Question From: K. WOOD - ALASKA . The quote below is taken from that publication. Leaves with numerous pale spots = Smut Leaves with white dust like covering = Powdery Mildew Leaves variously crumpled with irregular, pale yellowish patterns with insects visible more so with a magnifying glass = Red Spider Leaves variously crumpled with irregular, pale yellowish patterns with no insects visible with a magnifying glass = Virus Leaves wilt; stem interior with brown or black streaks = Wilt … This could be an indication of some kind of pest activity, aphids for example. Its growth is stunted and the leaves are blotchy and twisted. Ask an Expert is made up of groups and individual experts. It can also occur from water stress (too much or too little), nutrient deficiency, Here is a link to Growing Dahlias a publication from Iowa State University Extension. Looks like the start of a spider mite infestation. You can also remove those leaves and dispose of them in the trash. A virus? Once you see the webs, the population of mites are so high that you'll have a VERY hard time getting rid of them... so there is hope if you move quickly. Do not add infected plants to compost pile. Sadly, you may be witnessing mosaic virus in dahlias. Here is a link to a previous post that might also help. Other possibilities and solutions? This leaf curling can also occur from water stress (too much or too little) or a nutrient deficiency. If it's the older leaves with the damage, but the new leaves are healthy, then the plant should recover. Ask Nancy > Dahlia Leaves Are Curling. Also the lower leaves are starting to yellow a little bit. Hand picking may be the solution to beating these types of problems with dahlia. I have watered. Yellowing and leaf curl can mean the presence of a virus. The culprits are usually caterpillars or some form of larvae. Viruses cannot be controlled with insecticides. It can also occur from water stress (too much or too little), nutrient deficiency, Here is a link to Growing Dahlias a publication from Iowa State University Extension. Your dahlia is clearly not doing well. Dahlia Leaves Are Curling And No Bugs Have Been Detected; Some Dahlia Shoots Are Green But Very Short; Potted Dahlia Blooms Turn Brown And Dry Up In A Day Or Two; Dahlia Leaves Are Lighter Green Than Normal; Why Did Just One Dahlia Tuber Bulb Become Rotten And Have Little White Flies In The Soil; Dahlia Leaves Are Curling; Dahlia Has Not Sprouted Leaves This leaf curling can also occur from water stress (too much or too little) or a nutrient deficiency. For the last few years, I'm growing some dahlias. I can see no evidence of aphid activity. It could also be a virus, which can be more difficult to diagnose. You’re wondering if it’s missing some type of nutrient, but nothing seems to help. I started tubers indoors, green stalk is thick 5 inches tall but green leaves are curling under. None of my other dahlias seem to have this problem at the moment. Yellowing and leaf curl can mean the presence of a virus. Remove infected plants and discard away from the site. It could also be a virus, which can be more difficult to diagnose. Dahlia Leaves Are Curling. Infected plants also can be carriers without showing any symptoms. The curling back of the leaves is the earliest sign of mites. Mosaic virus in dahlias cause large scale disfigurement of the plant. These feed on leaf tissue and make Swiss cheese of the foliage, diminishing the plant’s ability to intake solar energy. Ask A Question; Search Our Site. I have no idea what could cause this? Have you checked for pest activity, are the leaves sticky? Viruses cannot be controlled with pesticides. Viruses cannot be controlled with insecticides. Plants may show a variety of leaf mottling patterns, necrotic and ring spots, and bubbling or distorted leaves, stem streaking, stunting, and wilting. The quote below is taken from that publication.Virus—Diagnosing a virus problem is often misleading if based on symptoms alone. Questions. As you can see on the picture below, the leaves are curled at the moment. Dahlia Mosaic Symptoms. Just keep an eye on them and watch for additional infestations. MY DAHLIAS HAVE COME UP JUST FINE, UNTIL A FEW … But this year I've got a problem with one of them. a few of our dahlias are exhibiting curling of new growth leaves accompanied by slight yellowing of the leaf. Newsletter Subscription. 777 Lawrence Avenue East Toronto, ON, Canada M3C 1P2 | Phone: 416-397-1345, Copyright © Toronto Master Gardeners 2019, Gardening Guides provide introductory information on a broad range of horticultural topics. Yardner's Advisor Newsletter provides information just for plants in your yard! If so you can spray with water. It is common to find new leaves completely chewed, lacy and barely still there. It's not unusual for older leaves to show curling, browning or yellowing as they age. Q: I'M IN ALASKA, WE START OUR DAHLIA 'S INDOORS, AS OUR LAST FROST IS LATE!