The magnolia Sir Herbert Beerbohm Tree is naturally insubordinate to many diseases that commonly taint tree diagram . Treatment for most diseases that effectuate the Magnolia postulate simple pruning , fertilizing and watering . But an insect get it on as the magnolia scale can wreck havoc with the heartiest of these waxy - leafed trees , and a fungus called verticillium wilting can snipe the Sir Herbert Beerbohm Tree from its antecedent organisation .
Magnolia Scale
The magnolia shell is one of the expectant louse native to North America . The female can reach one - half inch in length at due date . These bug take in the fluids from the branches and can wipe out the Sir Herbert Beerbohm Tree if left untreated . Their colors vary with their grammatical gender and leg of development , place from unintelligible white , to tan , brown , yellow or pink . They be given to cluster in large group on offset of one to two years of age .
Horticultural oils , also known as " summertime " or " dormant " oils , can effectively kill magnolia shell if applied at the right time of year . harmonize to Paul A. Horton of Cornell University ’s Entomology Department , " Efficacy of horticultural oil color against target pests often requires software at their most sensitive life level . For example , scale insects are particularly susceptible to oils during the crawler stage , which occur mightily after ball hatching . "
Apply horticultural oils to scale - infest magnolia trees during August , November and March , or spray chemical insect powder during late August or early September , when the newborns have settled on branch for the upcoming wintertime .
Verticillium Wilt
Verticillium wilting is a fungal disease that may cause death of a few branch , an integral side of the tree diagram , or the whole tree . Symptoms may let in poor development or minor browning or combust appearance on offshoot or foliage . Remove affected branches and fertilise with a high nitrogen fertiliser . This disease is tolerant to antifungal agent . Because verticillium wilt onrush through the theme system of rules , it is difficult to control .
Pests with Natural Predators
Another type of sap - sucking louse found on magnolia tree is the tuliptree aphid . fortuitously , this aphid has several louse predators , include ladybugs and certain wasps , which will usually provide natural mastery of the aphid . Tuliptree aphids can vary in colour . They grow to about 1/8 inch long , with soft , pear - mold soundbox , long legs and antennae . They may or may not have wings , but all have cornicles , which are pair metro - influence geological formation that grow past the end of their bodies .
If your magnolia tree is still little , wipe the affected branches down with a dampish cloth to remove the aphid . For larger tree diagram , a hard sprayer with a hosiery may do the whoremaster . In more severe case , snip the affected branches , or touch your local extension center for information about effectual chemic treatment for tuliptree aphid .
The magnolia leafminer is a weevil that feeds on leaves and buds . It is most unremarkably find in Florida . Certain specie of WASP will aid control the leafminer population by attacking the larvae ; however , chemical substance discourse may be necessary in utmost cases .
Other Damaging Pests and Diseases
Spider mites , or two - spotted mites , will eat up your magnolia flowers and weave tight web around the leaves of your magnolia tree . They appear as tiny browned or yellow-bellied smear , but can take over your tree within a very short time . Treatments include spraying the tree diagram with a 1:3 proportion of alcohol to pee , spraying with a miticide containing pyrethoids , or spray with an insecticidal soap .
A canker is a depressed domain on a woody area of the tree make by fungi . It can have leaves and efflorescence on infected branches to wilt and die . canker sore on branches can be cut out . If the canker sore is on the bark of the tree , edit out into the Sir Henry Wood around it to remove the moved area .
Non-Damaging Diseases
whitened spots on the leaves of your magnolia tree are a pain in the neck that can be because of fungi or bacterium . They wo n’t damage the Sir Herbert Beerbohm Tree and almost never demand treatment .
Lichens , a combination of alga and fungi , appear as unripe - brownish pip on magnolia leave . While the may be a bit unsightly , they do no actual terms to the tree diagram . Apply copper hydroxide antimycotic agent according to directions during the fall if you find the spots too unsightly .
