Monday, May 9, 2016

Leaf Gall Attacks Camellias and Azaleas



Have you noticed an azalea or a camellia whose leaves are 2-3 times the normal size and are real thick and fleshy?

They have leaf gall. Leaf gall is a very common disease that affects camellias and azaleas while they are putting on new leaves in the spring. This disease affects Camellia sasanqua (the small leaf camellia that blooms in the fall) more than Camellia japonica (the large leaf camellia that blooms in the winter).  The cool nights, overhead irrigation and rains in the early spring make this disease flourish.  This disease is caused by the fungus Exobasidium camelliae.  There is another Exobasidium fungus that affects azaleas in a very similar way. 

Leaf gall is the common name for this fungus.  The leaves become very large and fleshy.  The new growth is much thicker than normal and then the leaves break apart and release spores.  When the leaf breaks apart, you can see the lower part of the leaf turns white.  The disease spreads by wind and splashing water. A good layer of mulch will help with the splashing water.

The best control for leaf gall is to pick the infected leaves off as soon as you see them in the spring.  If you can pull them off before the spores develop, you can prevent the disease from spreading.  Once you pull them off, place them in a plastic bag (the one your newspaper comes in is handy, a dog poop bag, or any other plastic bag you might have around the house) and throw them away in the garbage or burn them in the ever so popular backyard fire pit. 

Usually this disease does not require chemical treatment.  Usually, the manual pulling off of leaves, limiting overhead irrigation in the spring when the nights are cool, and a good layer of mulch will keep the disease in check.  If you have a severe problem year after year, you could apply Mancozeb at bud break.  This control should be your last resort, and only used in severe cases. 

For this year, pull off as many infected leaves as you can.  Soon your plants should go back to producing its normal size leaves.  The leaves that were affected by leaf gall will soon wither, turn brown and fall off the shrub.

Usually I am against watering; however, with these warm windy days your lawn, trees, and shrubs could use a drink. All the new foliage requires water.

Are you protecting your yard from mosquitoes?

Always read, understand and follow product label. The product label is a Federal Law.