Rust Spots On Olive Tree Leaves

Severe infestations will deform and yellow leaves and cause leaf drop.

Rust spots on olive tree leaves. A year ago we purchased an olive sapling and it has started to develope rust spots should we be concerned and if so what action if any should we take. Olive scales oleander scales and california red scales frequently attack olive leaves stems and fruit. Rust is caused by a group of fungi from the pucciniales order. Treatment is comparable to the peacock spot s one.

Rabbits birds sheep and cattle all like the taste of olive leaves and new twigs. It is in a pot against a west slightly north facing wall. It causes sooty mold like symptoms on the underside of the leaves yellowing and leaf drop without leaf spots. Leaf spots often mature in one to two weeks.

Left untreated the spots get bigger and turn into bumpy looking pustules. When you see orange gold or reddish spots rupturing leaf surfaces you re dealing with rust. Rust on a young olive tree. It develops under similar conditions as peacock spot.

Eventually the pustules break open and release spores that are spread by wind or splashing water. Cankers galls and stunted growth can also be a result of. The first signs of rust are tiny specks or spots on leaves that range in color from orange to rusty brown brownish yellow purple and red. The latter s symptoms include slightly raised rust colored cracked lesions on the fruit as well as bright orange glistening lesions on the upper and lower sides of the leaves.

High humidity and prolonged leaf wetness encourage these pathogens. Olive lace bugs are sap sucking insects that feed on the underside of leaves resulting in the formation of rusty yellow spots. While it rarely kills plants rust fungus makes leaves unsightly and weakens the plant by interfering with photosynthesis the process a plant uses to make food. Rust may cause leaf spots or turn the entire leaf yellow or brown.

Rust diseases are favored by 4 to 8 hours of low light intensity warm temperatures and moisture humidity dew or rain followed by 8 to 16 hours of high light intensity high temperatures and slow drying of leaf surfaces. Cercospora leaf spot is a fungal foliar disease caused by mycocentrospora cladosporioides that can affect olive trees. Removing affected leaves drier conditions soil adjustment or chemical sprays can resolve the problem. Most leaf spot diseases need either water on the leaves or very high humidity for a prolonged period of time 12 to 24 hours to start an infection.

It shows up as a scattering of orange yellow or red spots on foliage. Mature leaf spots produce spores or bacteria that can be spread throughout the canopy which can start a second set of leaf spots or cause new infections on other plants.