Magnolia bacterial blight free#

The following material will help you identify these diseases and offers recommendations for treatment. This publication describes some of the most troublesome diseases of Georgia's landscape plants. Unfortunately, despite gardener's best efforts, disease-causing pathogens are also present. Cities, towns and neighborhoods are the very definition of 'southern gardens' filled with exquisite plants, both native and exotic. Georgia's natural and manmade landscapes and gardens have graced the pages of many magazines with elegance, beauty and solace.

General Disease Management Strategies in the Landscape.

Sprays applied before the crawlers are present, or after they have become dormant in the overwintering stage will have little effect. This is usually in late August to early September. Strategy 3: Standard Chemical Control - Magnolia scale can be satisfactorily controlled with a variety of insecticides if applied when the insects are in the freshly settled crawler stage. Be sure to check the spring buds as some damage may be caused on the flower buds if they have begun to swell. Dormant oils can be applied in October to November and again in March to kill the overwintering nymphs located on the stems. Be sure to thoroughly wet down the stems and leaves. Strategy 2: Summer and Dormant Oils - Horticultural oils (often called summer oils) at 1.5-2.0% applied after the crawlers have settled in late August can be very effective in reducing the scale population. Any plants with these remains should be avoided. The large scale exoskeletons often remain from the previous season.

Magnolia bacterial blight free#

Strategy 1: Obtain Pest Free Plants - Most of the magnolia scale infestations come with the plants, so carefully inspect the branches of plants being considered for purchase. Though there are several predators and parasites known that attack this scale, they rarely do an effective job of control, especially on smaller magnolias. The tiny, mobile crawlers move around until they find a suitable feeding site on which they settle down, feed, and remain through the winter. By late July and August the adult females begin to give birth to their young known as crawlers.

By July the females are covered with a powdery, white waxy coating and are turning more of a yellow- tan color. This is also the time that they produce excessive amounts of honeydew. The females continue to expand and by early June, they have turned a brownish-purple color. Soon after the males turn white, they emerge as tiny, pink to yellow gnat- like insects with two long waxy threads extending from the tip of the abdomen. The males remain small, about 1/8-inch, and soon turn a translucent white. At this time two distinct forms can be found, males and females. As temperatures warm in the spring, the scales begin to suck sap and have molted once by early May. The magnolia scale spends the winter on one to two year old twigs as tiny, dark-colored nymphs. The honeydew also attracts a ants, bees, wasps and flies which feed on it. This greatly detracts from the plant's normal ornamental value. A dark fungus, called black sooty mold grows on the honeydew which results in the leaves becoming blackened. The honeydew drips onto the foliage and branches. Like most soft scales, the excess plant sap is excreted as a sweet, sticky material called honeydew. Under a continuous and heavy attack trees may be killed. Badly infested branches and twigs are weakened and growth is retarded. Magnolia scales have sucking mouthparts and when heavy infestations completely encrust branches, the branches often die. It has also been reported to feed on Daphne and Virginia creeper. Saucer, star, lily and cucumbertree magnolias are the most common trees attacked. This wax is lost at the time that the crawlers emerge.Īs the name implies, this insect is primarily a pest of various species of magnolia. As the scales grow, they are often covered with a white mealy wax. Adult females may reach nearly 1/2-inch in diameter when fully grown. The magnolia scale, Neolecanium cornuparvum (Thro), is a large and conspicuous scale insect. Overwintering scales are controlled with dormant oil applied in the spring.

Magnolia scale is the most common scale and can be one half inch across. Scales of various types will infest twigs.

Prune out dead branches and fertilize with high nitrogen fertilizer. Verticillium wilt may cause death of a few branches or may kill the tree. Keep trees healthy with regular fertilization and by watering in dry weather. Rake up and dispose of infected leaves.Ĭanker diseases will kill branches. Leaf spots rarely require chemical controls. Magnolia may be subject to leaf spots caused by the bacterium Pseudomonas syringae or a large number of fungi.