can reach your roses. The Round-Up can leave the roots of a treated weed, pass through the soil, and be picked up by the roots of nearby rose bushes. http://link.springer.com/article/10.1007/s11104-007-9387-1# AND http://www.sciencedirect.com/science/article/pii/S116103010900063X Also, the glyphosate could remain bound in the soil for long time periods. "Glyphosate [(N-(phosphonomethyl)glycine)] is a widely used herbicide and it is known to compete for the same sorption sites in soil as phosphorus. Persistence and losses of glyphosate were monitored in a field with low phosphorus status and possible correlation between glyphosate and phosphorus leaching losses was studied. Glyphosate and its metabolite AMPA (aminomethyl phosphoric acid) residues in soil samples were analyzed after a single application in autumn. Twenty months after the application the residues of glyphosate and AMPA in the topsoil (0�25 cm) corresponded to 19% and 48%, respectively, of the applied amount of glyphosate, and traces of glyphosate and AMPA residues were detected in deeper soil layers (below 35 cm). These results indicate rather long persistence for glyphosate in boreal soils." http://www.springerlink.com/content/w1461w60366lk018/ Then, when you add fertilizer with P; the glyphosate could be released. "The results suggest that re-mobilization of glyphosate may represent an additional transfer pathway for glyphosate to non-target plants which is strongly influenced by soil characteristics such as P fixation potential, content of plant-available iron, pH, cation exchange capacity, sand content and soil organic matter." http://www.springerlink.com/content/t7h6601566432076/...See MoreHelp for my double knockout rose bushes!!
Comments (5)Our heat has been pretty high the last couple of weeks. I have many new bushes from one and two gallon pots that I planted this spring. All are own root. I check the ground an inch down before I water. If we get less that a quarter inch of rain I usually have to hand water using a wand every two days. If we get more than one quarter inch rain I wait until three to four days after the rain to water. I do have mine in beds with no grass or weeds and it is mulched so the water doesn't evaporate as fast. The key is how quickly is your ground drying out then set up a water schedule based on that. My schedule works great for me....See Moregardengal48 (PNW Z8/9)
7 years agoThat's Chewy......in desperate need of a haircut :-) He was tobacco colored as a pup (hence the name Chewbacca) but it has faded to more of a pale blonde with white highlights. He's my best bud!!
Patty W. zone 5a Illinois
7 years agoLisa C
7 years agoLisa C
7 years ago
jim1961 / Central Pennsylvania / Zone 6
7 years agolast modified: 7 years agoLittle green worms that are probably on the underside of your rose leaves munching...(size varies from tiny up to a inch long)... Sawfly larvae are called Rose Slugs....Least toxic spray would be safer insecticide soap or similar... Spinosad is very effective just be careful and follow directions as it can kill bees...
Some people pick them off there rose leaves and squish...
Our curled rose slug here are mostly found on top of the leaf... But usually other types are found UNDERNEATH the leaf...
Here's what our more mature rose slugs look like: The wasp eats them so he is a good guy in my book....lol
Patty W. zone 5a Illinois
7 years agoLisa C
7 years agojim1961 / Central Pennsylvania / Zone 6
7 years agogardengal48 (PNW Z8/9)
7 years agoLisa C
7 years ago
Lisa COriginal Author