Southern Blight (fungus - Sclerotium rolfsii): Southern blight, also called Crown Rot, is a soil-borne disease of ajuga that will be more serious in poorly drained soils. Plants suddenly turn yellow and die in patches during warm, humid weather. Bases of stems rot and turn brown or black. Frequently, a white mold develops in which small reddish-tan bodies (sclerotia) develop. These sclerotia survive the winter and other unfavorable conditions.
Other Diseases (fungi): Other fungi known to cause disease on Jasmine in Texas are Phoma (blossom blight), Colletotrichum gloeosporoides (leaf spot).
Crown Gall (bacterial - Agrobacterium tumefaciens): Both the stems and roots may have good size galls. Destroy heavily infected plants. Plants will lack vigor and may die back. If only a few galls, prune out and destroy. Sterilize pruner with 70% alcohol or 10% household bleach.
Powdery Mildew (fungus - Oidium spp.): White powdery mold or gray "felt" patches on leaves. Leaves may yellow, curl, and drop early. Prune to thin out shrub. Use preventive fungicide sprays.
Root Knot (nematode Meloidogyne spp.): See section on Root Knot Nematodes.
Other Diseases (fungi): Other fungi known to cause disease on euonymus in Texas are Phymatotrichum omnivorum (root rot), Exosporium concentricum(leaf spot), and Phyllosticta euonymi (leaf spot).
Rust (fungus -Puccinia dichondri): This rust, under humid conditions, may develop rapidly.
Root Rot (fungus - Phymatotrichum omnivorum): Affected plants wilt and die suddenly. Leaves of infected plants turn brown and remain on the plant. (For further information see section on Cotton Root Rot.)
Anthracnose (fungus - Colletotrichum omnivorum): A common disease of English ivy. Infected leaves have large tan-to-dark brown spots with a darker border. The center of infected areas may have small black spots formed by pycnidia (fruiting bodies of the fungus). Spots range in size from one-eighth inch to one-half inch in diameter. As the spots age, the centers may dry up and fall out giving a shredded or shot hole appearance. The fungus may also infect stems causing dark, sunken lesions. In some instances, the stem may be completely girdled causing death of the distal portion. Infected leaves should be picked off and destroyed. Avoid overhead watering. Foliar fungicide application at regular intervals are effective.
Bacterial Leaf Spot (bacteria - Xanthomonas spp.): Circular spots which are, at first, light green water-soaked areas. As the spots enlarge, they become brown-to-dark brown with red margins. Eventually, the center of the spots dry and crack. Young twigs and petioles are also attacked. Infection on stems and petioles causes a blackening and shriveling of the tissue. Cankers form and may girdle the stem. Tips of growing portions of the plant turn black and this blackening may extend downward into the older wood. Infected plants may fail to grow normally and have pale yellow-green foliage. Remove and destroy all infected plant tissue. Avoid overhead watering, overwatering and high temperatures, if possible.
Leaf Spots (fungi - Ramularia hedericola, Macrophoma spp., Glomerella cingulata, Phyllosticta concentrica): Brown lesions will occur on the leaves and may also infect the stem, causing girdling, collapse and death of apical portion. Infected leaves can be picked off and burned. Remaining foliage should be sprayed with a fungicide.
Sooty Mold (fungus, Capnodium sp., and others): The sooty mold fungus may develop on English ivy growing beneath certain trees. This mold lives on secretions of aphids and scale insects which fall from the tree above. This mold seldom causes damage. Control insects to prevent this problem.
Leaf Spots (fungi - Cercospora spp., Septoria sambucina and others): Avoid overhead irrigation. If spraying is necessary, apply a recommended fungicide.
Leaf Blight (fungus - Glomerularia lonicerae): This fungus blights the leaves during rainy seasons with light-colored, circular spots that can cause leaf death. Control by spraying with recommended fungicides.
Powdery Mildew (fungi - Microsphaera alni and Erysiphe polygoni): These powdery mildew form a white, powdery coating on both leaf surfaces and young stems. Microsphaera is rather widespread in the United States while Erysiphe occurs primarily in the western United States. Control by spraying with recommended fungicides.
Cotton Root Rot (fungus - Phymatotrichum omnivorum): Honeysuckle is only moderately susceptible to cotton root rot. (See section on Cotton Root Rot.)
Leaf Spots or Blights (fungus - several): Small-to-large round to irregular spots and blotches on leaves and pods. Leaves may be blighted and drop.
Crown Gall (bacterium - Agrobacterium tumefaciens): See section on Crown Gall.
Rarely Observed Diseases: Honeysuckle is also susceptible to thread blight, caused by the fungus Pellicularia koleroga, twig blight caused by the fungus Phoma mariae, rust caused by the fungus Puccinia festucae, hairy root caused by the bacterium Agrobacterium rhizogenes, and crown gall caused by the bacterium Agrobacterium tumefaciens.
Cotton Root Rot (fungus - Phymatotrichum omnivorum): Reported on lantana in Texas.
Powdery Mildew (fungus): Whitish, powdery mold patches on upper side of leaves and stems from midsummer on. Leaves may shrivel and drop early. Control with recommended fungicides.
Crown Rot (fungi - Sclerotium rolfsii, Sclerotium sclerotirum and Thielaviopsis basicola): Serious losses to phlox seedlings occur from these soil-borne fungi. Start in pasteurized soil.
Root Knot (nematode - Meloidogyne spp.): See section on Root Knot Nematodes.
Root Rots (fungi - Thielaviopsis basicola and Phymatotrichum omnivorum): Not usually serious enough to warrant control.
Rusts (fungi - Puccinia douglasii and Uromyces acuminatus): Not usually serious enough to warrant control.
Beet Curly Top (virus): See section on Curly Top.
Powdery Mildew (fungus- Microsphaera russellii): White, powdery blotches on foliage.
Smut (fungus - Ustilago oxalidis): Reported in Texas.
Crown Gall (bacterium - Agrobacterium tumefaciens): See section on Crown Gall.
Leaf Spot (fungus - Alternaria spp.): Brown circular-to-oval spots on leaves. Control with copper or other recommended fungicides.
Dodder (Parasitic plant - Cuscuta indecora): See section on Dodder.
Curly Top (virus): See section on Curly Top.
Aster Yellows (mycoplasma): Reported in Texas.
Consult the Chemical Control Supplement (B-1140A) for specific chemical control suggestions.