I have a lilac tree in which I keep a close eye on, This year for the first time , it is starting too bloom . I inspected the tree and notice a insect has been eating holes in the leaves and also some lighter blistery spots are appearing in the areas the little critter was eating the leaf. Please advise
Are you sure those lighter blistery spots in the leaves aren't just deteriating into the holes you see? And may not be an insects at all? Just a thought. Jim
It's hard to say for sure. I have noticed thousands of various trees including Lilacs in my area with the same symptoms you described, and getting worse every year. I feel that deep root watering and or deep root fertilizing, along with fall copper spraying on an annual basis will help create plant health. Thus making the tree/plant healthier and able to withstand heat and drought stress, which is all I can come up with for a cause for now. Just a suggestion. jim
Hi Teadams, Lilac leafminer comes to mind. You can click on the pic at the bottom of the page at this link. http://gov.pe.ca/af/agweb/index.php3?number=74338 Bacterial blight is another possibility. Click on the pic here too. http://www.ppdl.org/dd/id/bacterial_blight-lilac.html Newt
Newt's suggestions (blight and leafminer) are the two main problems that lilacs will get in BC. Bacterial Blight occurs in moist, mild weather. Young leaves will die back quickly, while black blotches will spread slowly on mature leaves. If it is bacterial blight, cut off all affected shoots far away from the infected area (steralizing your pruners between cuts will help prevent spread) and thin out other shoots to increase air circulation. A copper fungicide may help reduce bacterial blight. If it is lilac leaf miner (Gracillaria syringella), the damage is caused by larvae under the leaf surface. Removing the damaged leaves (which will contain these larvae) and disposing of them may help control this pest. There are other possiblities - for instance there is a lilac leaf blight (Hetersporium syringae) that forms diseased areas that dry out, crack and form "shot-holes." This fungus has brown,velvety spores and might be prevented with a copper fungicide. Caterpillers are also possible - but may have already grown up into butterflies and flown off!
Those are all common problems I deal with on a regular bases for many years in BC, and yes copper is quite effective. Even more effective when copper is sprayed anually to healthy trees. But I find this very common deformation of leaves right from bud break, and deteriation of the leaves "holes" growing all summer long. On almost every variety of tree from one end of the lowermainland to the other, from minimal damage to massive. I can't believe no one else has noticed this similarity. I can understand at this time of year thinking it's just our common spanworm, but I will tell all, something funny is going on. After 20yrs of dealing with pest insects and blights as a full time career, I have a hard time believing there could be that much blight going around. When climate change, heat and droughts are happening at the same time as this unusual leaf damage. Not that there is no more blight or insects, this just has a different look. Beware, Maples are the worse by a long shot! Please tell me I'm not some crazed worry wort. Jim.
Jim, you're not some crazed worry wort, just a worry wort in good company! Trust me, you aren't alone in the changes you see. Newt