Types of Garden Enemies
Control. Mulches or chemical ground treatments to inhibit apothecial production are useless in controlling this disease because there are always too many other azaleas in the neighborhood producing spores for secondary infection. Properly timed sprays give nearly perfect control. Start when early varieties are in bloom and midseason buds showing color, and spray 3 times a week until all the flowers are open, thereafter about once a week until bloom is over. This frequent treatment protects the new petals opening every day or so. Spraying twice a week gives fairly good control, but once a week is almost wasted effort; too much blight gets started between sprays. Use Dithane Z-78, 1 ounce to 5 gallons of water (11/4 pounds per 100 gallons), or Parzate, 4/5 ounce to 5 gallons (1 pound per 100).

The large azalea gardens open to the public at a fee now spray as a matter of course, knowing that their season will be prolonged several weeks and the revenue will far exceed all costs. City parks and parkways are also sprayed in some municipalities, but many home gardeners don't want to bother. It is perfectly possible to have perfect azaleas in your own garden with correctly timed and applied chemicals even though your neighbor does nothing. In fact, you can spray half a bush and have every flower perfect with every flower on the unsprayed side collapsed. I know, because I have done it myself more than once. For large power outfits liquid Dithane D-14 may be somewhat preferable, using 11/3 quarts D-14 with 1 pound 25% zinc sulfate, 1/2 pound hydrated lime, and 1 ounce of spreader B 1956 or 4 ounces of Dreft. The zinc sulfate is obligatory to avoid injury; the lime can sometimes be omitted.

Fig. 12

CAMELLIA FLOWER BLIGHT (Sderotinia camelliae). Like the azalea blight this disease is limited to flowers. It came from Japan and is prevalent in California, where it was first noticed in 1938, is fairly widespread in Oregon, and has been found in some gardens in North Carolina, Georgia, and Louisiana. Infection comes from quite large apothecia, up to an inch across, looking like small upturned toadstools, produced from large black sclerotia on the ground (see Figure 12). Symptoms start with small brown specks on the petals, frequently with darkening of the veins and browning of the center. Soon the whole flower blights and turns brown, but it is not slimy to the touch. As fallen flowers lie on moist earth or in mulch, large sclerotia are formed by a thickening of the base of the petals, often with several joined together into a compound structure. There is no secondary spore stage.




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