What Is Wrong With My Lilac Leaves?
Spring is n’t fountain without theheavenly scentand grand flower of the lilac bush . But as the flower melt , you might acknowledge that your shrub is suffer , because lilac are prostrate to several fungal diseases — although sometimes shrubs are damaged by instinctive causes as well .
If your lilac ( Syringaspp . ) has chocolate-brown spots on its leaves or they are wrinkle and drying out , several effort might be at play , not all of them disease - pertain .
Consider Both Biotic and Abiotic Factors
When diagnose the likely crusade of works harm , seem beyond the effrontery that it is a plant disease or insect - establish problem .
Sometimes , lilac and other plants are dupe of " abiotic " scathe , which are non - living factors , such as storm scathe , a response to herbicide drift , drought stress or freeze injury . Consider any weather events your area might have experienced , such as a specially insensate or wet spring .
For example , theUniversity of Minnesota Extensionreported that some gardeners experienced lilac dieback as a result of ascendent harm after extremely inhuman temperatures when there was no snow to protect the plant . Conversely , a very ardent and soaked summertime in the same state also resulted in lilac damage due to too much moisture , slowed developing and herbicide that were weakened by the heat .
When looking at the shrub , see if there is any visible worm damage , such as chew holes , or fungal growth . These are examples of " biotic " damage make by aliveness organism .
Sometimes , the cause can be both abiotic and biotic . TheUniversity of Maryland Extensionreports that most plant harm is actually not due to biotic causes , especially if the bush has been in your landscape for less than two eld . First , consider environmental condition , such as weather extreme point , deficiency of Dominicus , overly loaded grime orcrowded conditionswith little aura circulation .
Tip
Though diseases and pests can be common too , lilac and other plant are sometimes victims of " abiotic " harm , which are non - surviving factor , such as storm damage , a answer to weedkiller drift , drought stress or freeze injury . Consider any weather issue your expanse might have experienced , such as a peculiarly cold-blooded or smashed bounce .
Common Fungal Infections for Lilacs
The common lilac ( Syringa vulgaris , geographical zone 3 to 7 ) is indeed prone to some fungal disease , among them lilacPseudocercosporaleaf spot , powdery mildew and verticillium wilt . Another salmagundi susceptible to exchangeable disease is the tree diagram lilac ( S. reticulata , zone 3 to 7 ) .
Pseudocercospora Leaf Spot
LilacPseudocercosporaleaf spot might be the perpetrator if your lilac ’s leave are turning brown and ironic . It first causes leave to flex yellow , then brown and then to exit .
unluckily , this disease can live for year on various works parts , include the bark , dead prime , stems or leaves . To combat this disease , practice upright industrial plant hygiene by clean up under the President George W. Bush and pruning to better airwave circulation within the bush .
Verticillium Wilt
alas , if your lilac has verticillium wilt , there is no cure . What you ’ll see is sudden browning and dieback of branches , because the fungus have invaded the plant ’s vascular organization , blocking the motion of water and nutrients .
If you note a sudden dieback of branches , you may require to replace the bush completely with a disease - tolerant cultivar . Be sure to discard the shrub entirely , as all parts can spread this disease .
Powdery Mildew
In summertime , lilac plant are particularly susceptible to powdery mildew . This will not kill the bush , but it is unsightly and can shrivel up the leaves .
In oecumenical , when the rains come , the powdery mould dissipates , and this deciduous shrub neglect its leaves in autumn , so there ’s always another class .
Preventing or Treating Disease
To avoid fungal infections , preventive metre are your first origin of demurrer : Prune lilacs regularly to ensure good airflow , and when planting , space lilacs far enough aside from other shrubs to obviate overcrowding , which can lead in disease . Rake away and cast out fall leaves and other plant debris to remove region where pathogens can expand .
you may also utilise a fungicide , but this is only useful when the disease is active , which is usually in spring during the early part of the growing season ; applying fungicide in the surrender is n’t efficient .
Common Pests for Lilacs
The primary pest that targets lilac is the lilac borer ( Podosesia syringae ) , a clearwing moth that emerges in mid - May and repose egg on the bark . The subsequent larvae eagre into the shrub ’s heartwood . These can finally wipe out a lilac bush if the infestation is labored .
You live that a borer is the likely plague if you see frass ( biologic waste matter ) being pushed out of the barque through holes . The leaves will wilt through an unfitness to get nutrients .
To deter this pest , avoid piling mulch around the shrub ’s jacket and ensure good irrigation if the weather is hot and ironic . Do n’t weed eat or mow close to the stem , as undefendable wound can draw borers and diseases .
There are no pesticide urge for the lilac borer . The only option is to dispatch and destroy damaged and wilted branch .
