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Common Rose Pests - Part 1: Aphids and ThripsRead the article this discussion is about
This archived discussion is "read only".
» CarolWallace - Mark, I've had thrips and I've also had balling. Is the brownis Mark, I've had thrips and I've also had balling. Is the brownish edge on a rosebud that refuses to open a sign of thrips? Or is it also a sign of balling? I've always assumed balling, because it only occurs on a few of my plants -- the same ones, year after year. Carol virtually gardening-- posted by CarolWallace » Mark_Whitelaw - Carol, That is an excellent question. If just the edges on Carol,That is an excellent question. If just the edges on light colored roses turn brown, it usually signifies thrips. And although the rose will have brown edges, it will usually continue to open at least part way with the petals reflexing slightly, thus allowing you to physically check for the pest. OTOH, if the entire blossom turns brown (on light colored roses) and the blooms maintain a "ball shape," it is a sign of balling. In this case, the rose will seldom open more than just a little. And, as you no doubt have already discovered, some varieties are mose susceptible to balling than others. ('Clotilde Soupert' comes to mind first; sometimes 'Souvenir de la Malmaison' in real wet springs.) Likewise, the balling only occurs during periods of high humidity, continuous rainfall, or frequent over-the-top irrigation in places other than the desert southwest. The surefire determination, of course, is to smell and inspect the bloom. Balled roses will frequently smell like rotted apples (in effect, that's what they are). Conversely, thrips damage will be easily detected using the method described in the article, but the rose will retain some of its fragrance. In your case, I would suspect balling if the rose continues to do this year after year... in which case, my suggestion would be to shovel prune it and find a rose happier with your micro-environment. MarkW>Ft. Worth, TX/Zn 7b, Rose Garden -- posted by Mark_Whitelaw » CarolWallace - Mark, am I correct in assuming that the balling problem is more Mark, am I correct in assuming that the balling problem is more common on light colored roses? Thw two I have had this problem with were both David Austin roses, 'Fair Bianca' and 'Abraham Darby'-- both pale roses.Once we are past that first flush of bloom 'Abraham Darby' usually does just fine, blooming and growing mightily. 'Fair Bianca' seems to have shovel-pruned herself. I went out last spring to start my clean-up and she was gone. But then, she never did take well to my yard the way my other English roses have. Carol virtually gardening -- posted by CarolWallace » Mark_Whitelaw - Carol, >>am I correct in assuming that the balling problem is Carol,>>am I correct in assuming that the balling problem is more common on light colored roses?<< Not really. I have seen balling caused by over-the-top irrigation (performed every day)affect both orange and deep pink/red roses. It was in a commercial setting, however. MarkW>Ft. Worth, TX/Zn 7b, Rose Garden -- posted by Mark_Whitelaw » Mark_Whitelaw - UPDATE: Since this article was published, new information con UPDATE:Since this article was published, new information concerning additional biological controls for the aphids and thrips has been published: To the list you can now add the release of Aphidoletes aphidimyza, the Aphid Midge, a critter which has been successfully used in commercial aphid control both in greenhouses and orchards. Also add the predatory mite Amblyseius cucumeris and Orius sp. bugs to the list of controls for the Western Flower Thrips. In fact, the bugs are better than the mites for finding these pesky slivers in our roses. Okay. So you're not interested. :>) But I thought you should know anyway. Those scientists are finding more and more alternatives to pesticides every day! MarkW>Ft. Worth, TX/Zn 7b, Rose Garden -- posted by Mark_Whitelaw » MichelleL_2 - Are these mites safe to for other plants/people? Where do we Are these mites safe to for other plants/people?Where do we get them? -- posted by MichelleL_2 » Mark_Whitelaw - Michelle, "Predatory mites" are predators of other critters ( Michelle,"Predatory mites" are predators of other critters (in this case, thrips). They are totally harmless to humans, other mammals, and our plants. Amblyseius cucumeris is available from a wide variety of insectaries around the nation (27 of which I know of). Some of the more common distributors you may be familiar with include Peaceful Valley, Planet Natural, Biofac, and ARBICO (Arizona Biological Control). The latter company has a site on the internet from which you may order on-line. MarkW>Ft. Worth, TX/Zn 7b, Rose Garden -- posted by Mark_Whitelaw » WilliamG - Mark, would it be worth my while to explore for local sources of Mark, would it be worth my while to explore for local sources of the Amblyseius cucumeris as I am having some moderate infestations of thrip. Again I am trying to find effective controls which can be used on "food crops" as I have every intention to harvest roses for use in culinary and other applications (perhaps rosewater for finger bowls). I wish to stick with products I could use on veggies, herbs, etc.William Groth, Houston TX, -- posted by WilliamG » Mark_Whitelaw - Not really, William. Predatory mites must be mailordered beca Not really, William.Predatory mites must be mailordered because they have a very, very short "shelf life" (less than 72 hrs.). You can check with your nursery to see if they can mailorder them for you. But, quite frankly, I prefer to mailorder direct and thus cut out the "middle man's markup." When you mailorder, they must be shipped not slower than 2-day express mail... which is why they tend to be very expensive. MarkW>Ft. Worth, TX/Zn 7b, Rose Garden -- posted by Mark_Whitelaw
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